feat(transport-http): add GET /conversations/:id/mcp status endpoint

Mirrors the existing GET /conversations/:id/lsp route exactly: gates on the
persisted then effective cwd (null → empty servers), returns 503 when the
MCP service isn't loaded, and maps McpServerStatus → McpServerInfo
(conditionally including `error` per exactOptionalPropertyTypes).

Wires mcpService into CreateServerOptions + extension activate via a plain
host.getService (mirroring lspService; "mcp" added to dependsOn, route added
to contributes.routes), adds the @dispatch/mcp workspace dep, and re-exports
mcpServiceHandle / McpService / McpServerStatus from seam.ts. Adds 4 tests
mirroring the LSP status tests.

6 files changed, 231 insertions, 1 deletions

diff --git a/bun.lock b/bun.lock
index 3671dee..f7c0418 100644
--- a/bun.lock
+++ b/bun.lock
@@ -280,7 +280,7 @@
     },
     "packages/transport-contract": {
       "name": "@dispatch/transport-contract",
-      "version": "0.21.0",
+      "version": "0.22.0",
       "dependencies": {
         "@dispatch/ui-contract": "workspace:*",
         "@dispatch/wire": "workspace:*",
@@ -294,6 +294,7 @@
         "@dispatch/credential-store": "workspace:*",
         "@dispatch/kernel": "workspace:*",
         "@dispatch/lsp": "workspace:*",
+        "@dispatch/mcp": "workspace:*",
         "@dispatch/session-orchestrator": "workspace:*",
         "@dispatch/system-prompt": "workspace:*",
         "@dispatch/throughput-store": "workspace:*",
diff --git a/packages/transport-http/package.json b/packages/transport-http/package.json
index e39a992..d95436b 100644
--- a/packages/transport-http/package.json
+++ b/packages/transport-http/package.json
@@ -10,6 +10,7 @@
 		"@dispatch/credential-store": "workspace:*",
 		"@dispatch/kernel": "workspace:*",
 		"@dispatch/lsp": "workspace:*",
+		"@dispatch/mcp": "workspace:*",
 		"@dispatch/session-orchestrator": "workspace:*",
 		"@dispatch/throughput-store": "workspace:*",
 		"@dispatch/transport-contract": "workspace:*",
diff --git a/packages/transport-http/src/app.test.ts b/packages/transport-http/src/app.test.ts
index a84fa44..c7b7d31 100644
--- a/packages/transport-http/src/app.test.ts
+++ b/packages/transport-http/src/app.test.ts
@@ -29,6 +29,7 @@ import type {
 	ConversationStore,
 	CredentialStore,
 	LspService,
+	McpService,
 	SessionOrchestrator,
 	SystemPromptService,
 	WarmService,
@@ -397,6 +398,41 @@ function createCapturingLspService(
 	};
 }
 
+function createFakeMcpService(
+	statuses: readonly {
+		readonly id: string;
+		readonly state: "connecting" | "connected" | "error" | "disconnected";
+		readonly error?: string;
+		readonly toolCount: number;
+	}[] = [],
+): McpService {
+	return {
+		async status() {
+			return statuses;
+		},
+	};
+}
+
+function createCapturingMcpService(
+	statuses: readonly {
+		readonly id: string;
+		readonly state: "connecting" | "connected" | "error" | "disconnected";
+		readonly error?: string;
+		readonly toolCount: number;
+	}[] = [],
+): McpService & { readonly statusCalls: readonly string[] } {
+	const calls: string[] = [];
+	return {
+		get statusCalls() {
+			return calls;
+		},
+		async status(cwd) {
+			calls.push(cwd);
+			return statuses;
+		},
+	};
+}
+
 function createFakeSystemPromptService(
 	template: string = "custom template",
 ): SystemPromptService & {
@@ -2384,6 +2420,139 @@ describe("GET /conversations/:id/lsp", () => {
 	});
 });
 
+describe("GET /conversations/:id/mcp", () => {
+	it("MCP: returns null+empty when no persisted cwd — mcpService.status NOT called", async () => {
+		const cwdStore = new Map<string, string>(); // no persisted cwd
+		const store = createFakeConversationStore(new Map(), new Map(), cwdStore);
+		const mcp = createCapturingMcpService([
+			{
+				id: "freecad",
+				state: "connected" as const,
+				toolCount: 3,
+			},
+		]);
+		const app = createApp({
+			conversationStore: store,
+			orchestrator: createFakeOrchestrator([]),
+			credentialStore: createFakeCredentialStore([]),
+			mcpService: mcp,
+			logger: noopLogger,
+		});
+		const res = await app.request("/conversations/conv1/mcp");
+		expect(res.status).toBe(200);
+		const body = (await res.json()) as {
+			conversationId: string;
+			cwd: string | null;
+			servers: readonly unknown[];
+		};
+		expect(body.conversationId).toBe("conv1");
+		expect(body.cwd).toBeNull();
+		expect(body.servers).toEqual([]);
+		expect(mcp.statusCalls).toEqual([]); // status NOT called
+	});
+
+	it("MCP: maps service statuses to McpServerInfo[] when cwd is set (error omitted when undefined)", async () => {
+		const cwdStore = new Map<string, string>([["conv1", "/home/user/project"]]);
+		const store = createFakeConversationStore(new Map(), new Map(), cwdStore);
+		const mcpStatuses = [
+			{
+				id: "freecad",
+				state: "connected" as const,
+				toolCount: 5,
+			},
+			{
+				id: "broken",
+				state: "error" as const,
+				toolCount: 0,
+				error: "spawn failed",
+			},
+		];
+		const app = createApp({
+			conversationStore: store,
+			orchestrator: createFakeOrchestrator([]),
+			credentialStore: createFakeCredentialStore([]),
+			mcpService: createFakeMcpService(mcpStatuses),
+			logger: noopLogger,
+		});
+		const res = await app.request("/conversations/conv1/mcp");
+		expect(res.status).toBe(200);
+		const body = (await res.json()) as {
+			conversationId: string;
+			cwd: string | null;
+			servers: readonly {
+				readonly id: string;
+				readonly state: string;
+				readonly toolCount: number;
+				readonly error?: string;
+			}[];
+		};
+		expect(body.conversationId).toBe("conv1");
+		expect(body.cwd).toBe("/home/user/project");
+		expect(body.servers).toHaveLength(2);
+		expect(body.servers[0]?.id).toBe("freecad");
+		expect(body.servers[0]?.state).toBe("connected");
+		expect(body.servers[0]?.toolCount).toBe(5);
+		expect(body.servers[0]?.error).toBeUndefined();
+		expect(body.servers[1]?.id).toBe("broken");
+		expect(body.servers[1]?.state).toBe("error");
+		expect(body.servers[1]?.toolCount).toBe(0);
+		expect(body.servers[1]?.error).toBe("spawn failed");
+	});
+
+	it("MCP: uses effectiveCwd when persisted cwd is set — status called with resolved cwd", async () => {
+		const cwdStore = new Map<string, string>([["conv1", "subdir"]]);
+		const store = createFakeConversationStore(new Map(), new Map(), cwdStore);
+		const resolvedStore: ConversationStore = {
+			...store,
+			async getEffectiveCwd() {
+				return "/workspace/subdir";
+			},
+		};
+		const mcp = createCapturingMcpService([
+			{
+				id: "freecad",
+				state: "connected" as const,
+				toolCount: 2,
+			},
+		]);
+		const app = createApp({
+			conversationStore: resolvedStore,
+			orchestrator: createFakeOrchestrator([]),
+			credentialStore: createFakeCredentialStore([]),
+			mcpService: mcp,
+			logger: noopLogger,
+		});
+		const res = await app.request("/conversations/conv1/mcp");
+		expect(res.status).toBe(200);
+		const body = (await res.json()) as {
+			conversationId: string;
+			cwd: string | null;
+			servers: readonly { readonly id: string }[];
+		};
+		expect(body.conversationId).toBe("conv1");
+		expect(body.cwd).toBe("/workspace/subdir"); // effective, not persisted
+		expect(mcp.statusCalls).toEqual(["/workspace/subdir"]);
+		expect(body.servers).toHaveLength(1);
+		expect(body.servers[0]?.id).toBe("freecad");
+	});
+
+	it("MCP: returns 503 when mcpService is undefined", async () => {
+		const cwdStore = new Map<string, string>([["conv1", "/home/user/project"]]);
+		const store = createFakeConversationStore(new Map(), new Map(), cwdStore);
+		const app = createApp({
+			conversationStore: store,
+			orchestrator: createFakeOrchestrator([]),
+			credentialStore: createFakeCredentialStore([]),
+			// mcpService intentionally omitted
+			logger: noopLogger,
+		});
+		const res = await app.request("/conversations/conv1/mcp");
+		expect(res.status).toBe(503);
+		const body = (await res.json()) as { error: string };
+		expect(body.error).toBe("MCP service not available");
+	});
+});
+
 describe("POST /chat reasoningEffort", () => {
 	const allLevels: readonly ReasoningEffort[] = ["low", "medium", "high", "xhigh", "max"];
 
diff --git a/packages/transport-http/src/app.ts b/packages/transport-http/src/app.ts
index 2a98ea0..1d87383 100644
--- a/packages/transport-http/src/app.ts
+++ b/packages/transport-http/src/app.ts
@@ -13,6 +13,8 @@ import type {
 	LastMessageResponse,
 	LspServerInfo,
 	LspStatusResponse,
+	McpServerInfo,
+	McpStatusResponse,
 	ModelResponse,
 	ModelsResponse,
 	OpenConversationResponse,
@@ -57,6 +59,8 @@ import {
 	isValidWorkspaceSlug,
 	type LspServerStatus,
 	type LspService,
+	type McpServerStatus,
+	type McpService,
 	type SessionOrchestrator,
 	type SystemPromptService,
 	ThroughputQueryError,
@@ -71,6 +75,7 @@ export interface CreateServerOptions {
 	readonly warmService?: WarmService;
 	readonly compactionService?: CompactionService;
 	readonly lspService?: LspService;
+	readonly mcpService?: McpService;
 	/** Optional — system prompt builder service (GET/PUT template). */
 	readonly systemPromptService?: SystemPromptService;
 	/** Optional — defaults to a no-op store (recording disabled, empty reports). */
@@ -720,6 +725,53 @@ export function createApp(opts: CreateServerOptions): Hono {
 		}
 	});
 
+	// Mirrors GET /conversations/:id/lsp: gate on persisted then effective cwd,
+	// 503 when no MCP service, map McpServerStatus → McpServerInfo.
+	app.get("/conversations/:id/mcp", async (c) => {
+		const conversationId = c.req.param("id");
+		try {
+			const persistedCwd = await opts.conversationStore.getCwd(conversationId);
+			if (persistedCwd === null) {
+				log.info("conversations: mcp status read (no cwd)", { conversationId });
+				const body: McpStatusResponse = { conversationId, cwd: null, servers: [] };
+				return c.json(body, 200);
+			}
+
+			const effectiveCwd = await opts.conversationStore.getEffectiveCwd(conversationId);
+			if (effectiveCwd === null) {
+				log.info("conversations: mcp status read (no effective cwd)", { conversationId });
+				const body: McpStatusResponse = { conversationId, cwd: null, servers: [] };
+				return c.json(body, 200);
+			}
+
+			if (opts.mcpService === undefined) {
+				log.warn("conversations: mcp service not available", { conversationId });
+				return c.json({ error: "MCP service not available" }, 503);
+			}
+
+			const statuses = await opts.mcpService.status(effectiveCwd);
+			const servers: McpServerInfo[] = statuses.map((s: McpServerStatus) => {
+				const info: McpServerInfo = {
+					id: s.id,
+					state: s.state,
+					toolCount: s.toolCount,
+					...(s.error !== undefined ? { error: s.error } : {}),
+				};
+				return info;
+			});
+			log.info("conversations: mcp status read", {
+				conversationId,
+				cwd: effectiveCwd,
+				serverCount: servers.length,
+			});
+			const body: McpStatusResponse = { conversationId, cwd: effectiveCwd, servers };
+			return c.json(body, 200);
+		} catch (err) {
+			log.error("conversations: mcp status failure", { err });
+			return c.json({ error: "Failed to read MCP status" }, 500);
+		}
+	});
+
 	app.get("/conversations", async (c) => {
 		try {
 			// Optional `?status=` comma-separated filter (e.g. "active,idle").
diff --git a/packages/transport-http/src/extension.ts b/packages/transport-http/src/extension.ts
index ac6553c..0f46e6b 100644
--- a/packages/transport-http/src/extension.ts
+++ b/packages/transport-http/src/extension.ts
@@ -6,6 +6,7 @@ import {
 	conversationStoreHandle,
 	credentialStoreHandle,
 	lspServiceHandle,
+	mcpServiceHandle,
 	sessionOrchestratorHandle,
 	systemPromptHandle,
 	throughputStoreHandle,
@@ -21,6 +22,7 @@ export const manifest: Manifest = {
 		"conversation-store",
 		"credential-store",
 		"lsp",
+		"mcp",
 		"session-orchestrator",
 		"throughput-store",
 	],
@@ -37,6 +39,7 @@ export const manifest: Manifest = {
 			"/conversations/:id/cwd",
 			"/conversations/:id/last",
 			"/conversations/:id/lsp",
+			"/conversations/:id/mcp",
 			"/conversations/:id/open",
 			"/conversations/:id/queue",
 			"/conversations/:id/reasoning-effort",
@@ -75,6 +78,7 @@ export function createTransportHttpExtension(): Extension & {
 			const warmService = host.getService(cacheWarmHandle);
 			const compactionService = host.getService(compactionHandle);
 			const lspService = host.getService(lspServiceHandle);
+			const mcpService = host.getService(mcpServiceHandle);
 			const systemPromptService = host.getService(systemPromptHandle);
 			const logger = host.logger;
 
@@ -86,6 +90,7 @@ export function createTransportHttpExtension(): Extension & {
 				warmService,
 				compactionService,
 				lspService,
+				mcpService,
 				systemPromptService,
 				logger,
 				emit: host.emit.bind(host),
diff --git a/packages/transport-http/src/seam.ts b/packages/transport-http/src/seam.ts
index 1b359e4..e9dc4ce 100644
--- a/packages/transport-http/src/seam.ts
+++ b/packages/transport-http/src/seam.ts
@@ -4,6 +4,8 @@ export type { CredentialStore } from "@dispatch/credential-store";
 export { credentialStoreHandle } from "@dispatch/credential-store";
 export type { LspServerStatus, LspService } from "@dispatch/lsp";
 export { lspServiceHandle } from "@dispatch/lsp";
+export type { McpServerStatus, McpService } from "@dispatch/mcp";
+export { mcpServiceHandle } from "@dispatch/mcp";
 export type {
 	CompactionService,
 	SessionOrchestrator,