fix: parse fenced docs review json

scripts/docs-sync-review.ts

@@ -3,7 +3,6 @@ import { isAbsolute, resolve, sep } from 'node:path';
 import { pathToFileURL } from 'node:url';
 import {
   REVIEW_COMMENT_MARKER,
-  REVIEW_JSON_SCHEMA,
   buildReviewPrompts,
   classifyPullRequest,
   createDeferredResult,
@@ -188,6 +187,22 @@ export async function generateOpenAIReview(
   apiKey: string,
   fetchImpl: FetchLike = fetch,
 ): Promise<unknown> {
+  const response = await requestOpenAIReview(prompt, model, apiKey, fetchImpl, true);
+  const data = await response.json() as {
+    choices?: Array<{ message?: { content?: string | null } }>;
+  };
+  const text = data.choices?.[0]?.message?.content?.trim();
+  if (!text) throw new Error('OpenAI returned empty content.');
+  return parseReviewJson(text);
+}
+
+async function requestOpenAIReview(
+  prompt: string,
+  model: string,
+  apiKey: string,
+  fetchImpl: FetchLike,
+  useLowReasoning: boolean,
+): Promise<Response> {
   const response = await fetchImpl('https://api.openai.com/v1/chat/completions', {
     method: 'POST',
     headers: {
@@ -196,28 +211,30 @@ export async function generateOpenAIReview(
     },
     body: JSON.stringify({
       model,
-      messages: [{ role: 'user', content: prompt }],
-      temperature: 0.1,
-      reasoning_effort: 'low',
-      response_format: {
-        type: 'json_schema',
-        json_schema: {
-          name: 'docs_sync_review',
-          strict: true,
-          schema: REVIEW_JSON_SCHEMA,
+      messages: [
+        {
+          role: 'system',
+          content: 'Return only valid JSON matching the requested review object. Do not wrap it in markdown.',
         },
-      },
+        { role: 'user', content: prompt },
+      ],
+      temperature: 0.1,
+      ...(useLowReasoning ? { reasoning_effort: 'low' } : {}),
     }),
     signal: AbortSignal.timeout(180_000),
   });
+  if (response.status === 400 && useLowReasoning) {
+    return requestOpenAIReview(prompt, model, apiKey, fetchImpl, false);
+  }
   if (!response.ok) throw new Error(`OpenAI request failed with HTTP ${response.status}.`);
-  const data = await response.json() as {
-    choices?: Array<{ message?: { content?: string | null } }>;
-  };
-  const text = data.choices?.[0]?.message?.content?.trim();
-  if (!text) throw new Error('OpenAI returned empty content.');
+  return response;
+}
+
+function parseReviewJson(text: string): unknown {
+  const fenced = text.match(/^```(?:json)?\s*([\s\S]*?)\s*```$/i)?.[1];
+  const candidate = fenced ?? text;
   try {
-    return JSON.parse(text) as unknown;
+    return JSON.parse(candidate) as unknown;
   } catch {
     throw new Error('OpenAI returned invalid JSON.');
   }

src/docs-sync-review-cli.test.ts

@@ -356,11 +356,33 @@ describe('OpenAI and documentation boundaries', () => {
         body: expect.stringContaining('"reasoning_effort":"low"'),
       }),
     );
-    const requestInit = (fetchImpl.mock.calls as unknown as Array<[unknown, { body?: string }?]>)[0]?.[1];
-    expect(requestInit?.body).toContain('"response_format"');
     expect(result).toEqual({ verdict: 'no_update_needed', summary: 'Covered.', findings: [] });
   });
 
+  it('accepts fenced OpenAI JSON output', async () => {
+    const fetchImpl = vi.fn(async () => jsonResponse({
+      choices: [{ message: { content: '```json\n{"verdict":"no_update_needed","summary":"Covered.","findings":[]}\n```' } }],
+    }));
+
+    await expect(generateOpenAIReview('review prompt', 'gpt-test', 'api-key', fetchImpl))
+      .resolves.toEqual({ verdict: 'no_update_needed', summary: 'Covered.', findings: [] });
+  });
+
+  it('retries without low reasoning when the selected model rejects it', async () => {
+    const fetchImpl = vi.fn()
+      .mockResolvedValueOnce(jsonResponse({ error: { message: 'unsupported parameter' } }, 400))
+      .mockResolvedValueOnce(jsonResponse({
+        choices: [{ message: { content: '{"verdict":"no_update_needed","summary":"Covered.","findings":[]}' } }],
+      }));
+
+    await expect(generateOpenAIReview('review prompt', 'gpt-test', 'api-key', fetchImpl))
+      .resolves.toEqual({ verdict: 'no_update_needed', summary: 'Covered.', findings: [] });
+    expect((fetchImpl.mock.calls as unknown as Array<[unknown, { body?: string }]>)[0]?.[1]?.body)
+      .toContain('"reasoning_effort":"low"');
+    expect((fetchImpl.mock.calls as unknown as Array<[unknown, { body?: string }]>)[1]?.[1]?.body)
+      .not.toContain('reasoning_effort');
+  });
+
   it('defaults the docs review model to gpt-5.4-mini', async () => {
     const fetchImpl = vi.fn(async () => jsonResponse({
       choices: [{ message: { content: JSON.stringify({ verdict: 'no_update_needed', summary: 'Covered.', findings: [] }) } }],