FN-8666: add credential instance pickers

Add credential-instance selection across dashboard model configuration surfaces.

- Expose provider credential instances in custom model dropdowns and task, workflow, and settings forms.
- Persist per-role credential-instance overrides through dashboard APIs and effective model resolution.
- Document credential-instance precedence and cover dropdown/settings behavior, including task state synchronization.

Files changed:
 .changeset/fn-8666-credential-instance-picker.md   |   7 ++
 docs/settings-reference.md                         |   2 +
 docs/workflow-steps.md                             |   2 +-
 packages/dashboard/app/api.ts                      |   1 +
 packages/dashboard/app/api/models-usage.ts         |  27 ++++-
 packages/dashboard/app/api/tasks.ts                |   8 ++
 .../app/components/CustomModelDropdown.css         |  12 ++-
 .../app/components/CustomModelDropdown.tsx         |  71 ++++++++++++-
 .../dashboard/app/components/InlineCreateCard.tsx  |  23 +++-
 packages/dashboard/app/components/ListView.tsx     |  29 +++++-
 .../app/components/ModelSelectionModal.tsx         |  25 ++++-
 .../dashboard/app/components/ModelSelectorTab.tsx  |  29 +++++-
 packages/dashboard/app/components/NewTaskModal.tsx |  23 +++-
 .../dashboard/app/components/QuickEntryBox.tsx     |  28 +++++
 .../dashboard/app/components/SettingsModal.tsx     |   2 +
 .../dashboard/app/components/TaskDetailModal.tsx   |  32 +++++-
 packages/dashboard/app/components/TaskForm.tsx     |  18 ++++
 .../app/components/WorkflowNodeEditor.tsx          |  13 ++-
 .../app/components/WorkflowSettingsPanel.tsx       |  38 ++++++-
 ...ustomModelDropdown.credential-instance.test.tsx | 111 ++++++++++++++++++++
 .../__tests__/WorkflowSettingsPanel.test.tsx       |   9 +-
 .../app/components/effective-model-resolution.ts   |   8 +-
 .../settings/sections/GlobalModelsSection.tsx      |  31 +++++-
 .../settings/sections/ProjectModelsSection.tsx     | 116 ++++++++++++++++-----
 .../ProjectModelsSection.chatDefault.test.tsx      |  33 +++++-
 packages/dashboard/app/hooks/useFavorites.ts       |   6 +-
 packages/dashboard/app/hooks/useModelsCache.ts     |   5 +-
 .../src/routes/register-task-workflow-routes.ts    |  17 ++-
 28 files changed, 655 insertions(+), 71 deletions(-)

Fusion-Task-Id: FN-8666

Fusion-Task-Lineage: 6c3711b3-68b8-47a0-ac36-4b64846adf39

Co-authored-by: Fusion (runfusion.ai) <noreply@runfusion.ai>

.changeset/fn-8666-credential-instance-picker.md

@@ -0,0 +1,7 @@
+---
+"@runfusion/fusion": minor
+---
+
+summary: Let operators select configured credential instances from model pickers.
+category: feature
+dev: The picker displays a control only for providers with multiple configured instances.

docs/settings-reference.md

@@ -1808,6 +1808,8 @@ All three lanes (planning / executor / reviewer) follow the same precedence:
 5. Project `defaultProviderOverride` / `defaultModelIdOverride`
 6. Global `defaultProvider` / `defaultModelId` → automatic resolution
 
+A selected credential instance is part of the winning provider/model selection. The model picker shows a **Credential instance** control only when `/api/models` advertises two or more configured instances for that provider. Selecting **Default** removes the instance override entirely; providers with zero or one instance keep the unchanged picker UI.
+
 ## Mock provider (test mode)
 
 Set `defaultProvider: "mock"` at any tier in that hierarchy (or the per-task lane override) to force planning, executor, reviewer/validator, mission validation, merger, and heartbeat sessions onto the deterministic zero-network mock runtime.

docs/workflow-steps.md

@@ -562,7 +562,7 @@ A prompt-mode gate node can set its own model with:
 - `modelId`
 - `thinkingLevel` (`"off" | "minimal" | "low" | "medium" | "high" | "xhigh"`)
 
-If both model fields are set, node execution uses that provider/model pair; otherwise it falls back to default model selection. `thinkingLevel` is stored as `config.thinkingLevel` and can be set or cleared independently from the model pair. Runtime reasoning-effort precedence is **node/step `thinkingLevel` → task `thinkingLevel` → workflow lane thinking override (`executionThinkingLevel`, `planningThinkingLevel`, or `validatorThinkingLevel`) → global lane thinking override → project default thinking override → global `defaultThinkingLevel`**. The lane settings accept `off`, `minimal`, `low`, `medium`, `high`, or `xhigh`; unset means inherit. This applies to prompt/gate custom nodes, the `execute` and `step-execute` seams, triage/planning, and `step-review` reviewer sessions. Dashboard node summaries show unpinned provider/model state as **Default model**; the inspector's inline thinking selector shows the resolved project default (e.g. "Default (off)") when no node-level thinking value is pinned.
+If a node also sets `config.credentialInstanceId`, execution resolves that configured instance for the node's provider/model pair; clearing it uses the provider default credential. If both model fields are set, node execution uses that provider/model pair; otherwise it falls back to default model selection. `thinkingLevel` is stored as `config.thinkingLevel` and can be set or cleared independently from the model pair. Runtime reasoning-effort precedence is **node/step `thinkingLevel` → task `thinkingLevel` → workflow lane thinking override (`executionThinkingLevel`, `planningThinkingLevel`, or `validatorThinkingLevel`) → global lane thinking override → project default thinking override → global `defaultThinkingLevel`**. The lane settings accept `off`, `minimal`, `low`, `medium`, `high`, or `xhigh`; unset means inherit. This applies to prompt/gate custom nodes, the `execute` and `step-execute` seams, triage/planning, and `step-review` reviewer sessions. Dashboard node summaries show unpinned provider/model state as **Default model**; the inspector's inline thinking selector shows the resolved project default (e.g. "Default (off)") when no node-level thinking value is pinned.
 
 ## Default-On Behavior for New Tasks
 

packages/dashboard/app/api.ts

@@ -6,6 +6,7 @@
  */
 export * from "./api/legacy";
 export * from "./api/provider-status";
+export * from "./api/models-usage";
 export * from "./api/chat";
 export * from "./api-node";
 export * from "./api/report";

packages/dashboard/app/api/models-usage.ts

@@ -14,22 +14,45 @@ export interface ModelInfo {
   name: string;
   reasoning: boolean;
   contextWindow: number;
+  /** Provider-wide public instance metadata, attached by fetchModels for picker consumers. */
+  credentialInstances?: ProviderCredentialInstanceSummary[];
 }
 
 /** Response from the models endpoint */
+/** Public metadata for a configured provider credential; it never contains credential material. */
+export interface ProviderCredentialInstanceSummary {
+  id: string;
+  isDefault: boolean;
+  unavailableModelIds?: string[];
+}
+
 export interface ModelsResponse {
   models: ModelInfo[];
   favoriteProviders: string[];
   favoriteModels: string[];
   defaultProvider?: string;
+  /** Configured credential instances keyed by provider, omitted by older servers. */
+  providerInstances?: Record<string, { instances: ProviderCredentialInstanceSummary[] }>;
   defaultModelId?: string;
   resolvedPlanningProvider?: string;
   resolvedPlanningModelId?: string;
 }
 
 /** Fetch available AI models from the model registry along with favoriteProviders */
-export function fetchModels(): Promise<ModelsResponse> {
+export async function fetchModels(): Promise<ModelsResponse> {
-  return api<ModelsResponse>("/models");
+  const response = await api<ModelsResponse>("/models");
+
+  /*
+  FNXC:ModelDropdown 2026-08-01-09:49:
+  Every existing model picker already receives the catalog returned by this client. Attach public provider-instance summaries to those rows so callers that only retain `models` still receive the optional picker availability without a parallel endpoint or a second dropdown implementation.
+  */
+  return {
+    ...response,
+    models: (response.models ?? []).map((model) => ({
+      ...model,
+      credentialInstances: response.providerInstances?.[model.provider]?.instances,
+    })),
+  };
 }
 
 // --- Usage API ---

packages/dashboard/app/api/tasks.ts

@@ -323,12 +323,16 @@ export function updateTask(
     status?: null;
     modelProvider?: string | null;
     modelId?: string | null;
+    credentialInstanceId?: string | null;
     validatorModelProvider?: string | null;
     validatorModelId?: string | null;
+    validatorCredentialInstanceId?: string | null;
     planningModelProvider?: string | null;
     planningModelId?: string | null;
+    planningCredentialInstanceId?: string | null;
     mergerModelProvider?: string | null;
     mergerModelId?: string | null;
+    mergerCredentialInstanceId?: string | null;
     thinkingLevel?: string | null;
     validatorThinkingLevel?: string | null;
     planningThinkingLevel?: string | null;
@@ -382,6 +386,8 @@ export function batchUpdateTaskModels(
   nodeId?: string | null,
   thinkingLevel?: string | null,
   projectId?: string,
+  credentialInstanceId?: string | null,
+  validatorCredentialInstanceId?: string | null,
 ): Promise<{ updated: Task[]; count: number }> {
   return api<{ updated: Task[]; count: number }>(withProjectId("/tasks/batch-update-models", projectId), {
     method: "POST",
@@ -395,6 +401,8 @@ export function batchUpdateTaskModels(
       planningModelId,
       nodeId,
       ...(thinkingLevel !== undefined ? { thinkingLevel } : {}),
+      ...(credentialInstanceId !== undefined ? { credentialInstanceId } : {}),
+      ...(validatorCredentialInstanceId !== undefined ? { validatorCredentialInstanceId } : {}),
     }),
   });
 }

packages/dashboard/app/components/CustomModelDropdown.css

@@ -137,7 +137,8 @@ The model combobox is portaled outside Agent Settings but remains part of its ru
   border-bottom: var(--btn-border-width) solid var(--border);
 }
 
-.model-combobox-thinking {
+.model-combobox-thinking,
+.model-combobox-instance {
   position: relative;
   display: flex;
   align-items: center;
@@ -148,7 +149,8 @@ The model combobox is portaled outside Agent Settings but remains part of its ru
   border-bottom: var(--btn-border-width) solid var(--border);
 }
 
-.model-combobox-thinking-label {
+.model-combobox-thinking-label,
+.model-combobox-instance-label {
   flex: 1;
   min-width: 0;
   color: var(--text-muted);
@@ -156,7 +158,8 @@ The model combobox is portaled outside Agent Settings but remains part of its ru
   font-weight: 600;
 }
 
-.model-combobox-thinking-select {
+.model-combobox-thinking-select,
+.model-combobox-instance-select {
   flex: 1;
   min-width: 0;
 }
@@ -210,7 +213,8 @@ The Thinking Level <select> renders inside the createPortal dropdown (.model-com
   font-weight: 600;
 }
 
-.model-combobox-thinking::after {
+.model-combobox-thinking::after,
+.model-combobox-instance::after {
   content: "";
   position: absolute;
   right: calc(var(--space-md) + var(--space-sm));

packages/dashboard/app/components/CustomModelDropdown.tsx

@@ -3,7 +3,7 @@ import { useState, useEffect, useCallback, useMemo, useRef, useId } from "react"
 import { THINKING_LEVELS } from "@fusion/core";
 import { useTranslation } from "react-i18next";
 import { createPortal } from "react-dom";
-import type { ModelInfo } from "../api";
+import type { ModelInfo, ProviderCredentialInstanceSummary } from "../api";
 import { filterModels } from "../utils/modelFilter";
 import { ProviderIcon } from "./ProviderIcon";
 
@@ -39,6 +39,12 @@ export interface CustomModelDropdownProps {
   defaultThinkingLevel?: string;
   /** Explicitly render the optional inline thinking-level selector even without a change callback. */
   showThinkingLevel?: boolean;
+  /** Optional selected credential instance; empty or absent means provider default. */
+  credentialInstanceId?: string;
+  /** Called when the inline credential-instance selector changes; empty means clear the persisted override. */
+  onCredentialInstanceChange?: (instanceId: string) => void;
+  /** Available credential instances keyed by provider, as advertised by /api/models. */
+  credentialInstances?: Record<string, { instances: ProviderCredentialInstanceSummary[] }>;
 }
 
 interface DropdownPosition {
@@ -101,6 +107,9 @@ export function CustomModelDropdown({
   onThinkingLevelChange,
   defaultThinkingLevel,
   showThinkingLevel,
+  credentialInstanceId,
+  onCredentialInstanceChange,
+  credentialInstances,
 }: CustomModelDropdownProps) {
   const { t } = useTranslation("app");
   const placeholder = placeholderProp ?? t("model.selectPlaceholder", "Select a model…");
@@ -113,6 +122,7 @@ export function CustomModelDropdown({
   const [portalRoot, setPortalRoot] = useState<HTMLElement | null>(null);
   const [collapsedProviders, setCollapsedProviders] = useState<Set<string>>(loadCollapsedProviders);
   const generatedThinkingId = useId();
+  const generatedInstanceId = useId();
 
   const containerRef = useRef<HTMLDivElement>(null);
   const triggerRef = useRef<HTMLButtonElement>(null);
@@ -220,6 +230,38 @@ export function CustomModelDropdown({
     return slashIdx === -1 ? null : value.slice(0, slashIdx);
   }, [hasNoChangeOption, noChangeValue, value]);
 
+  const instanceOptions = useMemo(() => {
+    if (!currentProvider) return [];
+    const seen = new Set<string>();
+    const available = credentialInstances?.[currentProvider]?.instances
+      ?? models.find((model) => model.provider === currentProvider)?.credentialInstances
+      ?? [];
+    const deduplicated = available.filter((instance) => {
+      if (!instance.id || seen.has(instance.id)) return false;
+      seen.add(instance.id);
+      return true;
+    });
+    /*
+    FNXC:ModelDropdown 2026-08-01-09:13:
+    A stale persisted id is retained only after the availability threshold is met. It must not make a single-instance provider sprout this optional control.
+    */
+    if (deduplicated.length >= 2 && credentialInstanceId && !seen.has(credentialInstanceId)) {
+      deduplicated.push({ id: credentialInstanceId, isDefault: false });
+    }
+    return deduplicated;
+  }, [credentialInstanceId, credentialInstances, currentProvider, models]);
+  const shouldShowCredentialInstance = instanceOptions.length >= 2;
+  const normalizedCredentialInstanceId = credentialInstanceId ?? "";
+  const credentialInstanceSelectId = id ? `${id}-credential-instance` : `${generatedInstanceId}-credential-instance`;
+
+  /*
+  FNXC:ModelDropdown 2026-08-01-09:13:
+  Credential-instance selection is visible exactly when a selected provider advertises at least two distinct instances. Rendering nothing otherwise keeps existing and older-server picker menus structurally unchanged; ownership callbacks determine persistence, never visibility.
+
+  FNXC:ModelDropdown 2026-08-01-09:13:
+  A stale selected instance remains an explicit option rather than being cleared during render. Only an operator change may remove a persisted override, preventing unrelated saves from silently changing runtime credentials.
+  */
+
   const specialOptions = useMemo(() => {
     const options: Array<{ type: "default" | "no-change"; value: string; label: string }> = [];
     if (hasNoChangeOption) {
@@ -637,6 +679,28 @@ export function CustomModelDropdown({
         {t("models.count", { count: filteredModels.length, defaultValue_one: "{{count}} model", defaultValue_other: "{{count}} models" })}
       </div>
 
+      {shouldShowCredentialInstance && (
+        <div className="model-combobox-instance" onMouseDown={(e) => e.stopPropagation()} onClick={(e) => e.stopPropagation()}>
+          <label className="model-combobox-instance-label" htmlFor={credentialInstanceSelectId}>
+            {t("models.labels.credentialInstance", "Credential instance")}
+          </label>
+          <select
+            id={credentialInstanceSelectId}
+            className="thinking-level-select model-combobox-instance-select"
+            data-testid="custom-model-dropdown-credential-instance"
+            value={normalizedCredentialInstanceId}
+            onChange={(e) => onCredentialInstanceChange?.(e.target.value)}
+            disabled={disabled || !onCredentialInstanceChange}
+            aria-label={t("models.labels.credentialInstance", "Credential instance")}
+          >
+            <option value="">{t("models.credentialInstanceDefault", "Default")}</option>
+            {instanceOptions.map((instance) => (
+              <option key={instance.id} value={instance.id}>{instance.id}</option>
+            ))}
+          </select>
+        </div>
+      )}
+
       {shouldShowThinking && (
         <div className="model-combobox-thinking" onMouseDown={(e) => e.stopPropagation()} onClick={(e) => e.stopPropagation()}>
           <label className="model-combobox-thinking-label" htmlFor={thinkingSelectId}>
@@ -834,6 +898,11 @@ export function CustomModelDropdown({
               {thinkingBadgeLabel}
             </span>
           )}
+          {shouldShowCredentialInstance && normalizedCredentialInstanceId && (
+            <span className="model-badge model-badge-custom model-combobox-thinking-badge" data-testid="custom-model-dropdown-credential-instance-badge">
+              {normalizedCredentialInstanceId}
+            </span>
+          )}
           <span className="model-combobox-trigger-arrow">▼</span>
         </button>
       </div>

packages/dashboard/app/components/InlineCreateCard.tsx

@@ -118,12 +118,16 @@ export function InlineCreateCard({
   const [settings, setSettings] = useState<Settings | null>(null);
   const [selectedPresetId, setSelectedPresetId] = useState<string | undefined>(undefined);
   const [executorProvider, setExecutorProvider] = useState<string | undefined>(undefined);
+  const [credentialInstanceId, setCredentialInstanceId] = useState<string | undefined>(undefined);
   const [executorModelId, setExecutorModelId] = useState<string | undefined>(undefined);
   const [validatorProvider, setValidatorProvider] = useState<string | undefined>(undefined);
+  const [validatorCredentialInstanceId, setValidatorCredentialInstanceId] = useState<string | undefined>(undefined);
   const [validatorModelId, setValidatorModelId] = useState<string | undefined>(undefined);
   const [planningProvider, setPlanningProvider] = useState<string | undefined>(undefined);
+  const [planningCredentialInstanceId, setPlanningCredentialInstanceId] = useState<string | undefined>(undefined);
   const [planningModelId, setPlanningModelId] = useState<string | undefined>(undefined);
   const [mergerProvider, setMergerProvider] = useState<string | undefined>(undefined);
+  const [mergerCredentialInstanceId, setMergerCredentialInstanceId] = useState<string | undefined>(undefined);
   const [mergerModelId, setMergerModelId] = useState<string | undefined>(undefined);
   /* FNXC:Settings-ThinkingLevel 2026-07-09-00:00: quick-create board card carries the same per-task thinking-level override as the full New Task modal; "" means "use default". */
   const [thinkingLevel, setThinkingLevel] = useState<string>("");
@@ -500,12 +504,16 @@ export function InlineCreateCard({
       ...(selectedAgentId ? { assignedAgentId: selectedAgentId } : {}),
       modelPresetId: selectedPresetId,
       modelProvider: hasExecutorOverride ? executorProvider : undefined,
+      credentialInstanceId: hasExecutorOverride ? credentialInstanceId : undefined,
       modelId: hasExecutorOverride ? executorModelId : undefined,
       validatorModelProvider: hasValidatorOverride ? validatorProvider : undefined,
+      validatorCredentialInstanceId: hasValidatorOverride ? validatorCredentialInstanceId : undefined,
       validatorModelId: hasValidatorOverride ? validatorModelId : undefined,
       planningModelProvider: hasPlanningOverride ? planningProvider : undefined,
+      planningCredentialInstanceId: hasPlanningOverride ? planningCredentialInstanceId : undefined,
       planningModelId: hasPlanningOverride ? planningModelId : undefined,
       mergerModelProvider: hasMergerOverride ? mergerProvider : undefined,
+      mergerCredentialInstanceId: hasMergerOverride ? mergerCredentialInstanceId : undefined,
       mergerModelId: hasMergerOverride ? mergerModelId : undefined,
       validatorThinkingLevel: validatorThinkingLevel !== "" ? validatorThinkingLevel as ThinkingLevel : undefined,
       planningThinkingLevel: planningThinkingLevel !== "" ? planningThinkingLevel as ThinkingLevel : undefined,
@@ -532,7 +540,7 @@ export function InlineCreateCard({
     }
 
     await submitTask(input);
-  }, [description, submitting, selectedWorkflowId, dependencies, selectedAgentId, selectedPresetId, hasExecutorOverride, executorProvider, executorModelId, hasValidatorOverride, validatorProvider, validatorModelId, hasPlanningOverride, planningProvider, planningModelId, hasMergerOverride, mergerProvider, mergerModelId, thinkingLevel, validatorThinkingLevel, planningThinkingLevel, mergerThinkingLevel, optionalSteps.length, enabledOptionalStepIds, priority, effectiveNodeId, projectId, addToast, submitTask]);
+  }, [description, submitting, selectedWorkflowId, dependencies, selectedAgentId, selectedPresetId, hasExecutorOverride, executorProvider, credentialInstanceId, executorModelId, hasValidatorOverride, validatorProvider, validatorCredentialInstanceId, validatorModelId, hasPlanningOverride, planningProvider, planningCredentialInstanceId, planningModelId, hasMergerOverride, mergerProvider, mergerCredentialInstanceId, mergerModelId, thinkingLevel, validatorThinkingLevel, planningThinkingLevel, mergerThinkingLevel, optionalSteps.length, enabledOptionalStepIds, priority, effectiveNodeId, projectId, addToast, submitTask]);
 
   const handleDuplicateProceed = useCallback(async () => {
     const matches = duplicateMatches;
@@ -667,18 +675,21 @@ export function InlineCreateCard({
     const next = parseModelSelection(value);
     setExecutorProvider(next.provider);
     setExecutorModelId(next.modelId);
+    setCredentialInstanceId(undefined);
   }, []);
 
   const handleValidatorChange = useCallback((value: string) => {
     const next = parseModelSelection(value);
     setValidatorProvider(next.provider);
     setValidatorModelId(next.modelId);
+    setValidatorCredentialInstanceId(undefined);
   }, []);
 
   const handlePlanningModelChange = useCallback((value: string) => {
     const next = parseModelSelection(value);
     setPlanningProvider(next.provider);
     setPlanningModelId(next.modelId);
+    setPlanningCredentialInstanceId(undefined);
   }, []);
 
   const handleThinkingLevelChange = useCallback((value: string) => {
@@ -1239,7 +1250,15 @@ export function InlineCreateCard({
               onExecutorChange={handleExecutorChange}
               onValidatorChange={handleValidatorChange}
               onPlanningChange={handlePlanningModelChange}
-              onMergerChange={(value) => { const next = parseModelSelection(value); setMergerProvider(next.provider); setMergerModelId(next.modelId); }}
+              onMergerChange={(value) => { const next = parseModelSelection(value); setMergerProvider(next.provider); setMergerModelId(next.modelId); setMergerCredentialInstanceId(undefined); }}
+              credentialInstanceId={credentialInstanceId}
+              onCredentialInstanceChange={(value) => setCredentialInstanceId(value || undefined)}
+              validatorCredentialInstanceId={validatorCredentialInstanceId}
+              onValidatorCredentialInstanceChange={(value) => setValidatorCredentialInstanceId(value || undefined)}
+              planningCredentialInstanceId={planningCredentialInstanceId}
+              onPlanningCredentialInstanceChange={(value) => setPlanningCredentialInstanceId(value || undefined)}
+              mergerCredentialInstanceId={mergerCredentialInstanceId}
+              onMergerCredentialInstanceChange={(value) => setMergerCredentialInstanceId(value || undefined)}
               mergerThinkingLevel={mergerThinkingLevel}
               onMergerThinkingLevelChange={setMergerThinkingLevel}
               validatorThinkingLevel={validatorThinkingLevel}

packages/dashboard/app/components/ListView.tsx

@@ -606,7 +606,9 @@ export function ListView({
 
   // Bulk edit state and handlers (declared before clearSelection so every clear path resets pending lane edits)
   const [executorModel, setExecutorModel] = useState<string>("__no_change__");
+  const [credentialInstanceId, setCredentialInstanceId] = useState<string>("__no_change__");
   const [validatorModel, setValidatorModel] = useState<string>("__no_change__");
+  const [validatorCredentialInstanceId, setValidatorCredentialInstanceId] = useState<string>("__no_change__");
   const [bulkThinkingLevel, setBulkThinkingLevel] = useState<string>("__no_change__");
   const [nodeOverride, setNodeOverride] = useState<string>("__no_change__");
 
@@ -615,7 +617,9 @@ export function ListView({
       if (prev) {
         setSelectedTaskIds(new Set());
         setExecutorModel("__no_change__");
+        setCredentialInstanceId("__no_change__");
         setValidatorModel("__no_change__");
+        setValidatorCredentialInstanceId("__no_change__");
         setBulkThinkingLevel("__no_change__");
         setNodeOverride("__no_change__");
       }
@@ -640,7 +644,9 @@ export function ListView({
   const clearSelection = useCallback(() => {
     setSelectedTaskIds(new Set());
     setExecutorModel("__no_change__");
+    setCredentialInstanceId("__no_change__");
     setValidatorModel("__no_change__");
+    setValidatorCredentialInstanceId("__no_change__");
     setBulkThinkingLevel("__no_change__");
     setNodeOverride("__no_change__");
   }, []);
@@ -1779,6 +1785,8 @@ export function ListView({
       validatorModelId?: string | null;
       nodeId?: string | null;
       thinkingLevel?: ThinkingLevel | null;
+      credentialInstanceId?: string | null;
+      validatorCredentialInstanceId?: string | null;
     } = { taskIds };
 
     if (executorModel !== "__no_change__") {
@@ -1786,11 +1794,13 @@ export function ListView({
         // "Use default" - clear override
         payload.modelProvider = null;
         payload.modelId = null;
+        payload.credentialInstanceId = null;
       } else {
         const slashIdx = executorModel.indexOf("/");
         if (slashIdx !== -1) {
           payload.modelProvider = executorModel.slice(0, slashIdx);
           payload.modelId = executorModel.slice(slashIdx + 1);
+          payload.credentialInstanceId = null;
         }
       }
     }
@@ -1800,15 +1810,20 @@ export function ListView({
         // "Use default" - clear override
         payload.validatorModelProvider = null;
         payload.validatorModelId = null;
+        payload.validatorCredentialInstanceId = null;
       } else {
         const slashIdx = validatorModel.indexOf("/");
         if (slashIdx !== -1) {
           payload.validatorModelProvider = validatorModel.slice(0, slashIdx);
           payload.validatorModelId = validatorModel.slice(slashIdx + 1);
+          payload.validatorCredentialInstanceId = null;
         }
       }
     }
 
+    if (credentialInstanceId !== "__no_change__") payload.credentialInstanceId = credentialInstanceId || null;
+    if (validatorCredentialInstanceId !== "__no_change__") payload.validatorCredentialInstanceId = validatorCredentialInstanceId || null;
+
     if (nodeOverride !== "__no_change__") {
       if (nodeOverride === "") {
         payload.nodeId = null;
@@ -1840,6 +1855,8 @@ export function ListView({
         payload.nodeId,
         payload.thinkingLevel,
         projectId,
+        payload.credentialInstanceId,
+        payload.validatorCredentialInstanceId,
       );
 
       if (onTasksUpdated) {
@@ -1851,7 +1868,9 @@ export function ListView({
       // Reset state
       clearSelection();
       setExecutorModel("__no_change__");
+      setCredentialInstanceId("__no_change__");
       setValidatorModel("__no_change__");
+      setValidatorCredentialInstanceId("__no_change__");
       setBulkThinkingLevel("__no_change__");
       setNodeOverride("__no_change__");
     } catch (err) {
@@ -1859,7 +1878,7 @@ export function ListView({
     } finally {
       setIsApplying(false);
     }
-  }, [addToast, bulkThinkingLevel, clearSelection, executorModel, isTaskArchivedColumn, nodeOverride, onTasksUpdated, projectId, selectedTaskIds, tasks, validatorModel]);
+  }, [addToast, bulkThinkingLevel, clearSelection, credentialInstanceId, executorModel, isTaskArchivedColumn, nodeOverride, onTasksUpdated, projectId, selectedTaskIds, tasks, validatorCredentialInstanceId, validatorModel]);
 
   const closeContextMenu = useCallback(() => {
     setContextMenuState(null);
@@ -2776,7 +2795,9 @@ export function ListView({
             <CustomModelDropdown
               models={availableModels}
               value={executorModel}
-              onChange={setExecutorModel}
+              onChange={(value) => { setCredentialInstanceId("__no_change__"); setExecutorModel(value); }}
+              credentialInstanceId={credentialInstanceId === "__no_change__" ? undefined : credentialInstanceId}
+              onCredentialInstanceChange={setCredentialInstanceId}
               label={t("listView.executorModel", "Executor Model")}
               noChangeValue="__no_change__"
               noChangeLabel={t("listView.noChange", "No change")}
@@ -2790,7 +2811,9 @@ export function ListView({
             <CustomModelDropdown
               models={availableModels}
               value={validatorModel}
-              onChange={setValidatorModel}
+              onChange={(value) => { setValidatorCredentialInstanceId("__no_change__"); setValidatorModel(value); }}
+              credentialInstanceId={validatorCredentialInstanceId === "__no_change__" ? undefined : validatorCredentialInstanceId}
+              onCredentialInstanceChange={setValidatorCredentialInstanceId}
               label={t("listView.reviewerModel", "Reviewer Model")}
               noChangeValue="__no_change__"
               noChangeLabel={t("listView.noChange", "No change")}

packages/dashboard/app/components/ModelSelectionModal.tsx

@@ -22,6 +22,15 @@ interface ModelSelectionModalProps {
   onValidatorChange: (value: string) => void;
   onPlanningChange?: (value: string) => void;
   onMergerChange?: (value: string) => void;
+  /** Optional persisted instance overrides for task model lanes. */
+  credentialInstanceId?: string;
+  validatorCredentialInstanceId?: string;
+  planningCredentialInstanceId?: string;
+  mergerCredentialInstanceId?: string;
+  onCredentialInstanceChange?: (value: string) => void;
+  onValidatorCredentialInstanceChange?: (value: string) => void;
+  onPlanningCredentialInstanceChange?: (value: string) => void;
+  onMergerCredentialInstanceChange?: (value: string) => void;
   mergerThinkingLevel?: string;
   onMergerThinkingLevelChange?: (value: string) => void;
   validatorThinkingLevel?: string;
@@ -77,6 +86,14 @@ export function ModelSelectionModal({
   onValidatorChange,
   onPlanningChange,
   onMergerChange,
+  credentialInstanceId = "",
+  validatorCredentialInstanceId = "",
+  planningCredentialInstanceId = "",
+  mergerCredentialInstanceId = "",
+  onCredentialInstanceChange,
+  onValidatorCredentialInstanceChange,
+  onPlanningCredentialInstanceChange,
+  onMergerCredentialInstanceChange,
   mergerThinkingLevel = "",
   onMergerThinkingLevelChange,
   validatorThinkingLevel = "",
@@ -288,6 +305,8 @@ export function ModelSelectionModal({
                           onToggleModelFavorite={onToggleModelFavorite}
                           thinkingLevel={planningThinkingLevel}
                           onThinkingLevelChange={onPlanningThinkingLevelChange}
+                          credentialInstanceId={planningCredentialInstanceId}
+                          onCredentialInstanceChange={onPlanningCredentialInstanceChange}
                           defaultThinkingLevel={defaultThinkingLevel ?? "off"}
                         />
                       </div>
@@ -318,6 +337,8 @@ export function ModelSelectionModal({
                         onToggleModelFavorite={onToggleModelFavorite}
                         thinkingLevel={thinkingLevel}
                         onThinkingLevelChange={onThinkingLevelChange}
+                        credentialInstanceId={credentialInstanceId}
+                        onCredentialInstanceChange={onCredentialInstanceChange}
                         defaultThinkingLevel={defaultThinkingLevel ?? "off"}
                       />
                     </div>
@@ -326,7 +347,7 @@ export function ModelSelectionModal({
                   {onMergerChange ? <div className="task-detail-section"><div className="inline-create-model-row">
                     <label htmlFor="model-selection-merger" className="inline-create-model-label">{t("tasks.mergerModel", "Merger Model")}</label>
                     <span className={`model-badge ${hasMergerOverride ? "model-badge-custom" : "model-badge-default"}`}>{getModelBadgeLabel(models, mergerValue, t)}</span>
-                    <CustomModelDropdown id="model-selection-merger" label={t("tasks.mergerModel", "Merger Model")} value={mergerValue} onChange={onMergerChange} models={models} placeholder={t("tasks.usingDefault", "Using default")} favoriteProviders={favoriteProviders} onToggleFavorite={onToggleFavorite} favoriteModels={favoriteModels} onToggleModelFavorite={onToggleModelFavorite} thinkingLevel={mergerThinkingLevel} onThinkingLevelChange={onMergerThinkingLevelChange} defaultThinkingLevel={defaultThinkingLevel ?? "off"} />
+                    <CustomModelDropdown id="model-selection-merger" label={t("tasks.mergerModel", "Merger Model")} value={mergerValue} onChange={onMergerChange} models={models} placeholder={t("tasks.usingDefault", "Using default")} favoriteProviders={favoriteProviders} onToggleFavorite={onToggleFavorite} favoriteModels={favoriteModels} onToggleModelFavorite={onToggleModelFavorite} thinkingLevel={mergerThinkingLevel} onThinkingLevelChange={onMergerThinkingLevelChange} credentialInstanceId={mergerCredentialInstanceId} onCredentialInstanceChange={onMergerCredentialInstanceChange} defaultThinkingLevel={defaultThinkingLevel ?? "off"} />
                   </div></div> : null}
 
                   <div className="task-detail-section">
@@ -353,6 +374,8 @@ export function ModelSelectionModal({
                         onToggleModelFavorite={onToggleModelFavorite}
                         thinkingLevel={validatorThinkingLevel}
                         onThinkingLevelChange={onValidatorThinkingLevelChange}
+                        credentialInstanceId={validatorCredentialInstanceId}
+                        onCredentialInstanceChange={onValidatorCredentialInstanceChange}
                         defaultThinkingLevel={defaultThinkingLevel ?? "off"}
                       />
                     </div>

packages/dashboard/app/components/ModelSelectorTab.tsx

@@ -28,6 +28,7 @@ interface ModelSelectorTabProps {
 interface ModelSelection {
   provider?: string;
   modelId?: string;
+  credentialInstanceId?: string;
 }
 
 function normalizeModelField(value: string | null | undefined): string | undefined {
@@ -38,6 +39,7 @@ function getExecutorSelection(task: Task | TaskDetail): ModelSelection {
   return {
     provider: normalizeModelField(task.modelProvider),
     modelId: normalizeModelField(task.modelId),
+    credentialInstanceId: normalizeModelField(task.credentialInstanceId),
   };
 }
 
@@ -45,6 +47,7 @@ function getValidatorSelection(task: Task | TaskDetail): ModelSelection {
   return {
     provider: normalizeModelField(task.validatorModelProvider),
     modelId: normalizeModelField(task.validatorModelId),
+    credentialInstanceId: normalizeModelField(task.validatorCredentialInstanceId),
   };
 }
 
@@ -52,6 +55,7 @@ function getPlanningSelection(task: Task | TaskDetail): ModelSelection {
   return {
     provider: normalizeModelField(task.planningModelProvider),
     modelId: normalizeModelField(task.planningModelId),
+    credentialInstanceId: normalizeModelField(task.planningCredentialInstanceId),
   };
 }
 
@@ -59,6 +63,7 @@ function getMergerSelection(task: Task | TaskDetail): ModelSelection {
   return {
     provider: normalizeModelField(task.mergerModelProvider),
     modelId: normalizeModelField(task.mergerModelId),
+    credentialInstanceId: normalizeModelField(task.mergerCredentialInstanceId),
   };
 }
 
@@ -109,7 +114,7 @@ function getDropdownValue(selection: ModelSelection): string {
 }
 
 function selectionsEqual(a: ModelSelection, b: ModelSelection): boolean {
-  return a.provider === b.provider && a.modelId === b.modelId;
+  return a.provider === b.provider && a.modelId === b.modelId && a.credentialInstanceId === b.credentialInstanceId;
 }
 
 function getSuccessToastMessage(
@@ -141,6 +146,7 @@ export function ModelSelectorTab({ task, addToast, onTaskUpdated, settings, proj
   const { t } = useTranslation("app");
   const {
     availableModels,
+    providerInstances,
     favoriteProviders,
     favoriteModels,
     toggleFavoriteProvider,
@@ -213,7 +219,7 @@ export function ModelSelectorTab({ task, addToast, onTaskUpdated, settings, proj
     setSelectedMergerThinking(nextMergerThinking);
     setSavedMergerThinking(nextMergerThinking);
     setSavingTarget(null);
-  }, [task.id, task.modelProvider, task.modelId, task.validatorModelProvider, task.validatorModelId, task.planningModelProvider, task.planningModelId, task.mergerModelProvider, task.mergerModelId, task.thinkingLevel, task.validatorThinkingLevel, task.planningThinkingLevel, task.mergerThinkingLevel]);
+  }, [task.id, task.modelProvider, task.modelId, task.credentialInstanceId, task.validatorModelProvider, task.validatorModelId, task.validatorCredentialInstanceId, task.planningModelProvider, task.planningModelId, task.planningCredentialInstanceId, task.mergerModelProvider, task.mergerModelId, task.mergerCredentialInstanceId, task.thinkingLevel, task.validatorThinkingLevel, task.planningThinkingLevel, task.mergerThinkingLevel]);
 
   const executorValue = useMemo(() => getDropdownValue(selectedExecutor), [selectedExecutor]);
   const validatorValue = useMemo(() => getDropdownValue(selectedValidator), [selectedValidator]);
@@ -241,30 +247,38 @@ export function ModelSelectorTab({ task, addToast, onTaskUpdated, settings, proj
             ? {
                 modelProvider: nextSelection.provider ?? null,
                 modelId: nextSelection.modelId ?? null,
+                credentialInstanceId: nextSelection.credentialInstanceId ?? null,
               }
             : target === "validator"
               ? {
                   validatorModelProvider: nextSelection.provider ?? null,
                   validatorModelId: nextSelection.modelId ?? null,
+                  validatorCredentialInstanceId: nextSelection.credentialInstanceId ?? null,
                 }
               : target === "merger"
                 ? {
                     mergerModelProvider: nextSelection.provider ?? null,
                     mergerModelId: nextSelection.modelId ?? null,
+                    mergerCredentialInstanceId: nextSelection.credentialInstanceId ?? null,
                   }
                 : {
                   planningModelProvider: nextSelection.provider ?? null,
                   planningModelId: nextSelection.modelId ?? null,
+                  planningCredentialInstanceId: nextSelection.credentialInstanceId ?? null,
                 })
           : {
               modelProvider: (target === "executor" ? nextSelection : savedExecutor).provider ?? null,
               modelId: (target === "executor" ? nextSelection : savedExecutor).modelId ?? null,
+              credentialInstanceId: (target === "executor" ? nextSelection : savedExecutor).credentialInstanceId ?? null,
               validatorModelProvider: (target === "validator" ? nextSelection : savedValidator).provider ?? null,
               validatorModelId: (target === "validator" ? nextSelection : savedValidator).modelId ?? null,
+              validatorCredentialInstanceId: (target === "validator" ? nextSelection : savedValidator).credentialInstanceId ?? null,
               planningModelProvider: (target === "planning" ? nextSelection : savedPlanning).provider ?? null,
               planningModelId: (target === "planning" ? nextSelection : savedPlanning).modelId ?? null,
+              planningCredentialInstanceId: (target === "planning" ? nextSelection : savedPlanning).credentialInstanceId ?? null,
               mergerModelProvider: (target === "merger" ? nextSelection : savedMerger).provider ?? null,
               mergerModelId: (target === "merger" ? nextSelection : savedMerger).modelId ?? null,
+              mergerCredentialInstanceId: (target === "merger" ? nextSelection : savedMerger).credentialInstanceId ?? null,
             };
 
         /*
@@ -599,6 +613,9 @@ export function ModelSelectorTab({ task, addToast, onTaskUpdated, settings, proj
               value={executorValue}
               onChange={handleExecutorChange}
               models={availableModels}
+              credentialInstances={providerInstances}
+              credentialInstanceId={selectedExecutor.credentialInstanceId}
+              onCredentialInstanceChange={(credentialInstanceId) => void saveSelection("executor", { ...selectedExecutor, credentialInstanceId: credentialInstanceId || undefined })}
               disabled={isSaving}
               placeholder={t("models.placeholders.selectExecutor", "Select executor model…")}
               favoriteProviders={favoriteProviders}
@@ -632,6 +649,9 @@ export function ModelSelectorTab({ task, addToast, onTaskUpdated, settings, proj
               value={validatorValue}
               onChange={handleValidatorChange}
               models={availableModels}
+              credentialInstances={providerInstances}
+              credentialInstanceId={selectedValidator.credentialInstanceId}
+              onCredentialInstanceChange={(credentialInstanceId) => void saveSelection("validator", { ...selectedValidator, credentialInstanceId: credentialInstanceId || undefined })}
               disabled={isSaving}
               placeholder={t("models.placeholders.selectReviewer", "Select reviewer model…")}
               favoriteProviders={favoriteProviders}
@@ -665,6 +685,9 @@ export function ModelSelectorTab({ task, addToast, onTaskUpdated, settings, proj
               value={planningValue}
               onChange={handlePlanningChange}
               models={availableModels}
+              credentialInstances={providerInstances}
+              credentialInstanceId={selectedPlanning.credentialInstanceId}
+              onCredentialInstanceChange={(credentialInstanceId) => void saveSelection("planning", { ...selectedPlanning, credentialInstanceId: credentialInstanceId || undefined })}
               disabled={isSaving}
               placeholder={t("models.placeholders.selectPlanning", "Select planning model…")}
               favoriteProviders={favoriteProviders}
@@ -684,7 +707,7 @@ export function ModelSelectorTab({ task, addToast, onTaskUpdated, settings, proj
             <div className="model-selector-current">
               {mergerUsingDefault ? <span className="model-badge model-badge-default">{t("models.states.usingDefault", "Using default")}{effectiveMerger.provider && effectiveMerger.modelId ? ` (${effectiveMerger.provider}/${effectiveMerger.modelId})` : ""}</span> : <span className="model-badge model-badge-custom">{savedMerger.provider && <ProviderIcon provider={savedMerger.provider} size="sm" />}{savedMerger.provider}/{savedMerger.modelId}</span>}
             </div>
-            <CustomModelDropdown id="mergerModel" label={t("tasks.mergerModel", "Merger Model")} value={mergerValue} onChange={handleMergerChange} models={availableModels} disabled={isSaving} placeholder={t("tasks.usingDefault", "Using default")} favoriteProviders={favoriteProviders} onToggleFavorite={handleToggleFavorite} favoriteModels={favoriteModels} onToggleModelFavorite={handleToggleModelFavorite} thinkingLevel={selectedMergerThinking ?? ""} onThinkingLevelChange={handleMergerThinkingChange} defaultThinkingLevel={settings?.mergerThinkingLevel ?? "off"} />
+            <CustomModelDropdown id="mergerModel" label={t("tasks.mergerModel", "Merger Model")} value={mergerValue} onChange={handleMergerChange} models={availableModels} credentialInstances={providerInstances} credentialInstanceId={selectedMerger.credentialInstanceId} onCredentialInstanceChange={(credentialInstanceId) => void saveSelection("merger", { ...selectedMerger, credentialInstanceId: credentialInstanceId || undefined })} disabled={isSaving} placeholder={t("tasks.usingDefault", "Using default")} favoriteProviders={favoriteProviders} onToggleFavorite={handleToggleFavorite} favoriteModels={favoriteModels} onToggleModelFavorite={handleToggleModelFavorite} thinkingLevel={selectedMergerThinking ?? ""} onThinkingLevelChange={handleMergerThinkingChange} defaultThinkingLevel={settings?.mergerThinkingLevel ?? "off"} />
             <small>{t("models.descriptions.merger", "The AI model used to merge this task.")}</small>
           </div>
 

packages/dashboard/app/components/NewTaskModal.tsx

@@ -358,8 +358,11 @@ export function NewTaskModal({ isOpen, onClose, projectId, tasks, onCreateTask,
   const [isSubmitting, setIsSubmitting] = useState(false);
   const [duplicateMatches, setDuplicateMatches] = useState<DuplicateMatch[] | null>(null);
   const [executorModel, setExecutorModel] = useState("");
+  const [credentialInstanceId, setCredentialInstanceId] = useState<string | undefined>(undefined);
   const [validatorModel, setValidatorModel] = useState("");
+  const [validatorCredentialInstanceId, setValidatorCredentialInstanceId] = useState<string | undefined>(undefined);
   const [planningModel, setPlanningModel] = useState("");
+  const [planningCredentialInstanceId, setPlanningCredentialInstanceId] = useState<string | undefined>(undefined);
   const [thinkingLevel, setThinkingLevel] = useState<string>("");
   // FNXC:PlannerOversight 2026-07-04-00:00: Per-task override of the workflow-native plannerOversightLevel setting (FN-7508). "" means inherit from workflow.
   const [plannerOversightLevel, setPlannerOversightLevel] = useState<string>("");
@@ -575,8 +578,11 @@ export function NewTaskModal({ isOpen, onClose, projectId, tasks, onCreateTask,
     setDescription("");
     setDependencies([]);
     setExecutorModel("");
+    setCredentialInstanceId(undefined);
     setValidatorModel("");
+    setValidatorCredentialInstanceId(undefined);
     setPlanningModel("");
+    setPlanningCredentialInstanceId(undefined);
     setThinkingLevel("");
     setPlannerOversightLevel("");
     setSelectedPresetId("");
@@ -649,10 +655,13 @@ export function NewTaskModal({ isOpen, onClose, projectId, tasks, onCreateTask,
       modelPresetId: presetMode === "preset" ? selectedPresetId || undefined : undefined,
       modelProvider: executorModel && executorSlashIdx !== -1 ? executorModel.slice(0, executorSlashIdx) : undefined,
       modelId: executorModel && executorSlashIdx !== -1 ? executorModel.slice(executorSlashIdx + 1) : undefined,
+      ...(credentialInstanceId ? { credentialInstanceId } : {}),
       validatorModelProvider: validatorModel && validatorSlashIdx !== -1 ? validatorModel.slice(0, validatorSlashIdx) : undefined,
       validatorModelId: validatorModel && validatorSlashIdx !== -1 ? validatorModel.slice(validatorSlashIdx + 1) : undefined,
+      ...(validatorCredentialInstanceId ? { validatorCredentialInstanceId } : {}),
       planningModelProvider: planningModel && planningSlashIdx !== -1 ? planningModel.slice(0, planningSlashIdx) : undefined,
       planningModelId: planningModel && planningSlashIdx !== -1 ? planningModel.slice(planningSlashIdx + 1) : undefined,
+      ...(planningCredentialInstanceId ? { planningCredentialInstanceId } : {}),
       thinkingLevel: thinkingLevel !== "" ? thinkingLevel as "minimal" | "low" | "medium" | "high" | "xhigh" : undefined,
       // FNXC:PlannerOversight 2026-07-04-00:00: omit when "Inherit from workflow" ("") is selected so the task falls back to the workflow's effective plannerOversightLevel.
       ...(plannerOversightLevel !== "" ? { plannerOversightLevel: plannerOversightLevel as "off" | "observe" | "steer" | "autonomous" } : {}),
@@ -700,7 +709,7 @@ export function NewTaskModal({ isOpen, onClose, projectId, tasks, onCreateTask,
     resetForm();
     addToast(t("newTaskModal.taskCreated", "Created {{taskId}}", { taskId: task.id }), "success");
     onClose();
-  }, [executorModel, validatorModel, planningModel, thinkingLevel, plannerOversightLevel, dependencies, selectedWorkflowId, shouldSubmitEnabledWorkflowSteps, enabledWorkflowSteps, selectedAgentId, presetMode, selectedPresetId, reviewLevel, autoMerge, priority, nodeId, executionMode, branchMode, isBranchNameRequired, branch, baseBranch, githubTrackingEnabled, githubRepoOverrideTrimmed, onCreateTask, pendingImages, resetForm, addToast, t, onClose, projectId]);
+  }, [executorModel, credentialInstanceId, validatorModel, validatorCredentialInstanceId, planningModel, planningCredentialInstanceId, thinkingLevel, plannerOversightLevel, dependencies, selectedWorkflowId, shouldSubmitEnabledWorkflowSteps, enabledWorkflowSteps, selectedAgentId, presetMode, selectedPresetId, reviewLevel, autoMerge, priority, nodeId, executionMode, branchMode, isBranchNameRequired, branch, baseBranch, githubTrackingEnabled, githubRepoOverrideTrimmed, onCreateTask, pendingImages, resetForm, addToast, t, onClose, projectId]);
 
   const handleSubmit = useCallback(async () => {
     const trimmedDesc = description.trim();
@@ -1033,9 +1042,13 @@ export function NewTaskModal({ isOpen, onClose, projectId, tasks, onCreateTask,
         dependencies={dependencies}
         onDependenciesChange={setDependencies}
         executorModel={executorModel}
-        onExecutorModelChange={handleExecutorModelChange}
+        onExecutorModelChange={(value, meta) => { setCredentialInstanceId(undefined); handleExecutorModelChange(value, meta); }}
+        credentialInstanceId={credentialInstanceId}
+        onCredentialInstanceIdChange={(instanceId) => setCredentialInstanceId(instanceId || undefined)}
         validatorModel={validatorModel}
-        onValidatorModelChange={handleValidatorModelChange}
+        onValidatorModelChange={(value, meta) => { setValidatorCredentialInstanceId(undefined); handleValidatorModelChange(value, meta); }}
+        validatorCredentialInstanceId={validatorCredentialInstanceId}
+        onValidatorCredentialInstanceIdChange={(instanceId) => setValidatorCredentialInstanceId(instanceId || undefined)}
         presetMode={presetMode}
         onPresetModeChange={setPresetMode}
         selectedPresetId={selectedPresetId}
@@ -1055,7 +1068,9 @@ export function NewTaskModal({ isOpen, onClose, projectId, tasks, onCreateTask,
         onPlanningMode={onPlanningMode}
         onSubtaskBreakdown={onSubtaskBreakdown}
         planningModel={planningModel}
-        onPlanningModelChange={setPlanningModel}
+        onPlanningModelChange={(value) => { setPlanningCredentialInstanceId(undefined); setPlanningModel(value); }}
+        planningCredentialInstanceId={planningCredentialInstanceId}
+        onPlanningCredentialInstanceIdChange={(instanceId) => setPlanningCredentialInstanceId(instanceId || undefined)}
         thinkingLevel={thinkingLevel}
         plannerOversightLevel={plannerOversightLevel}
         onPlannerOversightLevelChange={setPlannerOversightLevel}

packages/dashboard/app/components/QuickEntryBox.tsx

@@ -199,12 +199,16 @@ export function QuickEntryBox({ onCreate, onMoveTask, addToast, tasks = [], avai
   const [activeModelSubmenu, setActiveModelSubmenu] = useState<"plan" | "executor" | "validator" | "merger" | null>(null);
   const [executorProvider, setExecutorProvider] = useState<string | undefined>(undefined);
   const [executorModelId, setExecutorModelId] = useState<string | undefined>(undefined);
+  const [credentialInstanceId, setCredentialInstanceId] = useState<string | undefined>(undefined);
   const [validatorProvider, setValidatorProvider] = useState<string | undefined>(undefined);
   const [validatorModelId, setValidatorModelId] = useState<string | undefined>(undefined);
+  const [validatorCredentialInstanceId, setValidatorCredentialInstanceId] = useState<string | undefined>(undefined);
   const [planningProvider, setPlanningProvider] = useState<string | undefined>(undefined);
   const [planningModelId, setPlanningModelId] = useState<string | undefined>(undefined);
+  const [planningCredentialInstanceId, setPlanningCredentialInstanceId] = useState<string | undefined>(undefined);
   const [mergerProvider, setMergerProvider] = useState<string | undefined>(undefined);
   const [mergerModelId, setMergerModelId] = useState<string | undefined>(undefined);
+  const [mergerCredentialInstanceId, setMergerCredentialInstanceId] = useState<string | undefined>(undefined);
   /* FNXC:Settings-ThinkingLevel 2026-07-09-00:00: inline quick-entry bar carries the same per-task thinking-level override as the full New Task modal; "" means "use default". */
   const [thinkingLevel, setThinkingLevel] = useState<string>("");
   const [validatorThinkingLevel, setValidatorThinkingLevel] = useState<string>("");
@@ -681,12 +685,16 @@ export function QuickEntryBox({ onCreate, onMoveTask, addToast, tasks = [], avai
     setPriorityPickerPosition(null);
     setExecutorProvider(undefined);
     setExecutorModelId(undefined);
+    setCredentialInstanceId(undefined);
     setValidatorProvider(undefined);
     setValidatorModelId(undefined);
+    setValidatorCredentialInstanceId(undefined);
     setPlanningProvider(undefined);
     setPlanningModelId(undefined);
+    setPlanningCredentialInstanceId(undefined);
     setMergerProvider(undefined);
     setMergerModelId(undefined);
+    setMergerCredentialInstanceId(undefined);
     setThinkingLevel("");
     setValidatorThinkingLevel("");
     setPlanningThinkingLevel("");
@@ -817,12 +825,16 @@ export function QuickEntryBox({ onCreate, onMoveTask, addToast, tasks = [], avai
         modelPresetId: selectedPresetId,
         modelProvider: hasExecutorOverride ? executorProvider : undefined,
         modelId: hasExecutorOverride ? executorModelId : undefined,
+        ...(hasExecutorOverride && credentialInstanceId ? { credentialInstanceId } : {}),
         validatorModelProvider: hasValidatorOverride ? validatorProvider : undefined,
         validatorModelId: hasValidatorOverride ? validatorModelId : undefined,
+        ...(hasValidatorOverride && validatorCredentialInstanceId ? { validatorCredentialInstanceId } : {}),
         planningModelProvider: hasPlanningOverride ? planningProvider : undefined,
         planningModelId: hasPlanningOverride ? planningModelId : undefined,
+        ...(hasPlanningOverride && planningCredentialInstanceId ? { planningCredentialInstanceId } : {}),
         mergerModelProvider: hasMergerOverride ? mergerProvider : undefined,
         mergerModelId: hasMergerOverride ? mergerModelId : undefined,
+        ...(hasMergerOverride && mergerCredentialInstanceId ? { mergerCredentialInstanceId } : {}),
         validatorThinkingLevel: validatorThinkingLevel !== "" ? (validatorThinkingLevel as ThinkingLevel) : undefined,
         planningThinkingLevel: planningThinkingLevel !== "" ? (planningThinkingLevel as ThinkingLevel) : undefined,
         mergerThinkingLevel: mergerThinkingLevel !== "" ? (mergerThinkingLevel as ThinkingLevel) : undefined,
@@ -901,12 +913,16 @@ export function QuickEntryBox({ onCreate, onMoveTask, addToast, tasks = [], avai
     hasExecutorOverride,
     executorProvider,
     executorModelId,
+    credentialInstanceId,
     hasValidatorOverride,
     validatorProvider,
     validatorModelId,
+    validatorCredentialInstanceId,
     hasPlanningOverride,
     planningProvider,
     planningModelId,
+    planningCredentialInstanceId,
+    mergerCredentialInstanceId,
     thinkingLevel,
     enabledOptionalStepIds,
     isFastMode,
@@ -1462,18 +1478,21 @@ export function QuickEntryBox({ onCreate, onMoveTask, addToast, tasks = [], avai
 
   const handlePlanningModelChange = useCallback((value: string) => {
     const next = parseModelSelection(value);
+    setPlanningCredentialInstanceId(undefined);
     setPlanningProvider(next.provider);
     setPlanningModelId(next.modelId);
   }, []);
 
   const handleExecutorChange = useCallback((value: string) => {
     const next = parseModelSelection(value);
+    setCredentialInstanceId(undefined);
     setExecutorProvider(next.provider);
     setExecutorModelId(next.modelId);
   }, []);
 
   const handleValidatorChange = useCallback((value: string) => {
     const next = parseModelSelection(value);
+    setValidatorCredentialInstanceId(undefined);
     setValidatorProvider(next.provider);
     setValidatorModelId(next.modelId);
   }, []);
@@ -1481,6 +1500,7 @@ export function QuickEntryBox({ onCreate, onMoveTask, addToast, tasks = [], avai
   const handleThinkingLevelChange = useCallback((value: string) => setThinkingLevel(value), []);
   const handleMergerModelChange = useCallback((value: string) => {
     const next = parseModelSelection(value);
+    setMergerCredentialInstanceId(undefined);
     setMergerProvider(next.provider);
     setMergerModelId(next.modelId);
   }, []);
@@ -2498,6 +2518,14 @@ export function QuickEntryBox({ onCreate, onMoveTask, addToast, tasks = [], avai
                     thinkingLevel={activeModelSubmenu === "executor" ? thinkingLevel : activeModelSubmenu === "plan" ? planningThinkingLevel : activeModelSubmenu === "validator" ? validatorThinkingLevel : mergerThinkingLevel}
                     onThinkingLevelChange={activeModelSubmenu === "executor" ? handleThinkingLevelChange : activeModelSubmenu === "plan" ? setPlanningThinkingLevel : activeModelSubmenu === "validator" ? setValidatorThinkingLevel : setMergerThinkingLevel}
                     defaultThinkingLevel={settings?.defaultThinkingLevel ?? "off"}
+                    credentialInstanceId={activeModelSubmenu === "plan" ? planningCredentialInstanceId : activeModelSubmenu === "executor" ? credentialInstanceId : activeModelSubmenu === "validator" ? validatorCredentialInstanceId : mergerCredentialInstanceId}
+                    onCredentialInstanceChange={(instanceId) => {
+                      const next = instanceId || undefined;
+                      if (activeModelSubmenu === "plan") setPlanningCredentialInstanceId(next);
+                      else if (activeModelSubmenu === "executor") setCredentialInstanceId(next);
+                      else if (activeModelSubmenu === "validator") setValidatorCredentialInstanceId(next);
+                      else setMergerCredentialInstanceId(next);
+                    }}
                   />
                   {modelsError && (
                     <div className="model-submenu-error">

packages/dashboard/app/components/SettingsModal.tsx

@@ -3877,8 +3877,10 @@ export function SettingsModal({
       name: nextName,
       executorProvider: presetDraft.executorProvider,
       executorModelId: presetDraft.executorModelId,
+      ...(presetDraft.executorCredentialInstanceId ? { executorCredentialInstanceId: presetDraft.executorCredentialInstanceId } : {}),
       validatorProvider: presetDraft.validatorProvider,
       validatorModelId: presetDraft.validatorModelId,
+      ...(presetDraft.validatorCredentialInstanceId ? { validatorCredentialInstanceId: presetDraft.validatorCredentialInstanceId } : {}),
     };
 
     setForm((current) => {

packages/dashboard/app/components/TaskDetailModal.tsx

@@ -1390,8 +1390,11 @@ export function TaskDetailContent({
   const [editBranch, setEditBranch] = useState(task.branch ?? "");
   const [editBaseBranch, setEditBaseBranch] = useState(task.baseBranch ?? "");
   const [editExecutorModel, setEditExecutorModel] = useState("");
+  const [editCredentialInstanceId, setEditCredentialInstanceId] = useState<string | undefined>(undefined);
   const [editValidatorModel, setEditValidatorModel] = useState("");
+  const [editValidatorCredentialInstanceId, setEditValidatorCredentialInstanceId] = useState<string | undefined>(undefined);
   const [editPlanningModel, setEditPlanningModel] = useState("");
+  const [editPlanningCredentialInstanceId, setEditPlanningCredentialInstanceId] = useState<string | undefined>(undefined);
   const [editThinkingLevel, setEditThinkingLevel] = useState("");
   // FNXC:PlannerOversight 2026-07-04-00:00: Per-task override of the workflow-native plannerOversightLevel setting (FN-7508). "" means "inherit from workflow" (clear-to-default).
   const [editPlannerOversightLevel, setEditPlannerOversightLevel] = useState("");
@@ -2144,8 +2147,11 @@ export function TaskDetailContent({
     const valModel = task.validatorModelProvider && task.validatorModelId ? `${task.validatorModelProvider}/${task.validatorModelId}` : "";
     const planModel = task.planningModelProvider && task.planningModelId ? `${task.planningModelProvider}/${task.planningModelId}` : "";
     setEditExecutorModel(execModel);
+    setEditCredentialInstanceId(task.credentialInstanceId);
     setEditValidatorModel(valModel);
+    setEditValidatorCredentialInstanceId(task.validatorCredentialInstanceId);
     setEditPlanningModel(planModel);
+    setEditPlanningCredentialInstanceId(task.planningCredentialInstanceId);
     setEditThinkingLevel(task.thinkingLevel ?? "");
     setEditPlannerOversightLevel(task.plannerOversightLevel ?? "");
     setEditNodeId(task.nodeId);
@@ -2208,6 +2214,9 @@ export function TaskDetailContent({
     if (editExecutorModel !== currentExecutorModel) {
       updates.modelProvider = executorSelection?.provider ?? null;
       updates.modelId = executorSelection?.modelId ?? null;
+      updates.credentialInstanceId = null;
+    } else if ((editCredentialInstanceId ?? "") !== (task.credentialInstanceId ?? "")) {
+      updates.credentialInstanceId = editCredentialInstanceId ?? null;
     }
 
     const validatorSelection = splitModelSelection(editValidatorModel);
@@ -2215,6 +2224,9 @@ export function TaskDetailContent({
     if (editValidatorModel !== currentValidatorModel) {
       updates.validatorModelProvider = validatorSelection?.provider ?? null;
       updates.validatorModelId = validatorSelection?.modelId ?? null;
+      updates.validatorCredentialInstanceId = null;
+    } else if ((editValidatorCredentialInstanceId ?? "") !== (task.validatorCredentialInstanceId ?? "")) {
+      updates.validatorCredentialInstanceId = editValidatorCredentialInstanceId ?? null;
     }
 
     const planningSelection = splitModelSelection(editPlanningModel);
@@ -2222,6 +2234,9 @@ export function TaskDetailContent({
     if (editPlanningModel !== currentPlanningModel) {
       updates.planningModelProvider = planningSelection?.provider ?? null;
       updates.planningModelId = planningSelection?.modelId ?? null;
+      updates.planningCredentialInstanceId = null;
+    } else if ((editPlanningCredentialInstanceId ?? "") !== (task.planningCredentialInstanceId ?? "")) {
+      updates.planningCredentialInstanceId = editPlanningCredentialInstanceId ?? null;
     }
 
     const currentThinkingLevel = task.thinkingLevel ?? "";
@@ -2269,7 +2284,7 @@ export function TaskDetailContent({
     }
 
     return { updates, error: null as string | null };
-  }, [editBaseBranch, editBranch, editDependencies, editDescription, editExecutionMode, editExecutorModel, editNodeId, editPlanningModel, editPriority, editReviewLevel, editSelectedWorkflowSteps, editSourceIssueExternalId, editSourceIssueProvider, editSourceIssueRepository, editSourceIssueUrl, editThinkingLevel, editPlannerOversightLevel, editTitle, editValidatorModel, task]);
+  }, [editBaseBranch, editBranch, editDependencies, editDescription, editExecutionMode, editCredentialInstanceId, editExecutorModel, editNodeId, editPlanningCredentialInstanceId, editPlanningModel, editPriority, editReviewLevel, editSelectedWorkflowSteps, editSourceIssueExternalId, editSourceIssueProvider, editSourceIssueRepository, editSourceIssueUrl, editThinkingLevel, editPlannerOversightLevel, editTitle, editValidatorCredentialInstanceId, editValidatorModel, task]);
 
   const persistEditChanges = useCallback(async (includeDescription: boolean) => {
     const { updates, error } = buildEditUpdates(includeDescription);
@@ -2370,8 +2385,11 @@ export function TaskDetailContent({
     editBranch,
     editBaseBranch,
     editExecutorModel,
+    editCredentialInstanceId,
     editValidatorModel,
+    editValidatorCredentialInstanceId,
     editPlanningModel,
+    editPlanningCredentialInstanceId,
     editThinkingLevel,
     editPlannerOversightLevel,
     editNodeId,
@@ -4532,11 +4550,17 @@ export function TaskDetailContent({
                 baseBranch={editBaseBranch}
                 onBaseBranchChange={setEditBaseBranch}
                 executorModel={editExecutorModel}
-                onExecutorModelChange={setEditExecutorModel}
+                onExecutorModelChange={(value) => { setEditCredentialInstanceId(undefined); setEditExecutorModel(value); }}
+                credentialInstanceId={editCredentialInstanceId}
+                onCredentialInstanceIdChange={(instanceId) => setEditCredentialInstanceId(instanceId || undefined)}
                 validatorModel={editValidatorModel}
-                onValidatorModelChange={setEditValidatorModel}
+                onValidatorModelChange={(value) => { setEditValidatorCredentialInstanceId(undefined); setEditValidatorModel(value); }}
+                validatorCredentialInstanceId={editValidatorCredentialInstanceId}
+                onValidatorCredentialInstanceIdChange={(instanceId) => setEditValidatorCredentialInstanceId(instanceId || undefined)}
                 planningModel={editPlanningModel}
-                onPlanningModelChange={setEditPlanningModel}
+                onPlanningModelChange={(value) => { setEditPlanningCredentialInstanceId(undefined); setEditPlanningModel(value); }}
+                planningCredentialInstanceId={editPlanningCredentialInstanceId}
+                onPlanningCredentialInstanceIdChange={(instanceId) => setEditPlanningCredentialInstanceId(instanceId || undefined)}
                 thinkingLevel={editThinkingLevel}
                 onThinkingLevelChange={setEditThinkingLevel}
                 plannerOversightLevel={editPlannerOversightLevel}

packages/dashboard/app/components/TaskForm.tsx

@@ -97,10 +97,16 @@ export interface TaskFormProps {
   onPriorityChange?: (value: TaskPriority) => void;
   executorModel: string;
   onExecutorModelChange: (value: string, meta?: TaskFormValueChangeMeta) => void;
+  credentialInstanceId?: string;
+  onCredentialInstanceIdChange?: (value: string) => void;
   validatorModel: string;
   onValidatorModelChange: (value: string, meta?: TaskFormValueChangeMeta) => void;
+  validatorCredentialInstanceId?: string;
+  onValidatorCredentialInstanceIdChange?: (value: string) => void;
   planningModel?: string;
   onPlanningModelChange?: (value: string) => void;
+  planningCredentialInstanceId?: string;
+  onPlanningCredentialInstanceIdChange?: (value: string) => void;
   thinkingLevel?: string;
   onThinkingLevelChange?: (value: string) => void;
   /*
@@ -216,10 +222,16 @@ export function TaskForm({
   onPriorityChange,
   executorModel,
   onExecutorModelChange,
+  credentialInstanceId,
+  onCredentialInstanceIdChange,
   validatorModel,
   onValidatorModelChange,
+  validatorCredentialInstanceId,
+  onValidatorCredentialInstanceIdChange,
   planningModel,
   onPlanningModelChange,
+  planningCredentialInstanceId,
+  onPlanningCredentialInstanceIdChange,
   thinkingLevel,
   onThinkingLevelChange,
   plannerOversightLevel,
@@ -1571,6 +1583,8 @@ export function TaskForm({
                 thinkingLevel={thinkingLevel || ""}
                 onThinkingLevelChange={onThinkingLevelChange ? (value) => onThinkingLevelChange(value) : undefined}
                 defaultThinkingLevel={settings?.defaultThinkingLevel ?? "off"}
+                credentialInstanceId={credentialInstanceId}
+                onCredentialInstanceChange={onCredentialInstanceIdChange}
               />
             </div>
             <div className="model-select-row">
@@ -1591,6 +1605,8 @@ export function TaskForm({
                 onToggleFavorite={handleToggleFavorite}
                 favoriteModels={favoriteModels}
                 onToggleModelFavorite={handleToggleModelFavorite}
+                credentialInstanceId={validatorCredentialInstanceId}
+                onCredentialInstanceChange={onValidatorCredentialInstanceIdChange}
               />
             </div>
             {onPlanningModelChange && (
@@ -1611,6 +1627,8 @@ export function TaskForm({
                   onToggleFavorite={handleToggleFavorite}
                   favoriteModels={favoriteModels}
                   onToggleModelFavorite={handleToggleModelFavorite}
+                  credentialInstanceId={planningCredentialInstanceId}
+                  onCredentialInstanceChange={onPlanningCredentialInstanceIdChange}
                 />
               </div>
             )}

packages/dashboard/app/components/WorkflowNodeEditor.tsx

@@ -4364,8 +4364,15 @@ function InnerEditor({
                         )}
                         onChange={(value) => {
                           const { provider, modelId } = parseModelDropdownValue(value);
-                          updateSelectedData({ config: { modelProvider: provider || undefined, modelId: modelId || undefined } });
+                          updateSelectedData({ config: {
+                            modelProvider: provider || undefined,
+                            modelId: modelId || undefined,
+                            // FNXC:ModelDropdown 2026-08-01-10:45: Explicit node-model changes cannot retain an instance selected for the previous provider.
+                            credentialInstanceId: undefined,
+                          } });
                         }}
+                        credentialInstanceId={String(selectedNode.data.config?.credentialInstanceId ?? "")}
+                        onCredentialInstanceChange={(credentialInstanceId) => updateSelectedData({ config: { credentialInstanceId: credentialInstanceId || undefined } })}
                         /*
                          * FNXC:Settings-ThinkingLevel 2026-07-10-00:00:
                          * Prompt model nodes expose the shared inline thinking selector only for the model executor, persisting `config.thinkingLevel` with Default clearing the key.
@@ -5102,9 +5109,13 @@ function InnerEditor({
                             modelProvider: provider || undefined,
                             modelId: modelId || undefined,
                             model: value || undefined,
+                            // FNXC:ModelDropdown 2026-08-01-10:45: Review-node model changes clear the prior credential-instance override.
+                            credentialInstanceId: undefined,
                           },
                         });
                       }}
+                      credentialInstanceId={String(selectedNode.data.config?.credentialInstanceId ?? "")}
+                      onCredentialInstanceChange={(credentialInstanceId) => updateSelectedData({ config: { credentialInstanceId: credentialInstanceId || undefined } })}
                       /*
                        * FNXC:Settings-ThinkingLevel 2026-07-10-00:00:
                        * Step-review nodes share the model dropdown thinking selector so review sessions can pin reasoning effort with the same node > task > settings precedence as executor steps.

packages/dashboard/app/components/WorkflowSettingsPanel.tsx

@@ -505,6 +505,7 @@ export interface WorkflowModelLanePair {
   providerId: string;
   modelId: string;
   thinkingId?: string;
+  credentialInstanceId?: string;
   label: string;
   help: string;
 }
@@ -525,6 +526,7 @@ export const WORKFLOW_MODEL_LANE_CATALOG: WorkflowModelLanePair[] = [
     providerId: "planningProvider",
     modelId: "planningModelId",
     thinkingId: "planningThinkingLevel",
+    credentialInstanceId: "planningCredentialInstanceId",
     label: "Plan/Triage Model",
     help: "Provider and model used when planning or triaging tasks. Leave unset to inherit from the default lane.",
   },
@@ -533,6 +535,7 @@ export const WORKFLOW_MODEL_LANE_CATALOG: WorkflowModelLanePair[] = [
     providerId: "planningFallbackProvider",
     modelId: "planningFallbackModelId",
     thinkingId: "planningFallbackThinkingLevel",
+    credentialInstanceId: "planningFallbackCredentialInstanceId",
     label: "Planning Fallback Model",
     help: "Fallback provider and model used when the primary Plan/Triage model cannot be used.",
   },
@@ -541,6 +544,7 @@ export const WORKFLOW_MODEL_LANE_CATALOG: WorkflowModelLanePair[] = [
     providerId: "executionProvider",
     modelId: "executionModelId",
     thinkingId: "executionThinkingLevel",
+    credentialInstanceId: "executionCredentialInstanceId",
     label: "Executor Model",
     help: "Provider and model used by task implementation agents. Leave unset to inherit from the default lane.",
   },
@@ -549,6 +553,7 @@ export const WORKFLOW_MODEL_LANE_CATALOG: WorkflowModelLanePair[] = [
     providerId: "executionFallbackProvider",
     modelId: "executionFallbackModelId",
     thinkingId: "executionFallbackThinkingLevel",
+    credentialInstanceId: "executionFallbackCredentialInstanceId",
     label: "Executor Fallback Model",
     help: "Fallback provider and model used when the primary Executor model cannot be used.",
   },
@@ -557,6 +562,7 @@ export const WORKFLOW_MODEL_LANE_CATALOG: WorkflowModelLanePair[] = [
     providerId: "validatorProvider",
     modelId: "validatorModelId",
     thinkingId: "validatorThinkingLevel",
+    credentialInstanceId: "validatorCredentialInstanceId",
     label: "Reviewer Model",
     help: "Provider and model used by review and validation agents. Leave unset to inherit from the default lane.",
   },
@@ -565,6 +571,7 @@ export const WORKFLOW_MODEL_LANE_CATALOG: WorkflowModelLanePair[] = [
     providerId: "validatorFallbackProvider",
     modelId: "validatorFallbackModelId",
     thinkingId: "validatorFallbackThinkingLevel",
+    credentialInstanceId: "validatorFallbackCredentialInstanceId",
     label: "Reviewer Fallback Model",
     help: "Fallback provider and model used when the primary Reviewer model cannot be used.",
   },
@@ -619,7 +626,12 @@ function ValuesTab({
     [settingsById],
   );
   const modelPairSettingIds = useMemo(
-    () => new Set(modelLanePairs.flatMap((pair) => [pair.providerId, pair.modelId, ...(pair.thinkingId ? [pair.thinkingId] : [])])),
+    () => new Set(modelLanePairs.flatMap((pair) => [
+      pair.providerId,
+      pair.modelId,
+      ...(pair.thinkingId ? [pair.thinkingId] : []),
+      ...(pair.credentialInstanceId ? [pair.credentialInstanceId] : []),
+    ])),
     [modelLanePairs],
   );
 
@@ -727,6 +739,8 @@ function ValuesTab({
       ...prev,
       [pair.providerId]: split?.provider ?? null,
       [pair.modelId]: split?.modelId ?? null,
+      // FNXC:ModelDropdown 2026-08-01-10:45: Persisted workflow lane selections clear any instance from the prior provider/model pair.
+      ...(pair.credentialInstanceId ? { [pair.credentialInstanceId]: null } : {}),
     }));
     setRejections((prev) => {
       if (!prev[pair.providerId] && !prev[pair.modelId]) return prev;
@@ -737,6 +751,12 @@ function ValuesTab({
     });
   };
 
+  const setModelPairCredentialInstanceValue = (pair: WorkflowModelLanePair, value: string) => {
+    if (!pair.credentialInstanceId) return;
+    // Default clears the stored override; workflow setting writes use null-as-delete.
+    setValue(pair.credentialInstanceId, value || null);
+  };
+
   const setModelPairThinkingValue = (pair: WorkflowModelLanePair, value: string) => {
     if (!pair.thinkingId) return;
     setValue(pair.thinkingId, value || null);
@@ -745,6 +765,7 @@ function ValuesTab({
   const clearModelPairValue = (pair: WorkflowModelLanePair) => {
     setModelPairValue(pair, "");
     setModelPairThinkingValue(pair, "");
+    setModelPairCredentialInstanceValue(pair, "");
   };
 
   const dirty = Object.keys(pending).length > 0;
@@ -807,8 +828,17 @@ function ValuesTab({
     const thinkingValue = pair.thinkingId && typeof valueOfSettingId(pair.thinkingId) === "string"
       ? (valueOfSettingId(pair.thinkingId) as string)
       : "";
-    const error = rejections[pair.providerId]?.message ?? rejections[pair.modelId]?.message ?? (pair.thinkingId ? rejections[pair.thinkingId]?.message : undefined);
+    const credentialInstanceId = pair.credentialInstanceId && typeof valueOfSettingId(pair.credentialInstanceId) === "string"
-    const customized = isCustomizedId(pair.providerId) || isCustomizedId(pair.modelId) || Boolean(pair.thinkingId && isCustomizedId(pair.thinkingId));
+      ? (valueOfSettingId(pair.credentialInstanceId) as string)
+      : "";
+    const error = rejections[pair.providerId]?.message
+      ?? rejections[pair.modelId]?.message
+      ?? (pair.thinkingId ? rejections[pair.thinkingId]?.message : undefined)
+      ?? (pair.credentialInstanceId ? rejections[pair.credentialInstanceId]?.message : undefined);
+    const customized = isCustomizedId(pair.providerId)
+      || isCustomizedId(pair.modelId)
+      || Boolean(pair.thinkingId && isCustomizedId(pair.thinkingId))
+      || Boolean(pair.credentialInstanceId && isCustomizedId(pair.credentialInstanceId));
     const dropdownDisabled = modelsLoading || availableModels.length === 0;
     const emptyHelp =
       !modelsLoading && availableModels.length === 0
@@ -833,6 +863,8 @@ function ValuesTab({
             models={availableModels}
             value={value}
             onChange={(next) => setModelPairValue(pair, next)}
+            credentialInstanceId={credentialInstanceId}
+            onCredentialInstanceChange={(value) => setModelPairCredentialInstanceValue(pair, value)}
             placeholder={t("workflowSettings.selectModel", "Select a model…")}
             defaultOptionLabel={t("workflowSettings.useInheritedModel", "Use inherited/default model")}
             disabled={dropdownDisabled}

packages/dashboard/app/components/__tests__/CustomModelDropdown.credential-instance.test.tsx

@@ -0,0 +1,111 @@
+import type { ComponentProps } from "react";
+import { describe, expect, it, vi } from "vitest";
+import { cleanup, render, screen } from "@testing-library/react";
+import userEvent from "@testing-library/user-event";
+import { CustomModelDropdown } from "../CustomModelDropdown";
+
+vi.mock("../ProviderIcon", () => ({
+  ProviderIcon: () => <span />,
+}));
+
+const models = [{ provider: "openai", id: "gpt-4o", name: "GPT-4o", reasoning: false, contextWindow: 128000 }];
+
+async function openDropdown(props: Partial<ComponentProps<typeof CustomModelDropdown>>) {
+  const user = userEvent.setup();
+  render(<CustomModelDropdown label="Model" value="openai/gpt-4o" onChange={vi.fn()} models={models} {...props} />);
+  await user.click(screen.getByRole("button", { name: "Model" }));
+  return user;
+}
+
+describe("CustomModelDropdown credential instance", () => {
+  it.each([undefined, {}, { openai: { instances: [] } }, { openai: { instances: [{ id: "only", isDefault: true }] } }])(
+    "renders no instance control unless the selected provider has two instances",
+    async (credentialInstances) => {
+      await openDropdown({ credentialInstances });
+      expect(screen.queryByTestId("custom-model-dropdown-credential-instance")).toBeNull();
+      expect(screen.queryByTestId("custom-model-dropdown-credential-instance-badge")).toBeNull();
+    },
+  );
+
+  it("keeps hidden menus structurally free of an instance shell at desktop and mobile breakpoints", async () => {
+    for (const width of [1024, 768, 480]) {
+      Object.defineProperty(window, "innerWidth", { configurable: true, value: width });
+      const user = await openDropdown({ credentialInstances: { openai: { instances: [{ id: "only", isDefault: true }] } } });
+      const menu = screen.getAllByTestId("model-combobox-portal").at(-1)!;
+      expect([...menu.children].map((element) => element.className)).not.toContain("model-combobox-instance");
+      expect(screen.queryByTestId("custom-model-dropdown-credential-instance")).toBeNull();
+      expect(screen.queryByTestId("custom-model-dropdown-credential-instance-badge")).toBeNull();
+      await user.keyboard("{Escape}");
+      cleanup();
+    }
+  });
+
+  it("shows availability-driven control even before an owner supplies a persistence callback", async () => {
+    await openDropdown({
+      credentialInstances: { openai: { instances: [{ id: "primary", isDefault: true }, { id: "backup", isDefault: false }] } },
+    });
+    expect(screen.getByTestId("custom-model-dropdown-credential-instance")).toBeDisabled();
+  });
+
+  it("deduplicates instances, preserves a stale selection, and emits empty only for Default", async () => {
+    const onCredentialInstanceChange = vi.fn();
+    const user = await openDropdown({
+      credentialInstanceId: "stale",
+      onCredentialInstanceChange,
+      credentialInstances: {
+        openai: { instances: [{ id: "primary", isDefault: true }, { id: "primary", isDefault: false }, { id: "backup", isDefault: false }] },
+      },
+    });
+
+    const select = screen.getByTestId("custom-model-dropdown-credential-instance") as HTMLSelectElement;
+    expect([...select.options].map((option) => option.value)).toEqual(["", "primary", "backup", "stale"]);
+    expect(select.value).toBe("stale");
+    await user.selectOptions(select, "backup");
+    expect(onCredentialInstanceChange).toHaveBeenLastCalledWith("backup");
+    await user.selectOptions(select, "");
+    expect(onCredentialInstanceChange).toHaveBeenLastCalledWith("");
+  });
+
+  it("recomputes availability after the selected provider changes without affecting keyboard dismissal", async () => {
+    const user = userEvent.setup();
+    const onChange = vi.fn();
+    const onCredentialInstanceChange = vi.fn();
+    const { rerender } = render(
+      <CustomModelDropdown
+        label="Model"
+        value="openai/gpt-4o"
+        onChange={onChange}
+        models={[
+          ...models,
+          { provider: "anthropic", id: "claude", name: "Claude", reasoning: false, contextWindow: 128000 },
+        ]}
+        credentialInstances={{
+          openai: { instances: [{ id: "primary", isDefault: true }, { id: "backup", isDefault: false }] },
+          anthropic: { instances: [{ id: "only", isDefault: true }] },
+        }}
+        onCredentialInstanceChange={onCredentialInstanceChange}
+      />,
+    );
+    await user.click(screen.getByRole("button", { name: "Model" }));
+    expect(screen.getByTestId("custom-model-dropdown-credential-instance")).toBeTruthy();
+    rerender(
+      <CustomModelDropdown
+        label="Model"
+        value="anthropic/claude"
+        onChange={onChange}
+        models={[
+          ...models,
+          { provider: "anthropic", id: "claude", name: "Claude", reasoning: false, contextWindow: 128000 },
+        ]}
+        credentialInstances={{
+          openai: { instances: [{ id: "primary", isDefault: true }, { id: "backup", isDefault: false }] },
+          anthropic: { instances: [{ id: "only", isDefault: true }] },
+        }}
+        onCredentialInstanceChange={onCredentialInstanceChange}
+      />,
+    );
+    expect(screen.queryByTestId("custom-model-dropdown-credential-instance")).toBeNull();
+    await user.keyboard("{Escape}");
+    expect(screen.queryByTestId("model-combobox-portal")).toBeNull();
+  });
+});

packages/dashboard/app/components/__tests__/WorkflowSettingsPanel.test.tsx

@@ -705,7 +705,7 @@ describe("WorkflowSettingsPanel — Values tab", () => {
     await waitFor(() => expect(mockUpdateValues).toHaveBeenCalledTimes(1));
     expect(mockUpdateValues).toHaveBeenCalledWith(
       "wf-1",
-      { planningProvider: "anthropic", planningModelId: "claude-sonnet" },
+      { planningProvider: "anthropic", planningModelId: "claude-sonnet", planningCredentialInstanceId: null },
       "proj-1",
     );
   });
@@ -759,6 +759,7 @@ describe("WorkflowSettingsPanel — Values tab", () => {
       validatorFallbackProvider: null,
       validatorFallbackModelId: null,
       validatorFallbackThinkingLevel: null,
+      validatorFallbackCredentialInstanceId: null,
     }, "proj-1");
   });
 
@@ -788,7 +789,7 @@ describe("WorkflowSettingsPanel — Values tab", () => {
     await waitFor(() => expect(mockUpdateValues).toHaveBeenCalledTimes(1));
     expect(mockUpdateValues).toHaveBeenCalledWith(
       "wf-1",
-      { planningProvider: null, planningModelId: null },
+      { planningProvider: null, planningModelId: null, planningCredentialInstanceId: null },
       "proj-1",
     );
   });
@@ -830,7 +831,7 @@ describe("WorkflowSettingsPanel — Values tab", () => {
     expect(mockUpdateValues).toHaveBeenNthCalledWith(
       2,
       "wf-1",
-      { planningProvider: "anthropic", planningModelId: "claude-sonnet" },
+      { planningProvider: "anthropic", planningModelId: "claude-sonnet", planningCredentialInstanceId: null },
       "proj-1",
     );
   });
@@ -871,7 +872,7 @@ describe("WorkflowSettingsPanel — Values tab", () => {
     expect(within(row).getByLabelText("Plan/Triage Model")).toHaveTextContent("Claude Sonnet");
     expect(mockUpdateValues).toHaveBeenCalledWith(
       "wf-1",
-      { planningProvider: "anthropic", planningModelId: "claude-sonnet" },
+      { planningProvider: "anthropic", planningModelId: "claude-sonnet", planningCredentialInstanceId: null },
       "proj-1",
     );
   });

packages/dashboard/app/components/effective-model-resolution.ts

@@ -83,9 +83,11 @@ export function extractAssignedRuntimeModel(agent: Agent | null | undefined): Mo
 
   const provider = isStringValue(runtimeConfig?.modelProvider) ? runtimeConfig.modelProvider.trim() : "";
   const modelId = isStringValue(runtimeConfig?.modelId) ? runtimeConfig.modelId.trim() : "";
+  const credentialInstanceId = isStringValue(runtimeConfig?.credentialInstanceId) ? runtimeConfig.credentialInstanceId.trim() : "";
   return {
     provider: provider || undefined,
     modelId: modelId || undefined,
+    ...(credentialInstanceId ? { credentialInstanceId } : {}),
   };
 }
 
@@ -191,7 +193,11 @@ export function resolveEffectivePlanning(
   settings?: Settings,
 ): ModelSelection {
   if (task.planningModelProvider && task.planningModelId) {
-    return { provider: task.planningModelProvider, modelId: task.planningModelId };
+    return {
+      provider: task.planningModelProvider,
+      modelId: task.planningModelId,
+      ...(task.planningCredentialInstanceId ? { credentialInstanceId: task.planningCredentialInstanceId } : {}),
+    };
   }
   const fromLog = extractPlanningModelFromLog(logEntries);
   if (fromLog) {

packages/dashboard/app/components/settings/sections/GlobalModelsSection.tsx

@@ -17,6 +17,18 @@ function toCommaSeparatedInput(values?: string[]): string {
 function fromCommaSeparatedInput(value: string): string[] {
     return value.split(",").map((item) => item.trim()).filter((item) => item.length > 0);
 }
+/*
+FNXC:SettingsCredentialInstance 2026-08-01-10:19:
+Each global model lane persists its credential instance alongside its provider/model pair. Clearing either the model or the instance must remove the override so runtime resolution returns to the provider default rather than retaining an orphaned credential choice.
+*/
+const GLOBAL_LANE_CREDENTIAL_INSTANCE_KEYS: Partial<Record<string, keyof Settings>> = {
+    execution: "executionGlobalCredentialInstanceId",
+    planning: "planningGlobalCredentialInstanceId",
+    validator: "validatorGlobalCredentialInstanceId",
+    merger: "mergerGlobalCredentialInstanceId",
+    summarization: "titleSummarizerGlobalCredentialInstanceId",
+    "import-translate": "importTranslateGlobalCredentialInstanceId",
+};
 export interface GlobalModelsSectionProps extends SectionBaseProps {
     availableModels: ModelInfo[];
     modelsLoading: boolean;
@@ -55,7 +67,7 @@ export function GlobalModelsSection({ form, setForm, availableModels, modelsLoad
             </div>
             <CustomModelDropdown id="defaultModel" label="Default Model" models={availableModels} value={selectedValue} onChange={(val) => {
                 if (!val) {
-                    setForm((f) => ({ ...f, defaultProvider: undefined, defaultModelId: undefined }));
+                    setForm((f) => ({ ...f, defaultProvider: undefined, defaultModelId: undefined, defaultCredentialInstanceId: undefined }));
                 }
                 else {
                     const slashIdx = val.indexOf("/");
@@ -63,9 +75,11 @@ export function GlobalModelsSection({ form, setForm, availableModels, modelsLoad
                         ...f,
                         defaultProvider: val.slice(0, slashIdx),
                         defaultModelId: val.slice(slashIdx + 1),
+                        // FNXC:ModelDropdown 2026-08-01-10:45: A provider/model change invalidates its credential-instance companion; preserve stale ids only during passive rendering, never across an explicit selection.
+                        defaultCredentialInstanceId: undefined,
                     }));
                 }
-            }} placeholder={t("settings.globalModels.useDefault", "Use default")} favoriteProviders={favoriteProviders} onToggleFavorite={onToggleFavorite} favoriteModels={favoriteModels} onToggleModelFavorite={onToggleModelFavorite}/>
+            }} credentialInstanceId={form.defaultCredentialInstanceId} onCredentialInstanceChange={(instanceId) => setForm((f) => ({ ...f, defaultCredentialInstanceId: instanceId || undefined }))} placeholder={t("settings.globalModels.useDefault", "Use default")} favoriteProviders={favoriteProviders} onToggleFavorite={onToggleFavorite} favoriteModels={favoriteModels} onToggleModelFavorite={onToggleModelFavorite}/>
           </div>
 
           <div className="form-group">
@@ -76,7 +90,7 @@ export function GlobalModelsSection({ form, setForm, availableModels, modelsLoad
             {/* FNXC:Settings-ThinkingLevel 2026-07-10-12:00: Global fallback model selection owns its own thinking-level companion (`fallbackThinkingLevel`). Clearing the fallback picker must clear the companion value so null-as-delete reset parity matches the per-lane model pickers. */}
             <CustomModelDropdown id="fallbackModel" label="Fallback Model" models={availableModels} value={form.fallbackProvider && form.fallbackModelId ? `${form.fallbackProvider}/${form.fallbackModelId}` : ""} onChange={(val) => {
                 if (!val) {
-                    setForm((f) => ({ ...f, fallbackProvider: undefined, fallbackModelId: undefined, fallbackThinkingLevel: undefined }));
+                    setForm((f) => ({ ...f, fallbackProvider: undefined, fallbackModelId: undefined, fallbackThinkingLevel: undefined, fallbackCredentialInstanceId: undefined }));
                 }
                 else {
                     const slashIdx = val.indexOf("/");
@@ -84,9 +98,11 @@ export function GlobalModelsSection({ form, setForm, availableModels, modelsLoad
                         ...f,
                         fallbackProvider: val.slice(0, slashIdx),
                         fallbackModelId: val.slice(slashIdx + 1),
+                        // FNXC:ModelDropdown 2026-08-01-10:45: Explicit model selection clears the prior provider's credential-instance override.
+                        fallbackCredentialInstanceId: undefined,
                     }));
                 }
-            }} placeholder={t("settings.globalModels.noFallback", "No fallback")} favoriteProviders={favoriteProviders} onToggleFavorite={onToggleFavorite} favoriteModels={favoriteModels} onToggleModelFavorite={onToggleModelFavorite} showThinkingLevel={(() => {
+            }} credentialInstanceId={form.fallbackCredentialInstanceId} onCredentialInstanceChange={(instanceId) => setForm((f) => ({ ...f, fallbackCredentialInstanceId: instanceId || undefined }))} placeholder={t("settings.globalModels.noFallback", "No fallback")} favoriteProviders={favoriteProviders} onToggleFavorite={onToggleFavorite} favoriteModels={favoriteModels} onToggleModelFavorite={onToggleModelFavorite} showThinkingLevel={(() => {
                 const selectedModel = availableModels.find((m) => m.provider === form.fallbackProvider && m.id === form.fallbackModelId);
                 return selectedModel ? Boolean(selectedModel.reasoning) : true;
             })()} thinkingLevel={form.fallbackThinkingLevel || ""} onThinkingLevelChange={(level) => setForm((f) => ({ ...f, fallbackThinkingLevel: (level as ThinkingLevel) || undefined }))} defaultThinkingLevel={form.defaultThinkingLevel}/>
@@ -129,6 +145,8 @@ export function GlobalModelsSection({ form, setForm, availableModels, modelsLoad
                 const model = form[lane.globalModelKey as keyof Settings] as string | undefined;
                 const value = provider && model ? `${provider}/${model}` : "";
                 const thinkingValue = getLaneThinkingValue(lane);
+                const credentialInstanceKey = GLOBAL_LANE_CREDENTIAL_INSTANCE_KEYS[lane.laneId];
+                const credentialInstanceId = credentialInstanceKey ? form[credentialInstanceKey] as string | undefined : undefined;
                 return (<div className="form-group" key={`global-${lane.laneId}`}>
                 {/* FNXC:SettingsHelp 2026-07-15-21:40: A global lane row is plain label + picker + one help string (unlike the project lanes, which add an inherited/override badge and a resolved fallback chain), so its helper text hangs off the shared "?" like every other row in this section. */}
                 <div className="settings-field-label-row">
@@ -141,6 +159,7 @@ export function GlobalModelsSection({ form, setForm, availableModels, modelsLoad
                                 ...f,
                                 [lane.globalProviderKey]: undefined,
                                 [lane.globalModelKey]: undefined,
+                                ...(credentialInstanceKey ? { [credentialInstanceKey]: undefined } : {}),
                             }));
                             resetLaneThinkingValue(lane);
                             return;
@@ -150,8 +169,10 @@ export function GlobalModelsSection({ form, setForm, availableModels, modelsLoad
                             ...f,
                             [lane.globalProviderKey]: selected.slice(0, slashIdx),
                             [lane.globalModelKey]: selected.slice(slashIdx + 1),
+                            // FNXC:ModelDropdown 2026-08-01-10:45: Lane selections cannot carry an instance override from the previously chosen provider.
+                            ...(credentialInstanceKey ? { [credentialInstanceKey]: undefined } : {}),
                         }));
-                    }} placeholder={t("settings.globalModels.useDefault", "Use default")} favoriteProviders={favoriteProviders} onToggleFavorite={onToggleFavorite} favoriteModels={favoriteModels} onToggleModelFavorite={onToggleModelFavorite} showThinkingLevel={Boolean(lane.globalThinkingKey)} thinkingLevel={thinkingValue} onThinkingLevelChange={(level) => updateLaneThinkingValue(lane, level)} defaultThinkingLevel={form.defaultThinkingLevel}/>
+                    }} credentialInstanceId={credentialInstanceId} onCredentialInstanceChange={credentialInstanceKey ? (instanceId) => setForm((f) => ({ ...f, [credentialInstanceKey]: instanceId || undefined })) : undefined} placeholder={t("settings.globalModels.useDefault", "Use default")} favoriteProviders={favoriteProviders} onToggleFavorite={onToggleFavorite} favoriteModels={favoriteModels} onToggleModelFavorite={onToggleModelFavorite} showThinkingLevel={Boolean(lane.globalThinkingKey)} thinkingLevel={thinkingValue} onThinkingLevelChange={(level) => updateLaneThinkingValue(lane, level)} defaultThinkingLevel={form.defaultThinkingLevel}/>
               </div>);
             })}
         </>)}

packages/dashboard/app/components/settings/sections/ProjectModelsSection.tsx

@@ -19,10 +19,21 @@ type WorkflowModelPair = {
     providerId: string;
     modelId: string;
     thinkingId?: string;
+    credentialInstanceId?: string;
     label: string;
     help: string;
 };
 const DEFAULT_WORKFLOW_ID = "builtin:coding";
+
+/*
+FNXC:SettingsCredentialInstance 2026-08-01-10:19:
+Project lanes that own persisted model overrides must carry their credential instance through the same form state. The empty Default choice deletes only that instance key, preserving provider/model selection while returning resolution to the provider default.
+*/
+const PROJECT_LANE_CREDENTIAL_INSTANCE_KEYS = {
+    default: "defaultCredentialInstanceIdOverride",
+    merger: "mergerCredentialInstanceId",
+    "import-translate": "importTranslateCredentialInstanceId",
+} as const satisfies Partial<Record<string, keyof Settings>>;
 /*
 FNXC:SettingsModels 2026-06-16-19:58:
 Fallback model lanes must be configurable in all Settings surfaces: General uses the global Fallback Model, Workflow Values uses declared workflow settings, and Project Models exposes workflow fallback pairs declared by the active default workflow plus project-scoped title-summarizer fallback keys so saves never PATCH undeclared keys.
@@ -39,6 +50,7 @@ const WORKFLOW_MODEL_PAIRS: WorkflowModelPair[] = [
         providerId: "planningProvider",
         modelId: "planningModelId",
         thinkingId: "planningThinkingLevel",
+        credentialInstanceId: "planningCredentialInstanceId",
         label: "Plan/Triage Model",
         help: "Provider and model used when planning or triaging tasks. Leave unset to fall through to the global lane, then the selected workflow.",
     },
@@ -47,6 +59,7 @@ const WORKFLOW_MODEL_PAIRS: WorkflowModelPair[] = [
         providerId: "planningFallbackProvider",
         modelId: "planningFallbackModelId",
         thinkingId: "planningFallbackThinkingLevel",
+        credentialInstanceId: "planningFallbackCredentialInstanceId",
         label: "Planning Fallback Model",
         help: "Fallback provider and model used when the primary Plan/Triage model cannot be used.",
     },
@@ -55,6 +68,7 @@ const WORKFLOW_MODEL_PAIRS: WorkflowModelPair[] = [
         providerId: "executionProvider",
         modelId: "executionModelId",
         thinkingId: "executionThinkingLevel",
+        credentialInstanceId: "executionCredentialInstanceId",
         label: "Executor Model",
         help: "Provider and model used while executing workflow steps. Leave unset to fall through to the global lane, then the selected workflow.",
     },
@@ -63,6 +77,7 @@ const WORKFLOW_MODEL_PAIRS: WorkflowModelPair[] = [
         providerId: "executionFallbackProvider",
         modelId: "executionFallbackModelId",
         thinkingId: "executionFallbackThinkingLevel",
+        credentialInstanceId: "executionFallbackCredentialInstanceId",
         label: "Executor Fallback Model",
         help: "Fallback provider and model used when the primary Executor model cannot be used.",
     },
@@ -71,6 +86,7 @@ const WORKFLOW_MODEL_PAIRS: WorkflowModelPair[] = [
         providerId: "validatorProvider",
         modelId: "validatorModelId",
         thinkingId: "validatorThinkingLevel",
+        credentialInstanceId: "validatorCredentialInstanceId",
         label: "Reviewer Model",
         help: "Provider and model used for workflow review or validation lanes. Leave unset to fall through to the global lane, then the selected workflow.",
     },
@@ -79,6 +95,7 @@ const WORKFLOW_MODEL_PAIRS: WorkflowModelPair[] = [
         providerId: "validatorFallbackProvider",
         modelId: "validatorFallbackModelId",
         thinkingId: "validatorFallbackThinkingLevel",
+        credentialInstanceId: "validatorFallbackCredentialInstanceId",
         label: "Reviewer Fallback Model",
         help: "Fallback provider and model used when the primary Reviewer model cannot be used.",
     },
@@ -90,7 +107,12 @@ function declaredWorkflowModelPairs(settings?: WorkflowSettingDefinition[]): Wor
         const model = settingsById.get(pair.modelId);
         const thinking = pair.thinkingId ? settingsById.get(pair.thinkingId) : undefined;
         return provider?.type === "string" && model?.type === "string" && (!pair.thinkingId || thinking?.type === "enum" || thinking?.type === "string");
-    });
+    }).map((pair) => ({
+        ...pair,
+        credentialInstanceId: settingsById.get(pair.credentialInstanceId ?? "")?.type === "string"
+            ? pair.credentialInstanceId
+            : undefined,
+    }));
 }
 function modelPairValue(values: Record<string, unknown>, pair: WorkflowModelPair): string {
     const provider = values[pair.providerId];
@@ -224,11 +246,12 @@ export function ProjectModelsSection({ form, setForm, models, projectId, onOpenW
             const next = { ...current };
             delete next[pair.providerId];
             delete next[pair.modelId];
+            if (pair.credentialInstanceId) delete next[pair.credentialInstanceId];
             return next;
         });
         setWorkflowPending((current) => {
             if (!value) {
-                return { ...current, [pair.providerId]: null, [pair.modelId]: null };
+                return { ...current, [pair.providerId]: null, [pair.modelId]: null, ...(pair.credentialInstanceId ? { [pair.credentialInstanceId]: null } : {}) };
             }
             const slashIdx = value.indexOf("/");
             if (slashIdx <= 0)
@@ -237,9 +260,22 @@ export function ProjectModelsSection({ form, setForm, models, projectId, onOpenW
                 ...current,
                 [pair.providerId]: value.slice(0, slashIdx),
                 [pair.modelId]: value.slice(slashIdx + 1),
+                // FNXC:ModelDropdown 2026-08-01-10:45: A user-selected provider/model pair must clear its prior credential-instance companion.
+                ...(pair.credentialInstanceId ? { [pair.credentialInstanceId]: null } : {}),
             };
         });
     }, [onWorkflowLanesChange]);
+    const setWorkflowCredentialInstanceValue = useCallback((pair: WorkflowModelPair, value: string) => {
+        if (!pair.credentialInstanceId) return;
+        onWorkflowLanesChange?.();
+        setWorkflowRejections((current) => {
+            if (!current[pair.credentialInstanceId as string]) return current;
+            const next = { ...current };
+            delete next[pair.credentialInstanceId as string];
+            return next;
+        });
+        setWorkflowPending((current) => ({ ...current, [pair.credentialInstanceId as string]: value || null }));
+    }, [onWorkflowLanesChange]);
     const setWorkflowThinkingValue = useCallback((pair: WorkflowModelPair, value: string) => {
         if (!pair.thinkingId)
             return;
@@ -256,7 +292,8 @@ export function ProjectModelsSection({ form, setForm, models, projectId, onOpenW
     const resetWorkflowPairValue = useCallback((pair: WorkflowModelPair) => {
         setWorkflowPairValue(pair, "");
         setWorkflowThinkingValue(pair, "");
-    }, [setWorkflowPairValue, setWorkflowThinkingValue]);
+        setWorkflowCredentialInstanceValue(pair, "");
+    }, [setWorkflowCredentialInstanceValue, setWorkflowPairValue, setWorkflowThinkingValue]);
     const saveWorkflowLanes = useCallback(async () => {
         if (!projectId || !workflowDirty)
             return;
@@ -301,6 +338,16 @@ export function ProjectModelsSection({ form, setForm, models, projectId, onOpenW
     // FNXC:GitHubImportTranslate 2026-07-15-09:30: The import-translate lane is project-scoped (like merger/summarization), so its project override must be editable here — otherwise the lane's projectProviderKey/projectModelKey would be unreachable and only the global lane could ever be set.
     // FNXC:SettingsModels 2026-07-15-12:00: Summarization is still project-scoped but is rendered with the AI summarization section below rather than the general Model Lanes list.
     const projectModelLanes = modelLanes.filter((lane) => ["default", "merger", "import-translate"].includes(lane.laneId));
+    const credentialInstanceKeyForLane = (lane: ModelLane): keyof Settings | undefined => PROJECT_LANE_CREDENTIAL_INSTANCE_KEYS[lane.laneId as keyof typeof PROJECT_LANE_CREDENTIAL_INSTANCE_KEYS];
+    const credentialInstanceValueForLane = (lane: ModelLane): string => {
+        const key = credentialInstanceKeyForLane(lane);
+        return key && typeof form[key] === "string" ? form[key] as string : "";
+    };
+    const setCredentialInstanceValueForLane = (lane: ModelLane, instanceId: string) => {
+        const key = credentialInstanceKeyForLane(lane);
+        if (!key) return;
+        setForm((current) => ({ ...current, [key]: instanceId || undefined } as SettingsFormState));
+    };
     const summarizationLane = modelLanes.find((lane) => lane.laneId === "summarization");
     const getProjectLaneLabel = (lane: ModelLane) => {
         if (lane.laneId === "default") {
@@ -343,10 +390,10 @@ export function ProjectModelsSection({ form, setForm, models, projectId, onOpenW
     const mergerFallbackThinkingValue = typeof form.mergerFallbackThinkingLevel === "string"
         ? form.mergerFallbackThinkingLevel
         : "";
-    const mergerFallbackCustomized = Boolean(mergerFallbackValue || mergerFallbackThinkingValue);
+    const mergerFallbackCustomized = Boolean(mergerFallbackValue || mergerFallbackThinkingValue || form.mergerFallbackCredentialInstanceId);
     const setMergerFallbackValue = (value: string) => {
         if (!value) {
-            setForm((f) => ({ ...f, mergerFallbackProvider: undefined, mergerFallbackModelId: undefined, mergerFallbackThinkingLevel: undefined } as SettingsFormState));
+            setForm((f) => ({ ...f, mergerFallbackProvider: undefined, mergerFallbackModelId: undefined, mergerFallbackThinkingLevel: undefined, mergerFallbackCredentialInstanceId: undefined } as SettingsFormState));
             return;
         }
         const slashIdx = value.indexOf("/");
@@ -354,13 +401,15 @@ export function ProjectModelsSection({ form, setForm, models, projectId, onOpenW
             ...f,
             mergerFallbackProvider: value.slice(0, slashIdx),
             mergerFallbackModelId: value.slice(slashIdx + 1),
+            // FNXC:ModelDropdown 2026-08-01-10:45: Explicit model selection clears the prior provider's credential-instance override.
+            mergerFallbackCredentialInstanceId: undefined,
         } as SettingsFormState));
     };
     const setMergerFallbackThinkingValue = (value: string) => {
         setForm((f) => ({ ...f, mergerFallbackThinkingLevel: value || undefined } as SettingsFormState));
     };
     const resetMergerFallbackValue = () => {
-        setForm((f) => ({ ...f, mergerFallbackProvider: undefined, mergerFallbackModelId: undefined, mergerFallbackThinkingLevel: undefined } as SettingsFormState));
+        setForm((f) => ({ ...f, mergerFallbackProvider: undefined, mergerFallbackModelId: undefined, mergerFallbackThinkingLevel: undefined, mergerFallbackCredentialInstanceId: undefined } as SettingsFormState));
     };
     const renderMergerFallbackLane = () => (
       <div className="form-group" data-testid="project-model-lane-merger-fallback">
@@ -375,7 +424,7 @@ export function ProjectModelsSection({ form, setForm, models, projectId, onOpenW
         </div>
         <div className="settings-model-lane-control-row">
           <div className="settings-model-lane-control-main">
-            <CustomModelDropdown id="mergerFallbackModel" label="Merger Fallback Model" models={availableModels} value={mergerFallbackValue} onChange={setMergerFallbackValue} placeholder={t("settings.projectModels.useGlobal", "Use global")} favoriteProviders={favoriteProviders} onToggleFavorite={onToggleFavorite} favoriteModels={favoriteModels} onToggleModelFavorite={onToggleModelFavorite} menuWidth="readable" showThinkingLevel={true} thinkingLevel={mergerFallbackThinkingValue} onThinkingLevelChange={setMergerFallbackThinkingValue} defaultThinkingLevel={form.defaultThinkingLevel}/>
+            <CustomModelDropdown id="mergerFallbackModel" label="Merger Fallback Model" models={availableModels} value={mergerFallbackValue} onChange={setMergerFallbackValue} placeholder={t("settings.projectModels.useGlobal", "Use global")} favoriteProviders={favoriteProviders} onToggleFavorite={onToggleFavorite} favoriteModels={favoriteModels} onToggleModelFavorite={onToggleModelFavorite} menuWidth="readable" showThinkingLevel={true} thinkingLevel={mergerFallbackThinkingValue} onThinkingLevelChange={setMergerFallbackThinkingValue} credentialInstanceId={form.mergerFallbackCredentialInstanceId} onCredentialInstanceChange={(instanceId) => setForm((f) => ({ ...f, mergerFallbackCredentialInstanceId: instanceId || undefined } as SettingsFormState))} defaultThinkingLevel={form.defaultThinkingLevel}/>
           </div>
           {mergerFallbackCustomized && (<button type="button" className="btn btn-ghost btn-sm" title={t("settings.projectModels.resetToInheritFromGlobal", "Reset to inherit from global")} onClick={resetMergerFallbackValue}>{t("settings.projectModels.reset", " Reset ")}</button>)}
         </div>
@@ -387,10 +436,10 @@ export function ProjectModelsSection({ form, setForm, models, projectId, onOpenW
     const titleSummarizerFallbackThinkingValue = typeof form.titleSummarizerFallbackThinkingLevel === "string"
         ? form.titleSummarizerFallbackThinkingLevel
         : "";
-    const titleSummarizerFallbackCustomized = Boolean(titleSummarizerFallbackValue || titleSummarizerFallbackThinkingValue);
+    const titleSummarizerFallbackCustomized = Boolean(titleSummarizerFallbackValue || titleSummarizerFallbackThinkingValue || form.titleSummarizerFallbackCredentialInstanceId);
     const setTitleSummarizerFallbackValue = (value: string) => {
         if (!value) {
-            setForm((f) => ({ ...f, titleSummarizerFallbackProvider: undefined, titleSummarizerFallbackModelId: undefined, titleSummarizerFallbackThinkingLevel: undefined } as SettingsFormState));
+            setForm((f) => ({ ...f, titleSummarizerFallbackProvider: undefined, titleSummarizerFallbackModelId: undefined, titleSummarizerFallbackThinkingLevel: undefined, titleSummarizerFallbackCredentialInstanceId: undefined } as SettingsFormState));
             return;
         }
         const slashIdx = value.indexOf("/");
@@ -398,13 +447,15 @@ export function ProjectModelsSection({ form, setForm, models, projectId, onOpenW
             ...f,
             titleSummarizerFallbackProvider: value.slice(0, slashIdx),
             titleSummarizerFallbackModelId: value.slice(slashIdx + 1),
+            // FNXC:ModelDropdown 2026-08-01-10:45: A newly chosen fallback model cannot inherit a credential instance from its predecessor.
+            titleSummarizerFallbackCredentialInstanceId: undefined,
         } as SettingsFormState));
     };
     const setTitleSummarizerFallbackThinkingValue = (value: string) => {
         setForm((f) => ({ ...f, titleSummarizerFallbackThinkingLevel: value || undefined } as SettingsFormState));
     };
     const resetTitleSummarizerFallbackValue = () => {
-        setForm((f) => ({ ...f, titleSummarizerFallbackProvider: undefined, titleSummarizerFallbackModelId: undefined, titleSummarizerFallbackThinkingLevel: undefined } as SettingsFormState));
+        setForm((f) => ({ ...f, titleSummarizerFallbackProvider: undefined, titleSummarizerFallbackModelId: undefined, titleSummarizerFallbackThinkingLevel: undefined, titleSummarizerFallbackCredentialInstanceId: undefined } as SettingsFormState));
     };
     /*
      * FNXC:SettingsModels 2026-07-15-12:00:
@@ -416,7 +467,7 @@ export function ProjectModelsSection({ form, setForm, models, projectId, onOpenW
         const status = getLaneStatus(lane);
         const value = getLaneValue(lane);
         const thinkingValue = getLaneThinkingValue(lane);
-        const isOverridden = status === "overridden" || Boolean(thinkingValue);
+        const isOverridden = status === "overridden" || Boolean(thinkingValue) || Boolean(credentialInstanceValueForLane(lane));
         const laneLabel = getProjectLaneLabel(lane);
         return (<div className="form-group" key={lane.laneId}>
         {/*
@@ -435,9 +486,9 @@ export function ProjectModelsSection({ form, setForm, models, projectId, onOpenW
         </div>
         <div className="settings-model-lane-control-row">
           <div className="settings-model-lane-control-main">
-            <CustomModelDropdown id={`${lane.laneId}Model`} label={laneLabel} models={availableModels} value={value} onChange={(val) => updateLaneValue(lane, val)} placeholder={lane.laneId === "default" ? "Use global default" : "Use global"} favoriteProviders={favoriteProviders} onToggleFavorite={onToggleFavorite} favoriteModels={favoriteModels} onToggleModelFavorite={onToggleModelFavorite} menuWidth="readable" showThinkingLevel={Boolean(lane.projectThinkingKey)} thinkingLevel={thinkingValue} onThinkingLevelChange={(level) => updateLaneThinkingValue(lane, level)} defaultThinkingLevel={form.defaultThinkingLevel}/>
+            <CustomModelDropdown id={`${lane.laneId}Model`} label={laneLabel} models={availableModels} value={value} onChange={(val) => { updateLaneValue(lane, val); setCredentialInstanceValueForLane(lane, ""); }} credentialInstanceId={credentialInstanceValueForLane(lane)} onCredentialInstanceChange={(instanceId) => setCredentialInstanceValueForLane(lane, instanceId)} placeholder={lane.laneId === "default" ? "Use global default" : "Use global"} favoriteProviders={favoriteProviders} onToggleFavorite={onToggleFavorite} favoriteModels={favoriteModels} onToggleModelFavorite={onToggleModelFavorite} menuWidth="readable" showThinkingLevel={Boolean(lane.projectThinkingKey)} thinkingLevel={thinkingValue} onThinkingLevelChange={(level) => updateLaneThinkingValue(lane, level)} defaultThinkingLevel={form.defaultThinkingLevel}/>
           </div>
-          {isOverridden && (<button type="button" className="btn btn-ghost btn-sm" title={t("settings.projectModels.resetToInheritFromGlobal", "Reset to inherit from global")} onClick={() => { resetLaneValue(lane); resetLaneThinkingValue(lane); }} style={{ whiteSpace: "nowrap" }}>{t("settings.projectModels.reset", " Reset ")}</button>)}
+          {isOverridden && (<button type="button" className="btn btn-ghost btn-sm" title={t("settings.projectModels.resetToInheritFromGlobal", "Reset to inherit from global")} onClick={() => { resetLaneValue(lane); resetLaneThinkingValue(lane); setCredentialInstanceValueForLane(lane, ""); }} style={{ whiteSpace: "nowrap" }}>{t("settings.projectModels.reset", " Reset ")}</button>)}
         </div>
       </div>);
     };
@@ -448,10 +499,10 @@ export function ProjectModelsSection({ form, setForm, models, projectId, onOpenW
     const chatDefaultThinkingValue = typeof form.chatDefaultThinkingLevel === "string"
         ? form.chatDefaultThinkingLevel
         : "";
-    const chatDefaultCustomized = Boolean(form.chatNewSessionMode || form.chatDefaultKind || form.chatDefaultAgentId || chatDefaultModelValue || chatDefaultThinkingValue);
+    const chatDefaultCustomized = Boolean(form.chatNewSessionMode || form.chatDefaultKind || form.chatDefaultAgentId || chatDefaultModelValue || chatDefaultThinkingValue || form.chatDefaultCredentialInstanceId);
     const setChatDefaultModelValue = (value: string) => {
         if (!value) {
-            setForm((f) => ({ ...f, chatDefaultKind: "model", chatDefaultAgentId: undefined, chatDefaultModelProvider: undefined, chatDefaultModelId: undefined, chatDefaultThinkingLevel: undefined } as SettingsFormState));
+            setForm((f) => ({ ...f, chatDefaultKind: "model", chatDefaultAgentId: undefined, chatDefaultModelProvider: undefined, chatDefaultModelId: undefined, chatDefaultThinkingLevel: undefined, chatDefaultCredentialInstanceId: undefined } as SettingsFormState));
             return;
         }
         const slashIdx = value.indexOf("/");
@@ -463,13 +514,15 @@ export function ProjectModelsSection({ form, setForm, models, projectId, onOpenW
             chatDefaultAgentId: undefined,
             chatDefaultModelProvider: value.slice(0, slashIdx),
             chatDefaultModelId: value.slice(slashIdx + 1),
+            // FNXC:ModelDropdown 2026-08-01-10:45: A fresh chat model selection must not reuse a previous provider's credential instance.
+            chatDefaultCredentialInstanceId: undefined,
         } as SettingsFormState));
     };
     const setChatDefaultThinkingValue = (value: string) => {
         setForm((f) => ({ ...f, chatDefaultThinkingLevel: value || undefined } as SettingsFormState));
     };
     const resetChatDefaultValue = () => {
-        setForm((f) => ({ ...f, chatNewSessionMode: undefined, chatDefaultKind: undefined, chatDefaultAgentId: undefined, chatDefaultModelProvider: undefined, chatDefaultModelId: undefined, chatDefaultThinkingLevel: undefined } as SettingsFormState));
+        setForm((f) => ({ ...f, chatNewSessionMode: undefined, chatDefaultKind: undefined, chatDefaultAgentId: undefined, chatDefaultModelProvider: undefined, chatDefaultModelId: undefined, chatDefaultThinkingLevel: undefined, chatDefaultCredentialInstanceId: undefined } as SettingsFormState));
     };
     return (<>
 
@@ -536,7 +589,7 @@ export function ProjectModelsSection({ form, setForm, models, projectId, onOpenW
           <button type="button" className={`chat-new-dialog-mode-btn${chatDefaultKind === "model" ? " chat-new-dialog-mode-btn--active" : ""}`} onClick={() => setForm((f) => ({ ...f, chatDefaultKind: "model", chatDefaultAgentId: undefined } as SettingsFormState))}>
             {t("settings.projectModels.chatDefaultKindModel", "Model")}
           </button>
-          <button type="button" className={`chat-new-dialog-mode-btn${chatDefaultKind === "agent" ? " chat-new-dialog-mode-btn--active" : ""}`} onClick={() => setForm((f) => ({ ...f, chatDefaultKind: "agent", chatDefaultModelProvider: undefined, chatDefaultModelId: undefined, chatDefaultThinkingLevel: undefined } as SettingsFormState))}>
+          <button type="button" className={`chat-new-dialog-mode-btn${chatDefaultKind === "agent" ? " chat-new-dialog-mode-btn--active" : ""}`} onClick={() => setForm((f) => ({ ...f, chatDefaultKind: "agent", chatDefaultModelProvider: undefined, chatDefaultModelId: undefined, chatDefaultThinkingLevel: undefined, chatDefaultCredentialInstanceId: undefined } as SettingsFormState))}>
             {t("settings.projectModels.chatDefaultKindAgent", "Agent")}
           </button>
         </div>
@@ -553,7 +606,7 @@ export function ProjectModelsSection({ form, setForm, models, projectId, onOpenW
           </div>
           <div className="settings-model-lane-control-row">
             <div className="settings-model-lane-control-main">
-              <CustomModelDropdown id="chatDefaultModel" label={t("settings.projectModels.chatDefaultModel", "Chat Default Model")} models={availableModels} value={chatDefaultModelValue} onChange={setChatDefaultModelValue} placeholder={t("settings.projectModels.selectChatDefaultModel", "Select a chat default model")} favoriteProviders={favoriteProviders} onToggleFavorite={onToggleFavorite} favoriteModels={favoriteModels} onToggleModelFavorite={onToggleModelFavorite} menuWidth="readable" showThinkingLevel={true} thinkingLevel={chatDefaultThinkingValue} onThinkingLevelChange={setChatDefaultThinkingValue} defaultThinkingLevel={form.defaultThinkingLevel}/>
+              <CustomModelDropdown id="chatDefaultModel" label={t("settings.projectModels.chatDefaultModel", "Chat Default Model")} models={availableModels} value={chatDefaultModelValue} onChange={setChatDefaultModelValue} credentialInstanceId={typeof form.chatDefaultCredentialInstanceId === "string" ? form.chatDefaultCredentialInstanceId : undefined} onCredentialInstanceChange={(instanceId) => setForm((current) => ({ ...current, chatDefaultCredentialInstanceId: instanceId || undefined } as SettingsFormState))} placeholder={t("settings.projectModels.selectChatDefaultModel", "Select a chat default model")} favoriteProviders={favoriteProviders} onToggleFavorite={onToggleFavorite} favoriteModels={favoriteModels} onToggleModelFavorite={onToggleModelFavorite} menuWidth="readable" showThinkingLevel={true} thinkingLevel={chatDefaultThinkingValue} onThinkingLevelChange={setChatDefaultThinkingValue} defaultThinkingLevel={form.defaultThinkingLevel}/>
             </div>
             {chatDefaultCustomized && (<button type="button" className="btn btn-ghost btn-sm" title={t("settings.projectModels.chatDefaultReset", "Reset Chat default")} onClick={resetChatDefaultValue}>{t("settings.projectModels.reset", " Reset ")}</button>)}
           </div>
@@ -564,7 +617,7 @@ export function ProjectModelsSection({ form, setForm, models, projectId, onOpenW
           </div>
           <div className="settings-model-lane-control-row">
             <div className="settings-model-lane-control-main">
-              <select id="chatDefaultAgentId" value={form.chatDefaultAgentId ?? ""} disabled={agentsLoading || agents.length === 0} onChange={(event) => setForm((f) => ({ ...f, chatDefaultKind: "agent", chatDefaultAgentId: event.target.value || undefined, chatDefaultModelProvider: undefined, chatDefaultModelId: undefined, chatDefaultThinkingLevel: undefined } as SettingsFormState))}>
+              <select id="chatDefaultAgentId" value={form.chatDefaultAgentId ?? ""} disabled={agentsLoading || agents.length === 0} onChange={(event) => setForm((f) => ({ ...f, chatDefaultKind: "agent", chatDefaultAgentId: event.target.value || undefined, chatDefaultModelProvider: undefined, chatDefaultModelId: undefined, chatDefaultThinkingLevel: undefined, chatDefaultCredentialInstanceId: undefined } as SettingsFormState))}>
                 <option value="">{agentsLoading ? t("settings.projectModels.loadingAgents", "Loading agents…") : t("settings.projectModels.selectChatDefaultAgent", "Select a chat default agent")}</option>
                 {agents.map((agent) => (<option key={agent.id} value={agent.id}>{agent.name} ({agent.role})</option>))}
               </select>
@@ -587,6 +640,8 @@ export function ProjectModelsSection({ form, setForm, models, projectId, onOpenW
                 const value = modelPairValue(effectiveWorkflowValues, pair);
                 const rawThinkingValue = pair.thinkingId ? effectiveWorkflowValues[pair.thinkingId] : undefined;
                 const thinkingValue: string = typeof rawThinkingValue === "string" ? rawThinkingValue : "";
+                const rawCredentialInstanceId = pair.credentialInstanceId ? effectiveWorkflowValues[pair.credentialInstanceId] : undefined;
+                const credentialInstanceId = typeof rawCredentialInstanceId === "string" ? rawCredentialInstanceId : "";
                 const modelCustomized = Object.prototype.hasOwnProperty.call(workflowPending, pair.providerId)
                     ? workflowPending[pair.providerId] !== null
                     : Boolean(workflowPayload?.stored && (Object.prototype.hasOwnProperty.call(workflowPayload.stored, pair.providerId)
@@ -596,8 +651,13 @@ export function ProjectModelsSection({ form, setForm, models, projectId, onOpenW
                         ? workflowPending[pair.thinkingId] !== null
                         : Boolean(workflowPayload?.stored && Object.prototype.hasOwnProperty.call(workflowPayload.stored, pair.thinkingId)))
                     : false;
-                const customized = modelCustomized || thinkingCustomized;
+                const credentialInstanceCustomized = pair.credentialInstanceId
-                const error = workflowRejections[pair.providerId]?.message ?? workflowRejections[pair.modelId]?.message ?? (pair.thinkingId ? workflowRejections[pair.thinkingId]?.message : undefined);
+                    ? (Object.prototype.hasOwnProperty.call(workflowPending, pair.credentialInstanceId)
+                        ? workflowPending[pair.credentialInstanceId] !== null
+                        : Boolean(workflowPayload?.stored && Object.prototype.hasOwnProperty.call(workflowPayload.stored, pair.credentialInstanceId)))
+                    : false;
+                const customized = modelCustomized || thinkingCustomized || credentialInstanceCustomized;
+                const error = workflowRejections[pair.providerId]?.message ?? workflowRejections[pair.modelId]?.message ?? (pair.thinkingId ? workflowRejections[pair.thinkingId]?.message : undefined) ?? (pair.credentialInstanceId ? workflowRejections[pair.credentialInstanceId]?.message : undefined);
                 return (<div className="form-group" key={pair.id} data-testid={`workflow-model-lane-${pair.id}`}>
                 <div className="settings-model-lane-label-row">
                   <label htmlFor={`workflow-${pair.id}-model`}>{pair.label}</label>
@@ -609,7 +669,7 @@ export function ProjectModelsSection({ form, setForm, models, projectId, onOpenW
                 </div>
                 <div className="settings-model-lane-control-row">
                   <div className="settings-model-lane-control-main">
-                    <CustomModelDropdown id={`workflow-${pair.id}-model`} label={pair.label} models={availableModels} value={value} onChange={(next) => setWorkflowPairValue(pair, next)} placeholder={t("settings.projectModels.useWorkflowDefault", "Use workflow default")} defaultOptionLabel="Use workflow default" favoriteProviders={favoriteProviders} onToggleFavorite={onToggleFavorite} favoriteModels={favoriteModels} onToggleModelFavorite={onToggleModelFavorite} menuWidth="readable" showThinkingLevel={Boolean(pair.thinkingId)} thinkingLevel={thinkingValue} onThinkingLevelChange={pair.thinkingId ? (level) => setWorkflowThinkingValue(pair, level) : undefined} defaultThinkingLevel={typeof form.defaultThinkingLevel === "string" ? form.defaultThinkingLevel : "off"}/>
+                    <CustomModelDropdown id={`workflow-${pair.id}-model`} label={pair.label} models={availableModels} value={value} onChange={(next) => setWorkflowPairValue(pair, next)} placeholder={t("settings.projectModels.useWorkflowDefault", "Use workflow default")} defaultOptionLabel="Use workflow default" favoriteProviders={favoriteProviders} onToggleFavorite={onToggleFavorite} favoriteModels={favoriteModels} onToggleModelFavorite={onToggleModelFavorite} menuWidth="readable" credentialInstanceId={credentialInstanceId} onCredentialInstanceChange={pair.credentialInstanceId ? (instanceId) => setWorkflowCredentialInstanceValue(pair, instanceId) : undefined} showThinkingLevel={Boolean(pair.thinkingId)} thinkingLevel={thinkingValue} onThinkingLevelChange={pair.thinkingId ? (level) => setWorkflowThinkingValue(pair, level) : undefined} defaultThinkingLevel={typeof form.defaultThinkingLevel === "string" ? form.defaultThinkingLevel : "off"}/>
                   </div>
                   {customized && (<button type="button" className="btn btn-ghost btn-sm" title={t("settings.projectModels.resetToInheritFromWorkflow", "Reset to inherit from workflow")} onClick={() => resetWorkflowPairValue(pair)} style={{ whiteSpace: "nowrap" }}>{t("settings.projectModels.reset", " Reset ")}</button>)}
                 </div>
@@ -687,7 +747,7 @@ export function ProjectModelsSection({ form, setForm, models, projectId, onOpenW
                   <label htmlFor="preset-executor-model">{t("settings.projectModels.executorModel", "Executor model")}</label>
                   <CustomModelDropdown id="preset-executor-model" label="Preset executor model" models={availableModels} value={presetDraft.executorProvider && presetDraft.executorModelId ? `${presetDraft.executorProvider}/${presetDraft.executorModelId}` : ""} onChange={(val) => {
                     if (!val) {
-                        setPresetDraft((current) => current ? { ...current, executorProvider: undefined, executorModelId: undefined } : current);
+                        setPresetDraft((current) => current ? { ...current, executorProvider: undefined, executorModelId: undefined, executorCredentialInstanceId: undefined } : current);
                         return;
                     }
                     const slashIdx = val.indexOf("/");
@@ -695,14 +755,15 @@ export function ProjectModelsSection({ form, setForm, models, projectId, onOpenW
                         ...current,
                         executorProvider: val.slice(0, slashIdx),
                         executorModelId: val.slice(slashIdx + 1),
+                        executorCredentialInstanceId: undefined,
                     } : current);
-                }} placeholder={t("settings.projectModels.useDefault", "Use default")} favoriteProviders={favoriteProviders} onToggleFavorite={onToggleFavorite} favoriteModels={favoriteModels} onToggleModelFavorite={onToggleModelFavorite} menuWidth="readable"/>
+                }} placeholder={t("settings.projectModels.useDefault", "Use default")} favoriteProviders={favoriteProviders} onToggleFavorite={onToggleFavorite} favoriteModels={favoriteModels} onToggleModelFavorite={onToggleModelFavorite} menuWidth="readable" credentialInstanceId={presetDraft.executorCredentialInstanceId} onCredentialInstanceChange={(instanceId) => setPresetDraft((current) => current ? { ...current, ...(instanceId ? { executorCredentialInstanceId: instanceId } : { executorCredentialInstanceId: undefined }) } : current)}/>
                 </div>
                 <div className="form-group">
                   <label htmlFor="preset-validator-model">{t("settings.projectModels.reviewerModel", "Reviewer model")}</label>
                   <CustomModelDropdown id="preset-validator-model" label="Preset reviewer model" models={availableModels} value={presetDraft.validatorProvider && presetDraft.validatorModelId ? `${presetDraft.validatorProvider}/${presetDraft.validatorModelId}` : ""} onChange={(val) => {
                     if (!val) {
-                        setPresetDraft((current) => current ? { ...current, validatorProvider: undefined, validatorModelId: undefined } : current);
+                        setPresetDraft((current) => current ? { ...current, validatorProvider: undefined, validatorModelId: undefined, validatorCredentialInstanceId: undefined } : current);
                         return;
                     }
                     const slashIdx = val.indexOf("/");
@@ -710,8 +771,9 @@ export function ProjectModelsSection({ form, setForm, models, projectId, onOpenW
                         ...current,
                         validatorProvider: val.slice(0, slashIdx),
                         validatorModelId: val.slice(slashIdx + 1),
+                        validatorCredentialInstanceId: undefined,
                     } : current);
-                }} placeholder={t("settings.projectModels.useDefault", "Use default")} favoriteProviders={favoriteProviders} onToggleFavorite={onToggleFavorite} favoriteModels={favoriteModels} onToggleModelFavorite={onToggleModelFavorite} menuWidth="readable"/>
+                }} placeholder={t("settings.projectModels.useDefault", "Use default")} favoriteProviders={favoriteProviders} onToggleFavorite={onToggleFavorite} favoriteModels={favoriteModels} onToggleModelFavorite={onToggleModelFavorite} menuWidth="readable" credentialInstanceId={presetDraft.validatorCredentialInstanceId} onCredentialInstanceChange={(instanceId) => setPresetDraft((current) => current ? { ...current, ...(instanceId ? { validatorCredentialInstanceId: instanceId } : { validatorCredentialInstanceId: undefined }) } : current)}/>
                 </div>
               </>)}
           </div>
@@ -802,7 +864,7 @@ export function ProjectModelsSection({ form, setForm, models, projectId, onOpenW
               </div>
               <div className="settings-model-lane-control-row">
                 <div className="settings-model-lane-control-main">
-                  <CustomModelDropdown id="titleSummarizerFallbackModel" label="Title Summarizer Fallback Model" models={availableModels} value={titleSummarizerFallbackValue} onChange={setTitleSummarizerFallbackValue} placeholder={t("settings.projectModels.useGlobal", "Use global")} favoriteProviders={favoriteProviders} onToggleFavorite={onToggleFavorite} favoriteModels={favoriteModels} onToggleModelFavorite={onToggleModelFavorite} menuWidth="readable" showThinkingLevel={true} thinkingLevel={titleSummarizerFallbackThinkingValue} onThinkingLevelChange={setTitleSummarizerFallbackThinkingValue} defaultThinkingLevel={form.defaultThinkingLevel}/>
+                  <CustomModelDropdown id="titleSummarizerFallbackModel" label="Title Summarizer Fallback Model" models={availableModels} value={titleSummarizerFallbackValue} onChange={setTitleSummarizerFallbackValue} placeholder={t("settings.projectModels.useGlobal", "Use global")} favoriteProviders={favoriteProviders} onToggleFavorite={onToggleFavorite} favoriteModels={favoriteModels} onToggleModelFavorite={onToggleModelFavorite} menuWidth="readable" showThinkingLevel={true} thinkingLevel={titleSummarizerFallbackThinkingValue} onThinkingLevelChange={setTitleSummarizerFallbackThinkingValue} credentialInstanceId={form.titleSummarizerFallbackCredentialInstanceId} onCredentialInstanceChange={(instanceId) => setForm((f) => ({ ...f, titleSummarizerFallbackCredentialInstanceId: instanceId || undefined } as SettingsFormState))} defaultThinkingLevel={form.defaultThinkingLevel}/>
                 </div>
                 {titleSummarizerFallbackCustomized && (<button type="button" className="btn btn-ghost btn-sm" title={t("settings.projectModels.resetToInheritFromGlobal", "Reset to inherit from global")} onClick={resetTitleSummarizerFallbackValue} style={{ whiteSpace: "nowrap" }}>{t("settings.projectModels.reset", " Reset ")}</button>)}
               </div>

packages/dashboard/app/components/settings/sections/__tests__/ProjectModelsSection.chatDefault.test.tsx

@@ -1,6 +1,7 @@
 // @vitest-environment jsdom
 import { useState } from "react";
 import { cleanup, fireEvent, render, screen } from "@testing-library/react";
+import userEvent from "@testing-library/user-event";
 import * as jestDomMatchers from "@testing-library/jest-dom/matchers";
 import { afterEach, beforeEach, describe, expect, it, vi } from "vitest";
 import { ProjectModelsSection } from "../ProjectModelsSection";
@@ -25,7 +26,7 @@ vi.mock("../../../../api", async (importOriginal) => {
 });
 
 vi.mock("../../../CustomModelDropdown", () => ({
-  CustomModelDropdown: ({ id, label, value, onChange, showThinkingLevel, thinkingLevel, onThinkingLevelChange, defaultThinkingLevel }: {
+  CustomModelDropdown: ({ id, label, value, onChange, showThinkingLevel, thinkingLevel, onThinkingLevelChange, defaultThinkingLevel, credentialInstanceId, onCredentialInstanceChange }: {
     id?: string;
     label: string;
     value?: string;
@@ -34,10 +35,13 @@ vi.mock("../../../CustomModelDropdown", () => ({
     thinkingLevel?: string;
     onThinkingLevelChange?: (value: string) => void;
     defaultThinkingLevel?: string;
+    credentialInstanceId?: string;
+    onCredentialInstanceChange?: (value: string) => void;
   }) => (
     <div data-testid={`mock-model-host-${id ?? label}`} data-value={value ?? ""} data-default-thinking={defaultThinkingLevel ?? ""}>
       <button type="button" data-testid={`mock-model-dropdown-${id ?? label}`} onClick={() => onChange?.("anthropic/claude-sonnet-4-5")}>{label}</button>
       {showThinkingLevel ? <button type="button" data-testid={`mock-thinking-${id ?? label}`} onClick={() => onThinkingLevelChange?.(thinkingLevel ? "" : "high")}>thinking:{thinkingLevel || "inherit"}</button> : null}
+      {onCredentialInstanceChange ? <><button type="button" data-testid={`mock-instance-${id ?? label}`} onClick={() => onCredentialInstanceChange("backup")}>instance:{credentialInstanceId || "default"}</button><button type="button" data-testid={`mock-instance-default-${id ?? label}`} onClick={() => onCredentialInstanceChange("")}>default instance</button></> : null}
     </div>
   ),
 }));
@@ -189,4 +193,31 @@ describe("ProjectModelsSection Chat default settings", () => {
       chatDefaultThinkingLevel: undefined,
     });
   });
+  it("round-trips a project lane credential instance and clears it with Default", async () => {
+    const user = userEvent.setup();
+    const lane = {
+      laneId: "merger",
+      label: "Merger Model",
+      globalProviderKey: "mergerGlobalProvider",
+      globalModelKey: "mergerGlobalModelId",
+      projectProviderKey: "mergerProvider",
+      projectModelKey: "mergerModelId",
+      helperText: "",
+      fallbackOrder: "",
+    } as ProjectModelsSectionModelProps["modelLanes"][number];
+    const laneModels = { ...models, modelLanes: [lane] };
+    let latestForm: SettingsFormState = { mergerProvider: "anthropic", mergerModelId: "claude-sonnet-4-5" } as SettingsFormState;
+    function Host() {
+      const [form, setForm] = useState(latestForm);
+      latestForm = form;
+      return <ProjectModelsSection form={form} setForm={setForm} models={laneModels} projectId="project-1" addToast={vi.fn()} />;
+    }
+    render(<Host />);
+
+    await user.click(screen.getByTestId("mock-instance-mergerModel"));
+    expect(latestForm.mergerCredentialInstanceId).toBe("backup");
+    await user.click(screen.getByTestId("mock-instance-default-mergerModel"));
+    expect(latestForm.mergerCredentialInstanceId).toBeUndefined();
+  });
+
 });

packages/dashboard/app/hooks/useFavorites.ts

@@ -1,5 +1,5 @@
 import { useCallback, useEffect, useRef, useState } from "react";
-import { updateGlobalSettings, type ModelInfo } from "../api";
+import { updateGlobalSettings, type ModelInfo, type ProviderCredentialInstanceSummary } from "../api";
 import { useModelsCache } from "./useModelsCache";
 
 /**
@@ -9,6 +9,7 @@ export interface UseFavoritesResult {
   availableModels: ModelInfo[];
   favoriteProviders: string[];
   favoriteModels: string[];
+  providerInstances: Record<string, { instances: ProviderCredentialInstanceSummary[] }>;
   toggleFavoriteProvider: (provider: string) => Promise<void>;
   toggleFavoriteModel: (modelId: string) => Promise<void>;
 }
@@ -17,7 +18,7 @@ export interface UseFavoritesResult {
  * Loads model catalog + favorites and exposes optimistic favorite toggles.
  */
 export function useFavorites(): UseFavoritesResult {
-  const { models, favoriteProviders: cachedFavoriteProviders, favoriteModels: cachedFavoriteModels, refresh } = useModelsCache();
+  const { models, favoriteProviders: cachedFavoriteProviders, favoriteModels: cachedFavoriteModels, providerInstances, refresh } = useModelsCache();
   const [availableModels, setAvailableModels] = useState<ModelInfo[]>(models);
   const [favoriteProviders, setFavoriteProviders] = useState<string[]>(cachedFavoriteProviders);
   const [favoriteModels, setFavoriteModels] = useState<string[]>(cachedFavoriteModels);
@@ -96,6 +97,7 @@ export function useFavorites(): UseFavoritesResult {
     availableModels,
     favoriteProviders,
     favoriteModels,
+    providerInstances,
     toggleFavoriteProvider,
     toggleFavoriteModel,
   };

packages/dashboard/app/hooks/useModelsCache.ts

@@ -1,5 +1,5 @@
 import { useCallback, useEffect, useRef, useState } from "react";
-import { fetchModels, type ModelInfo, type ModelsResponse } from "../api";
+import { fetchModels, type ModelInfo, type ModelsResponse, type ProviderCredentialInstanceSummary } from "../api";
 import { clearCache, readCache, SWR_CACHE_KEYS, SWR_DEFAULT_MAX_AGE_MS, writeCache } from "../utils/swrCache";
 
 interface ModelsCacheState {
@@ -8,6 +8,7 @@ interface ModelsCacheState {
   favoriteModels: string[];
   defaultProvider: string | null;
   defaultModelId: string | null;
+  providerInstances: Record<string, { instances: ProviderCredentialInstanceSummary[] }>;
 }
 
 export interface UseModelsCacheResult extends ModelsCacheState {
@@ -21,6 +22,7 @@ const EMPTY_MODELS_STATE: ModelsCacheState = {
   favoriteModels: [],
   defaultProvider: null,
   defaultModelId: null,
+  providerInstances: {},
 };
 
 let inflight: Promise<ModelsResponse> | null = null;
@@ -41,6 +43,7 @@ function toModelsCacheState(response: ModelsResponse | null | undefined): Models
     favoriteModels: response.favoriteModels ?? [],
     defaultProvider: response.defaultProvider ?? null,
     defaultModelId: response.defaultModelId ?? null,
+    providerInstances: response.providerInstances ?? {},
   };
 }
 

packages/dashboard/src/routes/register-task-workflow-routes.ts

@@ -3341,6 +3341,8 @@ export function registerTaskWorkflowRoutes(ctx: ApiRoutesContext, deps: TaskWork
         planningModelId,
         nodeId,
         thinkingLevel,
+        credentialInstanceId,
+        validatorCredentialInstanceId,
       } = req.body;
 
       // Validate taskIds
@@ -3360,13 +3362,18 @@ export function registerTaskWorkflowRoutes(ctx: ApiRoutesContext, deps: TaskWork
       const hasPlanningModel = planningModelProvider !== undefined || planningModelId !== undefined;
       const hasNodeId = nodeId !== undefined;
       const hasThinkingLevel = thinkingLevel !== undefined;
-      if (!hasExecutorModel && !hasValidatorModel && !hasPlanningModel && !hasNodeId && !hasThinkingLevel) {
+      const hasCredentialInstance = credentialInstanceId !== undefined || validatorCredentialInstanceId !== undefined;
+      if (!hasExecutorModel && !hasValidatorModel && !hasPlanningModel && !hasNodeId && !hasThinkingLevel && !hasCredentialInstance) {
         throw badRequest("At least one model field, thinkingLevel, or nodeId must be provided");
       }
 
       if (nodeId !== undefined && nodeId !== null && typeof nodeId !== "string") {
         throw badRequest("nodeId must be a string, null, or undefined");
       }
+      if ((credentialInstanceId !== undefined && credentialInstanceId !== null && typeof credentialInstanceId !== "string")
+        || (validatorCredentialInstanceId !== undefined && validatorCredentialInstanceId !== null && typeof validatorCredentialInstanceId !== "string")) {
+        throw badRequest("credential instance IDs must be strings, null, or undefined");
+      }
       if (thinkingLevel !== undefined && thinkingLevel !== null && (typeof thinkingLevel !== "string" || !THINKING_LEVELS.includes(thinkingLevel as ThinkingLevel))) {
         throw badRequest(`thinkingLevel must be one of ${THINKING_LEVELS.join(", ")}, null, or undefined`);
       }
@@ -3430,6 +3437,8 @@ export function registerTaskWorkflowRoutes(ctx: ApiRoutesContext, deps: TaskWork
         planningModelId?: string | null;
         nodeId?: string | null;
         thinkingLevel?: ThinkingLevel | null;
+        credentialInstanceId?: string | null;
+        validatorCredentialInstanceId?: string | null;
       } = {};
       if (validatedExecutor.provider !== undefined) {
         updates.modelProvider = validatedExecutor.provider;
@@ -3459,6 +3468,12 @@ export function registerTaskWorkflowRoutes(ctx: ApiRoutesContext, deps: TaskWork
       if (thinkingLevel !== undefined) {
         updates.thinkingLevel = thinkingLevel as ThinkingLevel | null;
       }
+      /*
+      FNXC:TaskBulkModels 2026-08-01-10:34:
+      Bulk model editing must persist explicit credential-instance choices and clear them on Default. Omitting unchanged lanes preserves the no-change sentinel rather than rewriting task overrides.
+      */
+      if (credentialInstanceId !== undefined) updates.credentialInstanceId = credentialInstanceId;
+      if (validatorCredentialInstanceId !== undefined) updates.validatorCredentialInstanceId = validatorCredentialInstanceId;
 
       // Update all tasks in parallel
       const updatePromises = taskIds.map(async (taskId) => {