refactor(mcp-server): prepare transport abstraction for HTTP

apps/mcp-server/src/index.ts

@@ -1,202 +1,18 @@
-/* AgentBridge MCP server.
+/* AgentBridge MCP server entry point.
  *
- * Speaks MCP over stdio. Exposes tools, resources, and prompts to AI agents
- * for discovering, scanning, and safely invoking AgentBridge actions on a
- * target URL.
+ * Speaks MCP over stdio by default. The shared server (tools, resources,
+ * prompts, dispatcher) lives in ./server.ts; the transport adapter lives
+ * in ./transports/stdio.ts. This file is intentionally tiny — it picks a
+ * transport and routes top-level startup errors to stderr.
+ *
+ * v0.4.0 will add an opt-in HTTP transport (see
+ * docs/designs/http-mcp-transport-auth.md). Until then, stdio is the
+ * only runtime transport.
  */
 
-import { Server } from "@modelcontextprotocol/sdk/server/index.js";
-import { StdioServerTransport } from "@modelcontextprotocol/sdk/server/stdio.js";
-import {
-  CallToolRequestSchema,
-  GetPromptRequestSchema,
-  ListPromptsRequestSchema,
-  ListResourcesRequestSchema,
-  ListToolsRequestSchema,
-  ReadResourceRequestSchema,
-} from "@modelcontextprotocol/sdk/types.js";
-import {
-  callAction,
-  discoverManifest,
-  getAuditLog,
-  listActions,
-  scanAgentReadiness,
-} from "./tools";
-import { PROMPTS, renderPrompt } from "./prompts";
-import { STATIC_RESOURCES, readResource } from "./resources";
-
-const server = new Server(
-  { name: "agentbridge", version: "0.3.0" },
-  { capabilities: { tools: {}, resources: {}, prompts: {} } },
-);
-
-// ── Tools ────────────────────────────────────────────────────────────
-const TOOLS = [
-  {
-    name: "discover_manifest",
-    title: "Discover AgentBridge manifest",
-    description:
-      "Fetch and summarize an AgentBridge manifest from a URL. Use this first to understand what actions a site exposes.",
-    inputSchema: {
-      type: "object",
-      properties: { url: { type: "string", description: "Origin URL of the target app" } },
-      required: ["url"],
-    },
-    outputSchema: {
-      type: "object",
-      properties: {
-        name: { type: "string" },
-        version: { type: "string" },
-        baseUrl: { type: "string" },
-        actionCount: { type: "number" },
-        actionsByRisk: { type: "object" },
-      },
-    },
-  },
-  {
-    name: "scan_agent_readiness",
-    title: "Scan agent readiness",
-    description:
-      "Score how agent-ready a URL is. Returns a 0–100 score, structured checks, and grouped recommendations.",
-    inputSchema: {
-      type: "object",
-      properties: { url: { type: "string" } },
-      required: ["url"],
-    },
-  },
-  {
-    name: "list_actions",
-    title: "List actions",
-    description: "List all actions in the AgentBridge manifest at a URL.",
-    inputSchema: {
-      type: "object",
-      properties: { url: { type: "string" } },
-      required: ["url"],
-    },
-  },
-  {
-    name: "call_action",
-    title: "Call an AgentBridge action",
-    description:
-      "Invoke an AgentBridge action. Risky actions return a confirmationRequired response with a confirmationToken; the client must re-call with confirmationApproved: true AND the same confirmationToken to execute. Optional idempotencyKey replays prior results for the same key+input.",
-    inputSchema: {
-      type: "object",
-      properties: {
-        url: { type: "string" },
-        actionName: { type: "string" },
-        input: { type: "object" },
-        confirmationApproved: { type: "boolean" },
-        confirmationToken: { type: "string" },
-        idempotencyKey: { type: "string" },
-      },
-      required: ["url", "actionName"],
-    },
-  },
-  {
-    name: "get_audit_log",
-    title: "Read audit log",
-    description:
-      "Read the local AgentBridge audit log. Filter by manifest URL with the optional `url` parameter.",
-    inputSchema: {
-      type: "object",
-      properties: {
-        url: { type: "string" },
-        limit: { type: "number" },
-      },
-    },
-  },
-];
-
-server.setRequestHandler(ListToolsRequestSchema, async () => ({ tools: TOOLS }));
-
-server.setRequestHandler(CallToolRequestSchema, async (req) => {
-  const { name, arguments: args = {} } = req.params;
-  try {
-    const result = await dispatchTool(name, args as Record<string, unknown>);
-    // Return both readable text (for human-facing MCP UIs) AND structured
-    // content (for agent-side parsing). Older clients ignore structuredContent.
-    return {
-      content: [
-        { type: "text", text: JSON.stringify(result, null, 2) },
-      ],
-      structuredContent: result as Record<string, unknown>,
-    };
-  } catch (err) {
-    return {
-      isError: true,
-      content: [{ type: "text", text: `Error: ${(err as Error).message}` }],
-    };
-  }
-});
-
-async function dispatchTool(name: string, args: Record<string, unknown>) {
-  switch (name) {
-    case "discover_manifest":
-      return discoverManifest({ url: String(args.url) });
-    case "scan_agent_readiness":
-      return scanAgentReadiness({ url: String(args.url) });
-    case "list_actions":
-      return listActions({ url: String(args.url) });
-    case "call_action":
-      return callAction({
-        url: String(args.url),
-        actionName: String(args.actionName),
-        input: (args.input as Record<string, unknown> | undefined) ?? {},
-        confirmationApproved: args.confirmationApproved === true,
-        confirmationToken:
-          typeof args.confirmationToken === "string" ? args.confirmationToken : undefined,
-        idempotencyKey:
-          typeof args.idempotencyKey === "string" ? args.idempotencyKey : undefined,
-      });
-    case "get_audit_log":
-      return getAuditLog({
-        url: typeof args.url === "string" ? args.url : undefined,
-        limit: typeof args.limit === "number" ? args.limit : undefined,
-      });
-    default:
-      throw new Error(`unknown tool: ${name}`);
-  }
-}
-
-// ── Resources ────────────────────────────────────────────────────────
-server.setRequestHandler(ListResourcesRequestSchema, async () => ({
-  resources: STATIC_RESOURCES,
-}));
-
-server.setRequestHandler(ReadResourceRequestSchema, async (req) => {
-  const { uri } = req.params;
-  const result = await readResource(uri);
-  return {
-    contents: [{ uri: result.uri, mimeType: result.mimeType, text: result.text }],
-  };
-});
-
-// ── Prompts ──────────────────────────────────────────────────────────
-server.setRequestHandler(ListPromptsRequestSchema, async () => ({
-  prompts: PROMPTS.map((p) => ({
-    name: p.name,
-    description: p.description,
-    arguments: p.arguments,
-  })),
-}));
-
-server.setRequestHandler(GetPromptRequestSchema, async (req) => {
-  const { name, arguments: args = {} } = req.params;
-  // SDK GetPromptResult is a discriminated union — cast to the index-signature
-  // form so TS doesn't try to narrow into the task-result branch.
-  return renderPrompt(name, args as Record<string, string>) as unknown as {
-    [x: string]: unknown;
-    description?: string;
-    messages: { role: "user"; content: { type: "text"; text: string } }[];
-  };
-});
-
-async function main() {
-  const transport = new StdioServerTransport();
-  await server.connect(transport);
-}
+import { runStdioServer } from "./transports/stdio";
 
-main().catch((err) => {
+runStdioServer().catch((err) => {
   console.error("[agentbridge-mcp] fatal:", err);
   process.exit(1);
 });