fix(translator): correct thought signatures for AG, Gemini CLI, Vertex; fix missing Vertex response translator

- Add DEFAULT_THINKING_AG_SIGNATURE, DEFAULT_THINKING_GEMINI_CLI_SIGNATURE, DEFAULT_THINKING_VERTEX_SIGNATURE
- Rename DEFAULT_THINKING_GEMINI_SIGNATURE → DEFAULT_THINKING_AG_SIGNATURE for clarity
- Pass provider-specific signature into openaiToGeminiBase (AG vs Gemini CLI)
- Replace synthetic thoughtSignatures with Vertex-native signature in postProcessForVertex
- Register Vertex → OpenAI response translator (fixes empty Vertex streaming responses)

Made-with: Cursor

open-sse/config/defaultThinkingSignature.js

@@ -1,7 +1,12 @@
 // Default signature for thinking mode when no signature from thinkingStore
 export const DEFAULT_THINKING_CLAUDE_SIGNATURE = "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";
 
-export const DEFAULT_THINKING_GEMINI_SIGNATURE = "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";
+export const DEFAULT_THINKING_AG_SIGNATURE = "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";
+
+export const DEFAULT_THINKING_VERTEX_SIGNATURE = "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";
+
+export const DEFAULT_THINKING_GEMINI_CLI_SIGNATURE = "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";
+
 
 export const DEFAULT_THINKING_TEXT = "...";
 

open-sse/translator/request/openai-to-gemini.js

@@ -1,6 +1,6 @@
 import { register } from "../index.js";
 import { FORMATS } from "../formats.js";
-import { DEFAULT_THINKING_GEMINI_SIGNATURE } from "../../config/defaultThinkingSignature.js";
+import { DEFAULT_THINKING_AG_SIGNATURE, DEFAULT_THINKING_GEMINI_CLI_SIGNATURE } from "../../config/defaultThinkingSignature.js";
 import { ANTIGRAVITY_DEFAULT_SYSTEM } from "../../config/appConstants.js";
 import { openaiToClaudeRequestForAntigravity } from "./openai-to-claude.js";
 
@@ -36,7 +36,7 @@ function sanitizeGeminiFunctionName(name) {
 }
 
 // Core: Convert OpenAI request to Gemini format (base for all variants)
-function openaiToGeminiBase(model, body, stream) {
+function openaiToGeminiBase(model, body, stream, signature = DEFAULT_THINKING_AG_SIGNATURE) {
   const result = {
     model: model,
     contents: [],
@@ -109,7 +109,7 @@ function openaiToGeminiBase(model, body, stream) {
             text: msg.reasoning_content
           });
           parts.push({
-            thoughtSignature: DEFAULT_THINKING_GEMINI_SIGNATURE,
+            thoughtSignature: signature,
             text: ""
           });
         }
@@ -128,7 +128,7 @@ function openaiToGeminiBase(model, body, stream) {
 
             const args = tryParseJSON(tc.function?.arguments || "{}");
             parts.push({
-              thoughtSignature: DEFAULT_THINKING_GEMINI_SIGNATURE,
+              thoughtSignature: signature,
               functionCall: {
                 id: tc.id,
                 name: sanitizeGeminiFunctionName(tc.function.name),
@@ -227,7 +227,7 @@ export function openaiToGeminiRequest(model, body, stream) {
 
 // OpenAI -> Gemini CLI (Cloud Code Assist)
 export function openaiToGeminiCLIRequest(model, body, stream) {
-  const gemini = openaiToGeminiBase(model, body, stream);
+  const gemini = openaiToGeminiBase(model, body, stream, DEFAULT_THINKING_GEMINI_CLI_SIGNATURE);
   const isClaude = model.toLowerCase().includes("claude");
 
   // Add thinking config for CLI

open-sse/translator/request/openai-to-vertex.js

@@ -1,29 +1,25 @@
 import { register } from "../index.js";
 import { FORMATS } from "../formats.js";
 import { openaiToGeminiRequest } from "./openai-to-gemini.js";
+import { DEFAULT_THINKING_VERTEX_SIGNATURE } from "../../config/defaultThinkingSignature.js";
 
 /**
  * Post-process a Gemini-format body for Vertex AI compatibility:
  *
- * 1. Strip `id` from every `functionCall` and `functionResponse` part.
- *    Vertex AI rejects requests that include these fields.
- *
- * 2. Strip synthetic `thoughtSignature` parts injected by the base translator.
- *    Vertex rejects fake thought signatures in multi-turn tool-call history;
- *    only real signatures emitted by Vertex itself should be replayed.
+ * 1. Replace all synthetic thoughtSignatures with Vertex-native signature.
+ * 2. Strip `id` from functionCall and functionResponse (Vertex rejects these).
  */
-function stripVertexIncompatibleFields(body) {
+function postProcessForVertex(body) {
   if (!body?.contents) return body;
 
   for (const turn of body.contents) {
     if (!Array.isArray(turn.parts)) continue;
 
-    // Remove standalone synthetic thoughtSignature parts (text === "" with thoughtSignature)
-    turn.parts = turn.parts.filter(
-      p => !(p.thoughtSignature !== undefined && p.text === "" && !p.thought)
-    );
-
     for (const part of turn.parts) {
+      // Replace any synthetic signature with Vertex-native one
+      if (part.thoughtSignature !== undefined) {
+        part.thoughtSignature = DEFAULT_THINKING_VERTEX_SIGNATURE;
+      }
       // Strip id from functionCall
       if (part.functionCall && "id" in part.functionCall) {
         delete part.functionCall.id;
@@ -32,10 +28,6 @@ function stripVertexIncompatibleFields(body) {
       if (part.functionResponse && "id" in part.functionResponse) {
         delete part.functionResponse.id;
       }
-      // Strip thoughtSignature injected alongside functionCall (synthetic signature)
-      if (part.functionCall && "thoughtSignature" in part) {
-        delete part.thoughtSignature;
-      }
     }
   }
 
@@ -44,7 +36,7 @@ function stripVertexIncompatibleFields(body) {
 
 export function openaiToVertexRequest(model, body, stream, credentials) {
   const gemini = openaiToGeminiRequest(model, body, stream, credentials);
-  return stripVertexIncompatibleFields(gemini);
+  return postProcessForVertex(gemini);
 }
 
 register(FORMATS.OPENAI, FORMATS.VERTEX, openaiToVertexRequest, null);

open-sse/translator/response/gemini-to-openai.js

@@ -241,4 +241,5 @@ export function geminiToOpenAIResponse(chunk, state) {
 register(FORMATS.GEMINI, FORMATS.OPENAI, null, geminiToOpenAIResponse);
 register(FORMATS.GEMINI_CLI, FORMATS.OPENAI, null, geminiToOpenAIResponse);
 register(FORMATS.ANTIGRAVITY, FORMATS.OPENAI, null, geminiToOpenAIResponse);
+register(FORMATS.VERTEX, FORMATS.OPENAI, null, geminiToOpenAIResponse);