fix: preserve Gemini thought signatures for tools

src/services/api/openaiShim.test.ts

@@ -10,6 +10,19 @@ const originalEnv = {
 
 const originalFetch = globalThis.fetch
 
+type OpenAIShimClient = {
+  beta: {
+    messages: {
+      create: (
+        params: Record<string, unknown>,
+        options?: Record<string, unknown>,
+      ) => Promise<unknown> & {
+        withResponse: () => Promise<{ data: AsyncIterable<Record<string, unknown>> }>
+      }
+    }
+  }
+}
+
 function makeSseResponse(lines: string[]): Response {
   const encoder = new TextEncoder()
   return new Response(
@@ -97,18 +110,7 @@ test('preserves usage from final OpenAI stream chunk with empty choices', async
     return makeSseResponse(chunks)
   }) as FetchType
 
-  const client = createOpenAIShimClient({}) as {
+  const client = createOpenAIShimClient({}) as OpenAIShimClient
-    beta: {
-      messages: {
-        create: (
-          params: Record<string, unknown>,
-          options?: Record<string, unknown>,
-        ) => Promise<unknown> & {
-          withResponse: () => Promise<{ data: AsyncIterable<Record<string, unknown>> }>
-        }
-      }
-    }
-  }
 
   const result = await client.beta.messages
     .create({
@@ -133,3 +135,180 @@ test('preserves usage from final OpenAI stream chunk with empty choices', async
   expect(usageEvent?.usage?.input_tokens).toBe(123)
   expect(usageEvent?.usage?.output_tokens).toBe(45)
 })
+
+test('preserves Gemini tool call extra_content in follow-up requests', async () => {
+  let requestBody: Record<string, unknown> | undefined
+
+  globalThis.fetch = (async (_input, init) => {
+    requestBody = JSON.parse(String(init?.body))
+
+    return new Response(
+      JSON.stringify({
+        id: 'chatcmpl-1',
+        model: 'google/gemini-3.1-pro-preview',
+        choices: [
+          {
+            message: {
+              role: 'assistant',
+              content: 'done',
+            },
+            finish_reason: 'stop',
+          },
+        ],
+        usage: {
+          prompt_tokens: 12,
+          completion_tokens: 4,
+          total_tokens: 16,
+        },
+      }),
+      {
+        headers: {
+          'Content-Type': 'application/json',
+        },
+      },
+    )
+  }) as FetchType
+
+  const client = createOpenAIShimClient({}) as OpenAIShimClient
+
+  await client.beta.messages.create({
+    model: 'google/gemini-3.1-pro-preview',
+    system: 'test system',
+    messages: [
+      { role: 'user', content: 'Use Bash' },
+      {
+        role: 'assistant',
+        content: [
+          {
+            type: 'tool_use',
+            id: 'call_1',
+            name: 'Bash',
+            input: { command: 'pwd' },
+            extra_content: {
+              google: {
+                thought_signature: 'sig-123',
+              },
+            },
+          },
+        ],
+      },
+      {
+        role: 'user',
+        content: [
+          {
+            type: 'tool_result',
+            tool_use_id: 'call_1',
+            content: 'D:\\repo',
+          },
+        ],
+      },
+    ],
+    max_tokens: 64,
+    stream: false,
+  })
+
+  const assistantWithToolCall = (requestBody?.messages as Array<Record<string, unknown>>).find(
+    message => Array.isArray(message.tool_calls),
+  ) as { tool_calls?: Array<Record<string, unknown>> } | undefined
+
+  expect(assistantWithToolCall?.tool_calls?.[0]).toMatchObject({
+    id: 'call_1',
+    type: 'function',
+    function: {
+      name: 'Bash',
+      arguments: JSON.stringify({ command: 'pwd' }),
+    },
+    extra_content: {
+      google: {
+        thought_signature: 'sig-123',
+      },
+    },
+  })
+})
+
+test('preserves Gemini tool call extra_content from streaming chunks', async () => {
+  globalThis.fetch = (async (_input, _init) => {
+    const chunks = makeStreamChunks([
+      {
+        id: 'chatcmpl-1',
+        object: 'chat.completion.chunk',
+        model: 'google/gemini-3.1-pro-preview',
+        choices: [
+          {
+            index: 0,
+            delta: {
+              role: 'assistant',
+              tool_calls: [
+                {
+                  index: 0,
+                  id: 'function-call-1',
+                  type: 'function',
+                  extra_content: {
+                    google: {
+                      thought_signature: 'sig-stream',
+                    },
+                  },
+                  function: {
+                    name: 'Bash',
+                    arguments: '{"command":"pwd"}',
+                  },
+                },
+              ],
+            },
+            finish_reason: null,
+          },
+        ],
+      },
+      {
+        id: 'chatcmpl-1',
+        object: 'chat.completion.chunk',
+        model: 'google/gemini-3.1-pro-preview',
+        choices: [
+          {
+            index: 0,
+            delta: {},
+            finish_reason: 'tool_calls',
+          },
+        ],
+      },
+    ])
+
+    return makeSseResponse(chunks)
+  }) as FetchType
+
+  const client = createOpenAIShimClient({}) as OpenAIShimClient
+
+  const result = await client.beta.messages
+    .create({
+      model: 'google/gemini-3.1-pro-preview',
+      system: 'test system',
+      messages: [{ role: 'user', content: 'Use Bash' }],
+      max_tokens: 64,
+      stream: true,
+    })
+    .withResponse()
+
+  const events: Array<Record<string, unknown>> = []
+  for await (const event of result.data) {
+    events.push(event)
+  }
+
+  const toolStart = events.find(
+    event =>
+      event.type === 'content_block_start' &&
+      typeof event.content_block === 'object' &&
+      event.content_block !== null &&
+      (event.content_block as Record<string, unknown>).type === 'tool_use',
+  ) as { content_block?: Record<string, unknown> } | undefined
+
+  expect(toolStart?.content_block).toMatchObject({
+    type: 'tool_use',
+    id: 'function-call-1',
+    name: 'Bash',
+    extra_content: {
+      google: {
+        thought_signature: 'sig-stream',
+      },
+    },
+  })
+})

src/services/api/openaiShim.ts

@@ -44,6 +44,7 @@ interface OpenAIMessage {
     id: string
     type: 'function'
     function: { name: string; arguments: string }
+    extra_content?: Record<string, unknown>
   }>
   tool_call_id?: string
   name?: string
@@ -190,7 +191,12 @@ function convertMessages(
 
         if (toolUses.length > 0) {
           assistantMsg.tool_calls = toolUses.map(
-            (tu: { id?: string; name?: string; input?: unknown }) => ({
+            (tu: {
+              id?: string
+              name?: string
+              input?: unknown
+              extra_content?: Record<string, unknown>
+            }) => ({
               id: tu.id ?? `call_${Math.random().toString(36).slice(2)}`,
               type: 'function' as const,
               function: {
@@ -200,6 +206,7 @@ function convertMessages(
                     ? tu.input
                     : JSON.stringify(tu.input ?? {}),
               },
+              ...(tu.extra_content ? { extra_content: tu.extra_content } : {}),
             }),
           )
         }
@@ -265,6 +272,7 @@ interface OpenAIStreamChunk {
         id?: string
         type?: string
         function?: { name?: string; arguments?: string }
+        extra_content?: Record<string, unknown>
       }>
     }
     finish_reason: string | null
@@ -406,6 +414,7 @@ async function* openaiStreamToAnthropic(
                   id: tc.id,
                   name: tc.function.name,
                   input: {},
+                  ...(tc.extra_content ? { extra_content: tc.extra_content } : {}),
                 },
               }
               contentBlockIndex++
@@ -689,6 +698,7 @@ class OpenAIShimMessages {
           tool_calls?: Array<{
             id: string
             function: { name: string; arguments: string }
+            extra_content?: Record<string, unknown>
           }>
         }
         finish_reason?: string
@@ -720,6 +730,7 @@ class OpenAIShimMessages {
           id: tc.id,
           name: tc.function.name,
           input,
+          ...(tc.extra_content ? { extra_content: tc.extra_content } : {}),
         })
       }
     }