fix: pipe the whole generate-spec prompt through stdin in the cursor provider

.changeset/generate-spec-cursor-stdin.md

@@ -0,0 +1,5 @@
+---
+'@redocly/cli': patch
+---
+
+Fixed the `cursor` AI provider of the `generate-spec` command sending only the instructions to the model: the current Cursor CLI ignores piped stdin when a prompt argument is present, so the operation to refine never reached it.

packages/cli/src/commands/generate-spec/__tests__/providers.test.ts

@@ -13,11 +13,13 @@ function stubChildProcess(stdout: string) {
     stdout: EventEmitter;
     stderr: EventEmitter;
     stdin: EventEmitter & { end: (input: string) => void };
+    pipedInput?: string;
   };
   child.stdout = new EventEmitter();
   child.stderr = new EventEmitter();
   child.stdin = Object.assign(new EventEmitter(), {
-    end: () => {
+    end: (input: string) => {
+      child.pipedInput = input;
       child.stdout.emit('data', Buffer.from(stdout));
       child.emit('close', 0);
     },
@@ -26,12 +28,13 @@ function stubChildProcess(stdout: string) {
 }
 
 describe('runProvider', () => {
+  let child: ReturnType<typeof stubChildProcess>;
+
   beforeEach(() => {
     vi.mocked(spawn).mockClear();
     // The stub is not a full ChildProcess; only the pieces runCommand touches.
-    vi.mocked(spawn).mockReturnValue(
-      stubChildProcess('refined output') as unknown as ReturnType<typeof spawn>
-    );
+    child = stubChildProcess('refined output');
+    vi.mocked(spawn).mockReturnValue(child as unknown as ReturnType<typeof spawn>);
   });
 
   it('runs the claude CLI isolated from the local configuration', async () => {
@@ -58,6 +61,7 @@ describe('runProvider', () => {
         env: expect.objectContaining({ CLAUDE_CODE_DISABLE_NONESSENTIAL_TRAFFIC: '1' }),
       })
     );
+    expect(child.pipedInput).toBe('user prompt');
   });
 
   it('runs the codex CLI without MCP servers and project docs', async () => {
@@ -80,15 +84,17 @@ describe('runProvider', () => {
       ],
       expect.objectContaining({ cwd: '/tmp/generate-spec-empty' })
     );
+    expect(child.pipedInput).toBe('sys prompt\n\nuser prompt');
   });
 
-  it('runs the cursor CLI with the workspace trusted', async () => {
+  it('runs the cursor CLI with the whole prompt piped through stdin', async () => {
     await runProvider('cursor', { system: 'sys prompt', user: 'user prompt' });
 
     expect(spawn).toHaveBeenCalledWith(
       'cursor-agent',
-      ['-p', '--output-format', 'text', '--trust', 'sys prompt'],
+      ['-p', '--output-format', 'text', '--trust'],
       expect.objectContaining({ cwd: '/tmp/generate-spec-empty' })
     );
+    expect(child.pipedInput).toBe('sys prompt\n\nuser prompt');
   });
 });

packages/cli/src/commands/generate-spec/ai/providers.ts

@@ -161,21 +161,21 @@ async function runCursor(request: ProviderRequest): Promise<ProviderResult> {
   if (request.model) {
     args.push('--model', request.model);
   }
-  // The instructions go in as the prompt argument; the piped stdin is
-  // attached as context, mirroring how the claude provider splits the two.
-  args.push(request.system);
+  // The Cursor CLI ignores piped stdin when a prompt argument is present,
+  // so the whole prompt goes through stdin, as with the codex provider.
+  const prompt = `${request.system}\n\n${request.user}`;
 
   // The Cursor CLI originally installed a "cursor-agent" binary and later
   // renamed it to "agent"; accept either.
   let result;
   try {
-    result = await runCommand('cursor-agent', args, request.user);
+    result = await runCommand('cursor-agent', args, prompt);
   } catch (error) {
     if (!(error instanceof CliNotFoundError)) {
       throw error;
     }
     try {
-      result = await runCommand('agent', args, request.user);
+      result = await runCommand('agent', args, prompt);
     } catch (fallbackError) {
       if (fallbackError instanceof CliNotFoundError) {
         throw new CliNotFoundError(