diff --git a/.changeset/mission-interview-cli-runtime-routing.md b/.changeset/mission-interview-cli-runtime-routing.md
new file mode 100644
index 0000000000..445625e8e1
--- /dev/null
+++ b/.changeset/mission-interview-cli-runtime-routing.md
@@ -0,0 +1,7 @@
+---
+"@runfusion/fusion": patch
+---
+
+summary: Route every AI lane through runtime resolution so CLI-runtime models (e.g. Cursor CLI) work everywhere chat does.
+category: fix
+dev: `createFnAgent` now delegates to `createResolvedAgentSession` (CLI runtime hint derivation, mock forcing, runtime-resolved visibility) with a host-registered default PluginRunner per project root; `DefaultPiRuntime` re-enters via a `__rawPiSession` marker into `createPiAgentSessionRaw`. Mission and milestone/slice interviews also pass their request-scoped pluginRunner and prompt via the engine `promptWithFallback` dispatcher, fixing "cursor-cli/auto ... not found in the pi model registry" in mission planning.
diff --git a/packages/dashboard/src/__tests__/interview-question-regeneration.test.ts b/packages/dashboard/src/__tests__/interview-question-regeneration.test.ts
index e3b4534821..f1796b388b 100644
--- a/packages/dashboard/src/__tests__/interview-question-regeneration.test.ts
+++ b/packages/dashboard/src/__tests__/interview-question-regeneration.test.ts
@@ -10,13 +10,19 @@ fresh question instead of throwing "No active question in session". A completed
 
 import { beforeEach, describe, expect, it, vi } from "vitest";
 
+/*
+FNXC:MissionInterviewRuntimeResolution 2026-08-16-14:37:
+Mission and milestone/slice interviews now build sessions through the shared
+`createResolvedAgentSession` seam (so CLI-runtime model selections route to their
+runtime plugins); mock that seam with the same scripted session factory.
+*/
 vi.mock("@fusion/engine", async (importOriginal) => {
   const actual = await importOriginal<typeof import("@fusion/engine")>();
   return {
     ...actual,
     buildSessionSkillContextSync: vi.fn(() => ({ skillSelectionContext: undefined })),
     resolveMcpServersForStore: vi.fn(async () => ({ servers: [] })),
-    createFnAgent: vi.fn(async () => ({
+    createResolvedAgentSession: vi.fn(async () => ({
       session: {
         state: { messages: [] as Array<{ role: string; content: string }> },
         prompt: vi.fn(async function (this: { state: { messages: Array<{ role: string; content: string }> } }) {
diff --git a/packages/dashboard/src/__tests__/mcp-lane-forwarding.test.ts b/packages/dashboard/src/__tests__/mcp-lane-forwarding.test.ts
index d1c82b071e..e8d994050f 100644
--- a/packages/dashboard/src/__tests__/mcp-lane-forwarding.test.ts
+++ b/packages/dashboard/src/__tests__/mcp-lane-forwarding.test.ts
@@ -49,8 +49,10 @@ const { createFnAgentMock, createResolvedAgentSessionMock, resolveMcpServersForS
     FNXC:PlanningRuntimeResolution 2026-07-24-16:20:
     Planning now builds its session through the shared runtime-resolving seam
     (`createResolvedAgentSession`), not a bare `createFnAgent` call, so the MCP-forwarding
-    contract for the planning lanes is asserted on that seam. The mission/target interview
-    lanes still construct through `createFnAgent` and keep their own mock.
+    contract for the planning lanes is asserted on that seam.
+    FNXC:MissionInterviewRuntimeResolution 2026-08-16-14:37: the mission and milestone/slice
+    interview lanes now build through the same seam so CLI-runtime model selections
+    (cursor-cli etc.) route to their runtime plugins; their assertions target it too.
     */
     createResolvedAgentSessionMock: vi.fn(makeScriptedAgent),
     resolveMcpServersForStoreMock: vi.fn(async () => ({
@@ -184,7 +186,7 @@ describe("dashboard MCP lane forwarding", () => {
     await createMissionInterviewAgent(session, "/tmp/fusion-dashboard-test", store);
 
     expect(resolveMcpServersForStoreMock).toHaveBeenCalledWith(store);
-    expect(createFnAgentMock).toHaveBeenCalledWith(expect.objectContaining({
+    expect(createResolvedAgentSessionMock).toHaveBeenCalledWith(expect.objectContaining({
       cwd: "/tmp/fusion-dashboard-test",
       tools: "readonly",
       allowMcpToolsInReadonly: true,
@@ -197,7 +199,7 @@ describe("dashboard MCP lane forwarding", () => {
 
     await createMissionInterviewAgent({ id: "mission-empty", thinkingOutput: "" } as never, "/tmp/fusion-dashboard-test", {} as never);
 
-    expect(createFnAgentMock).toHaveBeenCalledWith(expect.objectContaining({ mcpServers: [] }));
+    expect(createResolvedAgentSessionMock).toHaveBeenCalledWith(expect.objectContaining({ mcpServers: [] }));
   });
 
   it("forwards materialized MCP servers to milestone and slice interview agents", async () => {
@@ -207,7 +209,7 @@ describe("dashboard MCP lane forwarding", () => {
     await createTargetInterviewAgent(session, "/tmp/fusion-dashboard-test", store);
 
     expect(resolveMcpServersForStoreMock).toHaveBeenCalledWith(store);
-    expect(createFnAgentMock).toHaveBeenCalledWith(expect.objectContaining({
+    expect(createResolvedAgentSessionMock).toHaveBeenCalledWith(expect.objectContaining({
       cwd: "/tmp/fusion-dashboard-test",
       tools: "readonly",
       allowMcpToolsInReadonly: true,
@@ -220,6 +222,6 @@ describe("dashboard MCP lane forwarding", () => {
 
     await createTargetInterviewAgent({ id: "target-empty", targetType: "slice", thinkingOutput: "" } as never, "/tmp/fusion-dashboard-test", {} as never);
 
-    expect(createFnAgentMock).toHaveBeenCalledWith(expect.objectContaining({ mcpServers: [] }));
+    expect(createResolvedAgentSessionMock).toHaveBeenCalledWith(expect.objectContaining({ mcpServers: [] }));
   });
 });
diff --git a/packages/dashboard/src/milestone-slice-interview.ts b/packages/dashboard/src/milestone-slice-interview.ts
index 40238635db..e7053c5370 100644
--- a/packages/dashboard/src/milestone-slice-interview.ts
+++ b/packages/dashboard/src/milestone-slice-interview.ts
@@ -104,15 +104,28 @@ function parseTargetInterviewResponseImpl(text: string): TargetInterviewResponse
 // Export the parse function for tests
 export { parseTargetInterviewResponseImpl as parseTargetInterviewResponse };
 
-import { buildSessionSkillContextSync, createFnAgent as engineCreateFnAgent, resolveMcpServersForStore } from "@fusion/engine";
+import { buildSessionSkillContextSync, createResolvedAgentSession, promptWithFallback as enginePromptWithFallback, resolveMcpServersForStore } from "@fusion/engine";
 import { createPlanningBoardTools } from "./planning-board-tools.js";
 import { laneModelOptions, resolveLaneSessionModel } from "./lane-session-model.js";
 
 // eslint-disable-next-line @typescript-eslint/no-explicit-any
 type AgentResult = any;
 type SkillSelectionPluginRunner = Parameters<typeof buildSessionSkillContextSync>[3];
+/*
+FNXC:MissionInterviewRuntimeResolution 2026-08-16-14:37:
+Milestone/slice interviews must use the shared `createResolvedAgentSession` seam (like chat, Planning Mode, and the mission interview) instead of bare `createFnAgent`, which pins the session to the default pi runtime. Without the seam, a CLI-runtime model selection (cursor-cli, claude-cli, hermes, omp-cli, no-key grok-cli) failed with "not found in the pi model registry" while chat on the same model worked.
+*/
 // eslint-disable-next-line @typescript-eslint/no-explicit-any
-const createFnAgent: any = engineCreateFnAgent;
+const createFnAgent: any = async (options: any): Promise<AgentResult> => {
+  const { pluginRunner, runtimeHint, settings, ...runtimeOptions } = options ?? {};
+  return createResolvedAgentSession({
+    sessionPurpose: "executor",
+    ...(runtimeHint ? { runtimeHint } : {}),
+    ...(pluginRunner ? { pluginRunner } : {}),
+    ...(settings ? { settings } : {}),
+    ...runtimeOptions,
+  });
+};
 
 function ensureEngineReady(): Promise<void> {
   return Promise.resolve();
@@ -848,6 +861,8 @@ export async function createTargetInterviewAgent(
     mcpServers,
     ...laneModelOptions(model),
     allowMcpToolsInReadonly: true,
+    // FNXC:MissionInterviewRuntimeResolution 2026-08-16-14:37: forward the plugin runner so the shared seam can route CLI-runtime model selections to their runtime plugins.
+    ...(pluginRunner ? { pluginRunner } : {}),
     customTools: [...createPlanningBoardTools(store)],
     /*
     FNXC:InterviewSkills 2026-06-17-21:42:
@@ -990,7 +1005,9 @@ async function ensureInterviewAgent(
       if (abortSignal.aborted) {
         throw createAbortError();
       }
-      await session.agent!.session.prompt(
+      // FNXC:MissionInterviewRuntimeResolution 2026-08-16-14:37: prompt through the engine dispatcher — plugin CLI runtime sessions (cursor/grok/droid) have no session.prompt(); the shared seam bound the runtime's promptWithFallback onto the session and this delegates to it.
+      await enginePromptWithFallback(
+        session.agent!.session,
         [
           "Previous conversation summary:",
           historySummary,
@@ -1074,7 +1091,7 @@ async function continueAgentConversation(session: TargetInterviewSession, messag
         if (abortSignal.aborted) {
           throw createAbortError();
         }
-        await agent.session.prompt(message, { signal: abortSignal });
+        await enginePromptWithFallback(agent.session, message, { signal: abortSignal });
         if (abortSignal.aborted) {
           throw createAbortError();
         }
@@ -1121,7 +1138,8 @@ async function continueAgentConversation(session: TargetInterviewSession, messag
                 if (abortSignal.aborted) {
                   throw createAbortError();
                 }
-                await agent.session.prompt(
+                await enginePromptWithFallback(
+                  agent.session,
                   "Your previous response could not be parsed as JSON. " +
                   'Please respond with ONLY a valid JSON object: either {"type":"question","data":{...}} ' +
                   'or {"type":"complete","data":{"title":"...","description":"...","planningNotes":"...","verification":"..."}}' +
diff --git a/packages/dashboard/src/mission-interview.ts b/packages/dashboard/src/mission-interview.ts
index fed1e770c2..baffd56e5c 100644
--- a/packages/dashboard/src/mission-interview.ts
+++ b/packages/dashboard/src/mission-interview.ts
@@ -29,15 +29,28 @@ import {
 } from "./ai-session-diagnostics.js";
 import { createAbortError, GenerationGuard, isAbortError } from "./ai-session-timeout.js";
 
-import { buildSessionSkillContextSync, createFnAgent as engineCreateFnAgent, resolveMcpServersForStore } from "@fusion/engine";
+import { buildSessionSkillContextSync, createResolvedAgentSession, promptWithFallback as enginePromptWithFallback, resolveMcpServersForStore } from "@fusion/engine";
 import { createPlanningBoardTools } from "./planning-board-tools.js";
 
 // eslint-disable-next-line @typescript-eslint/no-explicit-any
 type AgentResult = any;
 type SkillPluginRunner = Parameters<typeof buildSessionSkillContextSync>[3];
 const MISSION_INTERVIEW_BUILTIN_WEB_TOOLS = ["WebSearch", "WebFetch"] as const;
+/*
+FNXC:MissionInterviewRuntimeResolution 2026-08-16-14:37:
+Mission interview sessions must go through the shared `createResolvedAgentSession` seam — the same one chat, Planning Mode (createPlanningRuntimeSession), executor, and reviewer use — NOT a bare `createFnAgent` call. Bare `createFnAgent` pins the session to the default pi runtime, so a CLI-runtime model selection (cursor-cli, claude-cli, hermes, omp-cli, no-key grok-cli) could never route to its runtime plugin and died with "Configured model cursor-cli/auto ... was not found in the pi model registry" while chat on the same model worked. The seam derives the CLI runtime hint from the selected provider and emits `session:runtime-resolved` run-audit visibility.
+*/
 // eslint-disable-next-line @typescript-eslint/no-explicit-any
-const createFnAgent: any = engineCreateFnAgent;
+const createFnAgent: any = async (options: any): Promise<AgentResult> => {
+  const { pluginRunner, runtimeHint, settings, ...runtimeOptions } = options ?? {};
+  return createResolvedAgentSession({
+    sessionPurpose: "executor",
+    ...(runtimeHint ? { runtimeHint } : {}),
+    ...(pluginRunner ? { pluginRunner } : {}),
+    ...(settings ? { settings } : {}),
+    ...runtimeOptions,
+  });
+};
 
 /**
  * Shared diagnostics helper for the mission-interview module.
@@ -942,6 +955,8 @@ export async function createMissionInterviewAgent(
     tools: "readonly",
     mcpServers,
     allowMcpToolsInReadonly: true,
+    // FNXC:MissionInterviewRuntimeResolution 2026-08-16-14:37: forward the plugin runner so the shared seam can route CLI-runtime model selections (cursor/claude/grok/omp/hermes) to their runtime plugins.
+    ...(pluginRunner ? { pluginRunner } : {}),
     ...(skillContext.skillSelectionContext ? { skillSelection: skillContext.skillSelectionContext } : {}),
     builtinToolsAllowlist: [...MISSION_INTERVIEW_BUILTIN_WEB_TOOLS],
     customTools: [...createPlanningBoardTools(store)],
@@ -1094,7 +1109,9 @@ async function ensureMissionInterviewAgent(
       if (abortSignal.aborted) {
         throw createAbortError();
       }
-      await session.agent!.session.prompt(
+      // FNXC:MissionInterviewRuntimeResolution 2026-08-16-14:37: prompt through the engine dispatcher — plugin CLI runtime sessions (cursor/grok/droid) have no session.prompt(); the shared seam bound the runtime's promptWithFallback onto the session and this delegates to it.
+      await enginePromptWithFallback(
+        session.agent!.session,
         [
           "Previous conversation summary:",
           historySummary,
@@ -1167,7 +1184,7 @@ async function continueAgentConversation(session: MissionInterviewSession, messa
         if (abortSignal.aborted) {
           throw createAbortError();
         }
-        await agent.session.prompt(message, { signal: abortSignal });
+        await enginePromptWithFallback(agent.session, message, { signal: abortSignal });
         if (abortSignal.aborted) {
           throw createAbortError();
         }
@@ -1214,7 +1231,8 @@ async function continueAgentConversation(session: MissionInterviewSession, messa
                 if (abortSignal.aborted) {
                   throw createAbortError();
                 }
-                await agent.session.prompt(
+                await enginePromptWithFallback(
+                  agent.session,
                   "Your previous response could not be parsed as JSON. " +
                   'Please respond with ONLY a valid JSON object: either {"type":"question","data":{...}} ' +
                   'or {"type":"complete","data":{"missionTitle":"...","missionDescription":"...","milestones":[...]}}. ' +
diff --git a/packages/engine/src/__tests__/pi-create-fn-agent.test.ts b/packages/engine/src/__tests__/pi-create-fn-agent.test.ts
index 45cd360749..15c0746e47 100644
--- a/packages/engine/src/__tests__/pi-create-fn-agent.test.ts
+++ b/packages/engine/src/__tests__/pi-create-fn-agent.test.ts
@@ -1333,6 +1333,15 @@ describe("wrapToolsWithActionGate", () => {
   });
 });
 
+/*
+FNXC:CliRuntimeRouting 2026-08-16-14:37:
+This file pins the RAW pi session constructor's behavior (auth, principals,
+skills, registry resolution, tool wrapping). The public `createFnAgent` now
+routes through createResolvedAgentSession, so every direct call here aliases
+`createPiAgentSessionRaw` — the function DefaultPiRuntime bridges into — to
+keep asserting pi internals rather than the routing seam (covered by
+agent-session-helpers/runtime-resolution tests).
+*/
 describe("createFnAgent", () => {
   beforeEach(() => {
     vi.clearAllMocks();
@@ -1370,7 +1379,7 @@ describe("createFnAgent", () => {
   });
 
   it("binds a durable chat principal to the host-tool prompt invocation when pi omits agentId", async () => {
-    const { createFnAgent } = await import("../pi.js");
+    const { createPiAgentSessionRaw: createFnAgent } = await import("../pi.js");
     const {
       __clearFusionSessionIdentityRegistryForTests,
       resolveFusionSessionPrincipal,
@@ -1430,7 +1439,7 @@ describe("createFnAgent", () => {
   });
 
   it("reaches the pi host-tool identity wrapper from a durable dashboard chat session", async () => {
-    const { createFnAgent } = await import("../pi.js");
+    const { createPiAgentSessionRaw: createFnAgent } = await import("../pi.js");
     const {
       __clearFusionSessionIdentityRegistryForTests,
       resolveFusionSessionPrincipal,
@@ -1514,7 +1523,7 @@ describe("createFnAgent", () => {
   });
 
   it("assigns distinct fail-closed principals to concurrent anonymous engine sessions", async () => {
-    const { createFnAgent } = await import("../pi.js");
+    const { createPiAgentSessionRaw: createFnAgent } = await import("../pi.js");
     const {
       __clearFusionSessionIdentityRegistryForTests,
       resolveFusionSessionPrincipal,
@@ -1558,7 +1567,7 @@ describe("createFnAgent", () => {
     FN-7956 hung AI merge review on extension fn_task_show (second TaskStore boot, no tool timeout).
     Merger sessions must not receive host @runfusion/fusion extension paths even with tools:coding.
     */
-    const { createFnAgent, setHostExtensionPaths } = await import("../pi.js");
+    const { createPiAgentSessionRaw: createFnAgent, setHostExtensionPaths } = await import("../pi.js");
     setHostExtensionPaths(["/mock/fusion-extension"]);
 
     await createFnAgent({
@@ -1578,7 +1587,7 @@ describe("createFnAgent", () => {
   });
 
   it("still injects host extensions for coding non-merger sessions", async () => {
-    const { createFnAgent, setHostExtensionPaths } = await import("../pi.js");
+    const { createPiAgentSessionRaw: createFnAgent, setHostExtensionPaths } = await import("../pi.js");
     setHostExtensionPaths(["/mock/fusion-extension"]);
 
     await createFnAgent({
@@ -1597,7 +1606,7 @@ describe("createFnAgent", () => {
   });
 
   it("passes task-scoped env into bash spawn hook when provided", async () => {
-    const { createFnAgent } = await import("../pi.js");
+    const { createPiAgentSessionRaw: createFnAgent } = await import("../pi.js");
 
     await createFnAgent({
       cwd: "/project",
@@ -1636,7 +1645,7 @@ describe("createFnAgent", () => {
   });
 
   it("keeps bash tool default behavior when taskEnv is not provided", async () => {
-    const { createFnAgent } = await import("../pi.js");
+    const { createPiAgentSessionRaw: createFnAgent } = await import("../pi.js");
 
     await createFnAgent({
       cwd: "/project",
@@ -1648,7 +1657,7 @@ describe("createFnAgent", () => {
   });
 
   it("keeps spawned env unchanged when taskEnv is empty", async () => {
-    const { createFnAgent } = await import("../pi.js");
+    const { createPiAgentSessionRaw: createFnAgent } = await import("../pi.js");
 
     await createFnAgent({
       cwd: "/project",
@@ -1665,7 +1674,7 @@ describe("createFnAgent", () => {
   });
 
   it("adds new task env keys absent from spawned env", async () => {
-    const { createFnAgent } = await import("../pi.js");
+    const { createPiAgentSessionRaw: createFnAgent } = await import("../pi.js");
 
     await createFnAgent({
       cwd: "/project",
@@ -1681,7 +1690,7 @@ describe("createFnAgent", () => {
   });
 
   it("preserves undefined task env values explicitly in merged env", async () => {
-    const { createFnAgent } = await import("../pi.js");
+    const { createPiAgentSessionRaw: createFnAgent } = await import("../pi.js");
 
     await createFnAgent({
       cwd: "/project",
@@ -1697,7 +1706,7 @@ describe("createFnAgent", () => {
   });
 
   it("injects PATH from task env when spawned env has no PATH", async () => {
-    const { createFnAgent } = await import("../pi.js");
+    const { createPiAgentSessionRaw: createFnAgent } = await import("../pi.js");
 
     await createFnAgent({
       cwd: "/project",
@@ -1725,7 +1734,7 @@ describe("createFnAgent", () => {
       return "worktree /project\nHEAD abc123\nbranch refs/heads/main\n";
     });
 
-    const { createFnAgent } = await import("../pi.js");
+    const { createPiAgentSessionRaw: createFnAgent } = await import("../pi.js");
 
     await expect(createFnAgent({
       cwd: "/project/.worktrees/fn-001",
@@ -1752,7 +1761,7 @@ describe("createFnAgent", () => {
         "worktree /project/.worktrees/fn-001\nHEAD def456\nbranch refs/heads/fusion/fn-001\n";
     });
 
-    const { createFnAgent } = await import("../pi.js");
+    const { createPiAgentSessionRaw: createFnAgent } = await import("../pi.js");
 
     await createFnAgent({
       cwd: "/project/.worktrees/fn-001",
@@ -1779,7 +1788,7 @@ describe("createFnAgent", () => {
         "worktree /project/.worktrees/task-branch\nHEAD def456\nbranch refs/heads/fusion/fn-001\n";
     });
 
-    const { createFnAgent } = await import("../pi.js");
+    const { createPiAgentSessionRaw: createFnAgent } = await import("../pi.js");
 
     // Pass skills parameter with a worktree cwd.
     // getProjectRootFromWorktree extracts /project from the .worktrees path,
@@ -1807,7 +1816,7 @@ describe("createFnAgent", () => {
       return value === "/project/.fusion";
     });
 
-    const { createFnAgent } = await import("../pi.js");
+    const { createPiAgentSessionRaw: createFnAgent } = await import("../pi.js");
 
     await createFnAgent({
       cwd: "/project/src/components",
@@ -1826,7 +1835,7 @@ describe("createFnAgent", () => {
     // No .fusion directory exists anywhere above cwd.
     existsSyncMock.mockImplementation(() => false);
 
-    const { createFnAgent } = await import("../pi.js");
+    const { createPiAgentSessionRaw: createFnAgent } = await import("../pi.js");
 
     await createFnAgent({
       cwd: "/unrelated/directory",
@@ -1850,7 +1859,7 @@ describe("createFnAgent", () => {
   });
 
   it("passes a project-trusted settings view through package-manager discovery", async () => {
-    const { createFnAgent } = await import("../pi.js");
+    const { createPiAgentSessionRaw: createFnAgent } = await import("../pi.js");
 
     await createFnAgent({
       cwd: "/tmp",
@@ -1882,7 +1891,7 @@ describe("createFnAgent", () => {
       errors: [],
     });
 
-    const { createFnAgent } = await import("../pi.js");
+    const { createPiAgentSessionRaw: createFnAgent } = await import("../pi.js");
 
     await createFnAgent({
       cwd: "/tmp",
@@ -1939,7 +1948,7 @@ describe("createFnAgent", () => {
       },
     ] as any);
 
-    const { createFnAgent } = await import("../pi.js");
+    const { createPiAgentSessionRaw: createFnAgent } = await import("../pi.js");
 
     await createFnAgent({
       cwd: "/tmp",
@@ -2034,7 +2043,7 @@ describe("createFnAgent", () => {
       },
     ] as any);
 
-    const { createFnAgent } = await import("../pi.js");
+    const { createPiAgentSessionRaw: createFnAgent } = await import("../pi.js");
 
     await createFnAgent({
       cwd: "/tmp",
@@ -2069,7 +2078,7 @@ describe("createFnAgent", () => {
   });
 
   it("avoids lock-based SettingsManager.create when loading extension providers", async () => {
-    const { createFnAgent } = await import("../pi.js");
+    const { createPiAgentSessionRaw: createFnAgent } = await import("../pi.js");
 
     await createFnAgent({
       cwd: "/tmp",
@@ -2090,7 +2099,7 @@ describe("createFnAgent", () => {
       provider === "zai" && modelId === "glm-5.1" ? undefined : { provider, id: modelId }
     ));
 
-    const { createFnAgent } = await import("../pi.js");
+    const { createPiAgentSessionRaw: createFnAgent } = await import("../pi.js");
 
     await expect(createFnAgent({
       cwd: "/tmp",
@@ -2116,7 +2125,7 @@ describe("createFnAgent", () => {
       return { provider, id: modelId };
     });
 
-    const { createFnAgent } = await import("../pi.js");
+    const { createPiAgentSessionRaw: createFnAgent } = await import("../pi.js");
 
     await createFnAgent({
       cwd: "/tmp",
@@ -2139,7 +2148,7 @@ describe("createFnAgent", () => {
       provider === "openai-codex" && modelId === "missing-model" ? undefined : { provider, id: modelId }
     ));
 
-    const { createFnAgent } = await import("../pi.js");
+    const { createPiAgentSessionRaw: createFnAgent } = await import("../pi.js");
 
     await expect(createFnAgent({
       cwd: "/tmp",
@@ -2170,7 +2179,7 @@ describe("createFnAgent", () => {
     ));
     getAllMock.mockReturnValue([]);
 
-    const { createFnAgent } = await import("../pi.js");
+    const { createPiAgentSessionRaw: createFnAgent } = await import("../pi.js");
 
     await expect(createFnAgent({
       cwd: "/tmp",
@@ -2209,7 +2218,7 @@ describe("createFnAgent", () => {
     ));
     getAllMock.mockReturnValue([{ provider: "grok-cli", id: "grok-4.5", name: "Grok 4.5" }]);
 
-    const { createFnAgent } = await import("../pi.js");
+    const { createPiAgentSessionRaw: createFnAgent } = await import("../pi.js");
 
     await createFnAgent({
       cwd: "/tmp",
@@ -2226,7 +2235,7 @@ describe("createFnAgent", () => {
   });
 
   it("creates a session when configured models resolve successfully", async () => {
-    const { createFnAgent } = await import("../pi.js");
+    const { createPiAgentSessionRaw: createFnAgent } = await import("../pi.js");
 
     await createFnAgent({
       cwd: "/tmp",
@@ -2249,7 +2258,7 @@ describe("createFnAgent", () => {
     getAllMock.mockReturnValue([]);
     findMock.mockImplementation((provider: string, modelId: string) => ({ provider, id: modelId }));
 
-    const { createFnAgent } = await import("../pi.js");
+    const { createPiAgentSessionRaw: createFnAgent } = await import("../pi.js");
     await createFnAgent({
       cwd: "/tmp",
       systemPrompt: "test",
@@ -2282,7 +2291,7 @@ describe("createFnAgent", () => {
     ]);
     findMock.mockImplementation((provider: string, modelId: string) => ({ provider, id: modelId }));
 
-    const { createFnAgent } = await import("../pi.js");
+    const { createPiAgentSessionRaw: createFnAgent } = await import("../pi.js");
     await createFnAgent({
       cwd: "/tmp",
       systemPrompt: "test",
@@ -2301,7 +2310,7 @@ describe("createFnAgent", () => {
     getAllMock.mockReturnValue([]);
     findMock.mockImplementation((provider: string, modelId: string) => ({ provider, id: modelId }));
 
-    const { createFnAgent } = await import("../pi.js");
+    const { createPiAgentSessionRaw: createFnAgent } = await import("../pi.js");
     await createFnAgent({
       cwd: "/tmp",
       systemPrompt: "test",
@@ -2336,7 +2345,7 @@ describe("createFnAgent", () => {
     getAllMock.mockReturnValue([existingLunaRow]);
     findMock.mockImplementation((provider: string, modelId: string) => ({ provider, id: modelId }));
 
-    const { createFnAgent } = await import("../pi.js");
+    const { createPiAgentSessionRaw: createFnAgent } = await import("../pi.js");
     await createFnAgent({
       cwd: "/tmp",
       systemPrompt: "test",
@@ -2372,7 +2381,7 @@ describe("createFnAgent", () => {
     getAllMock.mockReturnValue([{ provider: "anthropic", id: "claude-opus-4-8", name: "Claude Opus 4.8" }]);
     findMock.mockImplementation((provider: string, modelId: string) => ({ provider, id: modelId }));
 
-    const { createFnAgent } = await import("../pi.js");
+    const { createPiAgentSessionRaw: createFnAgent } = await import("../pi.js");
     await createFnAgent({
       cwd: "/tmp",
       systemPrompt: "test",
@@ -2400,7 +2409,7 @@ describe("createFnAgent", () => {
       ? { provider, id: modelId }
       : undefined);
 
-    const { createFnAgent } = await import("../pi.js");
+    const { createPiAgentSessionRaw: createFnAgent } = await import("../pi.js");
     await expect(createFnAgent({
       cwd: "/tmp",
       systemPrompt: "test",
@@ -2419,7 +2428,7 @@ describe("createFnAgent", () => {
     authStorageGetApiKeyMock.mockResolvedValue(undefined);
     findMock.mockImplementation((provider: string, modelId: string) => ({ provider, id: modelId }));
 
-    const { createFnAgent } = await import("../pi.js");
+    const { createPiAgentSessionRaw: createFnAgent } = await import("../pi.js");
     await createFnAgent({
       cwd: "/tmp",
       systemPrompt: "test",
@@ -2439,7 +2448,7 @@ describe("createFnAgent", () => {
       provider === "anthropic" ? "sk-ant-api03-direct" : undefined
     ));
 
-    const { createFnAgent } = await import("../pi.js");
+    const { createPiAgentSessionRaw: createFnAgent } = await import("../pi.js");
     await createFnAgent({
       cwd: "/tmp",
       systemPrompt: "test",
@@ -2470,7 +2479,7 @@ describe("createFnAgent", () => {
     });
     getAllMock.mockReturnValue([{ provider: "anthropic", id: "claude-opus-4-8" }]);
 
-    const { createFnAgent } = await import("../pi.js");
+    const { createPiAgentSessionRaw: createFnAgent } = await import("../pi.js");
     await createFnAgent({
       cwd: "/tmp",
       systemPrompt: "test",
@@ -2493,7 +2502,7 @@ describe("createFnAgent", () => {
     };
     createAgentSessionMock.mockResolvedValueOnce({ session });
 
-    const { createFnAgent } = await import("../pi.js");
+    const { createPiAgentSessionRaw: createFnAgent } = await import("../pi.js");
     const result = await createFnAgent({
       cwd: "/tmp",
       systemPrompt: "test",
@@ -2522,7 +2531,7 @@ describe("createFnAgent", () => {
       execute: vi.fn(),
     };
 
-    const { createFnAgent } = await import("../pi.js");
+    const { createPiAgentSessionRaw: createFnAgent } = await import("../pi.js");
     await createFnAgent({
       cwd: "/tmp",
       systemPrompt: "test",
@@ -2543,7 +2552,7 @@ describe("createFnAgent", () => {
       execute: vi.fn(),
     };
 
-    const { createFnAgent } = await import("../pi.js");
+    const { createPiAgentSessionRaw: createFnAgent } = await import("../pi.js");
     await createFnAgent({
       cwd: "/tmp",
       systemPrompt: "test",
@@ -2556,7 +2565,7 @@ describe("createFnAgent", () => {
   });
 
   it("does not allow extra builtin tools in readonly sessions by default", async () => {
-    const { createFnAgent } = await import("../pi.js");
+    const { createPiAgentSessionRaw: createFnAgent } = await import("../pi.js");
 
     await createFnAgent({
       cwd: "/tmp",
@@ -2569,7 +2578,7 @@ describe("createFnAgent", () => {
   });
 
   it("intersects readonly builtin allowlist with readonly policy", async () => {
-    const { createFnAgent } = await import("../pi.js");
+    const { createPiAgentSessionRaw: createFnAgent } = await import("../pi.js");
 
     await createFnAgent({
       cwd: "/tmp",
@@ -2590,7 +2599,7 @@ describe("createFnAgent", () => {
   });
 
   it("filters coding tools with a case-insensitive toolsAllowlist", async () => {
-    const { createFnAgent } = await import("../pi.js");
+    const { createPiAgentSessionRaw: createFnAgent } = await import("../pi.js");
 
     await createFnAgent({
       cwd: "/tmp",
@@ -2605,7 +2614,7 @@ describe("createFnAgent", () => {
   });
 
   it("keeps all coding tools when toolsAllowlist is undefined", async () => {
-    const { createFnAgent } = await import("../pi.js");
+    const { createPiAgentSessionRaw: createFnAgent } = await import("../pi.js");
 
     await createFnAgent({
       cwd: "/tmp",
@@ -2619,7 +2628,7 @@ describe("createFnAgent", () => {
   });
 
   it("exposes no coding tools when toolsAllowlist is empty", async () => {
-    const { createFnAgent } = await import("../pi.js");
+    const { createPiAgentSessionRaw: createFnAgent } = await import("../pi.js");
 
     await createFnAgent({
       cwd: "/tmp",
@@ -2643,7 +2652,7 @@ describe("createFnAgent", () => {
       execute: vi.fn(),
     };
 
-    const { createFnAgent } = await import("../pi.js");
+    const { createPiAgentSessionRaw: createFnAgent } = await import("../pi.js");
     await createFnAgent({
       cwd: "/tmp",
       systemPrompt: "test",
@@ -2659,7 +2668,7 @@ describe("createFnAgent", () => {
     const execute = vi.fn().mockResolvedValue({ content: [{ type: "text", text: "ok" }] });
     const permanentCreateApproval = vi.fn();
     const markApprovalCompleted = vi.fn();
-    const { createFnAgent } = await import("../pi.js");
+    const { createPiAgentSessionRaw: createFnAgent } = await import("../pi.js");
 
     await createFnAgent({
       cwd: "/tmp",
@@ -2700,7 +2709,7 @@ describe("createFnAgent", () => {
   });
 
   it("exposes connected MCP tools in readonly sessions only with the explicit opt-in", async () => {
-    const { createFnAgent } = await import("../pi.js");
+    const { createPiAgentSessionRaw: createFnAgent } = await import("../pi.js");
     const close = vi.fn(async () => undefined);
     const mcpClient = {
       connect: vi.fn(async () => undefined),
@@ -2764,7 +2773,7 @@ describe("createFnAgent", () => {
       clients.push(client);
       return client;
     });
-    const { createFnAgent } = await import("../pi.js");
+    const { createPiAgentSessionRaw: createFnAgent } = await import("../pi.js");
 
     try {
       await expect(createFnAgent({
@@ -2794,7 +2803,7 @@ describe("createFnAgent", () => {
   });
 
   it("keeps MCP tools out of readonly sessions without the explicit opt-in", async () => {
-    const { createFnAgent } = await import("../pi.js");
+    const { createPiAgentSessionRaw: createFnAgent } = await import("../pi.js");
     const mcpClient = {
       connect: vi.fn(async () => undefined),
       listTools: vi.fn(async () => ({ tools: [{ name: "lookup" }] })),
@@ -2821,7 +2830,7 @@ describe("createFnAgent", () => {
     const { piLog } = await import("../logger.js");
     // FNXC:EngineDiagnostics 2026-07-26-09:55: entry chatter is debug-gated.
     const debugSpy = vi.spyOn(piLog, "debug").mockImplementation(() => {});
-    const { createFnAgent } = await import("../pi.js");
+    const { createPiAgentSessionRaw: createFnAgent } = await import("../pi.js");
 
     await createFnAgent({
       cwd: "/tmp/private-worktree",
@@ -2874,7 +2883,7 @@ describe("createFnAgent", () => {
         },
       });
 
-    const { createFnAgent } = await import("../pi.js");
+    const { createPiAgentSessionRaw: createFnAgent } = await import("../pi.js");
     const { __clearFusionSessionIdentityRegistryForTests } = await import("@fusion/core");
     __clearFusionSessionIdentityRegistryForTests();
 
@@ -2942,7 +2951,7 @@ describe("createFnAgent", () => {
         },
       });
 
-    const { createFnAgent } = await import("../pi.js");
+    const { createPiAgentSessionRaw: createFnAgent } = await import("../pi.js");
 
     const { session } = await createFnAgent({
       cwd: "/tmp",
@@ -2965,7 +2974,7 @@ describe("createFnAgent", () => {
   });
 
   it("enables auto-compaction to prevent context-window overflow", async () => {
-    const { createFnAgent } = await import("../pi.js");
+    const { createPiAgentSessionRaw: createFnAgent } = await import("../pi.js");
 
     await createFnAgent({
       cwd: "/tmp",
@@ -2982,7 +2991,7 @@ describe("createFnAgent", () => {
   });
 
   it("passes compaction enabled alongside retry settings", async () => {
-    const { createFnAgent } = await import("../pi.js");
+    const { createPiAgentSessionRaw: createFnAgent } = await import("../pi.js");
 
     await createFnAgent({
       cwd: "/tmp",
@@ -3013,7 +3022,7 @@ describe("createFnAgent", () => {
     };
     createAgentSessionMock.mockResolvedValueOnce({ session });
 
-    const { createFnAgent } = await import("../pi.js");
+    const { createPiAgentSessionRaw: createFnAgent } = await import("../pi.js");
     const { session: guardedSession } = await createFnAgent({
       cwd: "/tmp",
       systemPrompt: "test",
@@ -3044,7 +3053,7 @@ describe("createFnAgent", () => {
       _rewriteFile: rewriteFile,
     };
 
-    const { createFnAgent } = await import("../pi.js");
+    const { createPiAgentSessionRaw: createFnAgent } = await import("../pi.js");
     await createFnAgent({
       cwd: "/tmp",
       systemPrompt: "test",
@@ -3090,7 +3099,7 @@ describe("createFnAgent", () => {
     };
     createAgentSessionMock.mockResolvedValueOnce({ session });
 
-    const { createFnAgent } = await import("../pi.js");
+    const { createPiAgentSessionRaw: createFnAgent } = await import("../pi.js");
     await createFnAgent({
       cwd: "/tmp",
       systemPrompt: "test",
@@ -3134,7 +3143,7 @@ describe("createFnAgent", () => {
       },
     });
 
-    const { createFnAgent } = await import("../pi.js");
+    const { createPiAgentSessionRaw: createFnAgent } = await import("../pi.js");
 
     await expect(createFnAgent({
       cwd: "/tmp",
@@ -3164,7 +3173,7 @@ describe("createFnAgent", () => {
     const anyModel = { provider: "anthropic", id: "claude" } as never;
 
     async function createAndCaptureRuntime(overrides: Record<string, unknown> = {}) {
-      const { createFnAgent } = await import("../pi.js");
+      const { createPiAgentSessionRaw: createFnAgent } = await import("../pi.js");
       await createFnAgent({
         cwd: "/tmp",
         systemPrompt: "test",
@@ -3283,7 +3292,7 @@ describe("createFnAgent", () => {
         },
       }));
 
-      const { createFnAgent: freshCreateFnAgent } = await import("../pi.js");
+      const { createPiAgentSessionRaw: freshCreateFnAgent } = await import("../pi.js");
 
       await freshCreateFnAgent({
         cwd: "/tmp",
@@ -3374,7 +3383,7 @@ describe("createFnAgent", () => {
         },
       }));
 
-      const { createFnAgent: freshCreateFnAgent } = await import("../pi.js");
+      const { createPiAgentSessionRaw: freshCreateFnAgent } = await import("../pi.js");
 
       await freshCreateFnAgent({
         cwd: "/tmp",
@@ -3396,7 +3405,15 @@ describe("createFnAgent", () => {
       }
     });
 
-    it("with skillSelection (specific requested names) activates skill filtering", async () => {
+    /*
+    FNXC:SkillResolution 2026-08-16-15:12:
+    FN-9114 changed requested skill names from an allow-list to ensure-present:
+    all enabled discovered skills stay available, and requested names only
+    guarantee inclusion (agent metadata is no longer an availability filter).
+    This test previously asserted the pre-FN-9114 allow-list narrowing and was
+    the one call-site-level assertion missed by that commit's test sweep.
+    */
+    it("with skillSelection (specific requested names) keeps all discovered skills and ensures requested ones are present", async () => {
       let capturedResourceLoaderOptions: any;
       vi.doMock("@earendil-works/pi-coding-agent", () => ({
         LegacyCredentialStorage: {
@@ -3462,7 +3479,7 @@ describe("createFnAgent", () => {
         },
       }));
 
-      const { createFnAgent: freshCreateFnAgent } = await import("../pi.js");
+      const { createPiAgentSessionRaw: freshCreateFnAgent } = await import("../pi.js");
 
       await freshCreateFnAgent({
         cwd: "/tmp",
@@ -3487,9 +3504,12 @@ describe("createFnAgent", () => {
         diagnostics: [],
       });
 
-      // Only paperclip should pass through (matching requested name)
-      expect(result.skills).toHaveLength(1);
-      expect(result.skills[0].name).toBe("paperclip");
+      // FN-9114: requested names are ensure-present, not an allow-list — every
+      // discovered skill stays available and the requested one is included.
+      expect(result.skills).toHaveLength(2);
+      expect(result.skills.map((skill: { name: string }) => skill.name)).toEqual(
+        expect.arrayContaining(["paperclip", "lint"]),
+      );
     });
 
     it("diagnostics are logged via structured logger with [skills] context", async () => {
diff --git a/packages/engine/src/agents/agent-session-helpers.ts b/packages/engine/src/agents/agent-session-helpers.ts
index 57ff4461ac..eb6b4d3b8d 100644
--- a/packages/engine/src/agents/agent-session-helpers.ts
+++ b/packages/engine/src/agents/agent-session-helpers.ts
@@ -48,6 +48,7 @@ import {
   wrapToolsWithRtkRewrite,
   type FallbackModelUsedPayload,
 } from "../pi.js";
+import * as piModuleForRegistration from "../pi.js";
 import type { RunAuditor } from "../util/run-audit.js";
 import { createFusionAuthStorage, resolveCredentialInstanceRef, type FusionAuthStorage } from "../auth/auth-storage.js";
 import { MockAgentRuntime } from "../providers/mock-provider.js";
@@ -1180,3 +1181,28 @@ export async function promptWithAutoRetry(
 export async function describeAgentModel(session: AgentSession): Promise<string> {
   return describeModel(session);
 }
+
+/*
+FNXC:CliRuntimeRouting 2026-08-16-14:37:
+Register this module's createResolvedAgentSession as pi.ts's routed session
+factory so bare `createFnAgent` callers get CLI runtime routing (cursor/claude/
+grok/omp/hermes), mock forcing, and runtime-resolved visibility without every
+lane importing the seam. Late-binding registration (mirrors core's
+setCreateFnAgent) instead of a static pi.ts -> agent-session-helpers import,
+which would create an eval-order-sensitive cycle (this module and
+runtime-resolution both import pi.ts). Runs once at module load; any host that
+loads @fusion/engine's index (all real hosts) gets it.
+
+Namespace access + try/catch on purpose: dozens of engine tests replace
+"../pi.js" with pure vi.mock factories that predate this export, and vitest's
+mock proxy THROWS on access to a missing export. Under such mocks the
+registration is skipped and their mocked createFnAgent behaves as before.
+*/
+try {
+  (piModuleForRegistration as { registerRoutedAgentSessionFactory?: (factory: (options: Record<string, unknown>) => Promise<import("../pi.js").AgentResult>) => void })
+    .registerRoutedAgentSessionFactory?.(
+      createResolvedAgentSession as unknown as (options: Record<string, unknown>) => Promise<import("../pi.js").AgentResult>,
+    );
+} catch {
+  // Mocked pi.js without the export: leave createFnAgent on its raw fallback.
+}
diff --git a/packages/engine/src/execution/runtime-resolution.ts b/packages/engine/src/execution/runtime-resolution.ts
index b85ed365c1..0ccd872ae9 100644
--- a/packages/engine/src/execution/runtime-resolution.ts
+++ b/packages/engine/src/execution/runtime-resolution.ts
@@ -108,11 +108,13 @@ export class DefaultPiRuntime implements AgentRuntime {
     Forward the resolved session budget explicitly across the default-pi bridge. A project setting of 0 becomes null before this point and must reach createFnAgent so the pi wrapper skips clamping just like plugin runtimes.
     */
     const { toolOutputMaxChars, mcpServers, ...agentOptions } = options;
+    // FNXC:CliRuntimeRouting 2026-08-16-14:37: `__rawPiSession` short-circuits createFnAgent's routed path — the seam resolved to THIS runtime, so routing the bridge again would recurse. createFnAgent stays the bridge target so tests mocking it keep intercepting pi-session construction.
     const result = await createFnAgent({
       ...agentOptions,
       toolOutputMaxChars,
       mcpServers: normalizeAgentRuntimeMcpServers(mcpServers),
-    });
+      __rawPiSession: true,
+    } as Parameters<typeof createFnAgent>[0]);
     /*
     FNXC:TriagePlanningRetry 2026-08-03-01:10:
     Pi dispatches fallback notification work before its prompt resolves, so it has a known finite
diff --git a/packages/engine/src/pi.ts b/packages/engine/src/pi.ts
index 693c05ef7f..4ac6168127 100644
--- a/packages/engine/src/pi.ts
+++ b/packages/engine/src/pi.ts
@@ -2313,7 +2313,112 @@ function withMcpPromptOptions(promptOptions: unknown, mcpServers: ResolvedMcpSer
   return { mcpServers };
 }
 
+/*
+FNXC:CliRuntimeRouting 2026-08-16-14:37:
+`createFnAgent` is now a ROUTED entry point: it delegates to the shared
+`createResolvedAgentSession` seam (registered below via
+`registerRoutedAgentSessionFactory` to avoid a static import cycle) so every
+caller — not just chat/executor/planning — gets CLI runtime routing
+(cursor-cli/claude-cli/hermes/omp-cli/no-key grok-cli), mock/test-mode forcing,
+and `session:runtime-resolved` visibility. Bare `createFnAgent` calls used to
+pin sessions to the default pi runtime, so a CLI-runtime model selection died
+with "not found in the pi model registry" in any lane that had not been
+individually migrated to the seam (mission interview was the third such
+incident after planning's 401 and this cursor one).
+
+The raw pi implementation lives on as `createPiAgentSessionRaw`, which is what
+`DefaultPiRuntime` (execution/runtime-resolution.ts) must call — the seam
+resolves to that runtime, so routing the runtime's own bridge through the seam
+again would recurse forever. When no routed factory is registered (isolated
+unit tests importing only pi.ts), `createFnAgent` falls back to the raw path,
+preserving pre-existing test behavior.
+
+Callers without an explicit `pluginRunner` resolve one from the host-registered
+default registry (`registerDefaultAgentPluginRunner`, populated by
+InProcessRuntime at plugin-system init), keyed by project root and matched by
+session cwd prefix so multi-project hosts route each session against its own
+project's plugin set.
+*/
+type RoutedAgentSessionFactory = (options: Record<string, unknown>) => Promise<AgentResult>;
+/*
+FNXC:CliRuntimeRouting 2026-08-16-14:37:
+`var` + lazy-init on purpose: agent-session-helpers registers the factory at
+its own module load, and under the pi.ts <-> helpers import cycle that call can
+run while pi.ts is still mid-evaluation. A `let`/`const` here sits in its
+temporal dead zone during that window and made every hoisted createFnAgent
+call throw "Cannot access before initialization"; `var` is hoisted-initialized
+and the Map is created on first touch.
+*/
+// eslint-disable-next-line no-var
+var routedAgentSessionFactory: RoutedAgentSessionFactory | undefined;
+// eslint-disable-next-line no-var
+var defaultAgentPluginRunners: Map<string, unknown> | undefined;
+
+function agentPluginRunnerRegistry(): Map<string, unknown> {
+  return (defaultAgentPluginRunners ??= new Map());
+}
+
+/** Late-binding registration seam (mirrors core's `setCreateFnAgent`): agent-session-helpers registers `createResolvedAgentSession` at module load. */
+export function registerRoutedAgentSessionFactory(factory: RoutedAgentSessionFactory): void {
+  routedAgentSessionFactory = factory;
+}
+
+/** Register a host PluginRunner as the ambient default for bare `createFnAgent` callers in the project rooted at `rootDir`. */
+export function registerDefaultAgentPluginRunner(rootDir: string, pluginRunner: unknown): void {
+  agentPluginRunnerRegistry().set(rootDir, pluginRunner);
+}
+
+export function unregisterDefaultAgentPluginRunner(rootDir: string): void {
+  agentPluginRunnerRegistry().delete(rootDir);
+}
+
+/** Resolve the ambient PluginRunner for a session cwd: longest registered project-root prefix wins; a sole registered runner matches any cwd. */
+function resolveDefaultAgentPluginRunner(cwd: string | undefined): unknown {
+  const registry = agentPluginRunnerRegistry();
+  if (registry.size === 0) return undefined;
+  if (cwd) {
+    let best: { rootDir: string; runner: unknown } | undefined;
+    for (const [rootDir, runner] of registry) {
+      if ((cwd === rootDir || cwd.startsWith(`${rootDir}/`)) && (!best || rootDir.length > best.rootDir.length)) {
+        best = { rootDir, runner };
+      }
+    }
+    if (best) return best.runner;
+  }
+  if (registry.size === 1) {
+    return registry.values().next().value;
+  }
+  return undefined;
+}
+
 export async function createFnAgent(options: AgentOptions): Promise<AgentResult> {
+  /*
+  FNXC:CliRuntimeRouting 2026-08-16-14:37:
+  `__rawPiSession` is DefaultPiRuntime's re-entry marker: the seam resolves to
+  that runtime, whose bridge calls back into createFnAgent (kept as the bridge
+  target so existing tests that mock createFnAgent still intercept pi-session
+  construction). The marker short-circuits to the raw constructor instead of
+  routing again, which would recurse forever.
+  */
+  const { __rawPiSession, ...routableOptions } = options as AgentOptions & { __rawPiSession?: boolean };
+  if (!__rawPiSession && routedAgentSessionFactory) {
+    const optionsWithRouting = routableOptions as AgentOptions & { pluginRunner?: unknown; runtimeHint?: string };
+    const pluginRunner = optionsWithRouting.pluginRunner ?? resolveDefaultAgentPluginRunner(routableOptions.cwd);
+    return routedAgentSessionFactory({
+      ...routableOptions,
+      sessionPurpose: routableOptions.sessionPurpose ?? "executor",
+      ...(pluginRunner ? { pluginRunner } : {}),
+    });
+  }
+  return createPiAgentSessionRaw(routableOptions as AgentOptions);
+}
+
+/**
+ * Raw pi-runtime session construction. Internal to the runtime layer: only
+ * `DefaultPiRuntime` (and the unregistered-factory fallback above) may call
+ * this — every product lane goes through `createFnAgent`'s routed path.
+ */
+export async function createPiAgentSessionRaw(options: AgentOptions): Promise<AgentResult> {
   /*
   FNXC:EngineDiagnostics 2026-07-26-09:55:
   createFnAgent is invoked on every agent/session start (executor, triage, chat, heartbeat, etc.). The entry log is steady-state bookkeeping — debug-only (FUSION_DEBUG=pi). Failures and auth issues stay on warn/error.
diff --git a/packages/engine/src/runtimes/in-process-runtime.ts b/packages/engine/src/runtimes/in-process-runtime.ts
index c647bf92be..5f4701234b 100644
--- a/packages/engine/src/runtimes/in-process-runtime.ts
+++ b/packages/engine/src/runtimes/in-process-runtime.ts
@@ -29,6 +29,7 @@ import {
   resolveTaskLifecycleColumns,
 } from "@fusion/core";
 import { Scheduler } from "../scheduler.js";
+import { registerDefaultAgentPluginRunner, unregisterDefaultAgentPluginRunner } from "../pi.js";
 import type { PrMonitor, PrComment } from "../merge/pr-monitor.js";
 import type { PrInfo } from "@fusion/core";
 import { TaskExecutor, type TaskExecutorOptions } from "../executor.js";
@@ -1123,6 +1124,17 @@ export class InProcessRuntime
         rootDir: this.config.workingDirectory,
       });
       await this.pluginRunner.init();
+      /*
+      FNXC:CliRuntimeRouting 2026-08-16-14:37:
+      Publish this project's PluginRunner as the ambient default for bare
+      `createFnAgent` callers (research providers, cron, evaluator, reflection,
+      core DI lanes, dashboard side-lanes) so their sessions route CLI-runtime
+      model selections (cursor-cli etc.) through the plugin runtime instead of
+      dying in pi's model registry. Keyed by project root; createFnAgent matches
+      the session cwd against registered roots so multi-project hosts stay
+      project-scoped.
+      */
+      registerDefaultAgentPluginRunner(this.config.workingDirectory, this.pluginRunner);
       /*
        * FNXC:PluginMcpServers 2026-07-22-12:00:
        * FN-8491 installs the sole session-facing provider on the project store.
@@ -2343,6 +2355,8 @@ export class InProcessRuntime
 
       // 8. Shutdown plugin runner
       if (this.pluginRunner) {
+        // FNXC:CliRuntimeRouting 2026-08-16-14:37: retract the ambient default runner published at init so bare createFnAgent callers never resolve a shut-down runner.
+        unregisterDefaultAgentPluginRunner(this.config.workingDirectory);
         await this.pluginRunner.shutdown();
         runtimeLog.log("PluginRunner shutdown complete");
       }