diff --git a/open-sse/executors/antigravity.js b/open-sse/executors/antigravity.js
index d3f41784..0fcbab81 100644
--- a/open-sse/executors/antigravity.js
+++ b/open-sse/executors/antigravity.js
@@ -5,8 +5,18 @@ import { OAUTH_ENDPOINTS, ANTIGRAVITY_HEADERS, INTERNAL_REQUEST_HEADER, AG_DEFAU
 import { HTTP_STATUS } from "../config/runtimeConfig.js";
 import { deriveSessionId } from "../utils/sessionManager.js";
 import { proxyAwareFetch } from "../utils/proxyFetch.js";
+import { cleanJSONSchemaForAntigravity } from "../translator/helpers/geminiHelper.js";
+
+// Sanitize function name: Gemini requires [a-zA-Z_][a-zA-Z0-9_.:\-]{0,63}
+function sanitizeFunctionName(name) {
+  if (!name) return "_unknown";
+  let s = name.replace(/[^a-zA-Z0-9_.:\-]/g, "_");
+  if (!/^[a-zA-Z_]/.test(s)) s = "_" + s;
+  return s.substring(0, 64);
+}
 
 const MAX_RETRY_AFTER_MS = 10000;
+const MAX_ANTIGRAVITY_OUTPUT_TOKENS = 16384;
 
 export class AntigravityExecutor extends BaseExecutor {
   constructor() {
@@ -53,14 +63,44 @@ export class AntigravityExecutor extends BaseExecutor {
       return c;
     });
 
+    // Sanitize tool schemas and function names before sending to Antigravity.
+    let tools = body.request?.tools;
+
+    if (tools && tools.length > 0) {
+      tools = tools
+        .map(group => {
+          if (!group.functionDeclarations) return group;
+          const cleanedDeclarations = group.functionDeclarations.map(fn => ({
+            ...fn,
+            name: sanitizeFunctionName(fn.name),
+            parameters: fn.parameters
+              ? cleanJSONSchemaForAntigravity(structuredClone(fn.parameters))
+              : { type: "object", properties: { reason: { type: "string", description: "Brief explanation" } }, required: ["reason"] }
+          }));
+
+          return {
+            ...group,
+            functionDeclarations: cleanedDeclarations
+          };
+        })
+        .filter(group => group.functionDeclarations?.length > 0)
+        .slice(0, 1);
+    }
+
+    const { tools: _originalTools, toolConfig: _originalToolConfig, ...requestWithoutTools } = body.request || {};
+    const generationConfig = { ...(requestWithoutTools.generationConfig || {}) };
+    if (generationConfig.maxOutputTokens > MAX_ANTIGRAVITY_OUTPUT_TOKENS) {
+      generationConfig.maxOutputTokens = MAX_ANTIGRAVITY_OUTPUT_TOKENS;
+    }
+
     const transformedRequest = {
-      ...body.request,
+      ...requestWithoutTools,
+      generationConfig,
       ...(contents && { contents }),
+      ...(tools && { tools }),
       sessionId: body.request?.sessionId || deriveSessionId(credentials?.email || credentials?.connectionId),
       safetySettings: undefined,
-      toolConfig: body.request?.tools?.length > 0
-        ? { functionCallingConfig: { mode: "VALIDATED" } }
-        : body.request?.toolConfig
+      ...(tools?.length > 0 && { toolConfig: { functionCallingConfig: { mode: "VALIDATED" } } })
     };
 
     return {
diff --git a/open-sse/translator/index.js b/open-sse/translator/index.js
index 442693a3..a018dc59 100644
--- a/open-sse/translator/index.js
+++ b/open-sse/translator/index.js
@@ -140,14 +140,11 @@ export function translateRequest(sourceFormat, targetFormat, model, body, stream
     }
   }
 
-  // Antigravity cloaking: rename client tools + inject decoys (anti-ban)
-  // Only apply for GitHub Copilot requests so other clients are unaffected.
+  // Antigravity cloaking/tool stripping is intentionally disabled for GitHub Copilot.
+  // Keep the translated request intact; final provider-specific sanitization happens
+  // in the Antigravity executor.
   if (provider === FORMATS.ANTIGRAVITY && clientTool === "github-copilot") {
-    const { cloakedBody, toolNameMap } = AntigravityExecutor.cloakTools(result, clientTool);
-    result = cloakedBody;
-    if (toolNameMap?.size > 0) {
-      result._toolNameMap = toolNameMap;
-    }
+    // No-op
   }
 
   return result;
diff --git a/open-sse/translator/request/openai-to-gemini.js b/open-sse/translator/request/openai-to-gemini.js
index 27f96dd1..b2043065 100644
--- a/open-sse/translator/request/openai-to-gemini.js
+++ b/open-sse/translator/request/openai-to-gemini.js
@@ -336,6 +336,20 @@ function wrapInCloudCodeEnvelopeForClaude(model, claudeRequest, credentials = nu
     }
   };
 
+  // Build tool_use id -> name map so functionResponse can use the correct name
+  const toolUseIdToName = {};
+  if (claudeRequest.messages && Array.isArray(claudeRequest.messages)) {
+    for (const msg of claudeRequest.messages) {
+      if (Array.isArray(msg.content)) {
+        for (const block of msg.content) {
+          if (block.type === "tool_use" && block.id && block.name) {
+            toolUseIdToName[block.id] = block.name;
+          }
+        }
+      }
+    }
+  }
+
   // Convert Claude messages to Gemini contents
   if (claudeRequest.messages && Array.isArray(claudeRequest.messages)) {
     for (const msg of claudeRequest.messages) {
@@ -349,7 +363,7 @@ function wrapInCloudCodeEnvelopeForClaude(model, claudeRequest, credentials = nu
             parts.push({
               functionCall: {
                 id: block.id,
-                name: block.name,
+                name: sanitizeGeminiFunctionName(block.name),
                 args: block.input || {}
               }
             });
@@ -358,10 +372,14 @@ function wrapInCloudCodeEnvelopeForClaude(model, claudeRequest, credentials = nu
             if (Array.isArray(content)) {
               content = content.map(c => c.type === "text" ? c.text : JSON.stringify(c)).join("\n");
             }
+            // Resolve the original tool name from the id — Gemini requires it to match the functionCall name
+            const resolvedName = toolUseIdToName[block.tool_use_id]
+              ? sanitizeGeminiFunctionName(toolUseIdToName[block.tool_use_id])
+              : "tool";
             parts.push({
               functionResponse: {
                 id: block.tool_use_id,
-                name: "unknown",
+                name: resolvedName,
                 response: { result: tryParseJSON(content) || content }
               }
             });