fix: serialize mcp batches

Author: thymikee

src/__tests__/cli-batch.test.ts

@@ -82,6 +82,16 @@ test('batch accepts legacy positionals/flags steps with deprecation warning', as
   });
 });
 
+test('batch rejects hybrid structured and legacy step shapes', async () => {
+  const result = await runCliCapture([
+    'batch',
+    '--steps',
+    '[{"command":"open","input":{},"positionals":["settings"]}]',
+  ]);
+  assert.equal(result.code, 1);
+  assert.match(result.stderr, /unknown legacy field\(s\): input/);
+});
+
 test('batch --steps-file returns clear error for missing file', async () => {
   const result = await runCliCapture([
     'batch',

src/cli/batch-steps.ts

@@ -53,7 +53,14 @@ function legacyStepToStructuredStep(legacyStep: LegacyCliBatchStep): BatchStep {
 }
 
 function isStructuredBatchStep(step: unknown): step is BatchStep {
-  return step !== null && typeof step === 'object' && !Array.isArray(step) && 'input' in step;
+  return (
+    step !== null &&
+    typeof step === 'object' &&
+    !Array.isArray(step) &&
+    'input' in step &&
+    !('positionals' in step) &&
+    !('flags' in step)
+  );
 }
 
 function readLegacyCliBatchStep(step: unknown, stepNumber: number): LegacyCliBatchStep {

src/commands/command-projection.ts

@@ -116,15 +116,15 @@ function readBatchStepInput(record: Record<string, unknown>, stepNumber: number)
 function readBatchStepRuntime(
   record: Record<string, unknown>,
   stepNumber: number,
-): unknown | undefined {
+): Record<string, unknown> | undefined {
   const runtime = record.runtime;
   if (
     runtime !== undefined &&
     (!runtime || typeof runtime !== 'object' || Array.isArray(runtime))
   ) {
     throw new AppError('INVALID_ARGS', `Batch step ${stepNumber} runtime must be an object.`);
   }
-  return runtime;
+  return runtime as Record<string, unknown> | undefined;
 }
 
 export function prepareDaemonCommandRequest(

src/mcp/__tests__/command-tools.test.ts

@@ -25,7 +25,7 @@ test('MCP command tool executor hides client creation behind an execution adapte
     {
       client,
       name: 'devices',
-      input: { stateDir: '/tmp/agent-device-mcp' },
+      input: {},
     },
   ]);
   assert.deepEqual(result.structuredContent, { name: 'devices', ok: true });

src/mcp/__tests__/router.test.ts

@@ -2,6 +2,7 @@ import assert from 'node:assert/strict';
 import { test } from 'vitest';
 import { listMcpExposedCommandNames } from '../../command-catalog.ts';
 import { handleMcpMessage } from '../router.ts';
+import { handleMcpPayload } from '../server.ts';
 
 test('MCP exposes every automatable CLI command as a structured direct tool', async () => {
   const response = await handleMcpMessage({
@@ -44,3 +45,16 @@ test('MCP exposes every automatable CLI command as a structured direct tool', as
   assert.equal((invalidFillResponse.result as { isError: boolean }).isError, true);
   assert.match(JSON.stringify(invalidFillResponse.result), /Expected target to be set/);
 });
+
+test('MCP JSON-RPC batches return responses in request order and skip notifications', async () => {
+  const response = await handleMcpPayload([
+    { jsonrpc: '2.0', id: 'first', method: 'ping' },
+    { jsonrpc: '2.0', method: 'notifications/initialized' },
+    { jsonrpc: '2.0', id: 'second', method: 'ping' },
+  ]);
+
+  assert.deepEqual(
+    (response as Array<{ id: string }>).map((entry) => entry.id),
+    ['first', 'second'],
+  );
+});

src/mcp/command-tools.ts

@@ -47,7 +47,7 @@ export function createCommandToolExecutor(
         throw new Error(`Unknown command tool: ${name}`);
       }
       const client = deps.createClient(readClientConfig(input));
-      const result = await deps.runCommand(client, name, input);
+      const result = await deps.runCommand(client, name, stripClientConfigFields(input));
       return {
         isError: false,
         structuredContent: result,
@@ -69,6 +69,12 @@ function readClientConfig(input: unknown): AgentDeviceClientConfig {
   return { stateDir };
 }
 
+function stripClientConfigFields(input: unknown): unknown {
+  if (!input || typeof input !== 'object' || Array.isArray(input)) return input;
+  const { stateDir: _stateDir, ...commandInput } = input as Record<string, unknown>;
+  return commandInput;
+}
+
 function renderToolText(value: unknown): string {
   return typeof value === 'string' ? value : JSON.stringify(value, null, 2);
 }

src/mcp/server.ts

@@ -1,18 +1,20 @@
 import { handleMcpMessage, type JsonRpcMessage } from './router.ts';
 
 type JsonRpcResponse = Awaited<NonNullable<ReturnType<typeof handleMcpMessage>>>;
+type JsonRpcId = string | number | null;
 type MessageSink = (message: JsonRpcMessage | JsonRpcMessage[]) => void;
 
 export async function runAgentDeviceMcpServer(): Promise<void> {
   const decoder = new McpMessageDecoder((messageOrBatch) => {
+    const fallbackId = fallbackErrorId(messageOrBatch);
     void handleMcpPayload(messageOrBatch)
       .then((response) => {
         if (response) writeMessage(response);
       })
       .catch((error: unknown) => {
         writeMessage({
           jsonrpc: '2.0',
-          id: null,
+          id: fallbackId,
           error: {
             code: -32603,
             message: error instanceof Error ? error.message : String(error),
@@ -44,7 +46,7 @@ export async function runAgentDeviceMcpServer(): Promise<void> {
   });
 }
 
-function handleMcpPayload(
+export function handleMcpPayload(
   messageOrBatch: JsonRpcMessage | JsonRpcMessage[],
 ): Promise<unknown | null> {
   if (Array.isArray(messageOrBatch)) {
@@ -54,12 +56,20 @@ function handleMcpPayload(
 }
 
 async function handleMcpBatch(messages: JsonRpcMessage[]): Promise<JsonRpcResponse[] | null> {
-  const responses = (
-    await Promise.all(messages.map(async (message) => await handleMcpMessage(message)))
-  ).flatMap(responseArray);
+  const responses: JsonRpcResponse[] = [];
+  for (const message of messages) {
+    responses.push(...responseArray(await handleMcpMessage(message)));
+  }
   return responses.length > 0 ? responses : null;
 }
 
+function fallbackErrorId(messageOrBatch: JsonRpcMessage | JsonRpcMessage[]): JsonRpcId {
+  if (Array.isArray(messageOrBatch)) {
+    return messageOrBatch.length === 1 ? (messageOrBatch[0]?.id ?? null) : null;
+  }
+  return messageOrBatch.id ?? null;
+}
+
 class McpMessageDecoder {
   private buffer = '';
   private readonly sink: MessageSink;