feat(auto): fan out swarm research units

src/resources/extensions/sf/auto/run-unit.js

@@ -193,6 +193,100 @@ function shouldRouteRunUnitViaSwarm(options) {
 	);
 }
 
+/**
+ * Build a bounded fan-out plan for autonomous swarm units.
+ *
+ * Purpose: let headless autonomy use multiple swarm agents only when the work is
+ * naturally parallel and low-conflict. Research and validation can split into
+ * independent read-only lanes; implementation stays single-agent unless a future
+ * planner provides explicit disjoint write scopes.
+ *
+ * Consumer: runUnitViaSwarm before dispatching an autonomous unit envelope.
+ *
+ * @param {string} unitType
+ * @param {string} _unitId
+ * @param {string} prompt
+ * @param {object} [options={}]
+ * @returns {{ reason: string, lanes: Array<{ id: string, targetAgent: string, workMode: string, instruction: string }> } | null}
+ */
+export function buildSwarmFanoutPlan(unitType, _unitId, prompt, options = {}) {
+	const fanoutFlag = process.env.SF_SWARM_FANOUT;
+	if (fanoutFlag === "0" || fanoutFlag === "false") return null;
+	if (isCheckpointOnlyProtocolPass(options)) return null;
+	if (options?.keepSession === true) return null;
+	if (options?.swarmFanout === false) return null;
+
+	const type = String(unitType ?? "").toLowerCase();
+	const text = String(prompt ?? "").toLowerCase();
+
+	if (type.includes("research") || text.includes("parallel research")) {
+		return {
+			reason:
+				"research units are read-heavy and can be checked from independent angles",
+			lanes: [
+				{
+					id: "source-scout",
+					targetAgent: "scout",
+					workMode: "research",
+					instruction:
+						"Find the most relevant repo evidence and external assumptions. Do not edit files.",
+				},
+				{
+					id: "contract-review",
+					targetAgent: "reviewer",
+					workMode: "review",
+					instruction:
+						"Review the proposed direction for purpose, consumer, and missing falsifiers. Do not edit files.",
+				},
+				{
+					id: "verification-map",
+					targetAgent: "verifier",
+					workMode: "verify",
+					instruction:
+						"Identify executable verification, likely tests, and failure boundaries. Do not edit files.",
+				},
+			],
+		};
+	}
+
+	if (
+		type.includes("validate") ||
+		type.includes("audit") ||
+		type.includes("gate") ||
+		type.includes("uat")
+	) {
+		return {
+			reason:
+				"validation benefits from independent review, verification, and challenge lanes",
+			lanes: [
+				{
+					id: "reviewer",
+					targetAgent: "reviewer",
+					workMode: "review",
+					instruction:
+						"Review the artifact against the stated contract. Do not edit files.",
+				},
+				{
+					id: "verifier",
+					targetAgent: "verifier",
+					workMode: "verify",
+					instruction:
+						"Run or identify verification evidence and report residual risk. Do not edit files.",
+				},
+				{
+					id: "adversary",
+					targetAgent: "adversary",
+					workMode: "challenge",
+					instruction:
+						"Challenge weak assumptions and look for counterexamples. Do not edit files.",
+				},
+			],
+		};
+	}
+
+	return null;
+}
+
 /**
  * Build the system prompt for a swarm worker executing an autonomous unit.
  *
@@ -422,6 +516,225 @@ async function runUnitViaSwarm(ctx, _pi, s, unitType, unitId, prompt, options) {
 		}
 	}
 
+	const fanoutPlan = buildSwarmFanoutPlan(unitType, unitId, prompt, options);
+	if (fanoutPlan && fanoutPlan.lanes.length > 1) {
+		debugLog("runUnit[swarm]", {
+			phase: "fanout-dispatch",
+			unitType,
+			unitId,
+			lanes: fanoutPlan.lanes.map((lane) => lane.targetAgent),
+		});
+		if (typeof ctx.ui?.notify === "function") {
+			ctx.ui.notify(
+				`[${unitType}] ${unitId} → swarm fan-out ${fanoutPlan.lanes.length} lanes`,
+				"info",
+			);
+		}
+
+		const laneResults = await Promise.all(
+			fanoutPlan.lanes.map(async (lane) => {
+				const lanePayload = [
+					`Fan-out lane: ${lane.id}`,
+					`Target agent: ${lane.targetAgent}`,
+					`Reason: ${fanoutPlan.reason}`,
+					"",
+					"Lane instruction:",
+					lane.instruction,
+					"",
+					"Original autonomous unit prompt:",
+					prompt,
+				].join("\n");
+				const laneEnvelope = {
+					...envelope,
+					workMode: lane.workMode,
+					targetAgent: lane.targetAgent,
+					payload: lanePayload,
+				};
+				const result = await swarmDispatchAndWait(basePath, laneEnvelope, {
+					timeoutMs,
+					noOutputTimeoutMs,
+					signal: controller.signal,
+					onEvent,
+				});
+				return { lane, result };
+			}),
+		);
+
+		const failedLane = laneResults.find(
+			({ result }) => result.error || result.reply === null,
+		);
+		if (failedLane) {
+			const reason =
+				failedLane.result.error ??
+				`lane ${failedLane.lane.id} returned no reply`;
+			debugLog("runUnit[swarm]", {
+				phase: "fanout-failed",
+				unitType,
+				unitId,
+				lane: failedLane.lane.id,
+				reason,
+			});
+			if (typeof ctx.ui?.notify === "function") {
+				ctx.ui.notify(
+					`[${unitType}] ${unitId} → swarm fan-out failed: ${reason}`,
+					"error",
+				);
+			}
+			return {
+				status: "cancelled",
+				requestDispatchedAt,
+				errorContext: {
+					message: reason,
+					category: "session-failed",
+					isTransient: true,
+				},
+			};
+		}
+
+		const replyText = laneResults
+			.map(({ lane, result }) => {
+				const reply = result.reply ?? "";
+				return `## ${lane.targetAgent}\n${reply}`;
+			})
+			.join("\n\n");
+		const hasCheckpointCall = collectedToolCalls.some(
+			(tc) => tc.name === "checkpoint",
+		);
+		if (!hasCheckpointCall) {
+			const verificationEvidence = laneResults.map(
+				({ lane, result }) =>
+					`swarm-agent:${lane.targetAgent}; replyMessageId:${result.replyMessageId ?? "unknown"}`,
+			);
+			collectedToolCalls.push({
+				type: "tool_use",
+				id: `swarm-fanout-cp-${Date.now()}`,
+				name: "checkpoint",
+				input: {
+					outcome: "continue",
+					unitType,
+					unitId,
+					summary: `Swarm fan-out completed ${laneResults.length} lanes.`,
+					completedItems: fanoutPlan.lanes.map(
+						(lane) => `${lane.targetAgent} completed ${lane.id}`,
+					),
+					remainingItems: [
+						`Synthesize fan-out findings for ${unitType} ${unitId}.`,
+					],
+					verificationEvidence,
+					pdd: {
+						purpose:
+							"Synthetic checkpoint injected because fan-out lanes returned text without a single parent checkpoint.",
+						consumer:
+							"phases-unit.js assessAutonomousSolverTurn + missing-checkpoint-repair loop",
+						contract:
+							"Outcome is 'continue' so the parent loop synthesizes independent lane findings.",
+						failureBoundary:
+							"If any lane fails, fan-out returns cancelled before synthesizing evidence.",
+						evidence: verificationEvidence.join("; "),
+						nonGoals:
+							"Does not claim implementation completion from read-only fan-out lanes.",
+						invariants:
+							"Read-only fan-out lanes are used only for naturally parallel research or validation units.",
+						assumptions:
+							"Independent lane replies are useful input for the next autonomous step.",
+					},
+				},
+			});
+			try {
+				appendAutonomousSolverCheckpoint(basePath, {
+					unitType,
+					unitId,
+					outcome: "continue",
+					summary: `Swarm fan-out completed ${laneResults.length} lanes.`,
+					completedItems: fanoutPlan.lanes.map(
+						(lane) => `${lane.targetAgent} completed ${lane.id}`,
+					),
+					remainingItems: [
+						`Synthesize fan-out findings for ${unitType} ${unitId}.`,
+					],
+					verificationEvidence,
+					pdd: {
+						purpose:
+							"Synthetic checkpoint from multi-agent fan-out when lanes returned without a parent checkpoint.",
+						consumer: "phases-unit.js assessAutonomousSolverTurn",
+						contract:
+							"Falls back to 'continue' so the loop uses the fan-out evidence without pretending completion.",
+						failureBoundary:
+							"appendAutonomousSolverCheckpoint failure is swallowed — the loop repairs via missing-checkpoint handling.",
+						evidence: verificationEvidence.join("; "),
+						nonGoals: "Does not synthesize completion.",
+						invariants:
+							"Synthetic checkpoints are only written when no real checkpoint exists.",
+						assumptions: "All fan-out lanes produced non-empty replies.",
+					},
+				});
+			} catch (cpErr) {
+				debugLog("runUnit[swarm]", {
+					phase: "fanout-synthesized-checkpoint-error",
+					unitType,
+					unitId,
+					error: getErrorMessage(cpErr),
+				});
+			}
+		}
+
+		try {
+			emitJournalEvent(basePath, {
+				ts: new Date().toISOString(),
+				eventType: "swarm-dispatch",
+				data: {
+					unitType,
+					unitId,
+					targetAgent: "fanout",
+					workMode: envelope.workMode,
+					toolCallCount: collectedToolCalls.length,
+					outcome: workerSignaledOutcome ?? "continue",
+					via: "autonomous-unit",
+					fanout: true,
+					lanes: fanoutPlan.lanes.map((lane) => lane.targetAgent),
+				},
+			});
+		} catch {
+			/* journal write failure must not break dispatch */
+		}
+
+		const contentBlocks = [
+			...collectedToolCalls,
+			{ type: "text", text: replyText },
+		];
+		return {
+			status: "completed",
+			event: {
+				messages: [
+					{
+						role: "assistant",
+						content: contentBlocks,
+						_swarm: true,
+						replyMessageId: laneResults
+							.map(({ result }) => result.replyMessageId)
+							.filter(Boolean)
+							.join(","),
+						targetAgent: "fanout",
+					},
+				],
+			},
+			requestDispatchedAt,
+			_via: "swarm",
+			_swarmResult: {
+				fanout: true,
+				reason: fanoutPlan.reason,
+				lanes: laneResults.map(({ lane, result }) => ({
+					id: lane.id,
+					targetAgent: lane.targetAgent,
+					replyMessageId: result.replyMessageId,
+				})),
+				reply: replyText,
+			},
+			swarmToolCallCount:
+				collectedToolCalls.length - (hasCheckpointCall ? 0 : 1),
+		};
+	}
+
 	let swarmResult;
 	try {
 		swarmResult = await swarmDispatchAndWait(basePath, envelope, {

src/resources/extensions/sf/tests/run-unit-via-swarm.test.mjs

@@ -134,15 +134,18 @@ function makeS(basePath = "/tmp/test-project") {
 let origEnv;
 let origNoOutputEnv;
 let origHeadlessEnv;
+let origFanoutEnv;
 
 beforeEach(() => {
 	vi.clearAllMocks();
 	origEnv = process.env.SF_AUTONOMOUS_VIA_SWARM;
 	origNoOutputEnv = process.env.SF_SWARM_NO_OUTPUT_TIMEOUT_MS;
 	origHeadlessEnv = process.env.SF_HEADLESS;
+	origFanoutEnv = process.env.SF_SWARM_FANOUT;
 	delete process.env.SF_AUTONOMOUS_VIA_SWARM;
 	delete process.env.SF_SWARM_NO_OUTPUT_TIMEOUT_MS;
 	delete process.env.SF_HEADLESS;
+	delete process.env.SF_SWARM_FANOUT;
 
 	// Default implementation for the happy-path tests: return a deterministic reply.
 	mockSwarmDispatchAndWait.mockImplementation(
@@ -173,6 +176,11 @@ afterEach(() => {
 	} else {
 		process.env.SF_HEADLESS = origHeadlessEnv;
 	}
+	if (origFanoutEnv === undefined) {
+		delete process.env.SF_SWARM_FANOUT;
+	} else {
+		process.env.SF_SWARM_FANOUT = origFanoutEnv;
+	}
 });
 
 // ─── Flag ON — happy path ─────────────────────────────────────────────────────
@@ -207,24 +215,19 @@ describe("runUnit — SF_AUTONOMOUS_VIA_SWARM=1 — happy path", () => {
 		const pi = makePi();
 		const s = makeS("/myproject");
 
-		await runUnit(
-			ctx,
-			pi,
-			s,
-			"research-slice",
-			"slice-42",
-			"research the topic",
-			{ scope: "milestone-1", priority: 7 },
-		);
+		await runUnit(ctx, pi, s, "execute-task", "task-42", "execute the task", {
+			scope: "milestone-1",
+			priority: 7,
+		});
 
 		expect(mockSwarmDispatchAndWait).toHaveBeenCalledOnce();
 		const [basePath, envelope, opts] = mockSwarmDispatchAndWait.mock.calls[0];
 
 		expect(basePath).toBe("/myproject");
-		expect(envelope.unitId).toBe("slice-42");
-		expect(envelope.unitType).toBe("research-slice");
-		expect(envelope.workMode).toBe("research"); // research-slice → research
-		expect(envelope.payload).toBe("research the topic");
+		expect(envelope.unitId).toBe("task-42");
+		expect(envelope.unitType).toBe("execute-task");
+		expect(envelope.workMode).toBe("build"); // execute-task → build
+		expect(envelope.payload).toBe("execute the task");
 		expect(envelope.scope).toBe("milestone-1");
 		expect(envelope.priority).toBe(7);
 		expect(envelope.executorPermissionLevel).toBe("low");
@@ -544,6 +547,71 @@ describe("runUnit — SF_AUTONOMOUS_VIA_SWARM=1 — happy path", () => {
 	});
 });
 
+describe("runUnit — swarm fan-out policy", () => {
+	test("research-slice_when_swarm_enabled_fans_out_to_independent_read_only_lanes", async () => {
+		process.env.SF_AUTONOMOUS_VIA_SWARM = "1";
+		mockSwarmDispatchAndWait.mockImplementation(
+			async (_basePath, envelope, _opts) => ({
+				messageId: `dispatch-${envelope.targetAgent}`,
+				targetAgent: envelope.targetAgent,
+				swarmName: "default",
+				envelope,
+				reply: `reply from ${envelope.targetAgent}`,
+				replyMessageId: `reply-${envelope.targetAgent}`,
+			}),
+		);
+
+		const ctx = makeCtx("/proj");
+		const pi = makePi();
+		const s = makeS("/proj");
+
+		const result = await runUnit(
+			ctx,
+			pi,
+			s,
+			"research-slice",
+			"M001/S01",
+			"research provider routing",
+			{},
+		);
+
+		expect(result.status).toBe("completed");
+		expect(mockSwarmDispatchAndWait).toHaveBeenCalledTimes(3);
+		const targetAgents = mockSwarmDispatchAndWait.mock.calls.map(
+			(call) => call[1].targetAgent,
+		);
+		expect(targetAgents).toEqual(["scout", "reviewer", "verifier"]);
+		expect(result._swarmResult.fanout).toBe(true);
+		expect(result._swarmResult.lanes).toHaveLength(3);
+		expect(result.event.messages[0].targetAgent).toBe("fanout");
+		expect(result.event.messages[0].content.at(-1).text).toContain("## scout");
+	});
+
+	test("execute-task_when_no_disjoint_scope_remains_single_agent", async () => {
+		process.env.SF_AUTONOMOUS_VIA_SWARM = "1";
+
+		const ctx = makeCtx("/proj");
+		const pi = makePi();
+		const s = makeS("/proj");
+
+		const result = await runUnit(
+			ctx,
+			pi,
+			s,
+			"execute-task",
+			"M001/S01/T01",
+			"implement a coupled change",
+			{},
+		);
+
+		expect(result.status).toBe("completed");
+		expect(mockSwarmDispatchAndWait).toHaveBeenCalledOnce();
+		expect(
+			mockSwarmDispatchAndWait.mock.calls[0][1].targetAgent,
+		).toBeUndefined();
+	});
+});
+
 // ─── Flag ON — error paths ────────────────────────────────────────────────────
 
 describe("runUnit — SF_AUTONOMOUS_VIA_SWARM=1 — error paths", () => {
@@ -760,6 +828,7 @@ describe("deriveWorkMode (via envelope.workMode in dispatch calls)", () => {
 	for (const [unitType, expectedWorkMode] of cases) {
 		test(`${unitType} → ${expectedWorkMode}`, async () => {
 			process.env.SF_AUTONOMOUS_VIA_SWARM = "1";
+			process.env.SF_SWARM_FANOUT = "0";
 
 			const ctx = makeCtx("/proj");
 			const pi = makePi();

src/resources/extensions/sf/tests/swarm.test.mjs

@@ -297,6 +297,29 @@ describe("SwarmDispatchLayer — routing", () => {
 		expect(agent.identity.role).toBe("reviewer");
 	});
 
+	test("dispatch_when_targetAgent_set_routes_to_named_agent", async () => {
+		const root = makeProject();
+		const layer = new SwarmDispatchLayer(root);
+
+		const result = await layer.dispatch({
+			unitId: "task-target-1",
+			unitType: "task",
+			workMode: "build",
+			targetAgent: "verifier",
+			payload: "verify task data",
+			priority: 5,
+			scope: "test-scope",
+		});
+
+		expect(result.messageId).toBeTruthy();
+		expect(result.targetAgent).toBe("verifier");
+
+		const swarm = await layer.getOrCreateSwarm();
+		const agent = swarm.get(result.targetAgent);
+		expect(agent).toBeDefined();
+		expect(agent.identity.role).toBe("verifier");
+	});
+
 	test("dispatchBatch_dispatches_all", async () => {
 		const root = makeProject();
 		const layer = new SwarmDispatchLayer(root);

src/resources/extensions/sf/uok/swarm-dispatch.js

@@ -168,6 +168,8 @@ async function getA2ATransport() {
  *   per unit type (e.g. ensure "checkpoint" is always available for execute-task units).
  * @property {string} [executorPermissionLevel] Optional: legacy SF permission
  *   extension level used by in-process headless worker sessions.
+ * @property {string} [targetAgent] Optional explicit target agent name. When
+ *   set, dispatch uses this agent instead of role-derived routing.
  */
 
 /**
@@ -266,7 +268,10 @@ export class SwarmDispatchLayer {
 	 */
 	async _busDispatch(envelope) {
 		const swarm = await this.getOrCreateSwarm();
-		const target = swarm.route(envelope);
+		const target =
+			envelope.targetAgent != null
+				? swarm.get(envelope.targetAgent)
+				: swarm.route(envelope);
 
 		if (!target) {
 			throw new Error(
@@ -324,7 +329,10 @@ export class SwarmDispatchLayer {
 	 */
 	async _a2aDispatch(envelope) {
 		const swarm = await this.getOrCreateSwarm();
-		const target = swarm.route(envelope);
+		const target =
+			envelope.targetAgent != null
+				? swarm.get(envelope.targetAgent)
+				: swarm.route(envelope);
 
 		if (!target) {
 			throw new Error(