refactor(workflow): cleanup engine re-exports, final verification (Phase 4)

- Remove all re-exports from @uncaged/workflow -> @uncaged/workflow-runtime
- Fix cli-workflow imports to use @uncaged/workflow-runtime for types
- Update bundle-validator to allow @uncaged/workflow-runtime imports
- Update init templates to reference @uncaged/workflow-runtime
- 378 tests passing, build + check clean

Refs #121, relates #125

.gitignore

@@ -3,3 +3,4 @@ dist/
 bun.lock
 *.tgz
 tsconfig.tsbuildinfo
+.npmrc

examples/hello-world.ts

@@ -1,45 +0,0 @@
-import { createWorkflow, END, type RoleDefinition } from "@uncaged/workflow";
-import * as z from "zod/v4";
-
-type Roles = {
-  greeter: { greeting: string };
-};
-
-const greeterMetaSchema = z.object({
-  greeting: z.string(),
-});
-
-export const descriptor = {
-  description: "A simple hello world workflow",
-  roles: {
-    greeter: {
-      description: "Generates a greeting",
-      schema: {
-        type: "object",
-        properties: { greeting: { type: "string" } },
-        required: ["greeting"],
-      },
-    },
-  },
-};
-
-const greeter: RoleDefinition<Roles["greeter"]> = {
-  description: "Generates a greeting",
-  systemPrompt: "You greet the user briefly.",
-  extractPrompt: "Extract the greeting string produced for the user.",
-  schema: greeterMetaSchema,
-  extractRefs: null,
-  extractMode: "single",
-};
-
-export const run = createWorkflow<Roles>(
-  {
-    roles: { greeter },
-    moderator(ctx) {
-      return ctx.steps.length === 0 ? "greeter" : END;
-    },
-  },
-  {
-    agent: async (ctx) => `Hello, ${ctx.start.content}`,
-  },
-);

examples/package.json

@@ -1,9 +0,0 @@
-{
-  "name": "@uncaged/workflow-examples",
-  "private": true,
-  "type": "module",
-  "dependencies": {
-    "@uncaged/workflow": "workspace:*",
-    "zod": "^4.0.0"
-  }
-}

package.json

@@ -2,10 +2,10 @@
   "name": "@uncaged/workflow-monorepo",
   "private": true,
   "workspaces": [
-    "packages/*",
-    "examples"
+    "packages/*"
   ],
   "scripts": {
+    "build": "bunx tsc --build",
     "check": "bunx tsc --build && biome check .",
     "typecheck": "bunx tsc --build",
     "format": "biome format --write .",

packages/cli-workflow/__tests__/commands.test.ts

@@ -3,7 +3,13 @@ import { mkdir, mkdtemp, readFile, rm, unlink, writeFile } from "node:fs/promise
 import { tmpdir } from "node:os";
 import { join } from "node:path";
 
-import { getGlobalCasDir, getRegisteredWorkflow, readWorkflowRegistry } from "@uncaged/workflow";
+import {
+  createContentMerkleNode,
+  getGlobalCasDir,
+  getRegisteredWorkflow,
+  readWorkflowRegistry,
+  serializeMerkleNode,
+} from "@uncaged/workflow";
 import { cmdCasGet, cmdCasList, cmdCasPut, cmdCasRm } from "../src/commands/cas/index.js";
 import {
   cmdAdd,
@@ -22,6 +28,10 @@ const fixtureDescriptor = `export const descriptor = { description: "fixture", r
 const wfPutImport = `import { putContentMerkleNode } from "@uncaged/workflow";
 `;
 
+function casStoredForm(raw: string): string {
+  return serializeMerkleNode(createContentMerkleNode(raw));
+}
+
 describe("cli workflow commands", () => {
   let prevEnv: string | undefined;
   let storageRoot: string;
@@ -402,21 +412,23 @@ export const run = async function* (input, options) {
   });
 
   test("cas put/get/list/rm use global cas dir (thread id not required for storage)", async () => {
-    const put = await cmdCasPut(storageRoot, "phase doc");
+    const raw = "phase doc";
+    const stored = casStoredForm(raw);
+    const put = await cmdCasPut(storageRoot, raw);
     expect(put.ok).toBe(true);
     if (!put.ok) {
       return;
     }
     const hash = put.value;
     const blobPath = join(getGlobalCasDir(storageRoot), `${hash}.txt`);
-    expect(await readFile(blobPath, "utf8")).toBe("phase doc");
+    expect(await readFile(blobPath, "utf8")).toBe(stored);
 
     const got = await cmdCasGet(storageRoot, hash);
     expect(got.ok).toBe(true);
     if (!got.ok) {
       return;
     }
-    expect(got.value).toBe("phase doc");
+    expect(got.value).toBe(stored);
 
     const listed = await cmdCasList(storageRoot);
     expect(listed.ok).toBe(true);

packages/cli-workflow/__tests__/init-template.test.ts

@@ -51,6 +51,7 @@ describe("init template", () => {
     };
     expect(pkg.type).toBe("module");
     expect(pkg.dependencies["@uncaged/workflow"]).toBeDefined();
+    expect(pkg.dependencies["@uncaged/workflow-runtime"]).toBeDefined();
     expect(pkg.dependencies.zod).toBeDefined();
     expect(pkg.name).toContain("review-pr");
 

packages/cli-workflow/__tests__/serve.test.ts

@@ -0,0 +1,104 @@
+import { describe, expect, test } from "bun:test";
+
+import { createContentMerkleNode, serializeMerkleNode } from "@uncaged/workflow";
+
+import { createApp } from "../src/commands/serve/app.js";
+
+function casStoredForm(raw: string): string {
+  return serializeMerkleNode(createContentMerkleNode(raw));
+}
+
+function buildApp(storageRoot: string) {
+  const app = createApp(storageRoot);
+  return {
+    fetch: (path: string, init?: RequestInit) =>
+      app.fetch(new Request(`http://localhost${path}`, init)),
+  };
+}
+
+describe("serve /healthz", () => {
+  test("returns ok", async () => {
+    const { fetch } = buildApp("/tmp/uncaged-serve-test-nonexistent");
+    const res = await fetch("/healthz");
+    expect(res.status).toBe(200);
+    const body = (await res.json()) as { ok: boolean };
+    expect(body.ok).toBe(true);
+  });
+});
+
+describe("serve /api/workflows", () => {
+  test("returns empty list for missing storage", async () => {
+    const { fetch } = buildApp("/tmp/uncaged-serve-test-nonexistent");
+    const res = await fetch("/api/workflows");
+    // Registry file won't exist, should return error
+    expect(res.status).toBe(200);
+  });
+});
+
+describe("serve /api/threads", () => {
+  test("returns empty list for missing storage", async () => {
+    const { fetch } = buildApp("/tmp/uncaged-serve-test-nonexistent");
+    const res = await fetch("/api/threads");
+    expect(res.status).toBe(200);
+    const body = (await res.json()) as { threads: unknown[] };
+    expect(body.threads).toEqual([]);
+  });
+
+  test("returns 404 for missing thread", async () => {
+    const { fetch } = buildApp("/tmp/uncaged-serve-test-nonexistent");
+    const res = await fetch("/api/threads/nonexistent-id");
+    expect(res.status).toBe(404);
+  });
+});
+
+describe("serve /api/threads/running", () => {
+  test("returns empty list for missing storage", async () => {
+    const { fetch } = buildApp("/tmp/uncaged-serve-test-nonexistent");
+    const res = await fetch("/api/threads/running");
+    expect(res.status).toBe(200);
+    const body = (await res.json()) as { threads: unknown[] };
+    expect(body.threads).toEqual([]);
+  });
+});
+
+describe("serve /api/cas", () => {
+  test("returns empty list for missing storage", async () => {
+    const { fetch } = buildApp("/tmp/uncaged-serve-test-nonexistent");
+    const res = await fetch("/api/cas");
+    expect(res.status).toBe(200);
+    const body = (await res.json()) as { hashes: unknown[] };
+    expect(body.hashes).toEqual([]);
+  });
+
+  test("returns 404 for missing hash", async () => {
+    const { fetch } = buildApp("/tmp/uncaged-serve-test-nonexistent");
+    const res = await fetch("/api/cas/nonexistent-hash");
+    expect(res.status).toBe(404);
+  });
+});
+
+describe("serve CAS round-trip", () => {
+  const tmpDir = `/tmp/uncaged-serve-cas-test-${Date.now()}`;
+
+  test("put then get", async () => {
+    const { fetch } = buildApp(tmpDir);
+
+    const putRes = await fetch("/api/cas", {
+      method: "POST",
+      headers: { "Content-Type": "application/json" },
+      body: JSON.stringify({ content: "hello world" }),
+    });
+    expect(putRes.status).toBe(201);
+    const putBody = (await putRes.json()) as { hash: string };
+    expect(typeof putBody.hash).toBe("string");
+
+    const getRes = await fetch(`/api/cas/${putBody.hash}`);
+    expect(getRes.status).toBe(200);
+    const getBody = (await getRes.json()) as { content: string };
+    expect(getBody.content).toBe(casStoredForm("hello world"));
+
+    // cleanup
+    const delRes = await fetch(`/api/cas/${putBody.hash}`, { method: "DELETE" });
+    expect(delRes.status).toBe(200);
+  });
+});

packages/cli-workflow/package.json

@@ -1,12 +1,14 @@
 {
   "name": "@uncaged/cli-workflow",
-  "version": "0.1.0",
+  "version": "0.2.0",
   "type": "module",
   "bin": {
     "uncaged-workflow": "src/cli.ts"
   },
   "dependencies": {
+    "@uncaged/workflow-runtime": "workspace:*",
     "@uncaged/workflow": "workspace:*",
+    "hono": "^4.12.18",
     "yaml": "^2.8.4"
   },
   "scripts": {

packages/cli-workflow/src/cli-dispatch.ts

@@ -4,6 +4,7 @@ import { getCommandRegistry } from "./cli-registry.js";
 import { formatCliUsage as formatCliUsageWithGroups } from "./cli-usage.js";
 import { createCasDispatcher } from "./commands/cas/index.js";
 import { createInitDispatcher } from "./commands/init/index.js";
+import { dispatchServe } from "./commands/serve/index.js";
 import { createThreadDispatcher, dispatchLive, dispatchRun } from "./commands/thread/index.js";
 import { createWorkflowDispatcher } from "./commands/workflow/index.js";
 import { formatSkillIndex, formatSkillTopic, getSkillTopics } from "./skill.js";
@@ -71,6 +72,7 @@ const COMMAND_TABLE: Record<string, DispatchFn> = {
   skill: dispatchSkill,
   run: dispatchRun,
   live: dispatchLive,
+  serve: dispatchServe,
 };
 
 export async function runCli(storageRoot: string, argv: string[]): Promise<number> {

packages/cli-workflow/src/cli-usage.ts

@@ -57,6 +57,17 @@ export function formatCliUsage(
   );
   lines.push("");
 
+  lines.push("Server:");
+  lines.push(
+    ...formatUsageCommandLines([
+      {
+        prefix: "serve [--port N] [--host ADDR]",
+        description: "Start HTTP API server (default: 127.0.0.1:7860)",
+      },
+    ]),
+  );
+  lines.push("");
+
   lines.push("Reference:");
   const skillTopicNames = skillTopics.map((t) => t.name).join(", ");
   lines.push(

packages/cli-workflow/src/commands/init/templates.ts

@@ -7,6 +7,7 @@ export function templatePackageJson(templateName: string): string {
       type: "module",
       dependencies: {
         "@uncaged/workflow": "^0.1.0",
+        "@uncaged/workflow-runtime": "^0.1.0",
         zod: "^4.0.0",
       },
     },
@@ -31,7 +32,7 @@ export function templateTsconfigJson(): string {
 }
 
 export function templateRolesTs(): string {
-  return `import type { RoleDefinition } from "@uncaged/workflow";
+  return `import type { RoleDefinition } from "@uncaged/workflow-runtime";
 import * as z from "zod/v4";
 
 export const HELLO_TEMPLATE_DESCRIPTION =
@@ -58,7 +59,7 @@ export const greeterRole: RoleDefinition<HelloTemplateMeta["greeter"]> = {
 }
 
 export function templateModeratorTs(): string {
-  return `import { END, type Moderator, type ModeratorContext } from "@uncaged/workflow";
+  return `import { END, type Moderator, type ModeratorContext } from "@uncaged/workflow-runtime";
 
 import type { HelloTemplateMeta } from "./roles.js";
 
@@ -74,7 +75,7 @@ export const helloTemplateModerator: Moderator<HelloTemplateMeta> = (
 }
 
 export function templateIndexTs(): string {
-  return `import type { WorkflowDefinition } from "@uncaged/workflow";
+  return `import type { WorkflowDefinition } from "@uncaged/workflow-runtime";
 
 import { helloTemplateModerator } from "./moderator.js";
 import {

packages/cli-workflow/src/commands/serve/app.ts

@@ -0,0 +1,20 @@
+import { Hono } from "hono";
+import { cors } from "hono/cors";
+
+import { createCasRoutes } from "./routes-cas.js";
+import { createThreadRoutes } from "./routes-thread.js";
+import { createWorkflowRoutes } from "./routes-workflow.js";
+
+export function createApp(storageRoot: string): Hono {
+  const app = new Hono();
+
+  app.use("*", cors());
+
+  app.get("/healthz", (c) => c.json({ ok: true }));
+
+  app.route("/api/workflows", createWorkflowRoutes(storageRoot));
+  app.route("/api/threads", createThreadRoutes(storageRoot));
+  app.route("/api/cas", createCasRoutes(storageRoot));
+
+  return app;
+}

packages/cli-workflow/src/commands/serve/index.ts

@@ -0,0 +1,3 @@
+export { createApp } from "./app.js";
+export { dispatchServe, startServer } from "./serve.js";
+export type { ServeOptions } from "./types.js";

packages/cli-workflow/src/commands/serve/routes-cas.ts

@@ -0,0 +1,56 @@
+import { createCasStore, garbageCollectCas, getGlobalCasDir } from "@uncaged/workflow";
+import { Hono } from "hono";
+
+export function createCasRoutes(storageRoot: string): Hono {
+  const app = new Hono();
+
+  app.get("/", async (c) => {
+    const casDir = getGlobalCasDir(storageRoot);
+    const cas = createCasStore(casDir);
+    const hashes = await cas.list();
+    return c.json({ hashes });
+  });
+
+  app.get("/:hash", async (c) => {
+    const casDir = getGlobalCasDir(storageRoot);
+    const cas = createCasStore(casDir);
+    const content = await cas.get(c.req.param("hash"));
+    if (content === null) {
+      return c.json({ error: "not found" }, 404);
+    }
+    return c.json({ hash: c.req.param("hash"), content });
+  });
+
+  app.post("/", async (c) => {
+    const body = await c.req.json<{ content: string }>();
+    if (typeof body.content !== "string") {
+      return c.json({ error: "content field required" }, 400);
+    }
+    const casDir = getGlobalCasDir(storageRoot);
+    const cas = createCasStore(casDir);
+    const hash = await cas.put(body.content);
+    return c.json({ hash }, 201);
+  });
+
+  app.delete("/:hash", async (c) => {
+    const casDir = getGlobalCasDir(storageRoot);
+    const cas = createCasStore(casDir);
+    const hash = c.req.param("hash");
+    const content = await cas.get(hash);
+    if (content === null) {
+      return c.json({ error: "not found" }, 404);
+    }
+    await cas.delete(hash);
+    return c.json({ ok: true });
+  });
+
+  app.post("/gc", async (c) => {
+    const result = await garbageCollectCas(storageRoot);
+    if (!result.ok) {
+      return c.json({ error: result.error }, 500);
+    }
+    return c.json(result.value);
+  });
+
+  return app;
+}

packages/cli-workflow/src/commands/serve/routes-thread.ts

@@ -0,0 +1,46 @@
+import { Hono } from "hono";
+
+import { readTextFileIfExists } from "../../fs-utils.js";
+import {
+  listHistoricalThreads,
+  listRunningThreads,
+  resolveThreadDataPath,
+} from "../../thread-scan.js";
+
+export function createThreadRoutes(storageRoot: string): Hono {
+  const app = new Hono();
+
+  app.get("/", async (c) => {
+    const nameFilter = c.req.query("workflow") ?? null;
+    const rows = await listHistoricalThreads(storageRoot, nameFilter);
+    return c.json({ threads: rows });
+  });
+
+  app.get("/running", async (c) => {
+    const rows = await listRunningThreads(storageRoot);
+    return c.json({ threads: rows });
+  });
+
+  app.get("/:threadId", async (c) => {
+    const threadId = c.req.param("threadId");
+    const dataPath = await resolveThreadDataPath(storageRoot, threadId);
+    if (dataPath === null) {
+      return c.json({ error: `thread not found: ${threadId}` }, 404);
+    }
+    const text = await readTextFileIfExists(dataPath);
+    if (text === null) {
+      return c.json({ error: `thread data missing: ${threadId}` }, 404);
+    }
+    const lines = text.trim().split("\n");
+    const records = lines.map((line) => {
+      try {
+        return JSON.parse(line) as unknown;
+      } catch {
+        return { raw: line };
+      }
+    });
+    return c.json({ threadId, records });
+  });
+
+  return app;
+}

packages/cli-workflow/src/commands/serve/routes-workflow.ts

@@ -0,0 +1,55 @@
+import {
+  getRegisteredWorkflow,
+  listRegisteredWorkflowNames,
+  readWorkflowRegistry,
+} from "@uncaged/workflow";
+import { Hono } from "hono";
+
+export function createWorkflowRoutes(storageRoot: string): Hono {
+  const app = new Hono();
+
+  app.get("/", async (c) => {
+    const reg = await readWorkflowRegistry(storageRoot);
+    if (!reg.ok) {
+      return c.json({ error: reg.error.message }, 500);
+    }
+    const names = listRegisteredWorkflowNames(reg.value);
+    const workflows = names.map((name) => {
+      const entry = reg.value.workflows[name];
+      return {
+        name,
+        hash: entry?.hash ?? null,
+        timestamp: entry?.timestamp ?? null,
+      };
+    });
+    return c.json({ workflows });
+  });
+
+  app.get("/:name", async (c) => {
+    const reg = await readWorkflowRegistry(storageRoot);
+    if (!reg.ok) {
+      return c.json({ error: reg.error.message }, 500);
+    }
+    const name = c.req.param("name");
+    const entry = getRegisteredWorkflow(reg.value, name);
+    if (entry === null) {
+      return c.json({ error: `workflow not found: ${name}` }, 404);
+    }
+    return c.json({ name, ...entry });
+  });
+
+  app.get("/:name/history", async (c) => {
+    const reg = await readWorkflowRegistry(storageRoot);
+    if (!reg.ok) {
+      return c.json({ error: reg.error.message }, 500);
+    }
+    const name = c.req.param("name");
+    const entry = getRegisteredWorkflow(reg.value, name);
+    if (entry === null) {
+      return c.json({ error: `workflow not found: ${name}` }, 404);
+    }
+    return c.json({ name, history: entry.history });
+  });
+
+  return app;
+}

packages/cli-workflow/src/commands/serve/serve.ts

@@ -0,0 +1,69 @@
+import { err, ok, type Result } from "@uncaged/workflow";
+import { serve } from "bun";
+
+import { printCliLine } from "../../cli-output.js";
+import { createApp } from "./app.js";
+import type { ServeOptions } from "./types.js";
+
+export function startServer(storageRoot: string, options: ServeOptions): void {
+  const app = createApp(storageRoot);
+
+  const server = serve({
+    fetch: app.fetch,
+    port: options.port,
+    hostname: options.hostname,
+  });
+
+  printCliLine(`uncaged-workflow API server listening on http://${server.hostname}:${server.port}`);
+}
+
+function parsePortValue(value: string | undefined): Result<number, string> {
+  if (value === undefined) {
+    return err("--port requires a value");
+  }
+  const parsed = Number.parseInt(value, 10);
+  if (!Number.isFinite(parsed) || parsed < 0 || parsed > 65535) {
+    return err(`invalid port: ${value}`);
+  }
+  return ok(parsed);
+}
+
+function parseServeArgv(argv: string[]): Result<ServeOptions, string> {
+  let port = 7860;
+  let hostname = "127.0.0.1";
+
+  for (let i = 0; i < argv.length; i++) {
+    const arg = argv[i];
+    if (arg === "--port" || arg === "-p") {
+      const portResult = parsePortValue(argv[i + 1]);
+      if (!portResult.ok) {
+        return portResult;
+      }
+      port = portResult.value;
+      i++;
+    } else if (arg === "--host") {
+      const next = argv[i + 1];
+      if (next === undefined) {
+        return err("--host requires a value");
+      }
+      hostname = next;
+      i++;
+    }
+  }
+
+  return ok({ port, hostname });
+}
+
+export async function dispatchServe(storageRoot: string, argv: string[]): Promise<number> {
+  const parsed = parseServeArgv(argv);
+  if (!parsed.ok) {
+    printCliLine(`error: ${parsed.error}`);
+    return 1;
+  }
+
+  startServer(storageRoot, parsed.value);
+
+  // Keep process alive
+  await new Promise(() => {});
+  return 0;
+}

packages/cli-workflow/src/commands/serve/types.ts

@@ -0,0 +1,4 @@
+export type ServeOptions = {
+  port: number;
+  hostname: string;
+};

packages/cli-workflow/src/commands/thread/live.ts

@@ -9,8 +9,8 @@ import {
   getGlobalCasDir,
   tryParseRoleStepRecord,
   tryParseWorkflowResultRecord,
-  type WorkflowCompletion,
 } from "@uncaged/workflow";
+import type { WorkflowCompletion } from "@uncaged/workflow-runtime";
 
 import { dimGreyLine, highlightLiveRole } from "../../cli-color.js";
 import { printCliError, printCliLine } from "../../cli-output.js";

packages/cli-workflow/tsconfig.json

@@ -17,6 +17,6 @@
     "rootDir": "src",
     "types": ["bun-types"]
   },
-  "references": [{ "path": "../workflow" }],
+  "references": [{ "path": "../workflow-runtime" }, { "path": "../workflow" }],
   "include": ["src/**/*.ts"]
 }

packages/workflow-agent-cursor/__tests__/cursor-agent.test.ts

@@ -1,5 +1,5 @@
 import { describe, expect, test } from "bun:test";
-import type { ExtractContext, ExtractFn } from "@uncaged/workflow";
+import type { ExtractContext, ExtractFn } from "@uncaged/workflow-runtime";
 import type * as z from "zod/v4";
 import { createCursorAgent, validateCursorAgentConfig } from "../src/index.js";
 

packages/workflow-agent-cursor/package.json

@@ -1,6 +1,6 @@
 {
   "name": "@uncaged/workflow-agent-cursor",
-  "version": "0.1.0",
+  "version": "0.2.0",
   "type": "module",
   "main": "src/index.ts",
   "types": "src/index.ts",
@@ -8,7 +8,7 @@
     "test": "bun test"
   },
   "dependencies": {
-    "@uncaged/workflow": "workspace:*",
+    "@uncaged/workflow-runtime": "workspace:*",
     "@uncaged/workflow-util-agent": "workspace:*",
     "zod": "^4.0.0"
   }

packages/workflow-agent-cursor/src/index.ts

@@ -1,4 +1,4 @@
-import type { AgentFn, ExtractContext } from "@uncaged/workflow";
+import type { AgentFn, ExtractContext } from "@uncaged/workflow-runtime";
 import { buildAgentPrompt, type SpawnCliError, spawnCli } from "@uncaged/workflow-util-agent";
 import * as z from "zod/v4";
 

packages/workflow-agent-cursor/src/types.ts

@@ -1,4 +1,4 @@
-import type { ExtractFn } from "@uncaged/workflow";
+import type { ExtractFn } from "@uncaged/workflow-runtime";
 
 export type CursorAgentConfig = {
   model: string | null;

packages/workflow-agent-cursor/src/validate-config.ts

@@ -1,4 +1,4 @@
-import { err, ok, type Result } from "@uncaged/workflow";
+import { err, ok, type Result } from "@uncaged/workflow-runtime";
 
 import type { CursorAgentConfig } from "./types.js";
 

packages/workflow-agent-hermes/package.json

@@ -1,6 +1,6 @@
 {
   "name": "@uncaged/workflow-agent-hermes",
-  "version": "0.1.0",
+  "version": "0.2.0",
   "type": "module",
   "main": "src/index.ts",
   "types": "src/index.ts",
@@ -8,7 +8,7 @@
     "test": "bun test"
   },
   "dependencies": {
-    "@uncaged/workflow": "workspace:*",
+    "@uncaged/workflow-runtime": "workspace:*",
     "@uncaged/workflow-util-agent": "workspace:*"
   }
 }

packages/workflow-agent-hermes/src/index.ts

@@ -1,4 +1,4 @@
-import type { AgentFn } from "@uncaged/workflow";
+import type { AgentFn } from "@uncaged/workflow-runtime";
 import { buildAgentPrompt, type SpawnCliError, spawnCli } from "@uncaged/workflow-util-agent";
 
 import type { HermesAgentConfig } from "./types.js";

packages/workflow-agent-hermes/src/validate-config.ts

@@ -1,4 +1,4 @@
-import { err, ok, type Result } from "@uncaged/workflow";
+import { err, ok, type Result } from "@uncaged/workflow-runtime";
 
 import type { HermesAgentConfig } from "./types.js";
 

packages/workflow-agent-llm/__tests__/create-llm-adapter.test.ts

@@ -2,7 +2,8 @@ import { describe, expect, test } from "bun:test";
 import { mkdtempSync } from "node:fs";
 import { tmpdir } from "node:os";
 import { join } from "node:path";
-import { createCasStore, START, type ThreadContext } from "@uncaged/workflow";
+import { createCasStore } from "@uncaged/workflow";
+import { START, type ThreadContext } from "@uncaged/workflow-runtime";
 
 import { createLlmAdapter } from "../src/create-llm-adapter.js";
 

packages/workflow-agent-llm/package.json

@@ -1,6 +1,6 @@
 {
   "name": "@uncaged/workflow-agent-llm",
-  "version": "0.1.0",
+  "version": "0.2.0",
   "type": "module",
   "main": "src/index.ts",
   "types": "src/index.ts",
@@ -8,6 +8,7 @@
     "test": "bun test"
   },
   "dependencies": {
-    "@uncaged/workflow": "workspace:*"
+    "@uncaged/workflow": "workspace:*",
+    "@uncaged/workflow-runtime": "workspace:*"
   }
 }

packages/workflow-agent-llm/src/create-llm-adapter.ts

@@ -5,7 +5,7 @@ import {
   type LlmProvider,
   ok,
   type Result,
-} from "@uncaged/workflow";
+} from "@uncaged/workflow-runtime";
 
 /** OpenAI chat completion message shape (passed to `/chat/completions`). */
 export type LlmMessage = { role: "system" | "user" | "assistant"; content: string };

packages/workflow-runtime/package.json

@@ -0,0 +1,16 @@
+{
+  "name": "@uncaged/workflow-runtime",
+  "version": "0.2.0",
+  "type": "module",
+  "main": "src/index.ts",
+  "types": "src/index.ts",
+  "scripts": {
+    "test": "bun test"
+  },
+  "peerDependencies": {
+    "zod": "^4.0.0"
+  },
+  "devDependencies": {
+    "zod": "^4.0.0"
+  }
+}

packages/workflow-runtime/src/bundle/index.ts

@@ -0,0 +1,2 @@
+export type { WorkflowDescriptor, WorkflowRoleDescriptor, WorkflowRoleSchema } from "./types.js";
+export { validateWorkflowDescriptor } from "./workflow-descriptor.js";

packages/workflow-runtime/src/bundle/types.ts

@@ -0,0 +1,13 @@
+/** JSON Schema fragment describing one role's `meta` shape (subset supported by code generation). */
+export type WorkflowRoleSchema = Record<string, unknown>;
+
+export type WorkflowRoleDescriptor = {
+  description: string;
+  schema: WorkflowRoleSchema;
+};
+
+/** Workflow metadata exported as `export const descriptor` from `.esm.js` bundles. */
+export type WorkflowDescriptor = {
+  description: string;
+  roles: Record<string, WorkflowRoleDescriptor>;
+};

packages/workflow-runtime/src/bundle/workflow-descriptor.ts

@@ -0,0 +1,40 @@
+import { err, ok, type Result } from "../util/index.js";
+
+import type { WorkflowDescriptor, WorkflowRoleDescriptor, WorkflowRoleSchema } from "./types.js";
+
+export function validateWorkflowDescriptor(value: unknown): Result<WorkflowDescriptor, string> {
+  if (value === null || typeof value !== "object" || Array.isArray(value)) {
+    return err("descriptor must be a non-array object");
+  }
+  const root = value as Record<string, unknown>;
+  const description = root.description;
+  if (typeof description !== "string") {
+    return err("descriptor.description must be a string");
+  }
+  const rolesRaw = root.roles;
+  if (rolesRaw === null || typeof rolesRaw !== "object" || Array.isArray(rolesRaw)) {
+    return err("descriptor.roles must be a non-array object");
+  }
+
+  const roles: Record<string, WorkflowRoleDescriptor> = {};
+  for (const [roleName, specUnknown] of Object.entries(rolesRaw)) {
+    if (specUnknown === null || typeof specUnknown !== "object" || Array.isArray(specUnknown)) {
+      return err(`descriptor.roles.${roleName} must be a non-array object`);
+    }
+    const spec = specUnknown as Record<string, unknown>;
+    const roleDesc = spec.description;
+    if (typeof roleDesc !== "string") {
+      return err(`descriptor.roles.${roleName}.description must be a string`);
+    }
+    const schema = spec.schema;
+    if (schema === null || typeof schema !== "object" || Array.isArray(schema)) {
+      return err(`descriptor.roles.${roleName}.schema must be a non-array object`);
+    }
+    roles[roleName] = {
+      description: roleDesc,
+      schema: schema as WorkflowRoleSchema,
+    };
+  }
+
+  return ok({ description, roles });
+}

packages/workflow-runtime/src/cas/index.ts

@@ -0,0 +1 @@
+export type { CasStore } from "./types.js";

packages/workflow-runtime/src/cas/types.ts

@@ -0,0 +1,6 @@
+export type CasStore = {
+  put(content: string): Promise<string>;
+  get(hash: string): Promise<string | null>;
+  delete(hash: string): Promise<void>;
+  list(): Promise<string[]>;
+};

packages/workflow-runtime/src/engine/create-workflow.ts

@@ -0,0 +1,185 @@
+import type { CasStore } from "../cas/types.js";
+import {
+  type AgentBinding,
+  type AgentContext,
+  type AgentFn,
+  END,
+  type ExtractContext,
+  type ModeratorContext,
+  type ResolveRoleMetaFn,
+  type RoleDefinition,
+  type RoleMeta,
+  type RoleOutput,
+  type RoleStep,
+  START,
+  type ThreadInput,
+  type WorkflowCompletion,
+  type WorkflowDefinition,
+  type WorkflowFn,
+  type WorkflowFnOptions,
+} from "../types.js";
+import { mergeRefsWithContentHash } from "../util/index.js";
+
+function isRoleNext<M extends RoleMeta>(
+  next: (keyof M & string) | typeof END,
+): next is keyof M & string {
+  return next !== END;
+}
+
+function resolveExtractedRefs(
+  roleDef: RoleDefinition<Record<string, unknown>>,
+  meta: unknown,
+): string[] {
+  const extractRefsFn = roleDef.extractRefs;
+  if (extractRefsFn === null || typeof extractRefsFn !== "function") {
+    return [];
+  }
+  return extractRefsFn(meta as Record<string, unknown>);
+}
+
+async function putContentBlob(store: CasStore, raw: string): Promise<string> {
+  return store.put(raw);
+}
+
+function agentForRole(binding: AgentBinding, roleName: string): AgentFn {
+  const overrides = binding.overrides;
+  const overrideFn: AgentFn | undefined =
+    overrides !== null ? overrides[roleName as keyof typeof overrides] : undefined;
+  return overrideFn !== undefined ? overrideFn : binding.agent;
+}
+
+type AdvanceOutcome<M extends RoleMeta> =
+  | { kind: "complete"; completion: WorkflowCompletion }
+  | { kind: "yield"; output: RoleOutput; step: RoleStep<M> };
+
+async function advanceOneRound<M extends RoleMeta>(
+  def: Pick<WorkflowDefinition<M>, "roles" | "moderator">,
+  binding: AgentBinding,
+  resolveRoleMeta: ResolveRoleMetaFn<M>,
+  params: {
+    start: ModeratorContext<M>["start"];
+    steps: RoleStep<M>[];
+    options: WorkflowFnOptions;
+  },
+): Promise<AdvanceOutcome<M>> {
+  const { start, steps, options } = params;
+  const modCtx: ModeratorContext<M> = {
+    threadId: options.threadId,
+    depth: options.depth,
+    start,
+    steps,
+  };
+
+  const next = def.moderator(modCtx);
+  if (!isRoleNext(next)) {
+    return {
+      kind: "complete",
+      completion: { returnCode: 0, summary: "completed: moderator returned END" },
+    };
+  }
+
+  const roleDef = def.roles[next];
+  if (roleDef === undefined) {
+    return { kind: "complete", completion: { returnCode: 1, summary: `unknown role: ${next}` } };
+  }
+
+  const agentCtx: AgentContext<M> = {
+    ...modCtx,
+    currentRole: { name: next, systemPrompt: roleDef.systemPrompt },
+    cas: options.cas,
+  };
+
+  const agent = agentForRole(binding, next);
+  const raw = await agent(agentCtx as unknown as AgentContext);
+
+  const extractCtx: ExtractContext<M> = {
+    ...agentCtx,
+    agentContent: raw,
+  };
+
+  const meta = await resolveRoleMeta(
+    roleDef as unknown as RoleDefinition<Record<string, unknown>>,
+    extractCtx,
+    options,
+  );
+
+  const contentHash = await putContentBlob(options.cas, raw);
+  const refs = mergeRefsWithContentHash(
+    resolveExtractedRefs(roleDef as unknown as RoleDefinition<Record<string, unknown>>, meta),
+    contentHash,
+  );
+
+  const step = {
+    role: next,
+    contentHash,
+    meta,
+    refs,
+    timestamp: Date.now(),
+  } as RoleStep<M>;
+
+  return {
+    kind: "yield",
+    output: {
+      role: step.role,
+      contentHash: step.contentHash,
+      meta: step.meta,
+      refs: step.refs,
+    },
+    step,
+  };
+}
+
+/**
+ * Binds pure role definitions + moderator to runtime agents.
+ * Assign with `export const run = createWorkflow(def, binding)` via `@uncaged/workflow-runtime`,
+ * which supplies {@link ResolveRoleMetaFn}.
+ */
+export function createWorkflow<M extends RoleMeta>(
+  def: Pick<WorkflowDefinition<M>, "roles" | "moderator">,
+  binding: AgentBinding,
+  resolveRoleMeta: ResolveRoleMetaFn<M>,
+): WorkflowFn {
+  return async function* workflowLoop(
+    input: ThreadInput,
+    options: WorkflowFnOptions,
+  ): AsyncGenerator<RoleOutput, WorkflowCompletion> {
+    const nowMs = Date.now();
+    const start: ModeratorContext<M>["start"] = {
+      role: START,
+      content: input.prompt,
+      meta: { maxRounds: options.maxRounds },
+      timestamp: nowMs,
+    };
+
+    const baseTs = Date.now();
+    let steps: RoleStep<M>[] = input.steps.map((out, i) => ({
+      role: out.role,
+      contentHash: out.contentHash,
+      meta: out.meta,
+      refs: out.refs,
+      timestamp: baseTs + i,
+    })) as RoleStep<M>[];
+
+    while (true) {
+      if (steps.length >= options.maxRounds) {
+        return {
+          returnCode: 0,
+          summary: `completed: reached maxRounds (${options.maxRounds})`,
+        };
+      }
+
+      const outcome = await advanceOneRound(def, binding, resolveRoleMeta, {
+        start,
+        steps,
+        options,
+      });
+
+      if (outcome.kind === "complete") {
+        return outcome.completion;
+      }
+
+      yield outcome.output;
+      steps = [...steps, outcome.step];
+    }
+  };
+}

packages/workflow-runtime/src/engine/index.ts

@@ -0,0 +1 @@
+export { createWorkflow } from "./create-workflow.js";

packages/workflow-runtime/src/extract/index.ts

@@ -0,0 +1 @@
+export type { ExtractFn } from "./types.js";

packages/workflow-runtime/src/extract/types.ts

@@ -0,0 +1,9 @@
+import type * as z from "zod/v4";
+
+import type { ExtractContext } from "../types.js";
+
+export type ExtractFn = <T extends Record<string, unknown>>(
+  schema: z.ZodType<T>,
+  prompt: string,
+  ctx: ExtractContext,
+) => Promise<T>;

packages/workflow-runtime/src/index.ts

@@ -0,0 +1,35 @@
+export type {
+  WorkflowDescriptor,
+  WorkflowRoleDescriptor,
+  WorkflowRoleSchema,
+} from "./bundle/types.js";
+export { validateWorkflowDescriptor } from "./bundle/workflow-descriptor.js";
+export type { CasStore } from "./cas/index.js";
+export { createWorkflow } from "./engine/index.js";
+export type { ExtractFn } from "./extract/index.js";
+export type {
+  AgentBinding,
+  AgentContext,
+  AgentFn,
+  ExtractContext,
+  ExtractMode,
+  LlmProvider,
+  Moderator,
+  ModeratorContext,
+  ResolveRoleMetaFn,
+  RoleDefinition,
+  RoleMeta,
+  RoleOutput,
+  RoleStep,
+  StartStep,
+  ThreadContext,
+  ThreadInput,
+  WorkflowCompletion,
+  WorkflowDefinition,
+  WorkflowFn,
+  WorkflowFnOptions,
+  WorkflowResult,
+} from "./types.js";
+export { END, START } from "./types.js";
+export type { Result } from "./util/index.js";
+export { err, ok } from "./util/index.js";

packages/workflow-runtime/src/types.ts

@@ -36,7 +36,7 @@ export type WorkflowCompletion = {
   summary: string;
 };
 
-/** Final thread outcome from {@link executeThread}, including Merkle thread root CAS hash. */
+/** Final thread outcome from executeThread, including Merkle thread root CAS hash. */
 export type WorkflowResult = WorkflowCompletion & {
   rootHash: string;
 };
@@ -115,10 +115,10 @@ export type ThreadContext<M extends RoleMeta = RoleMeta> = AgentContext<M>;
 /** Raw string output from an LLM/CLI adapter; meta is extracted by the engine. */
 export type AgentFn = (ctx: AgentContext) => Promise<string>;
 
-/** Runtime agent assignment (optional per-role overrides). */
+/** Runtime agent assignment (explicit null when no per-role overrides). */
 export type AgentBinding = {
   agent: AgentFn;
-  overrides?: Partial<Record<string, AgentFn>>;
+  overrides: Partial<Record<string, AgentFn>> | null;
 };
 
 /** Role wiring: prompts, schema, and human-readable description. */
@@ -148,3 +148,10 @@ export type WorkflowDefinition<M extends RoleMeta> = {
   roles: { [K in keyof M & string]: RoleDefinition<M[K]> };
   moderator: Moderator<M>;
 };
+
+/** Engine-injected meta extraction for workflow loops (single + react modes). */
+export type ResolveRoleMetaFn<M extends RoleMeta = RoleMeta> = (
+  roleDef: RoleDefinition<Record<string, unknown>>,
+  extractCtx: ExtractContext<M>,
+  options: WorkflowFnOptions,
+) => Promise<Record<string, unknown>>;

packages/workflow-runtime/src/util/index.ts

@@ -0,0 +1,3 @@
+export { mergeRefsWithContentHash } from "./refs-field.js";
+export { err, ok } from "./result.js";
+export type { Result } from "./types.js";

packages/workflow-runtime/src/util/refs-field.ts

@@ -0,0 +1,8 @@
+/** Append `contentHash` to `refs` when not already present (dedupe by first occurrence order). */
+export function mergeRefsWithContentHash(refs: string[], contentHash: string): string[] {
+  const out = [...refs];
+  if (!out.includes(contentHash)) {
+    out.push(contentHash);
+  }
+  return out;
+}

packages/workflow-runtime/src/util/result.ts

@@ -0,0 +1,9 @@
+import type { Result } from "./types.js";
+
+export function ok<T>(value: T): Result<T, never> {
+  return { ok: true, value };
+}
+
+export function err<E>(error: E): Result<never, E> {
+  return { ok: false, error };
+}

packages/workflow-runtime/src/util/types.ts

@@ -0,0 +1 @@
+export type Result<T, E = Error> = { ok: true; value: T } | { ok: false; error: E };

packages/workflow-runtime/tsconfig.json

@@ -0,0 +1,21 @@
+{
+  "compilerOptions": {
+    "target": "ES2022",
+    "lib": ["ES2022"],
+    "module": "NodeNext",
+    "moduleResolution": "NodeNext",
+    "strict": true,
+    "exactOptionalPropertyTypes": true,
+    "esModuleInterop": true,
+    "skipLibCheck": true,
+    "forceConsistentCasingInFileNames": true,
+    "declaration": true,
+    "declarationMap": true,
+    "sourceMap": true,
+    "composite": true,
+    "outDir": "dist",
+    "rootDir": "src",
+    "types": ["bun-types"]
+  },
+  "include": ["src/**/*.ts"]
+}

packages/workflow-template-develop/__tests__/develop-template.test.ts

@@ -5,7 +5,7 @@ import {
   type RoleStep,
   START,
   validateWorkflowDescriptor,
-} from "@uncaged/workflow";
+} from "@uncaged/workflow-runtime";
 import { buildDevelopDescriptor } from "../src/descriptor.js";
 import { developModerator } from "../src/index.js";
 import type { CommitterMeta, PlannerMeta } from "../src/roles/index.js";

packages/workflow-template-develop/package.json

@@ -1,6 +1,6 @@
 {
   "name": "@uncaged/workflow-template-develop",
-  "version": "0.1.0",
+  "version": "0.2.0",
   "type": "module",
   "main": "src/index.ts",
   "types": "src/index.ts",
@@ -9,6 +9,7 @@
   },
   "dependencies": {
     "@uncaged/workflow": "workspace:*",
+    "@uncaged/workflow-runtime": "workspace:*",
     "zod": "^4.0.0"
   }
 }

packages/workflow-template-develop/src/index.ts

@@ -1,9 +1,5 @@
-import {
-  type AgentBinding,
-  createWorkflow,
-  type WorkflowDefinition,
-  type WorkflowFn,
-} from "@uncaged/workflow";
+import { createWorkflow } from "@uncaged/workflow";
+import type { AgentBinding, WorkflowDefinition, WorkflowFn } from "@uncaged/workflow-runtime";
 
 import { developModerator } from "./moderator.js";
 import { DEVELOP_WORKFLOW_DESCRIPTION, type DevelopMeta, developRoles } from "./roles.js";

packages/workflow-template-develop/src/moderator.ts

@@ -1,5 +1,5 @@
-import type { Moderator, ModeratorContext } from "@uncaged/workflow";
-import { END } from "@uncaged/workflow";
+import type { Moderator, ModeratorContext } from "@uncaged/workflow-runtime";
+import { END } from "@uncaged/workflow-runtime";
 
 import type { DevelopMeta } from "./roles.js";
 

packages/workflow-template-develop/src/roles.ts

@@ -1,4 +1,4 @@
-import type { RoleDefinition } from "@uncaged/workflow";
+import type { RoleDefinition } from "@uncaged/workflow-runtime";
 import { type CoderMeta, coderRole } from "./roles/coder.js";
 import { type CommitterMeta, committerRole } from "./roles/committer.js";
 import { type PlannerMeta, plannerRole } from "./roles/planner.js";

packages/workflow-template-develop/src/roles/coder.ts

@@ -1,4 +1,4 @@
-import type { RoleDefinition } from "@uncaged/workflow";
+import type { RoleDefinition } from "@uncaged/workflow-runtime";
 import * as z from "zod/v4";
 
 export const coderMetaSchema = z.object({

packages/workflow-template-develop/src/roles/committer.ts

@@ -1,4 +1,4 @@
-import type { RoleDefinition } from "@uncaged/workflow";
+import type { RoleDefinition } from "@uncaged/workflow-runtime";
 import * as z from "zod/v4";
 
 export const committerMetaSchema = z.discriminatedUnion("status", [

packages/workflow-template-develop/src/roles/planner.ts

@@ -1,4 +1,4 @@
-import type { RoleDefinition } from "@uncaged/workflow";
+import type { RoleDefinition } from "@uncaged/workflow-runtime";
 import * as z from "zod/v4";
 
 export const phaseSchema = z.object({

packages/workflow-template-develop/src/roles/reviewer.ts

@@ -1,4 +1,4 @@
-import type { RoleDefinition } from "@uncaged/workflow";
+import type { RoleDefinition } from "@uncaged/workflow-runtime";
 import * as z from "zod/v4";
 
 export const reviewerMetaSchema = z.discriminatedUnion("status", [

packages/workflow-template-develop/src/roles/tester.ts

@@ -1,4 +1,4 @@
-import type { RoleDefinition } from "@uncaged/workflow";
+import type { RoleDefinition } from "@uncaged/workflow-runtime";
 import * as z from "zod/v4";
 
 export const testerMetaSchema = z.discriminatedUnion("status", [

packages/workflow-template-solve-issue/__tests__/solve-issue-template.test.ts

@@ -2,15 +2,14 @@ import { afterEach, describe, expect, test } from "bun:test";
 import { mkdtemp, rm } from "node:fs/promises";
 import { tmpdir } from "node:os";
 import { join } from "node:path";
+import { createCasStore, createExtract } from "@uncaged/workflow";
 import {
-  createCasStore,
-  createExtract,
   END,
   type ModeratorContext,
   type RoleStep,
   START,
   validateWorkflowDescriptor,
-} from "@uncaged/workflow";
+} from "@uncaged/workflow-runtime";
 import { buildSolveIssueDescriptor } from "../src/descriptor.js";
 import type { DeveloperMeta } from "../src/developer.js";
 import { createSolveIssueRun, solveIssueModerator } from "../src/index.js";

packages/workflow-template-solve-issue/package.json

@@ -1,6 +1,6 @@
 {
   "name": "@uncaged/workflow-template-solve-issue",
-  "version": "0.1.0",
+  "version": "0.2.0",
   "type": "module",
   "main": "src/index.ts",
   "types": "src/index.ts",
@@ -9,6 +9,7 @@
   },
   "dependencies": {
     "@uncaged/workflow": "workspace:*",
+    "@uncaged/workflow-runtime": "workspace:*",
     "zod": "^4.0.0"
   }
 }

packages/workflow-template-solve-issue/src/developer.ts

@@ -1,4 +1,4 @@
-import type { RoleDefinition } from "@uncaged/workflow";
+import type { RoleDefinition } from "@uncaged/workflow-runtime";
 import * as z from "zod/v4";
 
 export const developerMetaSchema = z.object({

packages/workflow-template-solve-issue/src/index.ts

@@ -1,10 +1,5 @@
-import {
-  type AgentBinding,
-  createWorkflow,
-  type WorkflowDefinition,
-  type WorkflowFn,
-  workflowAsAgent,
-} from "@uncaged/workflow";
+import { createWorkflow, workflowAsAgent } from "@uncaged/workflow";
+import type { AgentBinding, WorkflowDefinition, WorkflowFn } from "@uncaged/workflow-runtime";
 
 import { solveIssueModerator } from "./moderator.js";
 import { SOLVE_ISSUE_WORKFLOW_DESCRIPTION, type SolveIssueMeta, solveIssueRoles } from "./roles.js";

packages/workflow-template-solve-issue/src/moderator.ts

@@ -1,5 +1,5 @@
-import type { Moderator } from "@uncaged/workflow";
-import { END } from "@uncaged/workflow";
+import type { Moderator } from "@uncaged/workflow-runtime";
+import { END } from "@uncaged/workflow-runtime";
 
 import type { SolveIssueMeta } from "./roles.js";
 

packages/workflow-template-solve-issue/src/roles.ts

@@ -1,4 +1,4 @@
-import type { RoleDefinition } from "@uncaged/workflow";
+import type { RoleDefinition } from "@uncaged/workflow-runtime";
 import { type DeveloperMeta, developerRole } from "./developer.js";
 import { type PreparerMeta, preparerRole } from "./roles/preparer.js";
 import { type SubmitterMeta, submitterRole } from "./roles/submitter.js";

packages/workflow-template-solve-issue/src/roles/preparer.ts

@@ -1,4 +1,4 @@
-import type { RoleDefinition } from "@uncaged/workflow";
+import type { RoleDefinition } from "@uncaged/workflow-runtime";
 import * as z from "zod/v4";
 
 const toolchainSchema = z.object({

packages/workflow-template-solve-issue/src/roles/submitter.ts

@@ -1,4 +1,4 @@
-import type { RoleDefinition } from "@uncaged/workflow";
+import type { RoleDefinition } from "@uncaged/workflow-runtime";
 import * as z from "zod/v4";
 
 export const submitterMetaSchema = z.discriminatedUnion("status", [

packages/workflow-util-agent/__tests__/build-agent-prompt.test.ts

@@ -2,7 +2,8 @@ import { afterEach, beforeEach, describe, expect, test } from "bun:test";
 import { mkdtemp, rm } from "node:fs/promises";
 import { tmpdir } from "node:os";
 import { join } from "node:path";
-import { createCasStore, putContentMerkleNode, START, type ThreadContext } from "@uncaged/workflow";
+import { createCasStore, putContentMerkleNode } from "@uncaged/workflow";
+import { START, type ThreadContext } from "@uncaged/workflow-runtime";
 
 import { buildAgentPrompt } from "../src/index.js";
 

packages/workflow-util-agent/package.json

@@ -1,6 +1,6 @@
 {
   "name": "@uncaged/workflow-util-agent",
-  "version": "0.1.0",
+  "version": "0.2.0",
   "type": "module",
   "main": "src/index.ts",
   "types": "src/index.ts",
@@ -14,6 +14,7 @@
     "test": "bun test"
   },
   "dependencies": {
-    "@uncaged/workflow": "workspace:*"
+    "@uncaged/workflow": "workspace:*",
+    "@uncaged/workflow-runtime": "workspace:*"
   }
 }

packages/workflow-util-agent/src/build-agent-prompt.ts

@@ -1,5 +1,5 @@
-import type { AgentContext } from "@uncaged/workflow";
 import { getContentMerklePayload } from "@uncaged/workflow";
+import type { AgentContext } from "@uncaged/workflow-runtime";
 
 async function resolveStepText(ctx: AgentContext, contentHash: string): Promise<string> {
   const text = await getContentMerklePayload(ctx.cas, contentHash);

packages/workflow-util-agent/src/spawn-cli.ts

@@ -1,6 +1,6 @@
 import { spawn } from "node:child_process";
 
-import { err, ok, type Result } from "@uncaged/workflow";
+import { err, ok, type Result } from "@uncaged/workflow-runtime";
 
 export type SpawnCliError =
   | { kind: "non_zero_exit"; exitCode: number | null; stdout: string; stderr: string }

packages/workflow/__tests__/build-descriptor.test.ts

@@ -1,9 +1,8 @@
 import { describe, expect, test } from "bun:test";
+import { END } from "@uncaged/workflow-runtime";
 import * as z from "zod/v4";
-
 import { buildDescriptor } from "../src/bundle/build-descriptor.js";
 import { validateWorkflowDescriptor } from "../src/bundle/workflow-descriptor.js";
-import { END } from "../src/types.js";
 
 describe("buildDescriptor", () => {
   test("produces a descriptor that validates and includes JSON schemas per role", () => {

packages/workflow/__tests__/bundle-validator.test.ts

@@ -39,6 +39,16 @@ export const run = async function* (_input, options) {
     expect(r.ok).toBe(true);
   });
 
+  test("allows static import of @uncaged/workflow-runtime", () => {
+    const source = `${minimalDescriptor}import { createWorkflow } from "@uncaged/workflow-runtime";
+import { putContentMerkleNode } from "@uncaged/workflow";
+
+export const run = createWorkflow({ description: "x", roles: {}, moderator: () => "END" }, {});
+`;
+    const r = validateWorkflowBundle({ filePath: "/tmp/w.esm.js", source });
+    expect(r.ok).toBe(true);
+  });
+
   test("rejects wrong filename suffix", () => {
     const r = validateWorkflowBundle({
       filePath: "/tmp/w.js",

packages/workflow/__tests__/cas.test.ts

@@ -5,6 +5,11 @@ import { join } from "node:path";
 
 import { createCasStore } from "../src/cas/cas.js";
 import { hashString } from "../src/cas/hash.js";
+import { createContentMerkleNode, serializeMerkleNode } from "../src/cas/merkle.js";
+
+function casStoredForm(raw: string): string {
+  return serializeMerkleNode(createContentMerkleNode(raw));
+}
 
 describe("createCasStore", () => {
   let casDir: string;
@@ -19,25 +24,30 @@ describe("createCasStore", () => {
 
   test("put returns consistent hash for same content", async () => {
     const cas = createCasStore(casDir);
-    const h1 = await cas.put("hello world");
-    const h2 = await cas.put("hello world");
+    const raw = "hello world";
+    const stored = casStoredForm(raw);
+    const h1 = await cas.put(raw);
+    const h2 = await cas.put(raw);
     expect(h1).toBe(h2);
+    expect(h1).toBe(hashString(stored));
     expect(h1).toHaveLength(13);
   });
 
-  test("put returns hash matching hashString", async () => {
+  test("put returns hash matching hashString of merkle-stored form", async () => {
     const cas = createCasStore(casDir);
     const content = "some content to store";
+    const stored = casStoredForm(content);
     const h = await cas.put(content);
-    expect(h).toBe(hashString(content));
+    expect(h).toBe(hashString(stored));
   });
 
-  test("get returns stored content", async () => {
+  test("get returns merkle-serialized blob for raw puts", async () => {
     const cas = createCasStore(casDir);
     const content = "line1\nline2\nline3";
+    const stored = casStoredForm(content);
     const h = await cas.put(content);
     const retrieved = await cas.get(h);
-    expect(retrieved).toBe(content);
+    expect(retrieved).toBe(stored);
   });
 
   test("get returns null for missing hash", async () => {
@@ -76,11 +86,13 @@ describe("createCasStore", () => {
 
   test("put is idempotent — same content written twice causes no error", async () => {
     const cas = createCasStore(casDir);
-    const h1 = await cas.put("idempotent");
-    const h2 = await cas.put("idempotent");
+    const raw = "idempotent";
+    const stored = casStoredForm(raw);
+    const h1 = await cas.put(raw);
+    const h2 = await cas.put(raw);
     expect(h1).toBe(h2);
     const content = await cas.get(h1);
-    expect(content).toBe("idempotent");
+    expect(content).toBe(stored);
   });
 
   test("different content produces different hashes", async () => {

packages/workflow/__tests__/engine.test.ts

@@ -2,8 +2,8 @@ import { afterEach, describe, expect, test } from "bun:test";
 import { mkdir, mkdtemp, readFile, rm, writeFile } from "node:fs/promises";
 import { tmpdir } from "node:os";
 import { join } from "node:path";
+import { END } from "@uncaged/workflow-runtime";
 import * as z from "zod/v4";
-
 import { createCasStore } from "../src/cas/cas.js";
 import {
   createContentMerkleNode,
@@ -13,7 +13,6 @@ import {
 } from "../src/cas/merkle.js";
 import { createWorkflow } from "../src/engine/create-workflow.js";
 import { executeThread } from "../src/engine/engine.js";
-import { END } from "../src/types.js";
 import { createLogger } from "../src/util/logger.js";
 
 const plannerMetaSchema = z.object({
@@ -96,6 +95,98 @@ async function writeExtractRegistryConfig(storageRoot: string): Promise<void> {
   await writeFile(join(storageRoot, "workflow.yaml"), EXTRACT_REGISTRY_YAML, "utf8");
 }
 
+const SUPERVISOR_INTERVAL_REGISTRY_YAML = `config:
+  maxDepth: 3
+  supervisorInterval: 2
+  providers:
+    stub:
+      baseUrl: http://127.0.0.1:9
+      apiKey: test
+  models:
+    extract: stub/model
+    supervisor: stub/supervisor-cheap
+workflows: {}
+`;
+
+const SUPERVISOR_LONG_INTERVAL_REGISTRY_YAML = `config:
+  maxDepth: 3
+  supervisorInterval: 10
+  providers:
+    stub:
+      baseUrl: http://127.0.0.1:9
+      apiKey: test
+  models:
+    extract: stub/model
+    supervisor: stub/supervisor-cheap
+workflows: {}
+`;
+
+async function writeRegistryYaml(storageRoot: string, yaml: string): Promise<void> {
+  await writeFile(join(storageRoot, "workflow.yaml"), yaml, "utf8");
+}
+
+/** Extract rounds use tool_calls; supervisor uses plain `content` (no tools). */
+function installMockExtractThenSupervisor(params: {
+  extractArgs: ReadonlyArray<Record<string, unknown>>;
+  supervisorContent: string;
+  onSupervisorCall?: () => void;
+}): () => void {
+  const origFetch = globalThis.fetch;
+  let extractI = 0;
+  const mockFetch = async (
+    _input: Parameters<typeof fetch>[0],
+    init?: RequestInit,
+  ): Promise<Response> => {
+    const body = init?.body ? (JSON.parse(String(init.body)) as Record<string, unknown>) : {};
+    const tools = body.tools;
+    const hasTools = Array.isArray(tools) && tools.length > 0;
+    if (hasTools) {
+      const args =
+        params.extractArgs[extractI] ?? params.extractArgs[params.extractArgs.length - 1];
+      if (args === undefined) {
+        throw new Error("installMockExtractThenSupervisor: empty extractArgs");
+      }
+      extractI += 1;
+      const firstTool = tools[0] as Record<string, unknown>;
+      const fn = firstTool.function as Record<string, unknown> | undefined;
+      const toolName = typeof fn?.name === "string" ? fn.name : "extract";
+      return new Response(
+        JSON.stringify({
+          choices: [
+            {
+              message: {
+                tool_calls: [
+                  {
+                    type: "function",
+                    function: {
+                      name: toolName,
+                      arguments: JSON.stringify(args),
+                    },
+                  },
+                ],
+              },
+            },
+          ],
+        }),
+        { status: 200, headers: { "Content-Type": "application/json" } },
+      );
+    }
+    params.onSupervisorCall?.();
+    return new Response(
+      JSON.stringify({
+        choices: [{ message: { content: params.supervisorContent } }],
+      }),
+      { status: 200, headers: { "Content-Type": "application/json" } },
+    );
+  };
+  globalThis.fetch = Object.assign(mockFetch, {
+    preconnect: origFetch.preconnect.bind(origFetch),
+  }) as typeof fetch;
+  return () => {
+    globalThis.fetch = origFetch;
+  };
+}
+
 const demoWorkflow = createWorkflow<DemoMeta>(
   {
     roles: {
@@ -577,7 +668,7 @@ describe("executeThread", () => {
           },
           moderator: (ctx) => (ctx.steps.length === 0 ? "walker" : END),
         },
-        { agent: async () => dagRootHash },
+        { agent: async () => dagRootHash, overrides: null },
       );
 
       const threadId = "01KQXKW18CT8G75T53R8F4G7YG";
@@ -623,4 +714,102 @@ describe("executeThread", () => {
       await rm(root, { recursive: true, force: true });
     }
   });
+
+  test("supervisor stops thread when interval elapses and model returns stop", async () => {
+    restoreFetch = installMockExtractThenSupervisor({
+      extractArgs: [{ plan: "do-it", files: ["a.ts"] }, { diff: "+ok" }],
+      supervisorContent: "stop",
+    });
+
+    const root = await mkdtemp(join(tmpdir(), "wf-engine-sup-stop-"));
+    try {
+      const threadId = "01KQXKW18CT8G75T53R8F4G7YG";
+      const hash = "C9NMV6V2TQT81";
+      const dataPath = join(root, "logs", hash, `${threadId}.data.jsonl`);
+      const infoPath = join(root, "logs", hash, `${threadId}.info.jsonl`);
+      await mkdir(join(root, "logs", hash), { recursive: true });
+      await writeRegistryYaml(root, SUPERVISOR_INTERVAL_REGISTRY_YAML);
+      const cas = createCasStore(join(root, "cas"));
+
+      const logger = createLogger({ sink: { kind: "file", path: infoPath } });
+      const ac = new AbortController();
+
+      const result = await executeThread(
+        demoWorkflow,
+        "demo-flow",
+        { prompt: "supervisor-stop-case", steps: [] },
+        {
+          maxRounds: 20,
+          depth: 0,
+          signal: ac.signal,
+          awaitAfterEachYield: async () => {},
+          forkSourceThreadId: null,
+          prefilledDiskSteps: null,
+          storageRoot: root,
+        },
+        { threadId, hash, dataJsonlPath: dataPath, infoJsonlPath: infoPath, cas },
+        logger,
+      );
+
+      expect(result.returnCode).toBe(0);
+      expect(result.summary).toBe("completed: supervisor stopped thread");
+
+      const dataText = await readFile(dataPath, "utf8");
+      const lines = dataText
+        .trim()
+        .split("\n")
+        .filter((l) => l !== "");
+      expect(lines.length).toBe(3);
+    } finally {
+      await rm(root, { recursive: true, force: true });
+    }
+  });
+
+  test("supervisor is not invoked before supervisorInterval rounds", async () => {
+    let supervisorCalls = 0;
+    restoreFetch = installMockExtractThenSupervisor({
+      extractArgs: [{ plan: "do-it", files: ["a.ts"] }, { diff: "+ok" }],
+      supervisorContent: "stop",
+      onSupervisorCall: () => {
+        supervisorCalls += 1;
+      },
+    });
+
+    const root = await mkdtemp(join(tmpdir(), "wf-engine-sup-skip-"));
+    try {
+      const threadId = "01KQXKW18CT8G75T53R8F4G7YG";
+      const hash = "C9NMV6V2TQT81";
+      const dataPath = join(root, "logs", hash, `${threadId}.data.jsonl`);
+      const infoPath = join(root, "logs", hash, `${threadId}.info.jsonl`);
+      await mkdir(join(root, "logs", hash), { recursive: true });
+      await writeRegistryYaml(root, SUPERVISOR_LONG_INTERVAL_REGISTRY_YAML);
+      const cas = createCasStore(join(root, "cas"));
+
+      const logger = createLogger({ sink: { kind: "file", path: infoPath } });
+      const ac = new AbortController();
+
+      const result = await executeThread(
+        demoWorkflow,
+        "demo-flow",
+        { prompt: "no-supervisor-yet", steps: [] },
+        {
+          maxRounds: 20,
+          depth: 0,
+          signal: ac.signal,
+          awaitAfterEachYield: async () => {},
+          forkSourceThreadId: null,
+          prefilledDiskSteps: null,
+          storageRoot: root,
+        },
+        { threadId, hash, dataJsonlPath: dataPath, infoJsonlPath: infoPath, cas },
+        logger,
+      );
+
+      expect(supervisorCalls).toBe(0);
+      expect(result.returnCode).toBe(0);
+      expect(result.summary).toBe("completed: moderator returned END");
+    } finally {
+      await rm(root, { recursive: true, force: true });
+    }
+  });
 });

packages/workflow/__tests__/react-extract.test.ts

@@ -2,12 +2,11 @@ import { afterEach, describe, expect, test } from "bun:test";
 import { mkdtemp, rm } from "node:fs/promises";
 import { tmpdir } from "node:os";
 import { join } from "node:path";
+import type { LlmProvider } from "@uncaged/workflow-runtime";
 import * as z from "zod/v4";
-
 import { createCasStore } from "../src/cas/cas.js";
 import { createContentMerkleNode, serializeMerkleNode } from "../src/cas/merkle.js";
 import { reactExtract } from "../src/extract/react-extract.js";
-import type { LlmProvider } from "../src/types.js";
 
 const metaSchema = z.object({ seen: z.string() });
 

packages/workflow/__tests__/refs-tracking.test.ts

@@ -2,13 +2,12 @@ import { afterEach, describe, expect, test } from "bun:test";
 import { mkdir, mkdtemp, readFile, rm, writeFile } from "node:fs/promises";
 import { tmpdir } from "node:os";
 import { join } from "node:path";
+import { END } from "@uncaged/workflow-runtime";
 import * as z from "zod/v4";
-
 import { createCasStore } from "../src/cas/cas.js";
 import { createWorkflow } from "../src/engine/create-workflow.js";
 import { executeThread } from "../src/engine/engine.js";
 import { buildForkPlan, parseThreadDataJsonl } from "../src/engine/fork-thread.js";
-import { END } from "../src/types.js";
 import { createLogger } from "../src/util/logger.js";
 
 const phaseSchema = z.object({
@@ -102,6 +101,7 @@ const refsDemoWorkflow = createWorkflow<RefsDemoMeta>(
   },
   {
     agent: async () => "plan-output",
+    overrides: null,
   },
 );
 

packages/workflow/__tests__/registry.test.ts

@@ -132,6 +132,65 @@ workflows:
     expect(r.value.config.providers.dashscope?.apiKey).toBe("secret-key");
     expect(r.value.config.models.extract).toBe("dashscope/qwen-plus");
     expect(r.value.config.models.default).toBe("dashscope/qwen-turbo");
+    expect(r.value.config.supervisorInterval).toBe(3);
+  });
+
+  test("defaults supervisorInterval to 3 when omitted", () => {
+    const yaml = `
+config:
+  maxDepth: 0
+  providers:
+    p:
+      baseUrl: https://example.com
+      apiKey: k
+  models:
+    default: p/m
+workflows: {}
+`;
+    const r = parseWorkflowRegistryYaml(yaml);
+    expect(r.ok).toBe(true);
+    if (!r.ok || r.value.config === null) {
+      return;
+    }
+    expect(r.value.config.supervisorInterval).toBe(3);
+  });
+
+  test("parses explicit supervisorInterval", () => {
+    const yaml = `
+config:
+  maxDepth: 0
+  supervisorInterval: 7
+  providers:
+    p:
+      baseUrl: https://example.com
+      apiKey: k
+  models:
+    default: p/m
+workflows: {}
+`;
+    const r = parseWorkflowRegistryYaml(yaml);
+    expect(r.ok).toBe(true);
+    if (!r.ok || r.value.config === null) {
+      return;
+    }
+    expect(r.value.config.supervisorInterval).toBe(7);
+  });
+
+  test("parse errors when supervisorInterval is negative", () => {
+    const yaml = `
+config:
+  maxDepth: 0
+  supervisorInterval: -1
+  providers:
+    p:
+      baseUrl: https://example.com
+      apiKey: k
+  models:
+    default: p/m
+workflows: {}
+`;
+    const r = parseWorkflowRegistryYaml(yaml);
+    expect(r.ok).toBe(false);
   });
 
   test("parses config apiKey env: prefix from process.env", () => {

packages/workflow/__tests__/resolve-model.test.ts

@@ -6,6 +6,7 @@ import type { WorkflowConfig } from "../src/registry/index.js";
 function sampleConfig(): WorkflowConfig {
   return {
     maxDepth: 3,
+    supervisorInterval: 3,
     providers: {
       dashscope: {
         baseUrl: "https://dashscope.aliyuncs.com/compatible-mode/v1",
@@ -50,6 +51,7 @@ describe("resolveModel", () => {
   test("errs when scene missing and no default", () => {
     const config: WorkflowConfig = {
       maxDepth: 1,
+      supervisorInterval: 3,
       providers: {
         p: { baseUrl: "https://x", apiKey: "k" },
       },
@@ -69,6 +71,7 @@ describe("resolveModel", () => {
   test("errs when provider is unknown", () => {
     const config: WorkflowConfig = {
       maxDepth: 1,
+      supervisorInterval: 3,
       providers: {
         p: { baseUrl: "https://x", apiKey: "k" },
       },
@@ -87,6 +90,7 @@ describe("resolveModel", () => {
   test("errs on invalid model reference shape", () => {
     const config: WorkflowConfig = {
       maxDepth: 1,
+      supervisorInterval: 3,
       providers: {
         p: { baseUrl: "https://x", apiKey: "k" },
       },

packages/workflow/__tests__/supervisor.test.ts

@@ -0,0 +1,136 @@
+import { afterEach, describe, expect, test } from "bun:test";
+
+import { parseSupervisorDecisionText, runSupervisor } from "../src/engine/supervisor.js";
+import type { WorkflowConfig } from "../src/registry/index.js";
+import type { LogFn } from "../src/util/index.js";
+
+const noopLogger: LogFn = () => {};
+
+function supervisorOnlyConfig(): WorkflowConfig {
+  return {
+    maxDepth: 3,
+    supervisorInterval: 3,
+    providers: {
+      stub: { baseUrl: "http://127.0.0.1:9/v1", apiKey: "k" },
+    },
+    models: {
+      extract: "stub/extract-model",
+      supervisor: "stub/supervisor-model",
+    },
+  };
+}
+
+describe("parseSupervisorDecisionText", () => {
+  test("reads continue and stop case-insensitively", () => {
+    expect(parseSupervisorDecisionText("continue")).toBe("continue");
+    expect(parseSupervisorDecisionText("CONTINUE")).toBe("continue");
+    expect(parseSupervisorDecisionText("stop")).toBe("stop");
+    expect(parseSupervisorDecisionText("STOP.")).toBe("stop");
+  });
+
+  test("finds token inside a sentence", () => {
+    expect(parseSupervisorDecisionText("Answer: continue")).toBe("continue");
+    expect(parseSupervisorDecisionText("I recommend stop now")).toBe("stop");
+  });
+
+  test("when both appear, earlier token wins", () => {
+    expect(parseSupervisorDecisionText("continue then stop")).toBe("continue");
+    expect(parseSupervisorDecisionText("stop then continue")).toBe("stop");
+  });
+
+  test("defaults to continue when unclear", () => {
+    expect(parseSupervisorDecisionText("maybe later")).toBe("continue");
+  });
+});
+
+describe("runSupervisor", () => {
+  let restoreFetch: (() => void) | null = null;
+
+  afterEach(() => {
+    restoreFetch?.();
+    restoreFetch = null;
+  });
+
+  test("returns continue when supervisor model cannot be resolved (no fetch)", async () => {
+    const origFetch = globalThis.fetch;
+    restoreFetch = () => {
+      globalThis.fetch = origFetch;
+    };
+    globalThis.fetch = Object.assign(
+      async () => {
+        throw new Error("fetch should not run when supervisor is not configured");
+      },
+      { preconnect: origFetch.preconnect.bind(origFetch) },
+    ) as typeof fetch;
+
+    const config: WorkflowConfig = {
+      maxDepth: 1,
+      supervisorInterval: 3,
+      providers: {
+        stub: { baseUrl: "http://127.0.0.1:9/v1", apiKey: "k" },
+      },
+      models: {
+        extract: "stub/m",
+      },
+    };
+
+    const r = await runSupervisor({
+      config,
+      prompt: "task",
+      recentSteps: [{ role: "planner", summary: "{}" }],
+      logger: noopLogger,
+    });
+    expect(r.ok).toBe(true);
+    if (!r.ok) {
+      return;
+    }
+    expect(r.value).toBe("continue");
+  });
+
+  test("returns stop from chat/completions assistant content", async () => {
+    const origFetch = globalThis.fetch;
+    restoreFetch = () => {
+      globalThis.fetch = origFetch;
+    };
+    globalThis.fetch = Object.assign(
+      async () =>
+        new Response(
+          JSON.stringify({
+            choices: [{ message: { content: "stop" } }],
+          }),
+          { status: 200, headers: { "Content-Type": "application/json" } },
+        ),
+      { preconnect: origFetch.preconnect.bind(origFetch) },
+    ) as typeof fetch;
+
+    const r = await runSupervisor({
+      config: supervisorOnlyConfig(),
+      prompt: "do X",
+      recentSteps: [{ role: "a", summary: "{}" }],
+      logger: noopLogger,
+    });
+    expect(r.ok).toBe(true);
+    if (!r.ok) {
+      return;
+    }
+    expect(r.value).toBe("stop");
+  });
+
+  test("returns err on invalid JSON body", async () => {
+    const origFetch = globalThis.fetch;
+    restoreFetch = () => {
+      globalThis.fetch = origFetch;
+    };
+    globalThis.fetch = Object.assign(async () => new Response("not-json", { status: 200 }), {
+      preconnect: origFetch.preconnect.bind(origFetch),
+    }) as typeof fetch;
+
+    const r = await runSupervisor({
+      config: supervisorOnlyConfig(),
+      prompt: "p",
+      recentSteps: [],
+      logger: noopLogger,
+    });
+    expect(r.ok).toBe(false);
+  });
+});

packages/workflow/__tests__/workflow-as-agent-integration.test.ts

@@ -2,8 +2,8 @@ import { afterEach, describe, expect, test } from "bun:test";
 import { mkdir, mkdtemp, readdir, readFile, rm, writeFile } from "node:fs/promises";
 import { tmpdir } from "node:os";
 import { join } from "node:path";
+import { END } from "@uncaged/workflow-runtime";
 import * as z from "zod/v4";
-
 import { createCasStore } from "../src/cas/cas.js";
 import { hashWorkflowBundleBytes } from "../src/cas/hash.js";
 import { getContentMerklePayload, parseMerkleNode } from "../src/cas/merkle.js";
@@ -14,7 +14,6 @@ import {
   registerWorkflowVersion,
   writeWorkflowRegistry,
 } from "../src/registry/registry.js";
-import { END } from "../src/types.js";
 import { createLogger } from "../src/util/logger.js";
 import { workflowAsAgent } from "../src/workflow-as-agent.js";
 
@@ -153,7 +152,7 @@ describe("workflowAsAgent integration", () => {
           },
           moderator: (ctx) => (ctx.steps.length === 0 ? "caller" : END),
         },
-        { agent: workflowAsAgent("child-wf", { storageRoot: root }) },
+        { agent: workflowAsAgent("child-wf", { storageRoot: root }), overrides: null },
       );
 
       const threadId = "01KQXKW18CT8G75T53R8F4G7YG";

packages/workflow/__tests__/workflow-as-agent.test.ts

@@ -2,7 +2,7 @@ import { describe, expect, test } from "bun:test";
 import { mkdir, mkdtemp, rm, writeFile } from "node:fs/promises";
 import { tmpdir } from "node:os";
 import { join } from "node:path";
-
+import { type AgentContext, START } from "@uncaged/workflow-runtime";
 import { createCasStore } from "../src/cas/cas.js";
 import { hashWorkflowBundleBytes } from "../src/cas/hash.js";
 import { parseMerkleNode } from "../src/cas/merkle.js";
@@ -11,7 +11,6 @@ import {
   registerWorkflowVersion,
   writeWorkflowRegistry,
 } from "../src/registry/registry.js";
-import { type AgentContext, START } from "../src/types.js";
 import { workflowAsAgent } from "../src/workflow-as-agent.js";
 
 function makeAgentCtx(params: {
@@ -155,6 +154,7 @@ workflows: {}
         ...reg.value,
         config: {
           maxDepth: 2,
+          supervisorInterval: 3,
           providers: {
             local: {
               baseUrl: "http://127.0.0.1:9",

packages/workflow/package.json

@@ -1,6 +1,6 @@
 {
   "name": "@uncaged/workflow",
-  "version": "0.1.0",
+  "version": "0.2.0",
   "type": "module",
   "main": "src/index.ts",
   "types": "src/index.ts",
@@ -8,6 +8,7 @@
     "test": "bun test"
   },
   "dependencies": {
+    "@uncaged/workflow-runtime": "workspace:*",
     "acorn": "^8.16.0",
     "xxhashjs": "^0.2.2",
     "yaml": "^2.8.4"

packages/workflow/src/bundle/build-descriptor.ts

@@ -1,6 +1,5 @@
+import type { RoleMeta, WorkflowDefinition } from "@uncaged/workflow-runtime";
 import * as z from "zod/v4";
-
-import type { RoleMeta, WorkflowDefinition } from "../types.js";
 import type { WorkflowDescriptor, WorkflowRoleSchema } from "./types.js";
 
 function stripJsonSchemaMeta(json: Record<string, unknown>): WorkflowRoleSchema {

packages/workflow/src/bundle/bundle-validator.ts

@@ -38,7 +38,7 @@ function isAllowedImportSpecifier(spec: string): boolean {
   if (spec.startsWith(".") || spec.startsWith("/") || spec.startsWith("file:")) {
     return false;
   }
-  if (spec === "@uncaged/workflow") {
+  if (spec === "@uncaged/workflow" || spec === "@uncaged/workflow-runtime") {
     return true;
   }
   return isBuiltin(spec);

packages/workflow/src/bundle/extract-bundle-exports.ts

@@ -1,4 +1,4 @@
-import type { WorkflowFn } from "../types.js";
+import type { WorkflowFn } from "@uncaged/workflow-runtime";
 import { err, ok, type Result } from "../util/index.js";
 import { importWorkflowBundleModule } from "./bundle-import-env.js";
 import { ensureUncagedWorkflowSymlink } from "./ensure-uncaged-workflow-symlink.js";

packages/workflow/src/bundle/types.ts

@@ -1,18 +1,10 @@
-import type { WorkflowFn } from "../types.js";
+import type { WorkflowDescriptor, WorkflowFn } from "@uncaged/workflow-runtime";
 
-/** JSON Schema fragment describing one role's `meta` shape (subset supported by code generation). */
-export type WorkflowRoleSchema = Record<string, unknown>;
-
-export type WorkflowRoleDescriptor = {
-  description: string;
-  schema: WorkflowRoleSchema;
-};
-
-/** Workflow metadata exported as `export const descriptor` from `.esm.js` bundles. */
-export type WorkflowDescriptor = {
-  description: string;
-  roles: Record<string, WorkflowRoleDescriptor>;
-};
+export type {
+  WorkflowDescriptor,
+  WorkflowRoleDescriptor,
+  WorkflowRoleSchema,
+} from "@uncaged/workflow-runtime";
 
 export type WorkflowBundleValidationInput = {
   /** Absolute or relative path (used for `.esm.js` suffix checks). */

packages/workflow/src/bundle/workflow-descriptor.ts

@@ -1,40 +1 @@
-import { err, ok, type Result } from "../util/index.js";
-
-import type { WorkflowDescriptor, WorkflowRoleDescriptor, WorkflowRoleSchema } from "./types.js";
-
-export function validateWorkflowDescriptor(value: unknown): Result<WorkflowDescriptor, string> {
-  if (value === null || typeof value !== "object" || Array.isArray(value)) {
-    return err("descriptor must be a non-array object");
-  }
-  const root = value as Record<string, unknown>;
-  const description = root.description;
-  if (typeof description !== "string") {
-    return err("descriptor.description must be a string");
-  }
-  const rolesRaw = root.roles;
-  if (rolesRaw === null || typeof rolesRaw !== "object" || Array.isArray(rolesRaw)) {
-    return err("descriptor.roles must be a non-array object");
-  }
-
-  const roles: Record<string, WorkflowRoleDescriptor> = {};
-  for (const [roleName, specUnknown] of Object.entries(rolesRaw)) {
-    if (specUnknown === null || typeof specUnknown !== "object" || Array.isArray(specUnknown)) {
-      return err(`descriptor.roles.${roleName} must be a non-array object`);
-    }
-    const spec = specUnknown as Record<string, unknown>;
-    const roleDesc = spec.description;
-    if (typeof roleDesc !== "string") {
-      return err(`descriptor.roles.${roleName}.description must be a string`);
-    }
-    const schema = spec.schema;
-    if (schema === null || typeof schema !== "object" || Array.isArray(schema)) {
-      return err(`descriptor.roles.${roleName}.schema must be a non-array object`);
-    }
-    roles[roleName] = {
-      description: roleDesc,
-      schema: schema as WorkflowRoleSchema,
-    };
-  }
-
-  return ok({ description, roles });
-}
+export { validateWorkflowDescriptor } from "@uncaged/workflow-runtime";

packages/workflow/src/cas/cas.ts

@@ -2,8 +2,19 @@ import { mkdir, readdir, readFile, rename, unlink, writeFile } from "node:fs/pro
 import { join } from "node:path";
 
 import { hashString } from "./hash.js";
+import { createContentMerkleNode, parseMerkleNode, serializeMerkleNode } from "./merkle.js";
 import type { CasStore } from "./types.js";
 
+/** Raw strings become content merkle YAML; already-valid merkle documents pass through. */
+function normalizeCasPutContent(content: string): string {
+  try {
+    parseMerkleNode(content);
+    return content;
+  } catch {
+    return serializeMerkleNode(createContentMerkleNode(content));
+  }
+}
+
 export function createCasStore(casDir: string): CasStore {
   async function ensureDir(): Promise<void> {
     await mkdir(casDir, { recursive: true });
@@ -15,11 +26,12 @@ export function createCasStore(casDir: string): CasStore {
 
   return {
     async put(content: string): Promise<string> {
-      const hash = hashString(content);
+      const toStore = normalizeCasPutContent(content);
+      const hash = hashString(toStore);
       await ensureDir();
       const target = filePath(hash);
       const tmp = `${target}.tmp.${Date.now()}`;
-      await writeFile(tmp, content, "utf8");
+      await writeFile(tmp, toStore, "utf8");
       await rename(tmp, target);
       return hash;
     },

packages/workflow/src/cas/merkle.ts

@@ -77,10 +77,9 @@ export async function putThreadMerkleNode(
   return store.put(serializeMerkleNode(node));
 }
 
-/** Serializes a content Merkle node and stores it in CAS; returns its hash. */
+/** Stores agent/content text via CAS; {@link createCasStore} wraps raw strings as merkle content nodes. */
 export async function putContentMerkleNode(store: CasStore, content: string): Promise<string> {
-  const yamlText = serializeMerkleNode(createContentMerkleNode(content));
-  return store.put(yamlText);
+  return store.put(content);
 }
 
 /** Loads a CAS blob and returns the payload string for a `content` Merkle node. */

packages/workflow/src/cas/types.ts

@@ -1,9 +1,4 @@
-export type CasStore = {
-  put(content: string): Promise<string>;
-  get(hash: string): Promise<string | null>;
-  delete(hash: string): Promise<void>;
-  list(): Promise<string[]>;
-};
+export type { CasStore } from "@uncaged/workflow-runtime";
 
 export type MerkleNodeType = "content" | "step" | "thread";
 

packages/workflow/src/engine/create-workflow.ts

@@ -1,73 +1,12 @@
-import { putContentMerkleNode } from "../cas/index.js";
-import { buildExtractUserContent, reactExtract } from "../extract/index.js";
-import {
-  type AgentBinding,
-  type AgentContext,
-  END,
-  type ExtractContext,
-  type ModeratorContext,
-  type RoleDefinition,
-  type RoleMeta,
-  type RoleOutput,
-  type RoleStep,
-  START,
-  type ThreadInput,
-  type WorkflowCompletion,
-  type WorkflowDefinition,
-  type WorkflowFn,
-  type WorkflowFnOptions,
-} from "../types.js";
-import { mergeRefsWithContentHash } from "../util/index.js";
+import type {
+  AgentBinding,
+  RoleMeta,
+  WorkflowDefinition,
+  WorkflowFn,
+} from "@uncaged/workflow-runtime";
+import { createWorkflow as createWorkflowRuntime } from "@uncaged/workflow-runtime";
 
-function isRoleNext<M extends RoleMeta>(
-  next: (keyof M & string) | typeof END,
-): next is keyof M & string {
-  return next !== END;
-}
-
-function resolveExtractedRefs(
-  roleDef: RoleDefinition<Record<string, unknown>>,
-  meta: unknown,
-): string[] {
-  const extractRefsFn = roleDef.extractRefs;
-  if (extractRefsFn === null || typeof extractRefsFn !== "function") {
-    return [];
-  }
-  return extractRefsFn(meta as Record<string, unknown>);
-}
-
-async function resolveRoleMeta<M extends RoleMeta>(
-  roleDef: RoleDefinition<Record<string, unknown>>,
-  extractCtx: ExtractContext<M>,
-  options: WorkflowFnOptions,
-): Promise<Record<string, unknown>> {
-  if (roleDef.extractMode === "react") {
-    if (options.llmProvider === null) {
-      throw new Error(
-        'createWorkflow: WorkflowFnOptions.llmProvider is required when a role uses extractMode "react"',
-      );
-    }
-    const text = await buildExtractUserContent(
-      extractCtx as unknown as ExtractContext,
-      roleDef.extractPrompt,
-    );
-    const reactResult = await reactExtract({
-      text,
-      schema: roleDef.schema,
-      provider: options.llmProvider,
-      cas: options.cas,
-    });
-    if (!reactResult.ok) {
-      throw new Error(`react extract failed: ${reactResult.error}`);
-    }
-    return reactResult.value as Record<string, unknown>;
-  }
-  return (await options.extract(
-    roleDef.schema,
-    roleDef.extractPrompt,
-    extractCtx as unknown as ExtractContext,
-  )) as Record<string, unknown>;
-}
+import { resolveRoleMeta } from "./resolve-role-meta.js";
 
 /**
  * Binds pure role definitions + moderator to runtime agents.
@@ -78,98 +17,5 @@ export function createWorkflow<M extends RoleMeta>(
   def: Pick<WorkflowDefinition<M>, "roles" | "moderator">,
   binding: AgentBinding,
 ): WorkflowFn {
-  return async function* workflowLoop(
-    input: ThreadInput,
-    options: WorkflowFnOptions,
-  ): AsyncGenerator<RoleOutput, WorkflowCompletion> {
-    const nowMs = Date.now();
-    const start: ModeratorContext<M>["start"] = {
-      role: START,
-      content: input.prompt,
-      meta: { maxRounds: options.maxRounds },
-      timestamp: nowMs,
-    };
-
-    const baseTs = Date.now();
-    let steps: RoleStep<M>[] = input.steps.map((out, i) => ({
-      role: out.role,
-      contentHash: out.contentHash,
-      meta: out.meta,
-      refs: out.refs,
-      timestamp: baseTs + i,
-    })) as RoleStep<M>[];
-
-    while (true) {
-      if (steps.length >= options.maxRounds) {
-        return {
-          returnCode: 0,
-          summary: `completed: reached maxRounds (${options.maxRounds})`,
-        };
-      }
-
-      const modCtx: ModeratorContext<M> = {
-        threadId: options.threadId,
-        depth: options.depth,
-        start,
-        steps,
-      };
-
-      const next = def.moderator(modCtx);
-
-      if (!isRoleNext(next)) {
-        return { returnCode: 0, summary: "completed: moderator returned END" };
-      }
-
-      const roleDef = def.roles[next];
-      if (roleDef === undefined) {
-        return { returnCode: 1, summary: `unknown role: ${next}` };
-      }
-
-      const agentCtx: AgentContext<M> = {
-        ...modCtx,
-        currentRole: { name: next, systemPrompt: roleDef.systemPrompt },
-        cas: options.cas,
-      };
-
-      const agent = binding.overrides?.[next] ?? binding.agent;
-
-      const raw = await agent(agentCtx as unknown as AgentContext);
-
-      const extractCtx: ExtractContext<M> = {
-        ...agentCtx,
-        agentContent: raw,
-      };
-
-      const meta = await resolveRoleMeta(
-        roleDef as unknown as RoleDefinition<Record<string, unknown>>,
-        extractCtx,
-        options,
-      );
-
-      const contentHash = await putContentMerkleNode(options.cas, raw);
-
-      const refs = mergeRefsWithContentHash(
-        resolveExtractedRefs(roleDef as unknown as RoleDefinition<Record<string, unknown>>, meta),
-        contentHash,
-      );
-
-      const ts = Date.now();
-      const step = {
-        role: next,
-        contentHash,
-        meta,
-        refs,
-        timestamp: ts,
-      } as RoleStep<M>;
-
-      yield {
-        role: step.role,
-        contentHash: step.contentHash,
-        meta: step.meta,
-        refs: step.refs,
-      };
-
-      steps = [...steps, step];
-    }
-  };
+  return createWorkflowRuntime(def, binding, resolveRoleMeta);
 }

packages/workflow/src/engine/engine.ts

@@ -1,6 +1,13 @@
 import { appendFile, mkdir } from "node:fs/promises";
 import { dirname } from "node:path";
-
+import type {
+  LlmProvider,
+  ThreadInput,
+  WorkflowCompletion,
+  WorkflowFn,
+  WorkflowFnOptions,
+  WorkflowResult,
+} from "@uncaged/workflow-runtime";
 import {
   type CasStore,
   getContentMerklePayload,
@@ -9,23 +16,21 @@ import {
 } from "../cas/index.js";
 import { resolveModel } from "../config/index.js";
 import { createExtract } from "../extract/index.js";
-import { readWorkflowRegistry } from "../registry/index.js";
-import type {
-  LlmProvider,
-  ThreadInput,
-  WorkflowCompletion,
-  WorkflowFn,
-  WorkflowFnOptions,
-  WorkflowResult,
-} from "../types.js";
+import { readWorkflowRegistry, type WorkflowConfig } from "../registry/index.js";
 import { err, type LogFn, normalizeRefsField, ok, type Result } from "../util/index.js";
 
+import { runSupervisor } from "./supervisor.js";
 import type { ExecuteThreadIo, ExecuteThreadOptions } from "./types.js";
 
-async function resolveExtractRuntime(
-  storageRoot: string,
-): Promise<
-  Result<{ extract: ReturnType<typeof createExtract>; llmProvider: LlmProvider }, string>
+async function resolveEngineRegistryRuntime(storageRoot: string): Promise<
+  Result<
+    {
+      extract: ReturnType<typeof createExtract>;
+      llmProvider: LlmProvider;
+      workflowConfig: WorkflowConfig;
+    },
+    string
+  >
 > {
   const reg = await readWorkflowRegistry(storageRoot);
   if (!reg.ok) {
@@ -45,7 +50,7 @@ async function resolveExtractRuntime(
     apiKey: ex.apiKey,
     model: ex.model,
   };
-  return ok({ extract: createExtract(llmProvider), llmProvider });
+  return ok({ extract: createExtract(llmProvider), llmProvider, workflowConfig: cfg });
 }
 
 async function appendDataLine(path: string, record: unknown): Promise<void> {
@@ -79,9 +84,66 @@ async function finalizeThreadResult(params: {
   };
 }
 
+async function finalizeAbortedThread(params: {
+  cas: CasStore;
+  workflowName: string;
+  threadId: string;
+  stepMerkleHashes: string[];
+  logger: LogFn;
+  abortLogTag: string;
+}): Promise<WorkflowResult> {
+  params.logger(params.abortLogTag, `thread ${params.threadId} aborted`);
+  return finalizeThreadResult({
+    cas: params.cas,
+    workflowName: params.workflowName,
+    threadId: params.threadId,
+    stepMerkleHashes: params.stepMerkleHashes,
+    completion: { returnCode: 130, summary: "thread aborted" },
+  });
+}
+
+async function maybeSupervisorHaltsThread(params: {
+  workflowConfig: WorkflowConfig;
+  input: ThreadInput;
+  written: number;
+  recentSupervisorSteps: readonly { role: string; summary: string }[];
+  logger: LogFn;
+  threadId: string;
+  cas: CasStore;
+  workflowName: string;
+  stepMerkleHashes: string[];
+}): Promise<WorkflowResult | null> {
+  const interval = params.workflowConfig.supervisorInterval;
+  if (interval <= 0 || params.written % interval !== 0) {
+    return null;
+  }
+  const sup = await runSupervisor({
+    config: params.workflowConfig,
+    prompt: params.input.prompt,
+    recentSteps: params.recentSupervisorSteps,
+    logger: params.logger,
+  });
+  if (!sup.ok) {
+    params.logger("K6PW9NYT", `supervisor skipped: ${sup.error}`);
+    return null;
+  }
+  if (sup.value !== "stop") {
+    return null;
+  }
+  params.logger("M4QX8VHN", `thread ${params.threadId} stopped by supervisor`);
+  return finalizeThreadResult({
+    cas: params.cas,
+    workflowName: params.workflowName,
+    threadId: params.threadId,
+    stepMerkleHashes: params.stepMerkleHashes,
+    completion: { returnCode: 0, summary: "completed: supervisor stopped thread" },
+  });
+}
+
 async function driveWorkflowGenerator(params: {
   fn: WorkflowFn;
   workflowName: string;
+  workflowConfig: WorkflowConfig;
   input: ThreadInput;
   bundleOptions: WorkflowFnOptions;
   executeOptions: ExecuteThreadOptions;
@@ -94,6 +156,7 @@ async function driveWorkflowGenerator(params: {
   const {
     fn,
     workflowName,
+    workflowConfig,
     input,
     bundleOptions,
     executeOptions,
@@ -105,16 +168,20 @@ async function driveWorkflowGenerator(params: {
   } = params;
   const gen = fn(input, bundleOptions);
   let written = 0;
+  const recentSupervisorSteps: { role: string; summary: string }[] = input.steps.map((s) => ({
+    role: s.role,
+    summary: JSON.stringify(s.meta),
+  }));
 
   while (true) {
     if (executeOptions.signal.aborted) {
-      logger("V8JX4NP2", `thread ${threadId} aborted`);
-      return await finalizeThreadResult({
+      return await finalizeAbortedThread({
         cas,
         workflowName,
         threadId,
         stepMerkleHashes,
-        completion: { returnCode: 130, summary: "thread aborted" },
+        logger,
+        abortLogTag: "V8JX4NP2",
       });
     }
 
@@ -172,6 +239,11 @@ async function driveWorkflowGenerator(params: {
 
     logger("N7BW4YHQ", `thread ${threadId} wrote role ${step.role}`);
 
+    recentSupervisorSteps.push({
+      role: step.role,
+      summary: JSON.stringify(step.meta),
+    });
+
     await Promise.race([
       executeOptions.awaitAfterEachYield(),
       new Promise<void>((resolve) => {
@@ -184,15 +256,30 @@ async function driveWorkflowGenerator(params: {
     ]);
 
     if (executeOptions.signal.aborted) {
-      logger("V8JX4NP4", `thread ${threadId} aborted`);
-      return await finalizeThreadResult({
+      return await finalizeAbortedThread({
         cas,
         workflowName,
         threadId,
         stepMerkleHashes,
-        completion: { returnCode: 130, summary: "thread aborted" },
+        logger,
+        abortLogTag: "V8JX4NP4",
       });
     }
+
+    const supervised = await maybeSupervisorHaltsThread({
+      workflowConfig,
+      input,
+      written,
+      recentSupervisorSteps,
+      logger,
+      threadId,
+      cas,
+      workflowName,
+      stepMerkleHashes,
+    });
+    if (supervised !== null) {
+      return supervised;
+    }
   }
 }
 
@@ -280,9 +367,9 @@ export async function executeThread(
     });
   }
 
-  const extractRuntime = await resolveExtractRuntime(options.storageRoot);
-  if (!extractRuntime.ok) {
-    throw new Error(extractRuntime.error);
+  const registryRuntime = await resolveEngineRegistryRuntime(options.storageRoot);
+  if (!registryRuntime.ok) {
+    throw new Error(registryRuntime.error);
   }
 
   const bundleOptions: WorkflowFnOptions = {
@@ -290,13 +377,14 @@ export async function executeThread(
     maxRounds: options.maxRounds,
     depth: options.depth,
     cas: io.cas,
-    extract: extractRuntime.value.extract,
-    llmProvider: extractRuntime.value.llmProvider,
+    extract: registryRuntime.value.extract,
+    llmProvider: registryRuntime.value.llmProvider,
   };
 
   return await driveWorkflowGenerator({
     fn,
     workflowName,
+    workflowConfig: registryRuntime.value.workflowConfig,
     input,
     bundleOptions,
     executeOptions: options,

packages/workflow/src/engine/fork-thread.ts

@@ -1,4 +1,4 @@
-import type { WorkflowCompletion } from "../types.js";
+import type { WorkflowCompletion } from "@uncaged/workflow-runtime";
 import { err, normalizeRefsField, ok, type Result } from "../util/index.js";
 
 import type { ForkHistoricalStep, ForkPlan, ParsedThreadStartRecord } from "./types.js";

packages/workflow/src/engine/index.ts

@@ -17,6 +17,7 @@ export type {
   GcResult,
   ParsedThreadStartRecord,
   PrefilledDiskStep,
+  SupervisorDecision,
   ThreadPauseGate,
 } from "./types.js";
 export { getWorkerHostScriptPath } from "./worker-entry-path.js";

packages/workflow/src/engine/resolve-role-meta.ts

@@ -0,0 +1,42 @@
+import type {
+  ExtractContext,
+  RoleDefinition,
+  RoleMeta,
+  WorkflowFnOptions,
+} from "@uncaged/workflow-runtime";
+
+import { buildExtractUserContent } from "../extract/extract-fn.js";
+import { reactExtract } from "../extract/react-extract.js";
+
+export async function resolveRoleMeta<M extends RoleMeta>(
+  roleDef: RoleDefinition<Record<string, unknown>>,
+  extractCtx: ExtractContext<M>,
+  options: WorkflowFnOptions,
+): Promise<Record<string, unknown>> {
+  if (roleDef.extractMode === "react") {
+    if (options.llmProvider === null) {
+      throw new Error(
+        'createWorkflow: WorkflowFnOptions.llmProvider is required when a role uses extractMode "react"',
+      );
+    }
+    const text = await buildExtractUserContent(
+      extractCtx as unknown as ExtractContext,
+      roleDef.extractPrompt,
+    );
+    const reactResult = await reactExtract({
+      text,
+      schema: roleDef.schema,
+      provider: options.llmProvider,
+      cas: options.cas,
+    });
+    if (!reactResult.ok) {
+      throw new Error(`react extract failed: ${reactResult.error}`);
+    }
+    return reactResult.value as Record<string, unknown>;
+  }
+  return (await options.extract(
+    roleDef.schema,
+    roleDef.extractPrompt,
+    extractCtx as unknown as ExtractContext,
+  )) as Record<string, unknown>;
+}

packages/workflow/src/engine/supervisor.ts

@@ -0,0 +1,140 @@
+import { resolveModel } from "../config/index.js";
+import type { WorkflowConfig } from "../registry/index.js";
+import { err, type LogFn, ok, type Result } from "../util/index.js";
+
+import type { SupervisorDecision } from "./types.js";
+
+const SUPERVISOR_RECENT_STEP_LIMIT = 12;
+
+function chatCompletionsUrl(baseUrl: string): string {
+  const trimmed = baseUrl.replace(/\/+$/, "");
+  return `${trimmed}/chat/completions`;
+}
+
+function isRecord(value: unknown): value is Record<string, unknown> {
+  return typeof value === "object" && value !== null && !Array.isArray(value);
+}
+
+function readAssistantContent(parsed: unknown): string | null {
+  if (!isRecord(parsed)) {
+    return null;
+  }
+  const choices = parsed.choices;
+  if (!Array.isArray(choices) || choices.length === 0) {
+    return null;
+  }
+  const first = choices[0];
+  if (!isRecord(first)) {
+    return null;
+  }
+  const messageObj = first.message;
+  if (!isRecord(messageObj)) {
+    return null;
+  }
+  const content = messageObj.content;
+  if (typeof content !== "string") {
+    return null;
+  }
+  return content;
+}
+
+/** Lenient: accepts STOP/stop/stop. as prose; prefers {@link SupervisorDecision.stop} when both tokens appear. */
+export function parseSupervisorDecisionText(text: string): SupervisorDecision {
+  const lower = text.toLowerCase();
+  const stopWord = /\bstop\b/.test(lower);
+  const continueWord = /\bcontinue\b/.test(lower);
+  if (stopWord && continueWord) {
+    const si = lower.search(/\bstop\b/);
+    const ci = lower.search(/\bcontinue\b/);
+    return si <= ci ? "stop" : "continue";
+  }
+  if (stopWord) {
+    return "stop";
+  }
+  if (continueWord) {
+    return "continue";
+  }
+  if (lower.includes("stop")) {
+    return "stop";
+  }
+  if (lower.includes("continue")) {
+    return "continue";
+  }
+  return "continue";
+}
+
+type RunSupervisorArgs = {
+  config: WorkflowConfig;
+  prompt: string;
+  recentSteps: readonly { role: string; summary: string }[];
+  logger: LogFn;
+};
+
+/** Calls the `supervisor` scene LLM; opt-out when {@link resolveModel} fails (returns ok(`continue`)). */
+export async function runSupervisor(
+  args: RunSupervisorArgs,
+): Promise<Result<SupervisorDecision, string>> {
+  const resolved = resolveModel(args.config, "supervisor");
+  if (!resolved.ok) {
+    return ok("continue");
+  }
+  const provider = resolved.value;
+  const recent = args.recentSteps.slice(-SUPERVISOR_RECENT_STEP_LIMIT);
+  const stepsBlock = recent.map((s, index) => `${index + 1}. [${s.role}] ${s.summary}`).join("\n");
+
+  const body = {
+    model: provider.model,
+    messages: [
+      {
+        role: "system" as const,
+        content:
+          'You supervise a multi-step workflow. Decide if the thread should keep running or halt.\n\nReply with exactly one token: either "continue" (progress toward the goal, not obviously stuck) or "stop" (done, looping, or no progress). Do not add explanation.',
+      },
+      {
+        role: "user" as const,
+        content: `Original task:\n${args.prompt}\n\nRecent steps (oldest first):\n${stepsBlock === "" ? "(none)" : stepsBlock}`,
+      },
+    ],
+  };
+
+  let response: Response;
+  try {
+    response = await fetch(chatCompletionsUrl(provider.baseUrl), {
+      method: "POST",
+      headers: {
+        Authorization: `Bearer ${provider.apiKey}`,
+        "Content-Type": "application/json",
+      },
+      body: JSON.stringify(body),
+    });
+  } catch (cause) {
+    const message = cause instanceof Error ? cause.message : String(cause);
+    args.logger("R9CW4PLM", `supervisor request failed: ${message}`);
+    return err(`supervisor network error: ${message}`);
+  }
+
+  const responseText = await response.text();
+  if (!response.ok) {
+    args.logger("T3HN8VKQ", `supervisor HTTP ${response.status}: ${responseText.slice(0, 200)}`);
+    return err(`supervisor HTTP ${response.status}: ${responseText.slice(0, 500)}`);
+  }
+
+  let parsed: unknown;
+  try {
+    parsed = JSON.parse(responseText) as unknown;
+  } catch (cause) {
+    const message = cause instanceof Error ? cause.message : String(cause);
+    args.logger("W7BQ2NXM", `supervisor response is not JSON: ${message}`);
+    return err(`supervisor invalid JSON: ${message}`);
+  }
+
+  const content = readAssistantContent(parsed);
+  if (content === null || content.trim() === "") {
+    args.logger("Y4JX9PKW", "supervisor returned empty assistant content");
+    return err("supervisor empty assistant content");
+  }
+
+  const decision = parseSupervisorDecisionText(content);
+  args.logger("Z8KM5QWT", `supervisor says ${decision}`);
+  return ok(decision);
+}

packages/workflow/src/engine/types.ts

@@ -1,7 +1,9 @@
+import type { RoleOutput } from "@uncaged/workflow-runtime";
 import type { CasStore } from "../cas/index.js";
-import type { RoleOutput } from "../types.js";
 import type { Result } from "../util/index.js";
 
+export type SupervisorDecision = "continue" | "stop";
+
 export type ExecuteThreadIo = {
   threadId: string;
   hash: string;

packages/workflow/src/engine/worker.ts

@@ -1,9 +1,9 @@
 import { appendFile, mkdir, unlink, writeFile } from "node:fs/promises";
 import { createServer, type Socket } from "node:net";
 import { dirname, join } from "node:path";
+import type { RoleOutput, WorkflowFn, WorkflowResult } from "@uncaged/workflow-runtime";
 import { ensureUncagedWorkflowSymlink, importWorkflowBundleModule } from "../bundle/index.js";
 import { createCasStore } from "../cas/index.js";
-import type { RoleOutput, WorkflowFn, WorkflowResult } from "../types.js";
 import {
   createLogger,
   err,

packages/workflow/src/extract/extract-fn.ts

@@ -1,9 +1,7 @@
+import type { ExtractContext, ExtractFn, LlmProvider } from "@uncaged/workflow-runtime";
 import type * as z from "zod/v4";
-
 import { getContentMerklePayload } from "../cas/index.js";
-import type { ExtractContext, LlmProvider } from "../types.js";
 import { llmExtractWithRetry } from "./llm-extract.js";
-import type { ExtractFn } from "./types.js";
 
 /** Builds the user-side extraction prompt (thread + agent output + instruction). */
 export async function buildExtractUserContent(

packages/workflow/src/extract/react-extract.ts

@@ -1,7 +1,5 @@
+import type { CasStore, LlmProvider } from "@uncaged/workflow-runtime";
 import type * as z from "zod/v4";
-
-import type { CasStore } from "../cas/index.js";
-import type { LlmProvider } from "../types.js";
 import { err, ok, type Result } from "../util/index.js";
 
 import { extractFunctionToolFromZodSchema } from "./llm-extract.js";