fix: strip gemini cli tool ids (#756)

CHANGELOG.md

@@ -67,6 +67,7 @@
 - CLI: fix guardCancel typing for configure prompts. (#769) — thanks @steipete.
 - Providers: default groupPolicy to allowlist across providers and warn in doctor when groups are open.
 - MS Teams: add groupPolicy/groupAllowFrom gating for group chats and warn when groups are open.
+- Providers: strip tool call/result ids from Gemini CLI payloads to avoid API 400s. (#756)
 - Gateway/WebChat: include handshake validation details in the WebSocket close reason for easier debugging; preserve close codes.
 - Gateway/Auth: send invalid connect responses before closing the handshake; stabilize invalid-connect auth test.
 - Gateway: tighten gateway listener detection.

patches/@mariozechner__pi-ai@0.42.2.patch

@@ -62,6 +62,39 @@ index f07085c64390b211340d6a826b28ea9c2e77302f..7f758532246cc7b062df48e9cec4e6c9
 +                    }
 +                }
 +            }
-             if (output.length === 0)
+            if (output.length === 0)
-                 continue;
+                continue;
-             messages.push(...output);
+            messages.push(...output);
+diff --git a/dist/providers/google-shared.js b/dist/providers/google-shared.js
+index 866446158b0ee3e4c4a4f3f78c71ce72b9aab6a1..c7f9d8a0b0c7a25b62a0bb5f8a4f9d63ccad1d24 100644
+--- a/dist/providers/google-shared.js
++++ b/dist/providers/google-shared.js
+@@ -52,6 +52,8 @@ export function convertMessages(model, context) {
+     const contents = [];
+     const transformedMessages = transformMessages(context.messages, model);
++    const shouldStripFunctionId = typeof model.provider === "string" &&
++        model.provider.startsWith("google");
+     for (const msg of transformedMessages) {
+         if (msg.role === "user") {
+@@ -110,8 +112,8 @@ export function convertMessages(model, context) {
+                             args: block.arguments,
+                         },
+                     };
+-                    if (model.provider === "google-vertex" && part?.functionCall?.id) {
+-                        delete part.functionCall.id; // Vertex AI does not support 'id' in functionCall
++                    if (shouldStripFunctionId && part?.functionCall?.id) {
++                        delete part.functionCall.id; // Google Gemini/Vertex do not support 'id' in functionCall
+                     }
+                     if (block.thoughtSignature) {
+                         part.thoughtSignature = block.thoughtSignature;
+@@ -159,8 +161,8 @@ export function convertMessages(model, context) {
+                     ...(hasImages && supportsMultimodalFunctionResponse && { parts: imageParts }),
+                 },
+             };
+-            if (model.provider === "google-vertex" && functionResponsePart.functionResponse?.id) {
+-                delete functionResponsePart.functionResponse.id; // Vertex AI does not support 'id' in functionResponse
++            if (shouldStripFunctionId && functionResponsePart.functionResponse?.id) {
++                delete functionResponsePart.functionResponse.id; // Google Gemini/Vertex do not support 'id' in functionResponse
+             }
+             // Cloud Code Assist API requires all function responses to be in a single user turn.
+             // Check if the last content is already a user turn with function responses and merge.

src/providers/google-shared.test.ts

@@ -26,6 +26,20 @@ const makeModel = (id: string): Model<"google-generative-ai"> =>
     maxTokens: 1,
   }) as Model<"google-generative-ai">;
 
+const makeGeminiCliModel = (id: string): Model<"google-gemini-cli"> =>
+  ({
+    id,
+    name: id,
+    api: "google-gemini-cli",
+    provider: "google-gemini-cli",
+    baseUrl: "https://example.invalid",
+    reasoning: false,
+    input: ["text"],
+    cost: { input: 0, output: 0, cacheRead: 0, cacheWrite: 0 },
+    contextWindow: 1,
+    maxTokens: 1,
+  }) as Model<"google-gemini-cli">;
+
 describe("google-shared convertTools", () => {
   it("preserves parameters when type is missing", () => {
     const tools = [
@@ -493,4 +507,70 @@ describe("google-shared convertMessages", () => {
     const toolCall = asRecord(toolCallPart);
     expect(toolCall.functionCall).toBeTruthy();
   });
+
+  it("strips tool call and response ids for google-gemini-cli", () => {
+    const model = makeGeminiCliModel("gemini-3-flash");
+    const context = {
+      messages: [
+        {
+          role: "user",
+          content: "Use a tool",
+        },
+        {
+          role: "assistant",
+          content: [
+            {
+              type: "toolCall",
+              id: "call_1",
+              name: "myTool",
+              arguments: { arg: "value" },
+            },
+          ],
+          api: "google-gemini-cli",
+          provider: "google-gemini-cli",
+          model: "gemini-3-flash",
+          usage: {
+            input: 0,
+            output: 0,
+            cacheRead: 0,
+            cacheWrite: 0,
+            totalTokens: 0,
+            cost: {
+              input: 0,
+              output: 0,
+              cacheRead: 0,
+              cacheWrite: 0,
+              total: 0,
+            },
+          },
+          stopReason: "stop",
+          timestamp: 0,
+        },
+        {
+          role: "toolResult",
+          toolCallId: "call_1",
+          toolName: "myTool",
+          content: [{ type: "text", text: "Tool result" }],
+          isError: false,
+          timestamp: 0,
+        },
+      ],
+    } as unknown as Context;
+
+    const contents = convertMessages(model, context);
+    const parts = contents.flatMap((content) => content.parts ?? []);
+    const toolCallPart = parts.find(
+      (part) => typeof part === "object" && part !== null && "functionCall" in part,
+    );
+    const toolResponsePart = parts.find(
+      (part) =>
+        typeof part === "object" && part !== null && "functionResponse" in part,
+    );
+
+    const toolCall = asRecord(toolCallPart);
+    const toolResponse = asRecord(toolResponsePart);
+
+    expect(asRecord(toolCall.functionCall).id).toBeUndefined();
+    expect(asRecord(toolResponse.functionResponse).id).toBeUndefined();
+  });
 });