diff --git a/docs/python-repl.md b/docs/python-repl.md
index 47971cac6..f7588073c 100644
--- a/docs/python-repl.md
+++ b/docs/python-repl.md
@@ -10,6 +10,7 @@ It covers tool behavior, runner lifecycle, environment handling, execution seman
 - Subprocess kernel client: `src/eval/py/kernel.ts`
 - Python wrapper / NDJSON server: `src/eval/py/runner.py`
 - Prelude helpers loaded into every kernel: `src/eval/py/prelude.py`
+- Host-side subagent helper bridge: `src/eval/agent-bridge.ts`
 - MIME bundle renderer (text + structured outputs): `src/eval/py/display.ts`
 - Interactive-mode renderer for user-triggered Python runs: `src/modes/components/eval-execution.ts`
 - Runtime/env filtering and Python resolution: `src/eval/py/runtime.ts`
@@ -159,6 +160,8 @@ The runner additionally receives `PYTHONUNBUFFERED=1` and `PYTHONIOENCODING=utf-
 
 If Python preflight fails and `eval.js` is enabled, `eval` remains available for `js` cells; `py` cells fail with a Python-backend availability error.
 
+Python prelude helpers include `agent(prompt, *, agent_type="task", model=None, context=None, label=None, schema=None)`. It synchronously calls the host bridge, runs one subagent through the task executor, and returns the final text. When `schema` is supplied, the helper parses the subagent's JSON output and returns the object.
+
 ## Execution flow and cancellation/timeout
 
 ### Cell timeout
diff --git a/docs/tools/eval.md b/docs/tools/eval.md
index e589e633e..442c6e46c 100644
--- a/docs/tools/eval.md
+++ b/docs/tools/eval.md
@@ -9,6 +9,7 @@
 - Model-facing prompt: `packages/coding-agent/src/prompts/tools/eval.md`
 - Key collaborators:
   - `packages/coding-agent/src/eval/backend.ts` — backend execution contract
+  - `packages/coding-agent/src/eval/agent-bridge.ts` — host-side `agent()` bridge into the subagent executor
   - `packages/coding-agent/src/eval/js/executor.ts` — JS backend adapter
   - `packages/coding-agent/src/eval/js/worker-core.ts` — JS execution, VM context, display/log capture
   - `packages/coding-agent/src/eval/js/shared/prelude.txt` — JS global helper installer
@@ -131,11 +132,15 @@ Implemented in `packages/coding-agent/src/eval/js/worker-core.ts`, `packages/cod
   - `read`, `write`, `append`, `sort`, `uniq`, `counter`, `diff`, `tree`, `env`, `output`
   - `tool.<name>(args)` proxy for arbitrary session tool calls
   - `llm(prompt, opts?)` for oneshot, stateless LLM calls (see _Oneshot LLM helper_ below)
+  - `agent(prompt, opts?)` for a single subagent call, plus JS-only `parallel()` / `pipeline()` bounded-pool helpers (see _Subagent helper_ below)
 - JS helpers that touch the host/runtime boundary are async and `await`able; pure text helpers (`sort`, `uniq`, `counter`) return synchronously but may still be safely awaited.
 - JS helper signatures use a trailing options object rather than Python keyword arguments:
   - `await read(path, { offset?, limit? })`
   - `await tree(path = ".", { maxDepth?, hidden? })`
   - `sort(text, { reverse?, unique? })`, `uniq(text, { count? })`, `counter(items, { limit?, reverse? })`
+  - `await agent(prompt, { agentType?, model?, context?, label?, schema? })`
+  - `await parallel([() => agent("a"), () => agent("b")], { concurrency? })`
+  - `await pipeline(items, stage1, stage2, { concurrency? })`
 - `display(value)` behavior:
   - plain objects/arrays become JSON outputs
   - `{ type: "image", data, mimeType }` becomes an image output
@@ -156,7 +161,7 @@ Implemented in `packages/coding-agent/src/eval/py/executor.ts`, `packages/coding
   - initialize cwd / env / `sys.path`
   - execute `PYTHON_PRELUDE`
 - Python cells run in the runner's persistent asyncio event loop, so top-level `await` works; the prompt warns not to use `asyncio.run(...)`
-- The Python prelude defines helpers with the same surface as JS where practical, including `tool.<name>(args)` through a per-run loopback bridge
+- The Python prelude defines helpers with the same surface as JS where practical, including `tool.<name>(args)`, `llm(...)`, and `agent(...)` through a per-run loopback bridge
 - Synchronous statement blocks run in the default executor with ContextVar state copied in; the GIL still serializes bytecode execution, but awaited regions can interleave with sibling cells
 - Kernel `display_data` / `execute_result` messages map to:
   - `application/x-omp-status` → status event
@@ -182,6 +187,21 @@ Both runtimes expose `llm()` — a single stateless completion against a model t
 - `schema` (optional) is a plain JSON-Schema object. When present, the model is forced to call a single synthetic `respond` tool with that schema (loose, non-strict), and the helper returns the parsed object. When absent, the helper returns the completion string.
 - Errors surface as exceptions: unresolved tier, missing API key, an `error`/`aborted` stop reason, or empty output each raise.
 
+### Subagent helper (`agent`)
+
+Both runtimes expose `agent()` — a single subagent invocation routed through `packages/coding-agent/src/eval/agent-bridge.ts` into the same `runSubprocess(...)` path used by the `task` tool. It uses the current eval session's spawn policy and inherits the parent eval executor id, so parent and subagent code share JS/Python runtime state.
+
+- Signatures:
+  - JS: `await agent(prompt, { agentType?, model?, context?, label?, schema? })`
+  - Python: `agent(prompt, *, agent_type="task", model=None, context=None, label=None, schema=None)`
+- `agentType` / `agent_type` defaults to the bundled `task` agent and resolves through normal agent discovery, so project and user agents work.
+- `model` overrides the selected agent's model. Without it, normal per-agent settings and the agent frontmatter model apply.
+- `context` supplies shared background; `label` controls the `agent://<id>` output label prefix.
+- `schema` passes a JSON Schema to the subagent structured-output path. When present, the helper parses the final JSON text and returns an object.
+- Spawn restrictions use `session.getSessionSpawns()` exactly like the `task` tool. Eval-driven subagent recursion is capped at depth 3.
+- JS also exposes `parallel(thunks, { concurrency })` and `pipeline(items, ...stages, { concurrency })`; both use a bounded async pool with default concurrency 4, max 16, preserve item order, and propagate rejections.
+- Errors surface as exceptions: unknown or disabled agent, disallowed spawn, recursion cap, subagent failure, or invalid structured output all fail the eval cell.
+
 ### Multi-language call behavior
 
 A single tool call can mix Python and JS cells. Persistence is per language runtime:
@@ -202,12 +222,14 @@ A single tool call can mix Python and JS cells. Persistence is per language runt
 - Subprocesses / native bindings
   - Python availability check runs `<python> -c ...`.
   - Python backend spawns one `python -u runner.py` subprocess per kernel; cancellation sends `SIGINT`. Details in `docs/python-repl.md`.
+  - `agent()` runs one in-process subagent via the task executor; that subagent may use its configured tools.
 - Session state
   - `session.assertEvalExecutionAllowed?.()` can block execution.
   - `session.trackEvalExecution?.(...)` can register cancellable eval work.
   - `session.getSessionFile?.()`, `session.getEvalSessionId?.()`, and `session.getEvalKernelOwnerId?.()` influence VM/kernel reuse and artifact lookup.
   - JS VM contexts persist across eval calls until reset/disposal.
   - Python retained kernels persist until reset, owner cleanup, or process exit.
+  - `agent()` allocates `agent://<id>` output artifacts and reuses the parent's eval executor id.
 - User-visible prompts / interactive UI
   - none; stdin requests are rejected programmatically
 - Background work / cancellation
@@ -223,6 +245,8 @@ A single tool call can mix Python and JS cells. Persistence is per language runt
 - Output truncation window: 50KB default (`DEFAULT_MAX_BYTES` in `packages/coding-agent/src/session/streaming-output.ts`)
 - Output line cap inside truncation helpers: 3000 lines (`DEFAULT_MAX_LINES` in `packages/coding-agent/src/session/streaming-output.ts`)
 - Streaming tail buffer for live updates: `DEFAULT_MAX_BYTES * 2` = 100KB (`packages/coding-agent/src/tools/eval.ts`)
+- JS `parallel()` / `pipeline()` helper concurrency default: 4; maximum: 16
+- Eval-driven `agent()` recursion cap: task depth 3 (`EVAL_AGENT_MAX_DEPTH`)
 - Python retained kernel idle timeout: 5 minutes (`IDLE_TIMEOUT_MS` in `packages/coding-agent/src/eval/py/executor.ts`)
 - Python retained kernel cap: 4 sessions (`MAX_KERNEL_SESSIONS` in `packages/coding-agent/src/eval/py/executor.ts`)
 - Python retained kernel cleanup sweep: every 30s (`CLEANUP_INTERVAL_MS` in `packages/coding-agent/src/eval/py/executor.ts`)
diff --git a/packages/coding-agent/CHANGELOG.md b/packages/coding-agent/CHANGELOG.md
index 087dc04a6..9a7a54466 100644
--- a/packages/coding-agent/CHANGELOG.md
+++ b/packages/coding-agent/CHANGELOG.md
@@ -1,8 +1,11 @@
 # Changelog
 
 ## [Unreleased]
+
 ### Added
 
+- Added `agent()` eval options `agent_type`/`agentType`, `model`, `context`, and `label`, and returned structured JSON when `schema` is provided in JS and Python eval cells
+- Added `agent()` to the `eval` runtime so JS and Python cells can spawn one subagent through the existing task executor; JS eval also gained bounded `parallel()` and `pipeline()` helpers for orchestrating subagent calls.
 - Added search support for virtual internal URLs (including `omp://` roots) by resolving and scanning in-memory internal resources as search targets alongside filesystem paths
 - Added expansion of virtual internal URL search targets so `search` can match multiple internal documents when given `omp://`
 - Added `/omfg <complaint>` slash command that drafts a TTSR rule from a complaint, validates it against the current conversation, saves it to project or `~/.omp/agent/rules`, and registers it live.
@@ -18,6 +21,8 @@
 
 ### Fixed
 
+- Fixed `agent()` in eval to enforce plan-mode, spawn allowlist, and disabled-agent checks before launching subagents
+- Fixed recursive `agent()` calls from eval by enforcing the existing max subagent depth limit
 - Fixed runtime model switches (Ctrl+P cycling, `--model`, `/model`, model picker selections, and programmatic changes) so they no longer overwrite the persisted `modelRoles.default`; only the model picker's explicit "Set as default" action and settings changes persist the default.
 - Fixed `search` to honor line-range suffixes on virtual internal URL targets so matches outside the requested ranges are no longer returned
 - Fixed `search` to handle internal URLs without source files without incorrectly reporting `Path not found`, returning matches from virtual content instead
diff --git a/packages/coding-agent/src/eval/__tests__/agent-bridge.test.ts b/packages/coding-agent/src/eval/__tests__/agent-bridge.test.ts
new file mode 100644
index 000000000..6d71abc00
--- /dev/null
+++ b/packages/coding-agent/src/eval/__tests__/agent-bridge.test.ts
@@ -0,0 +1,342 @@
+import { afterAll, afterEach, describe, expect, it, vi } from "bun:test";
+import * as path from "node:path";
+import { TempDir } from "@oh-my-pi/pi-utils";
+import { Settings } from "../../config/settings";
+import * as taskDiscovery from "../../task/discovery";
+import type { PlanModeState } from "../../plan-mode/state";
+import type { ExecutorOptions } from "../../task/executor";
+import * as taskExecutor from "../../task/executor";
+import { AgentOutputManager } from "../../task/output-manager";
+import type { AgentDefinition, SingleResult } from "../../task/types";
+import type { ToolSession } from "../../tools";
+import { EVAL_AGENT_MAX_DEPTH, runEvalAgent } from "../agent-bridge";
+import { disposeAllVmContexts } from "../js/context-manager";
+import { executeJs } from "../js/executor";
+import { disposeAllKernelSessions, executePython } from "../py/executor";
+
+const taskAgent = {
+	name: "task",
+	description: "Task agent",
+	systemPrompt: "Run the task.",
+	source: "bundled",
+	spawns: "*",
+	model: ["pi/task"],
+} satisfies AgentDefinition;
+
+const reviewerAgent = {
+	name: "reviewer",
+	description: "Reviewer agent",
+	systemPrompt: "Review the task.",
+	source: "bundled",
+	model: ["pi/smol"],
+} satisfies AgentDefinition;
+
+interface SessionOptions {
+	cwd?: string;
+	sessionFile?: string | null;
+	artifactsDir?: string | null;
+	spawns?: string | null;
+	depth?: number;
+	activeModel?: string;
+	modelString?: string;
+	enableLsp?: boolean;
+	settings?: Settings;
+	outputManager?: AgentOutputManager;
+	planMode?: boolean;
+}
+
+function makeSession(options: SessionOptions = {}): ToolSession {
+	const settings =
+		options.settings ??
+		Settings.isolated({
+			"async.enabled": false,
+			"task.isolation.mode": "none",
+			"task.enableLsp": true,
+		});
+	const artifactsDir = options.artifactsDir ?? null;
+	return {
+		cwd: options.cwd ?? process.cwd(),
+		hasUI: false,
+		settings,
+		taskDepth: options.depth ?? 0,
+		enableLsp: options.enableLsp ?? true,
+		agentOutputManager: options.outputManager,
+		getSessionFile: () => options.sessionFile ?? null,
+		getSessionSpawns: () => options.spawns ?? "*",
+		getActiveModelString: () => options.activeModel ?? "p/active",
+		getModelString: () => options.modelString ?? "p/fallback",
+		getArtifactsDir: () => artifactsDir,
+		getSessionId: () => "test-session",
+		getEvalSessionId: () => "test-eval-session",
+		getPlanModeState: options.planMode
+			? () =>
+					({
+						enabled: true,
+						planFilePath: path.join(options.cwd ?? process.cwd(), "plan.md"),
+					}) satisfies PlanModeState
+			: undefined,
+	};
+}
+
+function mockAgents(agents: AgentDefinition[] = [taskAgent, reviewerAgent]): void {
+	vi.spyOn(taskDiscovery, "discoverAgents").mockResolvedValue({ agents, projectAgentsDir: null });
+}
+
+function singleResult(options: ExecutorOptions, overrides: Partial<SingleResult> = {}): SingleResult {
+	return {
+		index: options.index,
+		id: options.id,
+		agent: options.agent.name,
+		agentSource: options.agent.source,
+		task: options.task,
+		assignment: options.assignment,
+		description: options.description,
+		exitCode: 0,
+		output: "ok",
+		stderr: "",
+		truncated: false,
+		durationMs: 1,
+		tokens: 0,
+		...overrides,
+	};
+}
+
+function makeEvalSession(
+	tempDir: TempDir,
+	prefix: string,
+): { session: ToolSession; sessionFile: string; sessionId: string } {
+	const sessionFile = path.join(tempDir.path(), "session.jsonl");
+	const artifactsDir = sessionFile.slice(0, -6);
+	const session = makeSession({
+		cwd: tempDir.path(),
+		sessionFile,
+		artifactsDir,
+		outputManager: new AgentOutputManager(() => artifactsDir),
+	});
+	return { session, sessionFile, sessionId: `${prefix}:${crypto.randomUUID()}` };
+}
+
+describe("runEvalAgent", () => {
+	afterEach(() => {
+		vi.restoreAllMocks();
+	});
+
+	it("resolves the default task agent and agentType overrides", async () => {
+		mockAgents();
+		const runSpy = vi.spyOn(taskExecutor, "runSubprocess").mockImplementation(async options =>
+			singleResult(options, {
+				output: options.agent.name,
+			}),
+		);
+		const session = makeSession();
+
+		const defaultResult = await runEvalAgent({ prompt: "hello" }, { session });
+		const overrideResult = await runEvalAgent({ prompt: "hello", agentType: "reviewer" }, { session });
+
+		expect(defaultResult.text).toBe("task");
+		expect(overrideResult.text).toBe("reviewer");
+		expect(runSpy.mock.calls[0]?.[0].agent.name).toBe("task");
+		expect(runSpy.mock.calls[1]?.[0].agent.name).toBe("reviewer");
+	});
+
+	it("throws for an unknown agent", async () => {
+		mockAgents([taskAgent]);
+		vi.spyOn(taskExecutor, "runSubprocess").mockImplementation(async options => singleResult(options));
+
+		await expect(runEvalAgent({ prompt: "hello", agentType: "missing" }, { session: makeSession() })).rejects.toThrow(
+			'Unknown agent "missing"',
+		);
+	});
+
+	it("enforces spawn restrictions and the eval recursion cap", async () => {
+		mockAgents();
+		const runSpy = vi.spyOn(taskExecutor, "runSubprocess").mockImplementation(async options => singleResult(options));
+
+		await expect(runEvalAgent({ prompt: "hello" }, { session: makeSession({ spawns: "" }) })).rejects.toThrow(
+			"spawns disabled",
+		);
+		await expect(runEvalAgent({ prompt: "hello" }, { session: makeSession({ spawns: "reviewer" }) })).rejects.toThrow(
+			"Allowed: reviewer",
+		);
+		await expect(
+			runEvalAgent({ prompt: "hello" }, { session: makeSession({ depth: EVAL_AGENT_MAX_DEPTH }) }),
+		).rejects.toThrow("maximum depth");
+		expect(runSpy).not.toHaveBeenCalled();
+	});
+
+	it("throws instead of spawning from plan mode", async () => {
+		mockAgents();
+		const runSpy = vi.spyOn(taskExecutor, "runSubprocess").mockImplementation(async options => singleResult(options));
+
+		await expect(runEvalAgent({ prompt: "hello" }, { session: makeSession({ planMode: true }) })).rejects.toThrow(
+			"unavailable in plan mode",
+		);
+		expect(runSpy).not.toHaveBeenCalled();
+	});
+
+	it("passes the parent execution context and only sets outputSchema when schema is supplied", async () => {
+		mockAgents();
+		const runSpy = vi.spyOn(taskExecutor, "runSubprocess").mockImplementation(async options => singleResult(options));
+		const abortController = new AbortController();
+		const schema = { type: "object", properties: { ok: { type: "boolean" } } };
+		const session = makeSession({ depth: 2, activeModel: "p/current", modelString: "p/fallback" });
+
+		await runEvalAgent(
+			{ prompt: " hello ", context: " context ", label: "My Agent", model: "p/override", schema },
+			{ session, signal: abortController.signal },
+		);
+		await runEvalAgent({ prompt: "plain" }, { session });
+
+		const firstOptions = runSpy.mock.calls[0]?.[0];
+		const secondOptions = runSpy.mock.calls[1]?.[0];
+		if (!firstOptions || !secondOptions) throw new Error("runSubprocess was not called");
+		expect(firstOptions.taskDepth).toBe(2);
+		expect(firstOptions.signal).toBe(abortController.signal);
+		expect(firstOptions.parentActiveModelPattern).toBe("p/current");
+		expect(firstOptions.outputSchema).toBe(schema);
+		expect(firstOptions.assignment).toBe("hello");
+		expect(firstOptions.context).toBe("context");
+		expect(firstOptions.description).toBe("My Agent");
+		expect(firstOptions.modelOverride).toEqual(["p/override"]);
+		expect(secondOptions.outputSchema).toBeUndefined();
+	});
+
+	it("maps successful and failed subagent results", async () => {
+		mockAgents();
+		const runSpy = vi.spyOn(taskExecutor, "runSubprocess");
+		runSpy.mockImplementationOnce(async options =>
+			singleResult(options, {
+				id: "0-EvalAgent",
+				output: "done",
+				resolvedModel: "p/model",
+			}),
+		);
+		runSpy.mockImplementationOnce(async options =>
+			singleResult(options, {
+				exitCode: 1,
+				output: "",
+				stderr: "stderr",
+				error: "boom",
+			}),
+		);
+
+		const result = await runEvalAgent({ prompt: "hello" }, { session: makeSession() });
+		expect(result).toEqual({
+			text: "done",
+			details: { agent: "task", id: "0-EvalAgent", model: "p/model", structured: false },
+		});
+		await expect(runEvalAgent({ prompt: "fail" }, { session: makeSession() })).rejects.toThrow("boom");
+	});
+});
+
+describe("agent() through eval runtimes", () => {
+	afterEach(() => {
+		vi.restoreAllMocks();
+	});
+
+	afterAll(async () => {
+		await disposeAllVmContexts();
+		await disposeAllKernelSessions();
+	});
+
+	it("exposes agent() in JavaScript and parses structured output", async () => {
+		using tempDir = TempDir.createSync("@omp-eval-agent-js-");
+		const { session, sessionFile, sessionId } = makeEvalSession(tempDir, "js-agent");
+		mockAgents();
+		vi.spyOn(taskExecutor, "runSubprocess").mockImplementation(async options =>
+			singleResult(options, {
+				output: options.outputSchema ? '{"ok":true,"n":3}' : "hello from agent",
+			}),
+		);
+
+		const result = await executeJs(
+			'const text = await agent("hi"); const data = await agent("json", { schema: { type: "object" } }); return JSON.stringify([text, data]);',
+			{ cwd: tempDir.path(), sessionId, session, sessionFile },
+		);
+
+		expect(result.exitCode).toBe(0);
+		expect(JSON.parse(result.output.trim())).toEqual(["hello from agent", { ok: true, n: 3 }]);
+	});
+
+	it("runs JavaScript parallel() with bounded concurrency while preserving order", async () => {
+		using tempDir = TempDir.createSync("@omp-eval-agent-js-parallel-");
+		const { session, sessionFile, sessionId } = makeEvalSession(tempDir, "js-agent-parallel");
+		mockAgents();
+		let inFlight = 0;
+		let maxInFlight = 0;
+		vi.spyOn(taskExecutor, "runSubprocess").mockImplementation(async options => {
+			inFlight++;
+			maxInFlight = Math.max(maxInFlight, inFlight);
+			try {
+				await Bun.sleep(options.assignment === "a" ? 30 : 10);
+				return singleResult(options, { output: options.assignment ?? "" });
+			} finally {
+				inFlight--;
+			}
+		});
+
+		const result = await executeJs(
+			'const values = await parallel(["a", "b", "c", "d"].map(name => () => agent(name)), { concurrency: 2 }); return JSON.stringify(values);',
+			{ cwd: tempDir.path(), sessionId, session, sessionFile },
+		);
+
+		expect(result.exitCode).toBe(0);
+		expect(JSON.parse(result.output.trim())).toEqual(["a", "b", "c", "d"]);
+		expect(maxInFlight).toBeGreaterThan(1);
+		expect(maxInFlight).toBeLessThanOrEqual(2);
+	});
+
+	it("propagates JavaScript parallel() rejections", async () => {
+		using tempDir = TempDir.createSync("@omp-eval-agent-js-reject-");
+		const { session, sessionFile, sessionId } = makeEvalSession(tempDir, "js-agent-reject");
+		mockAgents();
+		vi.spyOn(taskExecutor, "runSubprocess").mockImplementation(async options => {
+			if (options.assignment === "bad") {
+				return singleResult(options, { exitCode: 1, output: "", stderr: "boom", error: "boom" });
+			}
+			return singleResult(options, { output: options.assignment ?? "" });
+		});
+
+		const result = await executeJs('await parallel([() => agent("ok"), () => agent("bad")], { concurrency: 2 });', {
+			cwd: tempDir.path(),
+			sessionId,
+			session,
+			sessionFile,
+		});
+
+		expect(result.exitCode).toBe(1);
+		expect(result.output).toContain("boom");
+	});
+
+	it("exposes agent() in the Python runtime", async () => {
+		using tempDir = TempDir.createSync("@omp-eval-agent-py-");
+		const { session, sessionFile, sessionId } = makeEvalSession(tempDir, "py-agent");
+		mockAgents();
+		vi.spyOn(taskExecutor, "runSubprocess").mockImplementation(async options =>
+			singleResult(options, { output: "hello from python" }),
+		);
+
+		const probe = await executePython('print("probe")', {
+			cwd: tempDir.path(),
+			sessionId: `${sessionId}:probe`,
+			sessionFile,
+			kernelMode: "per-call",
+		});
+		if (probe.exitCode === undefined && probe.cancelled) {
+			expect(probe.output).toBe("");
+			return;
+		}
+		expect(probe.exitCode).toBe(0);
+
+		const result = await executePython('print(agent("hi"))', {
+			cwd: tempDir.path(),
+			sessionId,
+			sessionFile,
+			kernelMode: "per-call",
+			toolSession: session,
+		});
+
+		expect(result.exitCode).toBe(0);
+		expect(result.output.trim()).toBe("hello from python");
+	});
+});
diff --git a/packages/coding-agent/src/eval/agent-bridge.ts b/packages/coding-agent/src/eval/agent-bridge.ts
new file mode 100644
index 000000000..c04715b00
--- /dev/null
+++ b/packages/coding-agent/src/eval/agent-bridge.ts
@@ -0,0 +1,281 @@
+/**
+ * Host-side handler for the eval `agent()` helper.
+ */
+import * as fs from "node:fs/promises";
+import * as os from "node:os";
+import * as path from "node:path";
+import { prompt, Snowflake } from "@oh-my-pi/pi-utils";
+import * as z from "zod/v4";
+import { resolveAgentModelPatterns } from "../config/model-resolver";
+import type { LocalProtocolOptions } from "../internal-urls";
+import { MCPManager } from "../mcp/manager";
+import subagentUserPromptTemplate from "../prompts/system/subagent-user-prompt.md" with { type: "text" };
+import * as taskDiscovery from "../task/discovery";
+import * as taskExecutor from "../task/executor";
+import { AgentOutputManager } from "../task/output-manager";
+import type { AgentDefinition, AgentProgress } from "../task/types";
+import type { ToolSession } from "../tools";
+import { ToolError } from "../tools/tool-errors";
+import type { JsStatusEvent } from "./js/shared/types";
+// Import review tools for side effects (registers subagent tool handlers).
+import "../tools/review";
+
+/** Synthetic bridge name reserved for the `agent()` helper across both runtimes. */
+export const EVAL_AGENT_BRIDGE_NAME = "__agent__";
+
+/** Hard recursion limit for eval-driven subagents. */
+export const EVAL_AGENT_MAX_DEPTH = 3;
+
+const DEFAULT_AGENT_TYPE = "task";
+const DEFAULT_AGENT_LABEL = "EvalAgent";
+
+const agentArgsSchema = z.object({
+	prompt: z.string().min(1, "prompt must be a non-empty string"),
+	agentType: z.string().min(1).optional(),
+	model: z.union([z.string().min(1), z.array(z.string().min(1)).min(1)]).optional(),
+	context: z.string().optional(),
+	label: z.string().optional(),
+	schema: z.unknown().optional(),
+});
+
+interface EvalAgentArgs {
+	prompt: string;
+	agentType?: string;
+	model?: string | string[];
+	context?: string;
+	label?: string;
+	schema?: unknown;
+}
+
+export interface EvalAgentBridgeOptions {
+	session: ToolSession;
+	signal?: AbortSignal;
+	emitStatus?: (event: JsStatusEvent) => void;
+}
+
+export interface EvalAgentResult {
+	text: string;
+	details: {
+		agent: string;
+		id: string;
+		model?: string | string[];
+		structured: boolean;
+	};
+}
+
+function parseAgentArgs(args: unknown): EvalAgentArgs {
+	const parsed = agentArgsSchema.safeParse(args);
+	if (!parsed.success) {
+		const issue = parsed.error.issues[0];
+		const where = issue?.path.length ? `${issue.path.join(".")}: ` : "";
+		throw new ToolError(`agent() received invalid arguments: ${where}${issue?.message ?? "bad input"}`);
+	}
+	return parsed.data;
+}
+
+function assertDepthAllowed(session: ToolSession): void {
+	const taskDepth = session.taskDepth ?? 0;
+	if (taskDepth >= EVAL_AGENT_MAX_DEPTH) {
+		throw new ToolError(
+			`agent() cannot spawn another agent at task depth ${taskDepth}; maximum depth is ${EVAL_AGENT_MAX_DEPTH}.`,
+		);
+	}
+}
+
+function assertSpawnAllowed(session: ToolSession, agentName: string): void {
+	const parentSpawns = session.getSessionSpawns() ?? "*";
+	if (parentSpawns === "*") return;
+	if (parentSpawns === "") {
+		throw new ToolError(`Cannot spawn '${agentName}'. Allowed: none (spawns disabled for this agent)`);
+	}
+	const allowedSpawns = parentSpawns.split(",").map(spawn => spawn.trim());
+	if (!allowedSpawns.includes(agentName)) {
+		throw new ToolError(`Cannot spawn '${agentName}'. Allowed: ${parentSpawns}`);
+	}
+}
+
+function assertAgentEnabled(session: ToolSession, agentName: string, agents: AgentDefinition[]): void {
+	const disabledAgents = session.settings.get("task.disabledAgents") as string[];
+	if (!disabledAgents.includes(agentName)) return;
+	const enabled = agents.filter(agent => !disabledAgents.includes(agent.name)).map(agent => agent.name);
+	throw new ToolError(
+		`Agent "${agentName}" is disabled in settings. Enable it via /agents, or use a different agent type.${enabled.length > 0 ? ` Available: ${enabled.join(", ")}` : ""}`,
+	);
+}
+
+function assertNotPlanMode(session: ToolSession): void {
+	if (session.getPlanModeState?.()?.enabled) {
+		throw new ToolError("agent() is unavailable in plan mode.");
+	}
+}
+
+function renderSubagentPrompt(assignment: string): string {
+	return prompt.render(subagentUserPromptTemplate, { assignment: assignment.trim(), independentMode: false });
+}
+
+function trimToUndefined(value: string | undefined): string | undefined {
+	const trimmed = value?.trim();
+	return trimmed ? trimmed : undefined;
+}
+
+function outputIdBase(label: string | undefined, agentName: string): string {
+	const source = trimToUndefined(label) ?? agentName ?? DEFAULT_AGENT_LABEL;
+	const sanitized = source.replace(/[^A-Za-z0-9_-]+/g, "").slice(0, 48);
+	return sanitized || DEFAULT_AGENT_LABEL;
+}
+
+function getOutputManager(session: ToolSession): AgentOutputManager {
+	if (session.agentOutputManager) return session.agentOutputManager;
+	const manager = new AgentOutputManager(session.getArtifactsDir ?? (() => null));
+	session.agentOutputManager = manager;
+	return manager;
+}
+
+async function getArtifacts(session: ToolSession): Promise<{
+	sessionFile: string | null;
+	artifactsDir: string;
+	contextFile?: string;
+}> {
+	const sessionFile = session.getSessionFile();
+	const sessionArtifactsDir = sessionFile ? sessionFile.slice(0, -6) : null;
+	const artifactsDir = sessionArtifactsDir ?? path.join(os.tmpdir(), `omp-eval-agent-${Snowflake.next()}`);
+	await fs.mkdir(artifactsDir, { recursive: true });
+
+	const shouldWriteConversationContext = session.settings.get("irc.enabled") !== true;
+	const compactContext = shouldWriteConversationContext ? session.getCompactContext?.() : undefined;
+	if (!compactContext) return { sessionFile, artifactsDir };
+
+	const contextFile = path.join(artifactsDir, "context.md");
+	await Bun.write(contextFile, compactContext);
+	return { sessionFile, artifactsDir, contextFile };
+}
+
+function emitProgressStatus(emitStatus: ((event: JsStatusEvent) => void) | undefined, progress: AgentProgress): void {
+	emitStatus?.({
+		op: "agent",
+		agent: progress.agent,
+		id: progress.id,
+		status: progress.status,
+		lastIntent: progress.lastIntent,
+		toolCount: progress.toolCount,
+		durationMs: progress.durationMs,
+		model: progress.resolvedModel ?? progress.modelOverride,
+	});
+}
+
+/**
+ * Run a single subagent on behalf of an eval cell's `agent()` call.
+ */
+export async function runEvalAgent(args: unknown, options: EvalAgentBridgeOptions): Promise<EvalAgentResult> {
+	const parsed = parseAgentArgs(args);
+	const agentName = parsed.agentType ?? DEFAULT_AGENT_TYPE;
+	const structured = Object.hasOwn(parsed, "schema");
+
+	assertNotPlanMode(options.session);
+	assertDepthAllowed(options.session);
+	assertSpawnAllowed(options.session, agentName);
+
+	const { agents } = await taskDiscovery.discoverAgents(options.session.cwd);
+	const agent = taskDiscovery.getAgent(agents, agentName);
+	if (!agent) {
+		const available = agents.map(candidate => candidate.name).join(", ") || "none";
+		throw new ToolError(`Unknown agent "${agentName}". Available: ${available}`);
+	}
+	assertAgentEnabled(options.session, agentName, agents);
+
+	const effectiveAgent = agent;
+	const parentActiveModelPattern = options.session.getActiveModelString?.();
+	const agentModelOverrides = options.session.settings.get("task.agentModelOverrides");
+	const modelOverride = resolveAgentModelPatterns({
+		settingsOverride: parsed.model ?? agentModelOverrides[agentName],
+		agentModel: effectiveAgent.model,
+		settings: options.session.settings,
+		activeModelPattern: parentActiveModelPattern,
+		fallbackModelPattern: options.session.getModelString?.(),
+	});
+	const availableSkills = [...(options.session.skills ?? [])];
+	const resolvedAutoloadSkills =
+		effectiveAgent.autoloadSkills?.length && availableSkills.length > 0
+			? effectiveAgent.autoloadSkills
+					.map(name => availableSkills.find(skill => skill.name === name))
+					.filter((skill): skill is NonNullable<typeof skill> => skill !== undefined)
+			: [];
+	const contextFiles = options.session.contextFiles?.filter(
+		file => path.basename(file.path).toLowerCase() !== "agents.md",
+	);
+	const localProtocolOptions: LocalProtocolOptions = options.session.localProtocolOptions ?? {
+		getArtifactsDir: options.session.getArtifactsDir ?? (() => null),
+		getSessionId: options.session.getSessionId ?? (() => null),
+	};
+	const parentArtifactManager = options.session.getArtifactManager?.() ?? undefined;
+	const parentEvalSessionId = options.session.getEvalSessionId?.() ?? undefined;
+	const mcpManager = options.session.mcpManager ?? MCPManager.instance();
+	const { sessionFile, artifactsDir, contextFile } = await getArtifacts(options.session);
+	const outputManager = getOutputManager(options.session);
+	const id = await outputManager.allocate(outputIdBase(parsed.label, agentName));
+	const assignment = parsed.prompt.trim();
+	const context = trimToUndefined(parsed.context);
+	const result = await taskExecutor.runSubprocess({
+		cwd: options.session.cwd,
+		agent: effectiveAgent,
+		task: renderSubagentPrompt(assignment),
+		assignment,
+		context,
+		description: trimToUndefined(parsed.label),
+		index: 0,
+		id,
+		taskDepth: options.session.taskDepth ?? 0,
+		modelOverride,
+		parentActiveModelPattern,
+		thinkingLevel: effectiveAgent.thinkingLevel,
+		outputSchema: structured ? parsed.schema : undefined,
+		sessionFile,
+		persistArtifacts: Boolean(sessionFile),
+		artifactsDir,
+		contextFile,
+		enableLsp: (options.session.enableLsp ?? true) && options.session.settings.get("task.enableLsp"),
+		signal: options.signal,
+		eventBus: options.session.eventBus,
+		onProgress: progress => emitProgressStatus(options.emitStatus, progress),
+		authStorage: options.session.authStorage,
+		modelRegistry: options.session.modelRegistry,
+		settings: options.session.settings,
+		mcpManager,
+		contextFiles,
+		skills: availableSkills,
+		autoloadSkills: resolvedAutoloadSkills,
+		workspaceTree: options.session.workspaceTree,
+		promptTemplates: options.session.promptTemplates,
+		localProtocolOptions,
+		parentArtifactManager,
+		parentHindsightSessionState: options.session.getHindsightSessionState?.(),
+		parentMnemosyneSessionState: options.session.getMnemosyneSessionState?.(),
+		parentTelemetry: options.session.getTelemetry?.(),
+		parentEvalSessionId,
+	});
+
+	if (result.exitCode !== 0 || result.error) {
+		const failureMessage =
+			result.error ?? result.stderr ?? result.abortReason ?? `agent() subagent '${agentName}' failed.`;
+		throw new ToolError(failureMessage);
+	}
+
+	options.emitStatus?.({
+		op: "agent",
+		agent: result.agent,
+		id: result.id,
+		status: "completed",
+		chars: result.output.length,
+		model: result.resolvedModel ?? modelOverride,
+	});
+
+	return {
+		text: result.output,
+		details: {
+			agent: result.agent,
+			id: result.id,
+			model: result.resolvedModel ?? modelOverride,
+			structured,
+		},
+	};
+}
diff --git a/packages/coding-agent/src/eval/js/shared/prelude.txt b/packages/coding-agent/src/eval/js/shared/prelude.txt
index 89f5a76a1..63eb07159 100644
--- a/packages/coding-agent/src/eval/js/shared/prelude.txt
+++ b/packages/coding-agent/src/eval/js/shared/prelude.txt
@@ -39,11 +39,63 @@ if (!globalThis.__omp_js_prelude_loaded__) {
 		return values.length === 1 ? values[0] : values;
 	};
 
+	const hasOwn = (object, key) => Object.prototype.hasOwnProperty.call(object, key);
+
 	const llm = async (prompt, opts = {}) => {
 		const o = toOptions(opts);
 		const res = await globalThis.__omp_call_tool__("__llm__", { prompt, ...o });
 		const text = res && typeof res === "object" ? res.text : res;
-		return o.schema ? JSON.parse(text) : text;
+		return hasOwn(o, "schema") ? JSON.parse(text) : text;
+	};
+
+	const agent = async (prompt, opts = {}) => {
+		const o = toOptions(opts);
+		const res = await globalThis.__omp_call_tool__("__agent__", { prompt, ...o });
+		const text = res && typeof res === "object" ? res.text : res;
+		return hasOwn(o, "schema") ? JSON.parse(text) : text;
+	};
+
+	const normalizeConcurrency = value => {
+		const number = Number(value ?? 4);
+		if (!Number.isFinite(number)) return 4;
+		return Math.max(1, Math.min(16, Math.trunc(number)));
+	};
+
+	const __pool = async (items, limit, fn) => {
+		const list = Array.from(items ?? []);
+		const concurrency = Math.min(normalizeConcurrency(limit), list.length);
+		const results = new Array(list.length);
+		let next = 0;
+		const worker = async () => {
+			while (true) {
+				const index = next++;
+				if (index >= list.length) return;
+				results[index] = await fn(list[index], index);
+			}
+		};
+		await Promise.all(Array.from({ length: concurrency }, () => worker()));
+		return results;
+	};
+
+	const parallel = async (thunks, opts = {}) =>
+		__pool(thunks, toOptions(opts).concurrency, (thunk, index) => {
+			if (typeof thunk !== "function") throw new TypeError("parallel() expects an iterable of functions");
+			return thunk(index);
+		});
+
+	const pipeline = async (items, ...stagesAndOptions) => {
+		let opts = {};
+		const last = stagesAndOptions.at(-1);
+		if (last && typeof last === "object" && !Array.isArray(last)) {
+			opts = last;
+			stagesAndOptions = stagesAndOptions.slice(0, -1);
+		}
+		let current = Array.from(items ?? []);
+		for (const stage of stagesAndOptions) {
+			if (typeof stage !== "function") throw new TypeError("pipeline() stages must be functions");
+			current = await __pool(current, toOptions(opts).concurrency, stage);
+		}
+		return current;
 	};
 
 	const display = value => {
@@ -70,6 +122,10 @@ if (!globalThis.__omp_js_prelude_loaded__) {
 	globalThis.tool = tool;
 	globalThis.llm = llm;
 	globalThis.output = output;
+	globalThis.agent = agent;
+	globalThis.parallel = parallel;
+	globalThis.pipeline = pipeline;
+	globalThis.__pool = __pool;
 	globalThis.read = read;
 	globalThis.write = write;
 	globalThis.append = append;
diff --git a/packages/coding-agent/src/eval/js/tool-bridge.ts b/packages/coding-agent/src/eval/js/tool-bridge.ts
index d587a3477..2689ad714 100644
--- a/packages/coding-agent/src/eval/js/tool-bridge.ts
+++ b/packages/coding-agent/src/eval/js/tool-bridge.ts
@@ -1,6 +1,7 @@
 import type { AgentTool, AgentToolResult } from "@oh-my-pi/pi-agent-core";
 import type { ToolSession } from "../../tools";
 import { ToolError } from "../../tools/tool-errors";
+import { EVAL_AGENT_BRIDGE_NAME, runEvalAgent } from "../agent-bridge";
 import { EVAL_LLM_BRIDGE_NAME, runEvalLlm } from "../llm-bridge";
 import type { JsStatusEvent } from "./shared/types";
 
@@ -105,6 +106,9 @@ export async function callSessionTool(name: string, args: unknown, options: Tool
 	if (name === EVAL_LLM_BRIDGE_NAME) {
 		return await runEvalLlm(args, options);
 	}
+	if (name === EVAL_AGENT_BRIDGE_NAME) {
+		return await runEvalAgent(args, options);
+	}
 	const tool = getTool(options.session, name);
 	const normalizedArgs = normalizeArgs(args);
 	const toolCallId = `js-${name}-${crypto.randomUUID()}`;
diff --git a/packages/coding-agent/src/eval/py/prelude.py b/packages/coding-agent/src/eval/py/prelude.py
index 24e761ab8..9f1bb60cd 100644
--- a/packages/coding-agent/src/eval/py/prelude.py
+++ b/packages/coding-agent/src/eval/py/prelude.py
@@ -479,3 +479,26 @@ if "__omp_prelude_loaded__" not in globals():
         res = _bridge_call("__llm__", args)
         text = res.get("text") if isinstance(res, dict) else res
         return json.loads(text) if schema is not None else text
+
+    def agent(prompt, *, agent_type="task", model=None, context=None, label=None, schema=None):
+        """Run a subagent and return its final output.
+
+        `agent_type` selects the subagent definition (default "task"). Pass
+        `model` to override that agent's model, `context` for shared background,
+        `label` for the output artifact id, and `schema` to request structured
+        JSON output; when `schema` is supplied the parsed object is returned.
+        """
+        args = {"prompt": prompt}
+        if agent_type is not None:
+            args["agentType"] = agent_type
+        if model is not None:
+            args["model"] = model
+        if context is not None:
+            args["context"] = context
+        if label is not None:
+            args["label"] = label
+        if schema is not None:
+            args["schema"] = schema
+        res = _bridge_call("__agent__", args)
+        text = res.get("text") if isinstance(res, dict) else res
+        return json.loads(text) if schema is not None else text
diff --git a/packages/coding-agent/src/prompts/tools/eval.md b/packages/coding-agent/src/prompts/tools/eval.md
index 2814b1e17..95789a084 100644
--- a/packages/coding-agent/src/prompts/tools/eval.md
+++ b/packages/coding-agent/src/prompts/tools/eval.md
@@ -46,6 +46,13 @@ tool.<name>(args) → unknown
     Invoke any session tool by name. `args` is the tool's parameter object.
 llm(prompt, model?="default", system?=None, schema?=None) → str | dict
     Oneshot, stateless LLM call (no history, no tools). `model` picks a tier: "smol" (fast), "default" (this session's model), "slow" (most capable). Pass `system` for a system prompt. Pass a JSON-Schema `schema` to force structured output and get the parsed object back; otherwise returns the completion text.
+agent(prompt, agent_type?="task", model?=None, context?=None, label?=None, schema?=None) → str | dict
+    Run a subagent and return its final output. Defaults to the bundled "task" agent; pass `agent_type`/`agentType` for another discovered agent. Pass a JSON-Schema `schema` to force structured output and get the parsed object back.
+{{#if js}}parallel(thunks, { concurrency?=4 }) → list
+    Run async thunks through a bounded pool (default concurrency 4, max 16), preserving input order and propagating failures.
+pipeline(items, ...stages, { concurrency?=4 }) → list
+    Apply async stage functions to each item with the same bounded-pool semantics; stage failures propagate.
+{{/if}}
 ```
 </prelude>
 
diff --git a/packages/coding-agent/test/eval/agent-bridge.test.ts b/packages/coding-agent/test/eval/agent-bridge.test.ts
new file mode 100644
index 000000000..87b401d1a
--- /dev/null
+++ b/packages/coding-agent/test/eval/agent-bridge.test.ts
@@ -0,0 +1,63 @@
+import { afterEach, describe, expect, it, vi } from "bun:test";
+import { Settings } from "../../src/config/settings";
+import { runEvalAgent } from "../../src/eval/agent-bridge";
+import type { LocalProtocolOptions } from "../../src/internal-urls";
+import type { MCPManager } from "../../src/mcp";
+import * as taskDiscovery from "../../src/task/discovery";
+import * as taskExecutor from "../../src/task/executor";
+import type { AgentDefinition, SingleResult } from "../../src/task/types";
+import type { ToolSession } from "../../src/tools";
+
+function createResult(): SingleResult {
+	return {
+		index: 0,
+		id: "0-Task",
+		agent: "task",
+		agentSource: "bundled",
+		task: "do work",
+		exitCode: 0,
+		output: "done",
+		stderr: "",
+		truncated: false,
+		durationMs: 1,
+		tokens: 0,
+	};
+}
+
+describe("runEvalAgent", () => {
+	afterEach(() => {
+		vi.restoreAllMocks();
+	});
+
+	it("forwards session-scoped MCP and local protocol options", async () => {
+		const agent: AgentDefinition = {
+			name: "task",
+			description: "Task agent",
+			systemPrompt: "Handle task",
+			source: "bundled",
+		};
+		vi.spyOn(taskDiscovery, "discoverAgents").mockResolvedValue({ agents: [agent], projectAgentsDir: null });
+		const runSubprocessSpy = vi.spyOn(taskExecutor, "runSubprocess").mockResolvedValue(createResult());
+
+		const mcpManager = { sentinel: "mcp" } as unknown as MCPManager;
+		const localProtocolOptions: LocalProtocolOptions = {
+			getArtifactsDir: () => "/tmp/parent-artifacts",
+			getSessionId: () => "parent-session",
+		};
+		const session = {
+			cwd: "/tmp",
+			settings: Settings.isolated(),
+			getSessionSpawns: () => "*",
+			getSessionFile: () => null,
+			mcpManager,
+			localProtocolOptions,
+		} as unknown as ToolSession;
+
+		await runEvalAgent({ prompt: "do work", agentType: "task" }, { session });
+
+		expect(runSubprocessSpy).toHaveBeenCalledTimes(1);
+		const options = runSubprocessSpy.mock.calls[0]?.[0];
+		expect(options?.mcpManager).toBe(mcpManager);
+		expect(options?.localProtocolOptions).toBe(localProtocolOptions);
+	});
+});