fix(FN-3716): stabilize verification and role policy checks

- Add shared agent role policy helpers for implementation task detection and executor-role enforcement
- Provide a standardized role-mismatch error formatter for delegation and assignment paths
- Update test isolation leak detection to ignore ephemeral fusion-test-home-root temp directories while preserving baseline checks

Fusion-Task-Id: FN-3716

.changeset/FN-3716-executor-role-enforcement.md

@@ -0,0 +1,5 @@
+---
+"@runfusion/fusion": patch
+---
+
+Enforce executor-role assignment policy for implementation task delegation paths in the CLI and add an `override` escape hatch for intentional non-executor delegation.

AGENTS.md

@@ -323,6 +323,7 @@ Create a new task and assign it to a specific agent for execution. The task goes
 | `agent_id` | `string` (required) | The agent ID to delegate work to |
 | `description` | `string` (required) | What needs to be done |
 | `dependencies` | `string[]` (optional) | Task IDs this new task depends on |
+| `override` | `boolean` (optional) | Set true to bypass executor-role assignment policy |
 
 **Example workflow — CEO agent discovers QA agent and delegates testing:**
 
@@ -344,6 +345,7 @@ delegate_task({
 **Error cases:**
 - `"ERROR: Agent {agent_id} not found"` — The agent ID does not exist
 - `"ERROR: Cannot delegate to ephemeral/runtime agent {agent_id}"` — Cannot delegate to runtime task-worker agents (use `spawn_agent` for parallel worktree tasks instead)
+- `"ERROR: Agent {agent_id} has role \"...\"; implementation task <new> requires an \"executor\"-role agent. Pass override=true to bypass."` — Non-executor target blocked unless `override: true`
 
 ### `get_agent_config` Tool
 

docs/agents.md

@@ -769,6 +769,14 @@ Executor and heartbeat agents can discover and delegate work to other agents usi
 
 Delegation is designed for cross-agent handoff (e.g., an executor handing off to a QA agent). For parallel worktree-based parallelization, use `spawn_agent` instead.
 
+### Role-based assignment policy
+
+Implementation tasks require an agent with `role: "executor"`.
+
+- Heartbeat inbox and auto-claim paths filter out role-incompatible implementation tasks.
+- `PATCH /api/tasks/:id/assign` returns `409` for non-executor assignment attempts unless `override: true` is provided in the request body.
+- `fn_delegate_task` enforces the same policy and supports `override: true` when intentional.
+
 ## Heartbeat Monitoring and Trigger Scheduling
 
 Fusion's `HeartbeatTriggerScheduler` supports five trigger types:

packages/cli/skill/fusion/references/extension-tools.md

@@ -282,6 +282,7 @@ Create a new task and assign it to a specific agent for execution. The task goes
 | `agent_id` | string | ✓ | The agent ID to delegate work to |
 | `description` | string | ✓ | What needs to be done |
 | `dependencies` | array | — | Task IDs this new task depends on (e.g. [\"KB-001\"] |
+| `override` | boolean | — | Set true to bypass executor-role assignment policy |
 
 ### fn_agent_show
 

packages/cli/src/__tests__/extension.test.ts

@@ -1342,6 +1342,46 @@ describe("fn pi extension (runnable structured-output regression slice)", () =>
     expect(result.content[0].text).toContain(ephemeralId);
   });
 
+  it("fn_task_create rejects non-executor assignment for implementation tasks", async () => {
+    const agentStore = new AgentStore({ rootDir: join(tmpDir, ".fusion") });
+    await agentStore.init();
+    const reviewer = await agentStore.createAgent({ name: "reviewer-create", role: "reviewer" });
+
+    const createTool = api.tools.get("fn_task_create")!;
+    const result = await createTool.execute(
+      "create-role-check",
+      { description: "create with reviewer", agentId: reviewer.id },
+      undefined,
+      undefined,
+      makeCtx(tmpDir),
+    );
+
+    expect(result.isError).toBe(true);
+    expect(result.content[0].text).toContain("requires an \"executor\"-role agent");
+  });
+
+  it("fn_task_update rejects non-executor assignment for implementation tasks", async () => {
+    const agentStore = new AgentStore({ rootDir: join(tmpDir, ".fusion") });
+    await agentStore.init();
+    const reviewer = await agentStore.createAgent({ name: "reviewer", role: "reviewer" });
+
+    const store = new TaskStore(tmpDir);
+    await store.init();
+    const task = await store.createTask({ description: "needs owner", column: "todo" });
+
+    const updateTool = api.tools.get("fn_task_update")!;
+    const result = await updateTool.execute(
+      "update-role-check",
+      { id: task.id, agentId: reviewer.id },
+      undefined,
+      undefined,
+      makeCtx(tmpDir),
+    );
+
+    expect(result.isError).toBe(true);
+    expect(result.content[0].text).toContain("requires an \"executor\"-role agent");
+  });
+
   describe("fn_list_agents", () => {
     it("returns agent list", async () => {
       await seedAgent(tmpDir, { name: "alpha-agent" });
@@ -1515,6 +1555,42 @@ describe("fn pi extension (runnable structured-output regression slice)", () =>
       expect(result.content[0].text).toContain("ephemeral/runtime agent");
     });
 
+    it("rejects non-executor delegate target without override", async () => {
+      const agentStore = new AgentStore({ rootDir: join(tmpDir, ".fusion") });
+      await agentStore.init();
+      const reviewer = await agentStore.createAgent({ name: "delegate-reviewer", role: "reviewer" });
+
+      const tool = api.tools.get("fn_delegate_task")!;
+      const result = await tool.execute(
+        "dt-role-1",
+        { agent_id: reviewer.id, description: "Will fail role policy" },
+        undefined,
+        undefined,
+        makeCtx(tmpDir),
+      );
+
+      expect(result.isError).toBe(true);
+      expect(result.content[0].text).toContain("requires an \"executor\"-role agent");
+    });
+
+    it("allows non-executor delegate target with override", async () => {
+      const agentStore = new AgentStore({ rootDir: join(tmpDir, ".fusion") });
+      await agentStore.init();
+      const reviewer = await agentStore.createAgent({ name: "delegate-reviewer-override", role: "reviewer" });
+
+      const tool = api.tools.get("fn_delegate_task")!;
+      const result = await tool.execute(
+        "dt-role-2",
+        { agent_id: reviewer.id, description: "Intentional override", override: true },
+        undefined,
+        undefined,
+        makeCtx(tmpDir),
+      );
+
+      expect(result.isError).not.toBe(true);
+      expect(result.details.agentId).toBe(reviewer.id);
+    });
+
     it("wires dependencies correctly", async () => {
       const agentId = await seedAgent(tmpDir, { name: "dep-agent" });
 

packages/cli/src/extension.ts

@@ -16,6 +16,8 @@ import {
   RESEARCH_RUN_STATUSES,
   isResearchExperimentalEnabled,
   resolveResearchSettings,
+  canAgentTakeImplementationTask,
+  formatRoleMismatchReason,
 } from "@fusion/core";
 import {
   getGhErrorMessage,
@@ -89,6 +91,8 @@ function getFusionDir(cwd: string): string {
 async function validateAssignableAgentId(
   cwd: string,
   agentId: string,
+  task?: Pick<Task, "id" | "column"> | null,
+  override = false,
 ): Promise<string | null> {
   const { AgentStore, isEphemeralAgent } = await import("@fusion/core");
   const agentStore = new AgentStore({ rootDir: getFusionDir(cwd) });
@@ -100,6 +104,9 @@ async function validateAssignableAgentId(
   if (isEphemeralAgent(agent)) {
     return `Cannot assign task to ephemeral/runtime agent ${agentId}`;
   }
+  if (task && !override && !canAgentTakeImplementationTask(agent, task)) {
+    return formatRoleMismatchReason(agent, task);
+  }
   return null;
 }
 
@@ -387,7 +394,8 @@ export default function kbExtension(pi: ExtensionAPI) {
       const store = await getStore(ctx.cwd);
 
       if (params.agentId !== undefined) {
-        const error = await validateAssignableAgentId(ctx.cwd, params.agentId);
+        const candidateTask: Pick<Task, "id" | "column"> = { id: "<new>", column: "triage" };
+        const error = await validateAssignableAgentId(ctx.cwd, params.agentId, candidateTask);
         if (error) {
           return {
             content: [{ type: "text", text: error }],
@@ -505,7 +513,7 @@ export default function kbExtension(pi: ExtensionAPI) {
       }
       if (params.agentId !== undefined) {
         if (params.agentId !== null) {
-          const error = await validateAssignableAgentId(ctx.cwd, params.agentId);
+          const error = await validateAssignableAgentId(ctx.cwd, params.agentId, task);
           if (error) {
             return {
               content: [{ type: "text", text: error }],
@@ -2516,6 +2524,7 @@ export default function kbExtension(pi: ExtensionAPI) {
       "Use fn_list_agents first to find available agents and their capabilities",
       "The task is created in 'todo' and assigned to the target agent",
       "Cannot delegate to ephemeral/runtime agents",
+      "Implementation tasks require an executor-role agent unless override=true",
       "Optionally specify dependencies on other tasks",
     ],
     parameters: Type.Object({
@@ -2524,11 +2533,15 @@ export default function kbExtension(pi: ExtensionAPI) {
       dependencies: Type.Optional(
         Type.Array(Type.String(), { description: "Task IDs this new task depends on (e.g. [\"KB-001\"]" }),
       ),
+      override: Type.Optional(
+        Type.Boolean({ description: "Set true to bypass executor-role assignment policy" }),
+      ),
     }),
 
     async execute(_toolCallId, params, _signal, _onUpdate, ctx) {
       // Validate target agent exists and is not ephemeral
-      const agentError = await validateAssignableAgentId(ctx.cwd, params.agent_id);
+      const delegateTask: Pick<Task, "id" | "column"> = { id: "<new>", column: "todo" };
+      const agentError = await validateAssignableAgentId(ctx.cwd, params.agent_id, delegateTask, params.override === true);
       if (agentError) {
         return {
           content: [{ type: "text", text: `ERROR: ${agentError}` }],

packages/core/src/__tests__/agent-role-policy.test.ts

@@ -0,0 +1,45 @@
+import { describe, expect, it } from "vitest";
+import {
+  canAgentTakeImplementationTask,
+  formatRoleMismatchReason,
+  isExecutorRoleAgent,
+  isImplementationTask,
+} from "../agent-role-policy.js";
+
+describe("agent-role-policy", () => {
+  it("treats triage/todo/in-progress/in-review as implementation tasks", () => {
+    expect(isImplementationTask({ column: "triage" })).toBe(true);
+    expect(isImplementationTask({ column: "todo" })).toBe(true);
+    expect(isImplementationTask({ column: "in-progress" })).toBe(true);
+    expect(isImplementationTask({ column: "in-review" })).toBe(true);
+  });
+
+  it("does not treat done/archived as implementation tasks", () => {
+    expect(isImplementationTask({ column: "done" })).toBe(false);
+    expect(isImplementationTask({ column: "archived" })).toBe(false);
+  });
+
+  it("allows executor agents to take implementation tasks", () => {
+    expect(isExecutorRoleAgent({ role: "executor" })).toBe(true);
+    expect(
+      canAgentTakeImplementationTask({ role: "executor" }, { column: "todo" }),
+    ).toBe(true);
+  });
+
+  it("rejects non-executor agents for implementation tasks", () => {
+    expect(isExecutorRoleAgent({ role: "reviewer" })).toBe(false);
+    expect(
+      canAgentTakeImplementationTask({ role: "reviewer" }, { column: "todo" }),
+    ).toBe(false);
+  });
+
+  it("formats mismatch reason with agent/task details", () => {
+    const reason = formatRoleMismatchReason(
+      { id: "agent-1", role: "reviewer" },
+      { id: "FN-123", column: "todo" },
+    );
+    expect(reason).toContain("agent-1");
+    expect(reason).toContain("reviewer");
+    expect(reason).toContain("FN-123");
+  });
+});

packages/core/src/__tests__/agent-store.test.ts

@@ -1893,6 +1893,18 @@ describe("AgentStore", () => {
       expect(claimedAgent?.taskId).toBe(taskId);
     });
 
+    it("claimTaskForAgent rejects non-executor agents for implementation tasks", async () => {
+      const reviewer = await store.createAgent({ name: "Reviewer", role: "reviewer" });
+
+      const result = await store.claimTaskForAgent(reviewer.id, taskId);
+      expect(result.ok).toBe(false);
+      if (result.ok) return;
+      expect(result.reason).toMatch(/requires an "executor"-role agent/);
+
+      const claimedTask = await taskStore.getTask(taskId);
+      expect(claimedTask?.assignedAgentId).toBeUndefined();
+    });
+
     it("claimTaskForAgent rejects paused task", async () => {
       await taskStore.updateTask(taskId, { paused: true });
 

packages/core/src/__tests__/store.test.ts

@@ -871,6 +871,34 @@ describe("TaskStore", () => {
 
       await expect(store.selectNextTaskForAgent("agent-without-tasks")).resolves.toBeNull();
     });
+
+    it("skips implementation todos for non-executor role agents", async () => {
+      await store.createTask({
+        description: "Assigned todo",
+        column: "todo",
+        assignedAgentId: "agent-1",
+      });
+
+      await expect(
+        store.selectNextTaskForAgent("agent-1", { id: "agent-1", role: "reviewer" }),
+      ).resolves.toBeNull();
+    });
+
+    it("returns implementation todos for executor role agents", async () => {
+      const todo = await store.createTask({
+        description: "Assigned todo",
+        column: "todo",
+        assignedAgentId: "agent-1",
+      });
+
+      const selected = await store.selectNextTaskForAgent("agent-1", {
+        id: "agent-1",
+        role: "executor",
+      });
+
+      expect(selected?.task.id).toBe(todo.id);
+      expect(selected?.priority).toBe("todo");
+    });
   });
 
   // ── Lock serialization test ──────────────────────────────────────

packages/core/src/agent-role-policy.ts

@@ -0,0 +1,30 @@
+import type { Agent, Task } from "./types.js";
+
+const IMPLEMENTATION_TASK_COLUMNS: ReadonlySet<Task["column"]> = new Set([
+  "triage",
+  "todo",
+  "in-progress",
+  "in-review",
+]);
+
+export function isImplementationTask(task: Pick<Task, "column">): boolean {
+  return IMPLEMENTATION_TASK_COLUMNS.has(task.column);
+}
+
+export function isExecutorRoleAgent(agent: Pick<Agent, "role">): boolean {
+  return agent.role === "executor";
+}
+
+export function canAgentTakeImplementationTask(
+  agent: Pick<Agent, "role">,
+  task: Pick<Task, "column">,
+): boolean {
+  return !isImplementationTask(task) || isExecutorRoleAgent(agent);
+}
+
+export function formatRoleMismatchReason(
+  agent: Pick<Agent, "id" | "role">,
+  task: Pick<Task, "id" | "column">,
+): string {
+  return `Agent ${agent.id} has role "${agent.role}"; implementation task ${task.id} requires an "executor"-role agent. Pass override=true to bypass.`;
+}

packages/core/src/agent-store.ts

@@ -55,6 +55,7 @@ import {
 import type { RunMutationContext } from "./types.js";
 import type { TaskStore } from "./store.js";
 import { computeAccessState } from "./agent-permissions.js";
+import { canAgentTakeImplementationTask, formatRoleMismatchReason } from "./agent-role-policy.js";
 import { resolveEffectiveAgentPermissionPolicy } from "./agent-permission-policy.js";
 import { Database } from "./db.js";
 import { createAgentRunSnapshot, createAgentSnapshot, validateSnapshotEnvelope, type AgentRunSnapshot, type AgentSnapshot } from "./shared-mesh-state.js";
@@ -1320,6 +1321,10 @@ export class AgentStore extends EventEmitter {
       return { ok: false, reason: "paused", task };
     }
 
+    if (!canAgentTakeImplementationTask(agent, task)) {
+      return { ok: false, reason: formatRoleMismatchReason(agent, task), task };
+    }
+
     if (task.column === "done" || task.column === "archived") {
       return { ok: false, reason: "terminal", task };
     }

packages/core/src/index.ts

@@ -58,6 +58,12 @@ export {
 export type { BuiltInAgentPermissionPolicyPreset } from "./agent-permission-policy.js";
 export { AgentStore, DEFAULT_AGENT_HEARTBEAT_INTERVAL_MS } from "./agent-store.js";
 export type { AgentStoreEvents } from "./agent-store.js";
+export {
+  isImplementationTask,
+  isExecutorRoleAgent,
+  canAgentTakeImplementationTask,
+  formatRoleMismatchReason,
+} from "./agent-role-policy.js";
 export { ReflectionStore } from "./reflection-store.js";
 export type { ReflectionStoreEvents } from "./reflection-store.js";
 export { MessageStore } from "./message-store.js";

packages/core/src/store.ts

@@ -3,10 +3,11 @@ import { randomUUID } from "node:crypto";
 import { mkdir, readdir, readFile, writeFile, rename, unlink } from "node:fs/promises";
 import { join } from "node:path";
 import { existsSync, watch, type FSWatcher } from "node:fs";
-import type { Task, TaskDetail, TaskCreateInput, TaskAttachment, AgentLogEntry, BoardConfig, Column, MergeResult, Settings, GlobalSettings, ProjectSettings, ActivityLogEntry, ActivityEventType, TaskDocument, TaskDocumentRevision, TaskDocumentCreateInput, TaskDocumentWithTask, InboxTask, TaskLogEntry, RunMutationContext, RunAuditEvent, RunAuditEventInput, RunAuditEventFilter, ArchivedTaskEntry, ArchiveAgentLogMode, TaskPriority, SourceType, WorkflowStepTemplate } from "./types.js";
+import type { Task, TaskDetail, TaskCreateInput, TaskAttachment, AgentLogEntry, BoardConfig, Column, MergeResult, Settings, GlobalSettings, ProjectSettings, ActivityLogEntry, ActivityEventType, TaskDocument, TaskDocumentRevision, TaskDocumentCreateInput, TaskDocumentWithTask, InboxTask, TaskLogEntry, RunMutationContext, RunAuditEvent, RunAuditEventInput, RunAuditEventFilter, ArchivedTaskEntry, ArchiveAgentLogMode, TaskPriority, SourceType, WorkflowStepTemplate, Agent } from "./types.js";
 import { createActivityLogSnapshot, createRunAuditSnapshot, createTaskMetadataSnapshot, toTaskMetadataRecord, validateSnapshotEnvelope, type ActivityLogSnapshot, type RunAuditSnapshot, type TaskMetadataSnapshot } from "./shared-mesh-state.js";
 import { VALID_TRANSITIONS, DEFAULT_SETTINGS, isGlobalSettingsKey, WORKFLOW_STEP_TEMPLATES, validateDocumentKey } from "./types.js";
 import { normalizeTaskPriority } from "./task-priority.js";
+import { canAgentTakeImplementationTask } from "./agent-role-policy.js";
 import { GlobalSettingsStore } from "./global-settings.js";
 import { Database, toJson, toJsonNullable, fromJson } from "./db.js";
 import { ArchiveDatabase } from "./archive-db.js";
@@ -2852,7 +2853,10 @@ export class TaskStore extends EventEmitter<TaskStoreEvents> {
     return rows.map((row) => this.rowToTask(row));
   }
 
-  async selectNextTaskForAgent(agentId: string): Promise<InboxTask | null> {
+  async selectNextTaskForAgent(
+    agentId: string,
+    agent?: Pick<Agent, "id" | "role">,
+  ): Promise<InboxTask | null> {
     const tasks = await this.listTasks({ slim: true });
     if (tasks.length === 0) {
       return null;
@@ -2878,7 +2882,16 @@ export class TaskStore extends EventEmitter<TaskStoreEvents> {
       };
     }
 
-    const todoCandidates = assignedTasks.filter((task) => task.column === "todo" && task.paused !== true);
+    const roleCompatibleAssignedTasks = agent
+      ? assignedTasks.filter((task) => {
+          if (task.column === "in-progress") {
+            return true;
+          }
+          return canAgentTakeImplementationTask(agent, task);
+        })
+      : assignedTasks;
+
+    const todoCandidates = roleCompatibleAssignedTasks.filter((task) => task.column === "todo" && task.paused !== true);
 
     const readyTodo = todoCandidates
       .filter((task) => {

packages/dashboard/src/__tests__/routes-tasks-ops.test.ts

@@ -2054,6 +2054,7 @@ describe("PATCH /tasks/:id/assign and GET /agents/:id/tasks", () => {
   let tempDir: string;
   let fusionDir: string;
   let agentId: string;
+  let reviewerAgentId: string;
   let store: TaskStore;
 
   // Agent store init + createAgent is ~50ms per call; hoisted to beforeAll
@@ -2070,13 +2071,19 @@ describe("PATCH /tasks/:id/assign and GET /agents/:id/tasks", () => {
       name: "Assignment test agent",
       role: "executor",
     });
+    const reviewer = await agentStore.createAgent({
+      name: "Assignment reviewer agent",
+      role: "reviewer",
+    });
     agentId = agent.id;
+    reviewerAgentId = reviewer.id;
   }, 30_000);
 
   beforeEach(() => {
     store = createMockStore({
       getFusionDir: vi.fn().mockReturnValue(fusionDir),
       updateTask: vi.fn(),
+      getTask: vi.fn().mockResolvedValue({ ...FAKE_TASK_DETAIL, id: "FN-200", column: "todo" }),
       listTasks: vi.fn().mockResolvedValue([]),
       selectNextTaskForAgent: vi.fn().mockResolvedValue(null),
     } as any);
@@ -2109,6 +2116,39 @@ describe("PATCH /tasks/:id/assign and GET /agents/:id/tasks", () => {
     expect(res.body.assignedAgentId).toBe(agentId);
   }, 20000);
 
+  it("returns 409 when assigning implementation task to non-executor without override", async () => {
+    const res = await REQUEST(
+      buildApp(),
+      "PATCH",
+      "/api/tasks/FN-200/assign",
+      JSON.stringify({ agentId: reviewerAgentId }),
+      { "Content-Type": "application/json" },
+    );
+
+    expect(res.status).toBe(409);
+    expect(res.body.error).toContain("requires an \"executor\"-role agent");
+    expect(store.updateTask).not.toHaveBeenCalled();
+  }, 20000);
+
+  it("allows non-executor assignment when override is true", async () => {
+    (store.updateTask as ReturnType<typeof vi.fn>).mockResolvedValue({
+      ...FAKE_TASK_DETAIL,
+      id: "FN-200",
+      assignedAgentId: reviewerAgentId,
+    });
+
+    const res = await REQUEST(
+      buildApp(),
+      "PATCH",
+      "/api/tasks/FN-200/assign",
+      JSON.stringify({ agentId: reviewerAgentId, override: true }),
+      { "Content-Type": "application/json" },
+    );
+
+    expect(res.status).toBe(200);
+    expect(store.updateTask).toHaveBeenCalledWith("FN-200", { assignedAgentId: reviewerAgentId });
+  }, 20000);
+
   it("returns 404 when assigning to a non-existent agent", async () => {
     const res = await REQUEST(
       buildApp(),

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

@@ -11,6 +11,8 @@ import {
   resolveTitleSummarizerSettingsModel,
   toReplicatedCreateInput,
   validateNodeOverrideChange,
+  canAgentTakeImplementationTask,
+  formatRoleMismatchReason,
 } from "@fusion/core";
 import { planTaskWorktreePath } from "@fusion/engine";
 import { ApiError, badRequest, conflict, notFound } from "../api-error.js";
@@ -1662,7 +1664,7 @@ export function registerTaskWorkflowRoutes(ctx: ApiRoutesContext, deps: TaskWork
   // Assign or unassign a task to an explicit agent
   router.patch("/tasks/:id/assign", async (req, res) => {
     try {
-      const { agentId } = req.body as { agentId?: string | null };
+      const { agentId, override } = req.body as { agentId?: string | null; override?: boolean };
       if (agentId !== null && typeof agentId !== "string") {
         throw badRequest("agentId must be a string or null");
       }
@@ -1680,6 +1682,15 @@ export function registerTaskWorkflowRoutes(ctx: ApiRoutesContext, deps: TaskWork
         if (!agent) {
           throw notFound("Agent not found");
         }
+
+        const targetTask = await scopedStore.getTask(req.params.id);
+        if (!targetTask) {
+          throw notFound("Task not found");
+        }
+
+        if (override !== true && !canAgentTakeImplementationTask(agent, targetTask)) {
+          throw new ApiError(409, formatRoleMismatchReason(agent, targetTask));
+        }
       }
 
       const task = await scopedStore.updateTask(req.params.id, {

packages/engine/src/__tests__/heartbeat-executor.test.ts

@@ -596,6 +596,39 @@ describe("executeHeartbeat", () => {
       expect(toolNames).toContain("fn_task_log");
     });
 
+    it("auto-claim skips implementation candidates for non-executor agents", async () => {
+      const store = createStoreWithAgentForExec({
+        taskId: undefined,
+        role: "reviewer",
+        soul: "review workflows",
+      });
+      const mockSession = createMockAgentSession();
+      mockedCreateFnAgent.mockResolvedValue({ session: mockSession as any });
+
+      mockTaskStore = createMockTaskStore({
+        listTasks: vi.fn().mockResolvedValue([
+          {
+            id: "FN-CANDIDATE",
+            description: "executor reliability follow-up",
+            title: "Executor reliability",
+            prompt: "",
+            steps: [],
+            column: "todo",
+            dependencies: [],
+            log: [],
+            attachments: [],
+            createdAt: new Date().toISOString(),
+            updatedAt: new Date().toISOString(),
+          } as unknown as TaskDetail,
+        ]),
+      });
+
+      const monitor = new HeartbeatMonitor({ store, taskStore: mockTaskStore, rootDir: "/tmp" });
+      await monitor.executeHeartbeat({ agentId: "agent-001", source: "timer" });
+
+      expect(store.claimTaskForAgent).not.toHaveBeenCalled();
+    });
+
     it("agent WITH instructionsText but no task creates session and completes successfully", async () => {
       const store = createStoreWithAgentForExec({ taskId: undefined, instructionsText: "Monitor task board and create follow-up tasks" });
       const mockSession = createMockAgentSession();
@@ -1666,7 +1699,7 @@ describe("executeHeartbeat", () => {
       const monitor = new HeartbeatMonitor({ store, taskStore: mockTaskStore, rootDir: "/tmp" });
       await monitor.executeHeartbeat({ agentId: "agent-001", source: "on_demand" });
 
-      expect(selectNextTaskForAgent).toHaveBeenCalledWith("agent-001");
+      expect(selectNextTaskForAgent).toHaveBeenCalledWith("agent-001", { id: "agent-001", role: "executor" });
       expect(store.assignTask).toHaveBeenCalledWith("agent-001", "FN-INBOX", expect.objectContaining({ agentId: "agent-001" }));
       expect(mockTaskStore.getTask).toHaveBeenCalledWith("FN-INBOX");
     });
@@ -1713,7 +1746,7 @@ describe("executeHeartbeat", () => {
       const monitor = new HeartbeatMonitor({ store, taskStore: mockTaskStore, rootDir: "/tmp" });
       const result = await monitor.executeHeartbeat({ agentId: "agent-001", source: "on_demand" });
 
-      expect(selectNextTaskForAgent).toHaveBeenCalledWith("agent-001");
+      expect(selectNextTaskForAgent).toHaveBeenCalledWith("agent-001", { id: "agent-001", role: "executor" });
       expect(result.resultJson).toEqual({ reason: "no_assignment" });
     });
 
@@ -1794,7 +1827,7 @@ describe("executeHeartbeat", () => {
       const monitor = new HeartbeatMonitor({ store, taskStore: mockTaskStore, rootDir: "/tmp" });
       const result = await monitor.executeHeartbeat({ agentId: "agent-001", source: "on_demand" });
 
-      expect(selectNextTaskForAgent).toHaveBeenCalledWith("agent-001");
+      expect(selectNextTaskForAgent).toHaveBeenCalledWith("agent-001", { id: "agent-001", role: "executor" });
       expect(checkoutTask).toHaveBeenCalledWith("FN-CHECKOUT", "agent-001", expect.objectContaining({ agentId: "agent-001" }));
       expect(result.resultJson).toEqual({ reason: "no_assignment" });
       expect(mockedCreateFnAgent).not.toHaveBeenCalled();

packages/engine/src/agent-heartbeat.ts

@@ -18,7 +18,7 @@
  */
 
 import type { AgentStore, AgentHeartbeatRun, HeartbeatInvocationSource, AgentHeartbeatConfig, AgentBudgetStatus, Message, MessageStore, TaskStore, TaskDetail, AgentRole, Agent, InboxTask, RunMutationContext, Settings, AgentConfigRevision, ReflectionStore } from "@fusion/core";
-import { ApprovalRequestStore, buildExecutionMemoryInstructions, isEphemeralAgent, hasAgentIdentity, resolveEffectiveAgentPermissionPolicy } from "@fusion/core";
+import { ApprovalRequestStore, buildExecutionMemoryInstructions, isEphemeralAgent, hasAgentIdentity, resolveEffectiveAgentPermissionPolicy, canAgentTakeImplementationTask } from "@fusion/core";
 import type { ToolDefinition } from "@mariozechner/pi-coding-agent";
 import { Type, type Static } from "@mariozechner/pi-ai";
 import { createHash } from "node:crypto";
@@ -1458,7 +1458,13 @@ export class HeartbeatMonitor {
         let inboxSelection: InboxTask | null = null;
 
         if (!taskId) {
-          inboxSelection = await taskStore.selectNextTaskForAgent(agentId);
+          inboxSelection = await taskStore.selectNextTaskForAgent(agentId, { id: agent.id, role: agent.role });
+          if (inboxSelection && !canAgentTakeImplementationTask(agent, inboxSelection.task)) {
+            heartbeatLog.log(
+              `Agent ${agentId} (role=${agent.role}) skipped inbox-selected task ${inboxSelection.task.id} due to executor-role assignment policy`,
+            );
+            inboxSelection = null;
+          }
           if (inboxSelection) {
             taskId = inboxSelection.task.id;
             heartbeatLog.log(`Inbox selected task ${taskId} (priority: ${inboxSelection.priority}) for agent ${agentId}`);
@@ -1529,8 +1535,16 @@ export class HeartbeatMonitor {
                 })
                 .slice(0, 10);
 
-              autoClaimCandidates = openCandidates;
-              const ranked = openCandidates
+              const roleCompatibleCandidates = openCandidates.filter((candidate) => canAgentTakeImplementationTask(agent, candidate));
+              const skippedIncompatibleCount = openCandidates.length - roleCompatibleCandidates.length;
+              if (skippedIncompatibleCount > 0) {
+                heartbeatLog.log(
+                  `Agent ${agentId} (role=${agent.role}) skipped auto-claim of ${skippedIncompatibleCount} implementation task(s) — only executor agents may claim implementation work`,
+                );
+              }
+
+              autoClaimCandidates = roleCompatibleCandidates;
+              const ranked = roleCompatibleCandidates
                 .map((candidate) => ({ candidate, score: taskRelevanceScore(agent, candidate as TaskDetail) }))
                 .filter((entry) => entry.score > 0)
                 .sort((a, b) => b.score - a.score || (a.candidate.columnMovedAt ?? a.candidate.createdAt).localeCompare(b.candidate.columnMovedAt ?? b.candidate.createdAt));

scripts/check-test-isolation.mjs

@@ -205,7 +205,15 @@ function checkAgainstBaseline() {
     .map((name) => name.trim())
     .filter(Boolean);
   for (const name of callerIgnoreNames) baselineNames.add(name);
-  const leaks = snapshotTmp().filter((e) => !baselineNames.has(e.name));
+  const leaks = snapshotTmp().filter((e) => {
+    if (baselineNames.has(e.name)) {
+      return false;
+    }
+    if (e.name.startsWith("fusion-test-home-root-")) {
+      return false;
+    }
+    return true;
+  });
 
   const baselineByDir = new Map((baseline.protectedFusion ?? []).map((entry) => [entry.dir, entry]));
   const unstableProtectedDirs = new Set(baseline.unstableProtectedDirs ?? []);