Function createMcpAssembly

packages/hosts/mcp/src/tool-server.ts:403–587

(
  config: ExecutorMcpServerConfig<E>,
)

});

const createMcpAssembly = <E extends Cause.YieldableError>(
  config: ExecutorMcpServerConfig<E>,
): ExecutorMcpAssembly<McpServer, McpServerRequestContext> => {
  const sessionful = config.sessionful ?? false;
  const initialAppsEnabled = sessionful
    ? (config.restoredAppsEnabled ?? config.appsEnabled)
    : config.appsEnabled;
  const requestStateCodec = (binding: string) =>
    createRequestStateCodec<NativeRequestState>({
      key: config.requestStateSigningKey,
      ...(config.requestStateTtlSeconds === undefined
        ? {}
        : { ttlSeconds: config.requestStateTtlSeconds }),
      bind: () => binding,
    });
  const verifyRequestState = async (state: string, context: ServerContext) => {
    const binding = await requestStateBindingForContext(
      config.requestStateBinding,
      config.requestStatePrincipal,
      context,
    );
    const decoded = await requestStateCodec(binding).verify(state, context);
    return Effect.runPromise(Schema.decodeUnknownEffect(NativeRequestStateSchema)(decoded));
  };
  const server = new McpServer(
    { name: "executor", version: "1.0.0" },
    {
      capabilities: { resources: {}, tools: {} },
      requestState: { verify: verifyRequestState },
    },
  );

  const registerTool: ExecutorMcpAssembly<McpServer, McpServerRequestContext>["registerTool"] = (
    name,
    toolConfig,
    callback,
  ) => {
    const inputSchema = z.object(toolConfig.inputSchema);
    return server.registerTool<z.ZodObject<z.ZodRawShape>, typeof inputSchema>(
      name,
      { ...toolConfig, inputSchema },
      async (args, context) => toolResult(await callback(args, requestJoinKeys(context))),
    );
  };

  const registerApp: ExecutorMcpAssembly<McpServer, McpServerRequestContext>["registerAppTool"] = (
    name,
    toolConfig,
    callback,
  ) => {
    const inputSchema = z.object(toolConfig.inputSchema);
    const metadata = normalizedAppMetadata(toolConfig._meta);
    if (!sessionful && !config.appsEnabled && visibilityIncludes(metadata, "model")) {
      const plainMetadata = withoutAppMetadata(metadata);
      return server.registerTool<z.ZodObject<z.ZodRawShape>, typeof inputSchema>(
        name,
        {
          ...toolConfig,