fix(vision): stop read_image from poisoning text-provider sessions

Image turns already get a vision-model description injected into the prompt,
but the agent kept calling read_image to "confirm" the pictures. Those tool
results carry base64 image parts that Goose persists, so every later turn
against the text-only chat provider failed with `unknown variant image_url`
before the agent could write the page. WeChat page requests therefore fell
through to the fail-closed delivery message.

Drop read_image for the turn whenever a vision model handles the images, say
so explicitly in the injected prompt, and teach the poison scan to recognise
tool image parts so already-polluted sessions rotate instead of failing again.

Co-authored-by: Cursor <cursoragent@cursor.com>

tkmind-proxy.test.mjs

@@ -22,6 +22,8 @@ async function withFakeGoosedSession(
   const replyBodies = [];
   const startBodies = [];
   const updateBodies = [];
+  const addedExtensions = [];
+  let activeExtensions = [{ name: 'memory', available_tools: [] }];
   let activeConversation = conversation;
   let server;
 
@@ -67,9 +69,7 @@ async function withFakeGoosedSession(
       }
       if (req.method === 'GET' && req.url === '/sessions/session-1/extensions') {
         res.writeHead(200, { 'Content-Type': 'application/json' });
-        res.end(JSON.stringify({
-          extensions: [{ name: 'memory', available_tools: [] }],
-        }));
+        res.end(JSON.stringify({ extensions: activeExtensions }));
         return;
       }
       if (req.method === 'POST' && req.url === '/sessions/session-1/reply') {
@@ -78,6 +78,23 @@ async function withFakeGoosedSession(
         res.end(JSON.stringify({ ok: true }));
         return;
       }
+      if (
+        req.method === 'POST'
+        && (req.url === '/agent/add_extension'
+          || req.url === '/agent/remove_extension'
+          || req.url === '/agent/restart')
+      ) {
+        if (req.url === '/agent/add_extension') {
+          addedExtensions.push(body);
+          activeExtensions = [...activeExtensions, body.config];
+        }
+        if (req.url === '/agent/remove_extension') {
+          activeExtensions = activeExtensions.filter((ext) => ext?.name !== body.name);
+        }
+        res.writeHead(200, { 'Content-Type': 'application/json' });
+        res.end(JSON.stringify({ ok: true }));
+        return;
+      }
       if (req.method === 'POST' && req.url === '/agent/harness_remember') {
         harnessEntries.push(body);
         res.writeHead(200, { 'Content-Type': 'application/json' });
@@ -102,6 +119,7 @@ async function withFakeGoosedSession(
       replyBodies,
       startBodies,
       updateBodies,
+      addedExtensions,
     });
   } finally {
     if (server?.listening) {
@@ -1707,11 +1725,130 @@ test('submitSessionReplyForUser applies the shared Qwen vision preprocessing pat
     const forwardedText = replyBodies[0]?.user_message?.content?.[0]?.text ?? '';
     assert.match(forwardedText, /Qwen VL 图片描述/);
     assert.match(forwardedText, /一件蓝色产品/);
+    assert.match(forwardedText, /禁止调用 read_image/);
     assert.equal(replyBodies[0]?.user_message?.metadata?.imageUrls, undefined);
     assert.ok(Array.isArray(replyBodies[0]?.user_message?.metadata?.archivedImageUrls));
   });
 });
 
+function createReadImagePolicyUserAuth(workingDir) {
+  return {
+    ...createMemoryTestUserAuth(workingDir),
+    async getAgentSessionPolicy() {
+      return {
+        gooseMode: 'chat',
+        enableContextMemory: true,
+        extensionOverrides: [
+          { name: 'memory', available_tools: [] },
+          { name: 'developer', available_tools: ['write', 'edit', 'read_image'] },
+        ],
+      };
+    },
+    async ownsSession() {
+      return true;
+    },
+    async canUseChat() {
+      return { ok: true };
+    },
+    async getUserById() {
+      return { id: 'user-1' };
+    },
+    async getUserPublishLayout() {
+      return { publicUrl: 'https://example.com/MindSpace/user-1' };
+    },
+    async resolveUserPolicies() {
+      return { unrestricted: true, policies: {} };
+    },
+  };
+}
+
+function developerToolsFromAddedExtensions(addedExtensions) {
+  const developer = addedExtensions
+    .map((body) => body?.config)
+    .find((config) => config?.name === 'developer');
+  return developer?.available_tools ?? null;
+}
+
+test('image turns drop read_image so vision results cannot poison the text provider', async () => {
+  await withFakeGoosedSession(async ({ apiTarget, workingDir, addedExtensions }) => {
+    const proxy = createTkmindProxy({
+      apiTarget,
+      apiSecret: 'test-secret',
+      userAuth: createReadImagePolicyUserAuth(workingDir),
+      localFetchAsset: async () => ({
+        buffer: Buffer.from('fake-image'),
+        mimeType: 'image/jpeg',
+      }),
+      llmProviderService: {
+        async applyBestProviderForSession() {
+          return { ok: true };
+        },
+        async hasVisionKey() {
+          return true;
+        },
+        async analyzeImagesWithVision() {
+          return '四张汉服写真。';
+        },
+      },
+    });
+
+    await proxy.submitSessionReplyForUser(
+      'user-1',
+      'session-1',
+      'request-image-turn',
+      {
+        id: 'message-image-turn',
+        role: 'user',
+        content: [{ type: 'text', text: '用刚才发的4张图片做成主题页面' }],
+        metadata: {
+          imageUrls: [
+            '/api/mindspace/v1/assets/asset-1/download?inline=1',
+            '/api/mindspace/v1/assets/asset-2/download?inline=1',
+          ],
+        },
+      },
+    );
+
+    const developerTools = developerToolsFromAddedExtensions(addedExtensions);
+    assert.ok(developerTools, 'developer extension should still be provisioned');
+    assert.deepEqual(developerTools, ['write', 'edit']);
+  });
+});
+
+test('text-only turns keep read_image available', async () => {
+  await withFakeGoosedSession(async ({ apiTarget, workingDir, addedExtensions }) => {
+    const proxy = createTkmindProxy({
+      apiTarget,
+      apiSecret: 'test-secret',
+      userAuth: createReadImagePolicyUserAuth(workingDir),
+      llmProviderService: {
+        async applyBestProviderForSession() {
+          return { ok: true };
+        },
+        async hasVisionKey() {
+          return true;
+        },
+      },
+    });
+
+    await proxy.submitSessionReplyForUser(
+      'user-1',
+      'session-1',
+      'request-text-turn',
+      {
+        id: 'message-text-turn',
+        role: 'user',
+        content: [{ type: 'text', text: '把页面标题改成星尘之门' }],
+      },
+    );
+
+    assert.deepEqual(
+      developerToolsFromAddedExtensions(addedExtensions),
+      ['write', 'edit', 'read_image'],
+    );
+  });
+});
+
 test('submitSessionReplyForUser passes current prompt to Memory V2 resolve before existing reply path', async () => {
   let resolveInput = null;
   await withFakeGoosedSession(async ({ apiTarget, workingDir }) => {