FN-9043: fix workspace completion commit detection

Resolve workspace configuration consistently so task completion observes commits across acquired repositories.

- Add a host-scoped, memoized workspace configuration resolver and preserve live configuration through executor dependency bags.
- Resolve workspace configuration before planning, worktree, graph, cleanup, and task-done paths.
- Aggregate workspace commit observations and cover partial-repository completion cases.

Files changed:
 .changeset/fn-9043-workspace-no-commits.md         |   7 ++
 .../executor-workspace-config-propagation.test.ts  | 116 +++++++++++++++++++++
 .../engine/src/executor/cleanup-task-worktree.ts   |   6 +-
 .../create-authoritative-workflow-seams.ts         |   6 +-
 packages/engine/src/executor/deps-bags.ts          |  74 ++++++++++---
 .../executor/ensure-graph-custom-node-worktree.ts  |  14 ++-
 .../executor/ensure-task-worktree-for-planning.ts  |   8 +-
 packages/engine/src/executor/get-worktree-path.ts  |   3 +
 packages/engine/src/executor/mark-stuck-aborted.ts |   6 +-
 .../engine/src/executor/run-graph-custom-node.ts   |   8 +-
 packages/engine/src/executor/run-implementation.ts |   6 +-
 .../src/executor/workspace-config-resolver.ts      |  40 +++++++
 .../src/executor/worktree-task-done-scope-leak.ts  |   8 +-
 .../src/executor/worktree-verify-invariants.ts     |  44 ++++----
 14 files changed, 287 insertions(+), 59 deletions(-)

Fusion-Task-Id: FN-9043

Fusion-Task-Lineage: fc012b8e-c9cb-47e8-81a7-c9590a63a980

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

.changeset/fn-9043-workspace-no-commits.md

@@ -0,0 +1,7 @@
+---
+"@runfusion/fusion": patch
+---
+
+summary: Fix workspace task completion when changes land in only one repository.
+category: fix
+dev: Adds a per-host workspace resolver, resolves before executor workspace branches, normalizes empty configs, and aggregates commit counts across acquired repositories.

packages/engine/src/__tests__/executor-workspace-config-propagation.test.ts

@@ -0,0 +1,116 @@
+import { afterEach, describe, expect, it } from "vitest";
+import { execSync } from "node:child_process";
+import { EventEmitter } from "node:events";
+import { mkdirSync, writeFileSync } from "node:fs";
+import { mkdtempSync, rmSync } from "node:fs";
+import os from "node:os";
+import path from "node:path";
+import type { Task, TaskStore } from "@fusion/core";
+import { TaskExecutor } from "../executor.js";
+import { resolveWorkspaceConfigOnce } from "../executor/workspace-config-resolver.js";
+import { createWorkspaceFixture, hasGit, type WorkspaceFixture } from "./_workspace-fixture.js";
+
+const describeIfGit = hasGit ? describe : describe.skip;
+const TASK_ID = "FN-9043";
+const BRANCH = "fusion/fn-9043";
+
+function createStore(): TaskStore {
+  return Object.assign(new EventEmitter(), { getSettings: async () => ({}) }) as unknown as TaskStore;
+}
+
+function makeTask(worktrees: Task["workspaceWorktrees"]): Task {
+  return {
+    id: TASK_ID, title: "workspace verification", description: "", column: "in-progress",
+    dependencies: [], steps: [], currentStep: 0, log: [], createdAt: new Date().toISOString(),
+    updatedAt: new Date().toISOString(), branch: BRANCH, workspaceWorktrees: worktrees,
+  } as Task;
+}
+
+function addWorktree(fx: WorkspaceFixture, repo: string, commit: boolean): { worktreePath: string; baseCommitSha: string } {
+  const repoPath = fx.repoPath(repo);
+  const baseCommitSha = fx.git(repo, "git rev-parse HEAD");
+  const worktreePath = path.join(repoPath, ".worktrees", TASK_ID);
+  fx.git(repo, `git worktree add -b ${BRANCH} ${worktreePath} HEAD`);
+  if (commit) {
+    execSync('git config user.email "test@example.com"', { cwd: worktreePath });
+    execSync('git config user.name "Test"', { cwd: worktreePath });
+    mkdirSync(path.join(worktreePath, "src"), { recursive: true });
+    writeFileSync(path.join(worktreePath, "src", "change.ts"), "export {}\n");
+    execSync("git add src/change.ts && git commit -m workspace-change", { cwd: worktreePath });
+  }
+  return { worktreePath, baseCommitSha };
+}
+
+/**
+ * FNXC:Workspace 2026-08-14-21:06:
+ * Completion must load workspace mode from its natural undefined host state; injecting the field
+ * masks the non-git-root regression reported by issue #3435.
+ */
+describeIfGit("FN-9043 workspace config propagation", () => {
+  let fixture: WorkspaceFixture | undefined;
+  afterEach(() => fixture?.cleanup());
+
+  it("normalizes an empty workspace config to cached single-repo mode", async () => {
+    const rootDir = mkdtempSync(path.join(os.tmpdir(), "fusion-empty-workspace-"));
+    try {
+      mkdirSync(path.join(rootDir, ".fusion"));
+      writeFileSync(path.join(rootDir, ".fusion", "workspace.json"), '{"repos":[]}');
+      const host: { workspaceConfig: unknown } = { workspaceConfig: undefined };
+      const deps = {
+        rootDir,
+        workspaceConfigOwner: host,
+        getWorkspaceConfig: () => host.workspaceConfig as null | undefined,
+        setWorkspaceConfig: (config: unknown) => { host.workspaceConfig = config; },
+      };
+      expect(await resolveWorkspaceConfigOnce(deps)).toBeNull();
+      expect(host.workspaceConfig).toBeNull();
+      expect(await resolveWorkspaceConfigOnce(deps)).toBeNull();
+    } finally {
+      rmSync(rootDir, { recursive: true, force: true });
+    }
+  });
+
+  it("uses sub-repo invariants when only one acquired repository has commits", async () => {
+    fixture = await createWorkspaceFixture();
+    const a = addWorktree(fixture, "repo-a", false);
+    const b = addWorktree(fixture, "repo-b", true);
+    const store = createStore();
+    const executor = new TaskExecutor(store, fixture.rootDir);
+    expect((executor as any).workspaceConfig).toBeUndefined();
+
+    const result = await (executor as any).verifyWorktreeInvariants(makeTask({
+      "repo-a": { ...a, branch: BRANCH },
+      "repo-b": { ...b, branch: BRANCH },
+    }));
+
+    expect(result).toEqual({ ok: true });
+    expect((executor as any).workspaceConfig?.repos).toEqual(["repo-a", "repo-b"]);
+  });
+
+  it("accepts commits in the first acquired repository too", async () => {
+    fixture = await createWorkspaceFixture();
+    const a = addWorktree(fixture, "repo-a", true);
+    const b = addWorktree(fixture, "repo-b", false);
+    const executor = new TaskExecutor(createStore(), fixture.rootDir);
+
+    await expect((executor as any).verifyWorktreeInvariants(makeTask({
+      "repo-a": { ...a, branch: BRANCH },
+      "repo-b": { ...b, branch: BRANCH },
+    }))).resolves.toEqual({ ok: true });
+  });
+
+  it("keeps no_commits blocking when every inspected sub-repo is empty", async () => {
+    fixture = await createWorkspaceFixture();
+    const a = addWorktree(fixture, "repo-a", false);
+    const b = addWorktree(fixture, "repo-b", false);
+    const executor = new TaskExecutor(createStore(), fixture.rootDir);
+
+    const result = await (executor as any).verifyWorktreeInvariants(makeTask({
+      "repo-a": { ...a, branch: BRANCH },
+      "repo-b": { ...b, branch: BRANCH },
+    }));
+
+    expect(result).toMatchObject({ ok: false, reason: "no_commits", expected: "> 0" });
+    if (!result.ok) expect(result.observed).toBe("repo-a=0, repo-b=0");
+  });
+});

packages/engine/src/executor/cleanup-task-worktree.ts

@@ -16,6 +16,7 @@ type AnyFn = (...args: any[]) => any;
 export type CleanupTaskWorktreeDeps = {
   store: TaskStore;
   workspaceConfig: WorkspaceConfig | null | undefined;
+  ensureWorkspaceConfig?: () => Promise<WorkspaceConfig | null>;
   activeWorktrees: Map<string, Set<string>>;
   getActiveWorktreePaths: (taskId: string) => string[];
   removeOwnWorktreeWithReconcile: AnyFn;
@@ -25,13 +26,16 @@ export async function cleanupTaskWorktree(
   deps: CleanupTaskWorktreeDeps,
   taskId: string,
 ): Promise<void> {
+  const workspaceConfig = deps.ensureWorkspaceConfig
+    ? await deps.ensureWorkspaceConfig()
+    : deps.workspaceConfig;
   const worktreePaths = deps.getActiveWorktreePaths(taskId);
   if (worktreePaths.length === 0) return;
 
   deps.activeWorktrees.delete(taskId);
 
   // FNXC:Workspace 2026-06-21-12:00: KTD1 — in workspace mode the tracked path is the non-git workspace root (browse-only), never a removable worktree. Drop the in-memory tracking above but never remove the root. Per-repo worktree teardown returns in Phase B.
-  if (deps.workspaceConfig) {
+  if (workspaceConfig) {
     return;
   }
   // Non-workspace tasks hold a one-element set — preserve the original single-path removal semantics.

packages/engine/src/executor/create-authoritative-workflow-seams.ts

@@ -55,6 +55,7 @@ export type CreateAuthoritativeWorkflowSeamsDeps = {
     [k: string]: unknown;
   };
   workspaceConfig: WorkspaceConfig | null | undefined;
+  ensureWorkspaceConfig?: () => Promise<WorkspaceConfig | null>;
   activeWorkflowPrincipals: Map<string, { agentId: string; nodeInstanceId: string; agent?: import("@fusion/core").Agent }>;
   graphSeamGoverningNodeId: Map<string, string>;
   graphSeamThinkingLevel: Map<string, ThinkingLevel>;
@@ -423,8 +424,11 @@ export function createAuthoritativeWorkflowSeams(
           const invoke = () => invokeReviewerForCwd(cwd);
           return sem ? sem.runNested(invoke) : invoke();
         };
+        const workspaceConfig = deps.ensureWorkspaceConfig
+          ? await deps.ensureWorkspaceConfig()
+          : deps.workspaceConfig;
         const invokeReviewer = () =>
-          deps.workspaceConfig && reviewCwd === worktreePath
+          workspaceConfig && reviewCwd === worktreePath
             ? deps.reviewWorkspacePerRepo(detail, (cwd: string) => runForCwd(cwd))
             : runForCwd(reviewCwd);
 

packages/engine/src/executor/deps-bags.ts

@@ -17,6 +17,7 @@ import type { WorktreeInvariantDeps } from "./worktree-verify-invariants.js";
 import type { NonContinuableSessionDeps } from "./non-continuable-session.js";
 import { facadeFields, facadeMethods } from "./facade-methods.js";
 import * as pure from "./pure-bindings.js";
+import { resolveWorkspaceConfigOnce } from "./workspace-config-resolver.js";
 import {
   MAX_WORKTREE_RETRIES,
   WORKTREE_RETRY_DELAYS,
@@ -89,20 +90,23 @@ export type WorktreeInvariantDepsSource = {
   rootDir: string;
   store: TaskStore;
   workspaceConfig: unknown | null | undefined;
+  ensureWorkspaceConfig?: () => Promise<unknown | null>;
   getActiveWorktreePaths: (taskId: string) => string[];
   getRunContextFor: (taskId: string) => EngineRunContext | undefined;
   emitWorktreeReanchoredAudit: WorktreeInvariantDeps["emitWorktreeReanchoredAudit"];
 };
 
 export function buildWorktreeInvariantDeps(src: WorktreeInvariantDepsSource): WorktreeInvariantDeps {
-  return {
+  const bag = {
     rootDir: src.rootDir,
     store: src.store,
-    workspaceConfig: src.workspaceConfig,
+    ensureWorkspaceConfig: src.ensureWorkspaceConfig,
     getActiveWorktreePaths: src.getActiveWorktreePaths,
     getRunContextFor: src.getRunContextFor,
     emitWorktreeReanchoredAudit: src.emitWorktreeReanchoredAudit,
   };
+  // FNXC:Workspace 2026-08-14-21:06: Workspace mode must remain live through every bag re-projection; a getter/setter preserves host writes in strict-mode callers.
+  return defineLiveWorkspaceConfig(bag, src);
 }
 
 export type NonContinuableSessionDepsSource = NonContinuableSessionDeps;
@@ -185,12 +189,32 @@ export function buildHandleGraphFailureDeps(host: any): any {
  * runImplementation deps bag peeled from TaskExecutor (U4). Constants are injected by the
  * façade so the free builder stays free of executor-constants coupling.
  */
+function defineLiveWorkspaceConfig<T extends object>(bag: T, owner: { workspaceConfig: unknown }): T & { workspaceConfig: unknown } {
+  Object.defineProperty(bag, "workspaceConfig", {
+    enumerable: true,
+    configurable: true,
+    get: () => owner.workspaceConfig,
+    set: (value: unknown) => { owner.workspaceConfig = value; },
+  });
+  return bag as T & { workspaceConfig: unknown };
+}
+
+function withWorkspaceResolver(host: any): () => Promise<unknown | null> {
+  return () => resolveWorkspaceConfigOnce({
+    rootDir: host.rootDir,
+    workspaceConfigOwner: host,
+    getWorkspaceConfig: () => host.workspaceConfig,
+    setWorkspaceConfig: (config) => { host.workspaceConfig = config; },
+  });
+}
+
 export function buildRunImplementationDeps(
   host: any,
   constants: { BRANCH_CONFLICT_TRIPWIRE_THRESHOLD: number; MAX_AUTO_RECOVERY_ATTEMPTS: number },
 ): any {
-  return {
-    ...facadeFields(host, ["store", "rootDir", "workspaceConfig"]),
+  const bag = {
+    ...facadeFields(host, ["store", "rootDir"]),
+    ensureWorkspaceConfig: withWorkspaceResolver(host),
     options: host.options as any,
     BRANCH_CONFLICT_TRIPWIRE_THRESHOLD: constants.BRANCH_CONFLICT_TRIPWIRE_THRESHOLD,
     MAX_AUTO_RECOVERY_ATTEMPTS: constants.MAX_AUTO_RECOVERY_ATTEMPTS,
@@ -228,11 +252,13 @@ export function buildRunImplementationDeps(
     ]),
     sharedWorkerTools: buildSharedWorkerToolsDeps(host),
   };
+  return defineLiveWorkspaceConfig(bag, host);
 }
 
 export function buildRunGraphCustomNodeDeps(host: any): any {
-  return {
-    ...facadeFields(host, ["store", "rootDir", "workspaceConfig"]),
+  const bag = {
+    ...facadeFields(host, ["store", "rootDir"]),
+    ensureWorkspaceConfig: withWorkspaceResolver(host),
     options: host.options as { pluginRunner?: unknown; [k: string]: unknown },
     graphUnattendedRuns: host.graphUnattendedRuns,
     ...facadeMethods(host, [
@@ -243,15 +269,17 @@ export function buildRunGraphCustomNodeDeps(host: any): any {
       "runRawCliCommand",
     ]),
   };
+  return defineLiveWorkspaceConfig(bag, host);
 }
 
 export function buildCreateAuthoritativeWorkflowSeamsDeps(host: any): any {
-  return {
+  const bag = {
     store: host.store,
     rootDir: host.rootDir,
+    ensureWorkspaceConfig: withWorkspaceResolver(host),
     options: host.options as { mergeRequester?: unknown; pluginRunner?: unknown; [k: string]: unknown },
     ...facadeFields(host, [
-      "workspaceConfig", "activeWorkflowPrincipals", "graphSeamGoverningNodeId", "graphSeamThinkingLevel",
+      "activeWorkflowPrincipals", "graphSeamGoverningNodeId", "graphSeamThinkingLevel",
       "graphStepActiveContext", "graphRethinkNarrations", "pausedAborted",
       "mergeRequester",
     ]),
@@ -263,6 +291,7 @@ export function buildCreateAuthoritativeWorkflowSeamsDeps(host: any): any {
       "unregisterSubagentSession",
     ]),
   };
+  return defineLiveWorkspaceConfig(bag, host);
 }
 
 export function buildCreateSpawnAgentToolDeps(host: any): any {
@@ -320,9 +349,9 @@ export function buildFinalizeAcceptedNoOpCompletionDeps(host: any): any {
 }
 
 export function buildMarkStuckAbortedDeps(host: any): any {
-  return {
+  const bag = {
     ...facadeFields(host, [
-      "store", "rootDir", "workspaceConfig",
+      "store", "rootDir",
       "activeStepExecutors", "stuckAborted", "executing",
       "activeWorktrees", "loopRecoveryState",
     ]),
@@ -331,7 +360,9 @@ export function buildMarkStuckAbortedDeps(host: any): any {
       "awaitAbortInFlightTaskWork", "clearPausedAborted", "resetStepsIfWorkLost",
       "hasActiveWorktreeBinding",
     ]),
+    ensureWorkspaceConfig: withWorkspaceResolver(host),
   };
+  return defineLiveWorkspaceConfig(bag, host);
 }
 
 export function buildRunGraphTaskStepDeps(host: any): any {
@@ -377,6 +408,7 @@ export function buildEnsureGraphCustomNodeWorktreeDeps(host: any, runConfiguredC
   return {
     store: host.store,
     rootDir: host.rootDir,
+    workspaceConfigOwner: host,
     getWorkspaceConfig: () => host.workspaceConfig,
     setWorkspaceConfig: (c: unknown) => { host.workspaceConfig = c; },
     ...facadeMethods(host, [
@@ -422,12 +454,14 @@ export function buildRunRawCliCommandDeps(host: any, runConfiguredCommand: any =
 }
 
 export function buildEvaluateTaskDoneScopeLeakDeps(host: any): any {
-  return {
-    ...facadeFields(host, ["store", "workspaceConfig"]),
+  const bag = {
+    ...facadeFields(host, ["store"]),
+    ensureWorkspaceConfig: withWorkspaceResolver(host),
     ...facadeMethods(host, [
       "getRunContextFor", "captureUncommittedModifiedFiles", "captureModifiedFiles",
     ]),
   };
+  return defineLiveWorkspaceConfig(bag, host);
 }
 
 export function buildScheduleCompletedTaskWatchdogDeps(
@@ -652,11 +686,13 @@ export function buildHandleImplicitTaskDoneRefusalDeps(host: any): any {
 }
 
 export function buildCleanupTaskWorktreeDeps(host: any): any {
-  return {
-    ...facadeFields(host, ["store", "workspaceConfig", "activeWorktrees"]),
+  const bag = {
+    ...facadeFields(host, ["store", "activeWorktrees"]),
+    ensureWorkspaceConfig: withWorkspaceResolver(host),
     getActiveWorktreePaths: (id: string) => host.getActiveWorktreePaths(id),
     removeOwnWorktreeWithReconcile: (...args: unknown[]) => host.removeOwnWorktreeWithReconcile(...args),
   };
+  return defineLiveWorkspaceConfig(bag, host);
 }
 
 export function buildResumeTaskForAgentDeps(host: any): any {
@@ -1059,6 +1095,7 @@ export function buildEnsureTaskWorktreeForPlanningDeps(host: any): any {
   return {
     store: host.store,
     rootDir: host.rootDir,
+    workspaceConfigOwner: host,
     getWorkspaceConfig: () => host.workspaceConfig,
     setWorkspaceConfig: (cfg: unknown) => { host.workspaceConfig = cfg; },
     ensureGraphCustomNodeWorktree: (t: unknown, s: unknown, nodeId: string, refresh?: boolean) =>
@@ -1191,12 +1228,15 @@ export function buildAdoptColumnAgentForNodeDeps(host: any): any {
 }
 
 export function buildWorktreeInvariantFacadeDeps(host: any): any {
-  return buildWorktreeInvariantDeps({
-    ...facadeFields(host, ["rootDir", "store", "workspaceConfig"]),
+  const facade = {
+    ...facadeFields(host, ["rootDir", "store"]),
+    ensureWorkspaceConfig: withWorkspaceResolver(host),
     ...facadeMethods(host, [
       "getActiveWorktreePaths", "getRunContextFor", "emitWorktreeReanchoredAudit",
     ]),
-  });
+  };
+  // FNXC:Workspace 2026-08-14-21:06: Object spread snapshots accessors, so the invariant's two-hop facade explicitly re-projects the live getter/setter.
+  return buildWorktreeInvariantDeps(defineLiveWorkspaceConfig(facade, host));
 }
 
 export function buildHandleDepAbortCleanupDeps(host: any): any {

packages/engine/src/executor/ensure-graph-custom-node-worktree.ts

@@ -9,19 +9,21 @@
  * Per-node worktree acquisition is expected graph plumbing once the task has a worktree.
  */
 import type { Settings, Task, TaskDetail, TaskStore } from "@fusion/core";
-import { loadWorkspaceConfig, type RunCommandResult } from "@fusion/core";
+import { type RunCommandResult, type WorkspaceConfig } from "@fusion/core";
 import { executorLog } from "../logger.js";
 import { generateSyntheticRunId, createRunAuditor, type EngineRunContext, type RunAuditor } from "../util/run-audit.js";
 import { acquireTaskWorktree } from "../worktree/worktree-acquisition.js";
 import { captureBaseCommitSha } from "./worktree-git-refs.js";
 import { createConfiguredCommandAbortError } from "./task-predicates.js";
 import type { WorktreePool } from "../worktree/worktree-pool.js";
+import { resolveWorkspaceConfigOnce } from "./workspace-config-resolver.js";
 
 export type EnsureGraphCustomNodeWorktreeDeps = {
   store: TaskStore;
   rootDir: string;
-  getWorkspaceConfig: () => Awaited<ReturnType<typeof loadWorkspaceConfig>> | undefined;
-  setWorkspaceConfig: (config: Awaited<ReturnType<typeof loadWorkspaceConfig>>) => void;
+  workspaceConfigOwner: object;
+  getWorkspaceConfig: () => WorkspaceConfig | null | undefined;
+  setWorkspaceConfig: (config: WorkspaceConfig | null) => void;
   getRunContextFor: (taskId: string) => EngineRunContext | undefined;
   pool?: WorktreePool;
   secretsStore?: Parameters<typeof acquireTaskWorktree>[0]["secretsStore"];
@@ -53,11 +55,7 @@ export async function ensureGraphCustomNodeWorktree(
   nodeId: string,
   refreshStaleBase = false,
 ): Promise<TaskDetail> {
-  let workspaceConfig = deps.getWorkspaceConfig();
-  if (workspaceConfig === undefined) {
-    workspaceConfig = await loadWorkspaceConfig(deps.rootDir);
-    deps.setWorkspaceConfig(workspaceConfig);
-  }
+  const workspaceConfig = await resolveWorkspaceConfigOnce(deps);
   if (workspaceConfig && (workspaceConfig.repos.length ?? 0) > 0) {
     return task;
   }

packages/engine/src/executor/ensure-task-worktree-for-planning.ts

@@ -15,13 +15,14 @@
  */
 import { existsSync } from "node:fs";
 import type { Settings, TaskDetail, TaskStore, WorkspaceConfig } from "@fusion/core";
-import { loadWorkspaceConfig } from "@fusion/core";
 import { executorLog, formatError } from "../logger.js";
+import { resolveWorkspaceConfigOnce } from "./workspace-config-resolver.js";
 
 export type EnsureTaskWorktreeForPlanningDeps = {
   store: TaskStore;
   rootDir: string;
   /** Mutable holder so lazy load updates TaskExecutor.workspaceConfig. */
+  workspaceConfigOwner: object;
   getWorkspaceConfig: () => WorkspaceConfig | null | undefined;
   setWorkspaceConfig: (cfg: WorkspaceConfig | null) => void;
   ensureGraphCustomNodeWorktree: (
@@ -37,10 +38,7 @@ export async function ensureTaskWorktreeForPlanning(
   taskId: string,
 ): Promise<string | null> {
   try {
-    if (deps.getWorkspaceConfig() === undefined) {
-      deps.setWorkspaceConfig(await loadWorkspaceConfig(deps.rootDir));
-    }
-    const workspaceConfig = deps.getWorkspaceConfig();
+    const workspaceConfig = await resolveWorkspaceConfigOnce(deps);
     if (workspaceConfig && (workspaceConfig.repos.length ?? 0) > 0) return null;
 
     const live = await deps.store.getTask(taskId);

packages/engine/src/executor/get-worktree-path.ts

@@ -5,6 +5,9 @@
  * FNXC:Workspace 2026-06-21-12:00: KTD2 single-path-getter contract.
  * Returns the sole worktree path for single-repo tasks; undefined in workspace mode
  * (callers must use per-repo workspaceWorktrees).
+ *
+ * FNXC:Workspace 2026-08-14-21:06: Synchronous workspace readers never resolve config;
+ * their async calling lane must resolve it before reading this pure path selector.
  */
 export function getWorktreePath(
   workspaceConfig: unknown | null | undefined,

packages/engine/src/executor/mark-stuck-aborted.ts

@@ -19,6 +19,7 @@ export type MarkStuckAbortedDeps = {
   store: TaskStore;
   rootDir: string;
   workspaceConfig: unknown;
+  ensureWorkspaceConfig?: () => Promise<unknown | null>;
   activeStepExecutors: Map<string, { terminateAllSessions(): Promise<void> }>;
   stuckAborted: Map<string, boolean>;
   executing: Set<string>;
@@ -105,7 +106,10 @@ export function markStuckAborted(
         block below silently no-ops. Per-repo teardown is Phase B; until then make
         the skip visible rather than silent. Behavior is unchanged.
         */
-        if (deps.workspaceConfig && !worktreePath) {
+        const workspaceConfig = deps.ensureWorkspaceConfig
+          ? await deps.ensureWorkspaceConfig()
+          : deps.workspaceConfig;
+        if (workspaceConfig && !worktreePath) {
           await deps.store.logEntry(
             taskId,
             `workspace task ${taskId}: no singular worktree to force-requeue (per-repo teardown is Phase B)`,

packages/engine/src/executor/run-graph-custom-node.ts

@@ -43,6 +43,7 @@ export type RunGraphCustomNodeDeps = {
   store: TaskStore;
   rootDir: string;
   workspaceConfig: WorkspaceConfig | null | undefined;
+  ensureWorkspaceConfig?: () => Promise<WorkspaceConfig | null>;
   options: { pluginRunner?: unknown; agentStore?: AgentStore | null; [k: string]: unknown };
   graphUnattendedRuns: Set<string>;
   getRunContextFor: (taskId: string) => EngineRunContext | undefined;
@@ -188,6 +189,9 @@ export async function runGraphCustomNode(
       optionalGroupId,
       reviewerInlineFixes: (settings as Settings & { reviewerInlineFixes?: boolean }).reviewerInlineFixes,
     });
+    const workspaceConfig = deps.ensureWorkspaceConfig
+      ? await deps.ensureWorkspaceConfig()
+      : deps.workspaceConfig;
     let executionTarget = writeCapable ? await deps.store.getTask(live.id) : live;
 
     /*
@@ -209,7 +213,7 @@ export async function runGraphCustomNode(
     */
     const nodeDisplayName = typeof cfg.name === "string" && cfg.name.trim() ? cfg.name.trim() : node.id;
     const isPlanReviewNode = node.id === "plan-review-step" || nodeDisplayName === "Plan Review" || optionalGroupId === "plan-review";
-    if (!deps.workspaceConfig) {
+    if (!workspaceConfig) {
       const recordedWorktreeMissing = Boolean(executionTarget.worktree) && !existsSync(executionTarget.worktree!);
       /*
       A node with NO recorded worktree is pre-execution (planning / Plan Review): acquire one.
@@ -236,7 +240,7 @@ export async function runGraphCustomNode(
       }
     }
 
-    if (writeCapable && !executionTarget.worktree && !deps.workspaceConfig) {
+    if (writeCapable && !executionTarget.worktree && !workspaceConfig) {
       return { outcome: "failure", value: "no-worktree-for-write-node" };
     }
 

packages/engine/src/executor/run-implementation.ts

@@ -52,7 +52,6 @@ import {
   RetryStormError,
   columnsWithFlag,
   isEphemeralAgent,
-  loadWorkspaceConfig,
   resolveEphemeralTaskCreationPolicy,
   resolveExecutorFallbackModel,
   resolvePersistAgentThinkingLog,
@@ -216,6 +215,7 @@ export type RunImplementationDeps = {
   store: TaskStore;
   rootDir: string;
   workspaceConfig: WorkspaceConfig | null | undefined;
+  ensureWorkspaceConfig: () => Promise<WorkspaceConfig | null>;
   // eslint-disable-next-line @typescript-eslint/no-explicit-any -- TaskExecutorOptions is large and only partially used here
   options: any;
   stuckAborted: Map<string, boolean>;
@@ -608,9 +608,7 @@ export async function runImplementation(
         return;
       }
 
-      if (deps.workspaceConfig === undefined) {
-        deps.workspaceConfig = await loadWorkspaceConfig(deps.rootDir);
-      }
+      await deps.ensureWorkspaceConfig();
       /*
       FNXC:Workspace 2026-06-22-00:00:
       Workspace mode is only meaningful with at least one usable sub-repo. An empty `{ repos: [] }`

packages/engine/src/executor/workspace-config-resolver.ts

@@ -0,0 +1,40 @@
+import { loadWorkspaceConfig, type WorkspaceConfig } from "@fusion/core";
+
+/**
+ * FNXC:Workspace 2026-08-14-21:06:
+ * Workspace detection has one host-owned writer: a per-lane copy silently routes a multi-repo
+ * project through its non-git root. Memoization is per host so concurrent projects and tests
+ * cannot share configuration, and a config with no usable repositories is single-repo mode.
+ */
+const inFlightWorkspaceConfigLoads = new WeakMap<object, Promise<WorkspaceConfig | null>>();
+
+export type WorkspaceConfigResolverDeps = {
+  rootDir: string;
+  workspaceConfigOwner: object;
+  getWorkspaceConfig: () => WorkspaceConfig | null | undefined;
+  setWorkspaceConfig: (config: WorkspaceConfig | null) => void;
+};
+
+export async function resolveWorkspaceConfigOnce(
+  deps: WorkspaceConfigResolverDeps,
+): Promise<WorkspaceConfig | null> {
+  const current = deps.getWorkspaceConfig();
+  if (current !== undefined) return current;
+
+  const existing = inFlightWorkspaceConfigLoads.get(deps.workspaceConfigOwner);
+  if (existing) return existing;
+
+  const promise = loadWorkspaceConfig(deps.rootDir).then((config) => {
+    const normalized = config && config.repos.length > 0 ? config : null;
+    deps.setWorkspaceConfig(normalized);
+    return normalized;
+  });
+  inFlightWorkspaceConfigLoads.set(deps.workspaceConfigOwner, promise);
+  try {
+    return await promise;
+  } finally {
+    if (inFlightWorkspaceConfigLoads.get(deps.workspaceConfigOwner) === promise) {
+      inFlightWorkspaceConfigLoads.delete(deps.workspaceConfigOwner);
+    }
+  }
+}

packages/engine/src/executor/worktree-task-done-scope-leak.ts

@@ -16,6 +16,7 @@ import {
 export type TaskDoneScopeLeakDeps = {
   store: TaskStore;
   workspaceConfig: unknown | null | undefined;
+  ensureWorkspaceConfig?: () => Promise<unknown | null>;
   getRunContextFor: (taskId: string) => EngineRunContext | undefined;
   captureUncommittedModifiedFiles: (worktreePath: string) => Promise<string[]>;
   captureModifiedFiles: (
@@ -83,9 +84,12 @@ export async function evaluateTaskDoneScopeLeak(
   // off-scope files and would silently pass; we block it (scope is declared but unverifiable).
   // F6 (deterministic ordering): iterate sorted repo keys so the reported offending repo is stable
   // across runs/rehydrate.
+  const workspaceConfig = deps.ensureWorkspaceConfig
+    ? await deps.ensureWorkspaceConfig()
+    : deps.workspaceConfig;
   let touchedFiles: string[];
   let offendingRepo: string | undefined;
-  if (deps.workspaceConfig) {
+  if (workspaceConfig) {
     const workspaceWorktrees = task.workspaceWorktrees ?? {};
     const repoKeys = Object.keys(workspaceWorktrees).sort();
     // F2: declaredScope is non-empty here (the `declaredScope.length === 0` early-return above
@@ -146,7 +150,7 @@ export async function evaluateTaskDoneScopeLeak(
     }
   }
 
-  const offScopeFiles = (deps.workspaceConfig
+  const offScopeFiles = (workspaceConfig
     // In workspace mode `touchedFiles` is already the off-scope set (filtered per repo above).
     ? touchedFiles
     : touchedFiles

packages/engine/src/executor/worktree-verify-invariants.ts

@@ -35,6 +35,7 @@ export type WorktreeInvariantDeps = {
   rootDir: string;
   store: TaskStore;
   workspaceConfig: unknown | null | undefined;
+  ensureWorkspaceConfig?: () => Promise<unknown | null>;
   getActiveWorktreePaths: (taskId: string) => string[];
   getRunContextFor: (taskId: string) => EngineRunContext | undefined;
   emitWorktreeReanchoredAudit: (
@@ -52,10 +53,13 @@ export async function verifyWorktreeInvariants(
   allowReanchor = true,
   options?: { noOpCompletion?: boolean; noOpCompletionReason?: string },
 ): Promise<WorktreeInvariantResult> {
+  const workspaceConfig = deps.ensureWorkspaceConfig
+    ? await deps.ensureWorkspaceConfig()
+    : deps.workspaceConfig;
   const settings = await deps.store.getSettings();
   // FNXC:Workspace 2026-06-21-23:30: KTD2 — un-stubbed per-repo worktree-invariant verification.
   // Phase A returned a flat {ok:true} stub here (no root worktree to verify against the non-git root). Phase B iterates every `task.workspaceWorktrees` entry, asserting (a) the sub-repo worktree's git toplevel matches the recorded repo.worktreePath and (b) its HEAD is on the recorded `fusion/<id>` branch (repo.branch). The result union is PRESERVED EXACTLY — `{ok:true} | {ok:false; reason:'wrong_toplevel'|'wrong_branch'|'no_commits'; observed; expected}` — because the :10889 consumer switches on `reason` to drive requeue/handoff (:10894-10936). We ADD an optional `repo` field to the failure shape (purely additive; the consumer only reads reason/observed/expected) and return the FIRST failing repo. A zero-acquire workspace task (empty map) verifies vacuously → {ok:true}, matching Phase A so fn_task_done does not requeue it.
-  if (deps.workspaceConfig) {
+  if (workspaceConfig) {
     const workspaceWorktrees = task.workspaceWorktrees ?? {};
     // FNXC:Workspace 2026-06-22-00:00: KTD2 — resolve the SAME task-wide no-commit eligibility the singular path
     // uses (getNoCommitEligibilityReason / no-op-completion sentinel / prompt-derived), once, before the per-repo
@@ -79,6 +83,8 @@ export async function verifyWorktreeInvariants(
     }
     // FNXC:Workspace 2026-06-21-15:00: F6 — iterate sorted repo keys so the FIRST failing repo
     // returned here is deterministic across runs/rehydrate (the value is surfaced to the operator).
+    const commitCounts: string[] = [];
+    let totalCommitCount = 0;
     for (const repoRel of Object.keys(workspaceWorktrees).sort()) {
       const repo = workspaceWorktrees[repoRel];
       const expectedBranch = repo.branch || canonicalFusionBranchName(task.id);
@@ -154,12 +160,6 @@ export async function verifyWorktreeInvariants(
           expected: expectedBranch,
         };
       }
-      // FNXC:Workspace 2026-06-22-00:00: KTD2 — per-repo no_commits guard (parity with the singular path at :10821).
-      // Phase B originally returned {ok:true} after the toplevel/branch checks, so a workspace task could call
-      // fn_task_done having committed NOTHING in any sub-repo (scope-leak sees zero touched files, branch names match)
-      // and still advance to in-review. Enforce the same `git rev-list --count <base>..HEAD > 0` invariant per repo,
-      // gated by the SAME task-wide no-commit eligibility below so Plan-Only / no-op-sentinel tasks stay exempt.
-      // The first sub-repo with zero commits fails with reason:'no_commits' (consumer-stable union).
       if (!workspaceNoCommitEligibilityReason) {
         const repoBaseRef = await resolveDiffBaseRef(repo.worktreePath, repo.baseCommitSha);
         if (repoBaseRef) {
@@ -171,18 +171,18 @@ export async function verifyWorktreeInvariants(
               maxBuffer: 1024 * 1024,
             });
             const trimmedCount = stdout.trim();
-            if (trimmedCount) {
-              const count = Number.parseInt(trimmedCount, 10);
-              if (!Number.isFinite(count) || count <= 0) {
-                return {
-                  ok: false,
-                  reason: "no_commits",
-                  repo: repoRel,
-                  observed: Number.isFinite(count) ? String(count) : trimmedCount,
-                  expected: "> 0",
-                };
-              }
+            const count = Number.parseInt(trimmedCount, 10);
+            if (!Number.isFinite(count) || count < 0) {
+              return {
+                ok: false,
+                reason: "no_commits",
+                repo: repoRel,
+                observed: trimmedCount,
+                expected: `git rev-list --count ${repoBaseRef}..HEAD > 0`,
+              };
             }
+            commitCounts.push(`${repoRel}=${count}`);
+            totalCommitCount += count;
           } catch (error) {
             return {
               ok: false,
@@ -197,6 +197,14 @@ export async function verifyWorktreeInvariants(
         }
       }
     }
+    /*
+    FNXC:Workspace 2026-08-14-21:06:
+    A workspace task may legitimately change only a subset of acquired repositories. The commit
+    invariant is task-wide, because rejecting the first empty repository blocked committed work (issue #3435).
+    */
+    if (!workspaceNoCommitEligibilityReason && commitCounts.length > 0 && totalCommitCount === 0) {
+      return { ok: false, reason: "no_commits", observed: commitCounts.join(", "), expected: "> 0" };
+    }
     return { ok: true };
   }
   /*