feat(antigravity): initial steps for Antigravity anti-ban alignment

Cherry-picked from decolua/9router#141 (author: LinearSakana / zx <me@char.moe>)

- Implement client identity spoofing with numeric enums (ideType: 9, pluginType: 2)
- Add runtime platform detection for User-Agent and metadata
- Implement per-connection session ID caching (binary-compatible format)
- Add ANTIGRAVITY_HEADERS (X-Client-Name, X-Client-Version, x-goog-api-client)
- Add X-Machine-Session-Id header injection
- Align metadata/mode parameters across all Antigravity API calls
- Implement double injection for system prompt (raw + [ignore] wrapped)
- Rename internal anti-loop header to x-request-source for anonymity

Skipped: commit 6 (signature side-channel caching) — kept DEFAULT_THINKING_GEMINI_SIGNATURE
Co-authored-by: Cursor <cursoragent@cursor.com>

open-sse/config/constants.js

@@ -1,3 +1,79 @@
+import { platform, arch } from "os";
+
+// === Antigravity Binary Alignment: Numeric Enums ===
+// Reference: Antigravity binary analysis - google.internal.cloud.code.v1internal.ClientMetadata
+
+// IDE Type enum (numeric values as expected by Cloud Code API)
+export const IDE_TYPE = {
+  UNSPECIFIED: 0,
+  JETSKI: 10,        // Internal codename for Gemini CLI
+  ANTIGRAVITY: 9,
+  PLUGINS: 7
+};
+
+// Platform enum (as specified in Antigravity binary)
+export const PLATFORM = {
+  UNSPECIFIED: 0,
+  DARWIN_AMD64: 1,
+  DARWIN_ARM64: 2,
+  LINUX_AMD64: 3,
+  LINUX_ARM64: 4,
+  WINDOWS_AMD64: 5
+};
+
+// Plugin type enum (as specified in Antigravity binary)
+export const PLUGIN_TYPE = {
+  UNSPECIFIED: 0,
+  CLOUD_CODE: 1,
+  GEMINI: 2
+};
+
+/**
+ * Get the platform enum value based on the current OS.
+ * @returns {number} Platform enum value
+ */
+export function getPlatformEnum() {
+  const os = platform();
+  const architecture = arch();
+
+  if (os === "darwin") {
+    return architecture === "arm64" ? PLATFORM.DARWIN_ARM64 : PLATFORM.DARWIN_AMD64;
+  } else if (os === "linux") {
+    return architecture === "arm64" ? PLATFORM.LINUX_ARM64 : PLATFORM.LINUX_AMD64;
+  } else if (os === "win32") {
+    return PLATFORM.WINDOWS_AMD64;
+  }
+  return PLATFORM.UNSPECIFIED;
+}
+
+/**
+ * Generate platform-specific User-Agent string.
+ * @returns {string} User-Agent in format "antigravity/version os/arch"
+ */
+export function getPlatformUserAgent() {
+  const os = platform();
+  const architecture = arch();
+  return `antigravity/1.16.5 ${os}/${architecture}`;
+}
+
+// Centralized client metadata (used in request bodies for loadCodeAssist, onboardUser, etc.)
+// Using numeric enum values as expected by the Cloud Code API
+export const CLIENT_METADATA = {
+  ideType: IDE_TYPE.ANTIGRAVITY,   // 9 - identifies as Antigravity client
+  platform: getPlatformEnum(),      // Runtime platform detection
+  pluginType: PLUGIN_TYPE.GEMINI    // 2
+};
+
+// Internal anti-loop header to identify requests originating from this proxy
+export const INTERNAL_REQUEST_HEADER = { name: "x-request-source", value: "local" };
+
+// Antigravity headers
+export const ANTIGRAVITY_HEADERS = {
+  "X-Client-Name": "antigravity",
+  "X-Client-Version": "1.107.0",
+  "x-goog-api-client": "gl-node/18.18.2 fire/0.8.6 grpc/1.10.x"
+};
+
 // Provider configurations
 export const PROVIDERS = {
   claude: {
@@ -78,7 +154,7 @@ export const PROVIDERS = {
     ],
     format: "antigravity",
     headers: {
-      "User-Agent": "antigravity/1.104.0 darwin/arm64"
+      "User-Agent": getPlatformUserAgent()
     },
     clientId: "1071006060591-tmhssin2h21lcre235vtolojh4g403ep.apps.googleusercontent.com",
     clientSecret: "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"
@@ -181,7 +257,7 @@ export const PROVIDERS = {
 export const CLAUDE_SYSTEM_PROMPT = "You are Claude Code, Anthropic's official CLI for Claude.";
 
 // Antigravity default system prompt (required for API to work)
-export const ANTIGRAVITY_DEFAULT_SYSTEM = "Please ignore the following [ignore]You are Antigravity, a powerful agentic AI coding assistant designed by the Google Deepmind team working on Advanced Agentic Coding.You are pair programming with a USER to solve their coding task. The task may require creating a new codebase, modifying or debugging an existing codebase, or simply answering a question.**Absolute paths only****Proactiveness**[/ignore]";
+export const ANTIGRAVITY_DEFAULT_SYSTEM = "You are Antigravity, a powerful agentic AI coding assistant designed by the Google Deepmind team working on Advanced Agentic Coding.You are pair programming with a USER to solve their coding task. The task may require creating a new codebase, modifying or debugging an existing codebase, or simply answering a question.**Absolute paths only****Proactiveness**";
 
 // OAuth endpoints
 export const OAUTH_ENDPOINTS = {

open-sse/executors/antigravity.js

@@ -1,6 +1,7 @@
 import crypto from "crypto";
 import { BaseExecutor } from "./base.js";
-import { PROVIDERS, OAUTH_ENDPOINTS, HTTP_STATUS } from "../config/constants.js";
+import { PROVIDERS, OAUTH_ENDPOINTS, HTTP_STATUS, ANTIGRAVITY_HEADERS, INTERNAL_REQUEST_HEADER } from "../config/constants.js";
+import { deriveSessionId } from "../utils/sessionManager.js";
 
 const MAX_RETRY_AFTER_MS = 10000;
 
@@ -16,12 +17,14 @@ export class AntigravityExecutor extends BaseExecutor {
     return `${baseUrl}/v1internal:${action}`;
   }
 
-  buildHeaders(credentials, stream = true) {
+  buildHeaders(credentials, stream = true, sessionId = null) {
     return {
       "Content-Type": "application/json",
       "Authorization": `Bearer ${credentials.accessToken}`,
       "User-Agent": this.config.headers?.["User-Agent"] || "antigravity/1.104.0 darwin/arm64",
-      "X-9Router-Source": "9router",
+      [INTERNAL_REQUEST_HEADER.name]: INTERNAL_REQUEST_HEADER.value,
+      ...ANTIGRAVITY_HEADERS,
+      ...(sessionId && { "X-Machine-Session-Id": sessionId }),
       ...(stream && { "Accept": "text/event-stream" })
     };
   }
@@ -51,7 +54,7 @@ export class AntigravityExecutor extends BaseExecutor {
     const transformedRequest = {
       ...body.request,
       ...(contents && { contents }),
-      sessionId: body.request?.sessionId || this.generateSessionId(),
+      sessionId: body.request?.sessionId || deriveSessionId(credentials?.email || credentials?.connectionId),
       safetySettings: undefined,
       toolConfig: body.request?.tools?.length > 0
         ? { functionCallingConfig: { mode: "VALIDATED" } }
@@ -108,7 +111,7 @@ export class AntigravityExecutor extends BaseExecutor {
   }
 
   generateSessionId() {
-    return `-${Math.floor(Math.random() * 9_000_000_000_000_000_000)}`;
+    return crypto.randomUUID() + Date.now().toString();
   }
 
   parseRetryHeaders(headers) {
@@ -167,8 +170,9 @@ export class AntigravityExecutor extends BaseExecutor {
 
     for (let urlIndex = 0; urlIndex < fallbackCount; urlIndex++) {
       const url = this.buildUrl(model, stream, urlIndex);
-      const headers = this.buildHeaders(credentials, stream);
       const transformedBody = this.transformRequest(model, body, stream, credentials);
+      const sessionId = transformedBody.request?.sessionId;
+      const headers = this.buildHeaders(credentials, stream, sessionId);
 
       // Initialize retry counter for this URL
       if (!retryAttemptsByUrl[urlIndex]) {
@@ -200,7 +204,7 @@ export class AntigravityExecutor extends BaseExecutor {
           }
 
           if (retryMs && retryMs <= MAX_RETRY_AFTER_MS) {
-            log?.debug?.("RETRY", `${response.status} with Retry-After: ${Math.ceil(retryMs/1000)}s, waiting...`);
+            log?.debug?.("RETRY", `${response.status} with Retry-After: ${Math.ceil(retryMs / 1000)}s, waiting...`);
             await new Promise(resolve => setTimeout(resolve, retryMs));
             urlIndex--;
             continue;
@@ -211,13 +215,13 @@ export class AntigravityExecutor extends BaseExecutor {
             retryAttemptsByUrl[urlIndex]++;
             // Exponential backoff: 2s, 4s, 8s...
             const backoffMs = Math.min(1000 * (2 ** retryAttemptsByUrl[urlIndex]), MAX_RETRY_AFTER_MS);
-            log?.debug?.("RETRY", `429 auto retry ${retryAttemptsByUrl[urlIndex]}/${MAX_AUTO_RETRIES} after ${backoffMs/1000}s`);
+            log?.debug?.("RETRY", `429 auto retry ${retryAttemptsByUrl[urlIndex]}/${MAX_AUTO_RETRIES} after ${backoffMs / 1000}s`);
             await new Promise(resolve => setTimeout(resolve, backoffMs));
             urlIndex--;
             continue;
           }
 
-          log?.debug?.("RETRY", `${response.status}, Retry-After ${retryMs ? `too long (${Math.ceil(retryMs/1000)}s)` : 'missing'}, trying fallback`);
+          log?.debug?.("RETRY", `${response.status}, Retry-After ${retryMs ? `too long (${Math.ceil(retryMs / 1000)}s)` : 'missing'}, trying fallback`);
           lastStatus = response.status;
 
           if (urlIndex + 1 < fallbackCount) {

open-sse/services/usage.js

@@ -2,6 +2,8 @@
  * Usage Fetcher - Get usage data from provider APIs
  */
 
+import { CLIENT_METADATA, getPlatformUserAgent } from "../config/constants.js";
+
 // GitHub API config
 const GITHUB_CONFIG = {
   apiVersion: "2022-11-28",
@@ -15,7 +17,7 @@ const ANTIGRAVITY_CONFIG = {
   tokenUrl: "https://oauth2.googleapis.com/token",
   clientId: "1071006060591-tmhssin2h21lcre235vtolojh4g403ep.apps.googleusercontent.com",
   clientSecret: "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",
-  userAgent: "antigravity/1.11.3 Darwin/arm64",
+  userAgent: getPlatformUserAgent(),
 };
 
 // Codex (OpenAI) API config
@@ -220,7 +222,11 @@ async function getAntigravityUsage(accessToken, providerSpecificData) {
         "User-Agent": ANTIGRAVITY_CONFIG.userAgent,
         "Content-Type": "application/json",
       },
-      body: JSON.stringify(projectId ? { project: projectId } : {}),
+      body: JSON.stringify({
+        ...(projectId ? { project: projectId } : {}),
+        metadata: CLIENT_METADATA,
+        mode: 1
+      }),
     });
 
     if (response.status === 403) {
@@ -317,7 +323,7 @@ async function getAntigravitySubscriptionInfo(accessToken) {
         "User-Agent": ANTIGRAVITY_CONFIG.userAgent,
         "Content-Type": "application/json",
       },
-      body: JSON.stringify({ metadata: { ideType: "ANTIGRAVITY" } }),
+      body: JSON.stringify({ metadata: CLIENT_METADATA, mode: 1 }),
     });
 
     if (!response.ok) return null;

open-sse/translator/helpers/geminiHelper.js

@@ -85,9 +85,9 @@ export function generateRequestId() {
   return `agent-${crypto.randomUUID()}`;
 }
 
-// Generate session ID
+// Generate session ID (binary-compatible format: UUID + timestamp)
 export function generateSessionId() {
-  return `-${Math.floor(Math.random() * 9000000000000000000)}`;
+  return crypto.randomUUID() + Date.now().toString();
 }
 
 // Generate project ID

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

@@ -18,6 +18,7 @@ import {
   generateProjectId,
   cleanJSONSchemaForAntigravity
 } from "../helpers/geminiHelper.js";
+import { deriveSessionId } from "../../utils/sessionManager.js";
 
 // Core: Convert OpenAI request to Gemini format (base for all variants)
 function openaiToGeminiBase(model, body, stream) {
@@ -259,7 +260,7 @@ function wrapInCloudCodeEnvelope(model, geminiCLI, credentials = null, isAntigra
     userAgent: isAntigravity ? "antigravity" : "gemini-cli",
     requestId: isAntigravity ? `agent-${generateUUID()}` : generateRequestId(),
     request: {
-      sessionId: generateSessionId(),
+      sessionId: isAntigravity ? deriveSessionId(credentials?.email || credentials?.connectionId) : generateSessionId(),
       contents: geminiCLI.contents,
       systemInstruction: geminiCLI.systemInstruction,
       generationConfig: geminiCLI.generationConfig,
@@ -272,11 +273,16 @@ function wrapInCloudCodeEnvelope(model, geminiCLI, credentials = null, isAntigra
     envelope.requestType = "agent";
 
     // Inject required default system prompt for Antigravity
-    const defaultPart = { text: ANTIGRAVITY_DEFAULT_SYSTEM };
+    // Inject required default system prompt for Antigravity (double injection)
+    const systemParts = [
+      { text: ANTIGRAVITY_DEFAULT_SYSTEM },
+      { text: `Please ignore the following [ignore]${ANTIGRAVITY_DEFAULT_SYSTEM}[/ignore]` }
+    ];
+
     if (envelope.request.systemInstruction?.parts) {
-      envelope.request.systemInstruction.parts.unshift(defaultPart);
+      envelope.request.systemInstruction.parts.unshift(...systemParts);
     } else {
-      envelope.request.systemInstruction = { role: "user", parts: [defaultPart] };
+      envelope.request.systemInstruction = { role: "user", parts: systemParts };
     }
 
     // Add toolConfig for Antigravity
@@ -304,7 +310,7 @@ function wrapInCloudCodeEnvelopeForClaude(model, claudeRequest, credentials = nu
     requestId: `agent-${generateUUID()}`,
     requestType: "agent",
     request: {
-      sessionId: generateSessionId(),
+      sessionId: deriveSessionId(credentials?.email || credentials?.connectionId),
       contents: [],
       generationConfig: {
         temperature: claudeRequest.temperature || 1,
@@ -378,9 +384,11 @@ function wrapInCloudCodeEnvelopeForClaude(model, claudeRequest, credentials = nu
     }
   }
 
-  // Add system instruction (Antigravity default)
+  // Add system instruction (Antigravity default - double injection)
-  const defaultPart = { text: ANTIGRAVITY_DEFAULT_SYSTEM };
+  const systemParts = [
-  const systemParts = [defaultPart];
+    { text: ANTIGRAVITY_DEFAULT_SYSTEM },
+    { text: `Please ignore the following [ignore]${ANTIGRAVITY_DEFAULT_SYSTEM}[/ignore]` }
+  ];
 
   if (claudeRequest.system) {
     if (Array.isArray(claudeRequest.system)) {

open-sse/utils/sessionManager.js

@@ -0,0 +1,66 @@
+/**
+ * Session Manager for Antigravity Cloud Code
+ *
+ * Handles session ID generation and caching for prompt caching continuity.
+ * Mimics the Antigravity binary behavior: generates a session ID at startup
+ * and keeps it for the process lifetime, scoped per account/connection.
+ *
+ * Reference: antigravity-claude-proxy/src/cloudcode/session-manager.js
+ */
+
+import crypto from "crypto";
+
+// Runtime storage for session IDs (per connection/account)
+// Key: connectionId (email or identifier), Value: sessionId
+const runtimeSessionStore = new Map();
+
+/**
+ * Get or create a session ID for the given connection.
+ *
+ * The binary generates a session ID once at startup: `rs() + Date.now()`.
+ * Since 9router is long-running, we simulate this "per-launch" behavior by
+ * storing a generated ID in memory for each connection.
+ *
+ * - If 9router restarts, the ID changes (matching binary restart behavior).
+ * - Within a running instance, the ID is stable for that connection.
+ * - This enables prompt caching while using the EXACT random logic of the binary.
+ *
+ * @param {string} connectionId - The connection identifier (email or unique ID)
+ * @returns {string} A stable session ID string matching binary format
+ */
+export function deriveSessionId(connectionId) {
+    if (!connectionId) {
+        // Fallback for requests without a connection identifier
+        return generateBinaryStyleId();
+    }
+
+    // Check if we already have a session ID for this connection in this process run
+    if (runtimeSessionStore.has(connectionId)) {
+        return runtimeSessionStore.get(connectionId);
+    }
+
+    // Generate a new ID using the binary's exact logic
+    const newSessionId = generateBinaryStyleId();
+
+    // Store it for future requests from this connection
+    runtimeSessionStore.set(connectionId, newSessionId);
+
+    return newSessionId;
+}
+
+/**
+ * Generate a Session ID using the binary's exact logic.
+ * Format: `rs() + Date.now()` where `rs()` is randomUUID
+ *
+ * @returns {string} A session ID in binary format
+ */
+export function generateBinaryStyleId() {
+    return crypto.randomUUID() + Date.now().toString();
+}
+
+/**
+ * Clears all session IDs (e.g. useful for testing or explicit reset)
+ */
+export function clearSessionStore() {
+    runtimeSessionStore.clear();
+}

src/lib/oauth/constants/oauth.js

@@ -1,6 +1,20 @@
 /**
  * OAuth Configuration Constants
  */
+import { platform, arch } from "os";
+
+/**
+ * Get the platform enum value based on the current OS.
+ * Matches Antigravity binary's ClientMetadata.Platform enum.
+ */
+function getOAuthPlatformEnum() {
+  const os = platform();
+  const architecture = arch();
+  if (os === "darwin") return architecture === "arm64" ? 2 : 1;
+  if (os === "linux") return architecture === "arm64" ? 4 : 3;
+  if (os === "win32") return 5;
+  return 0;
+}
 
 // Claude OAuth Configuration (Authorization Code Flow with PKCE)
 export const CLAUDE_CONFIG = {
@@ -83,9 +97,17 @@ export const ANTIGRAVITY_CONFIG = {
   onboardUserEndpoint: "https://cloudcode-pa.googleapis.com/v1internal:onboardUser",
   loadCodeAssistUserAgent: "google-api-nodejs-client/9.15.1",
   loadCodeAssistApiClient: "google-cloud-sdk vscode_cloudshelleditor/0.1",
-  loadCodeAssistClientMetadata: `{"ideType":"IDE_UNSPECIFIED","platform":"PLATFORM_UNSPECIFIED","pluginType":"GEMINI"}`,
+  loadCodeAssistClientMetadata: JSON.stringify({ ideType: 9, platform: getOAuthPlatformEnum(), pluginType: 2 }),
 };
 
+/**
+ * Get client metadata using numeric enum values for API calls.
+ * @returns {{ ideType: number, platform: number, pluginType: number }}
+ */
+export function getOAuthClientMetadata() {
+  return { ideType: 9, platform: getOAuthPlatformEnum(), pluginType: 2 };
+}
+
 // OpenAI OAuth Configuration (Authorization Code Flow with PKCE)
 export const OPENAI_CONFIG = {
   clientId: "app_EMoamEEZ73f0CkXaXp7hrann",

src/lib/oauth/providers.js

@@ -14,6 +14,7 @@ import {
   GITHUB_CONFIG,
   KIRO_CONFIG,
   CURSOR_CONFIG,
+  getOAuthClientMetadata,
 } from "./constants/oauth";
 
 // Provider configurations
@@ -184,7 +185,8 @@ const PROVIDERS = {
               "Content-Type": "application/json",
             },
             body: JSON.stringify({
-              metadata: { ideType: "IDE_UNSPECIFIED", platform: "PLATFORM_UNSPECIFIED", pluginType: "GEMINI" },
+              metadata: getOAuthClientMetadata(),
+              mode: 1,
             }),
           }
         );
@@ -254,7 +256,7 @@ const PROVIDERS = {
         "X-Goog-Api-Client": ANTIGRAVITY_CONFIG.loadCodeAssistApiClient,
         "Client-Metadata": ANTIGRAVITY_CONFIG.loadCodeAssistClientMetadata,
       };
-      const metadata = { ideType: "IDE_UNSPECIFIED", platform: "PLATFORM_UNSPECIFIED", pluginType: "GEMINI" };
+      const metadata = getOAuthClientMetadata();
 
       // Fetch user info
       const userInfoRes = await fetch(`${ANTIGRAVITY_CONFIG.userInfoUrl}?alt=json`, {
@@ -269,7 +271,7 @@ const PROVIDERS = {
         const loadRes = await fetch(ANTIGRAVITY_CONFIG.loadCodeAssistEndpoint, {
           method: "POST",
           headers,
-          body: JSON.stringify({ metadata }),
+          body: JSON.stringify({ metadata, mode: 1 }),
         });
         if (loadRes.ok) {
           const data = await loadRes.json();
@@ -295,7 +297,7 @@ const PROVIDERS = {
             const onboardRes = await fetch(ANTIGRAVITY_CONFIG.onboardUserEndpoint, {
               method: "POST",
               headers,
-              body: JSON.stringify({ tierId, metadata, cloudaicompanionProject: projectId }),
+              body: JSON.stringify({ tierId, metadata, cloudaicompanionProject: projectId, mode: 1 }),
             });
             if (onboardRes.ok) {
               const result = await onboardRes.json();

src/lib/oauth/services/antigravity.js

@@ -1,4 +1,5 @@
 import crypto from "crypto";
+import { platform, arch } from "os";
 import open from "open";
 import { ANTIGRAVITY_CONFIG } from "../constants/oauth.js";
 import { getServerCredentials } from "../config/index.js";
@@ -92,12 +93,20 @@ export class AntigravityService {
 
   /**
    * Get metadata object for API calls
+   * Uses numeric enum values matching Antigravity binary specifications
    */
   getMetadata() {
+    const os = platform();
+    const architecture = arch();
+    let platformEnum = 0; // UNSPECIFIED
+    if (os === "darwin") platformEnum = architecture === "arm64" ? 2 : 1;
+    else if (os === "linux") platformEnum = architecture === "arm64" ? 4 : 3;
+    else if (os === "win32") platformEnum = 5;
+
     return {
-      ideType: "IDE_UNSPECIFIED",
+      ideType: 9,        // ANTIGRAVITY
-      platform: "PLATFORM_UNSPECIFIED",
+      platform: platformEnum,
-      pluginType: "GEMINI",
+      pluginType: 2,     // GEMINI
     };
   }
 
@@ -108,7 +117,7 @@ export class AntigravityService {
     const response = await fetch(this.config.loadCodeAssistEndpoint, {
       method: "POST",
       headers: this.getApiHeaders(accessToken),
-      body: JSON.stringify({ metadata: this.getMetadata() }),
+      body: JSON.stringify({ metadata: this.getMetadata(), mode: 1 }),
     });
 
     if (!response.ok) {
@@ -149,6 +158,7 @@ export class AntigravityService {
         tierId,
         metadata: this.getMetadata(),
         cloudaicompanionProject: projectId,
+        mode: 1,
       }),
     });
 

src/lib/oauth/services/gemini.js

@@ -1,6 +1,6 @@
 import crypto from "crypto";
 import open from "open";
-import { GEMINI_CONFIG } from "../constants/oauth.js";
+import { GEMINI_CONFIG, getOAuthClientMetadata } from "../constants/oauth.js";
 import { getServerCredentials } from "../config/index.js";
 import { startLocalServer } from "../utils/server.js";
 import { spinner as createSpinner } from "../utils/ui.js";
@@ -71,18 +71,11 @@ export class GeminiCLIService {
           "Content-Type": "application/json",
           "User-Agent": "google-api-nodejs-client/9.15.1",
           "X-Goog-Api-Client": "google-cloud-sdk vscode_cloudshelleditor/0.1",
-          "Client-Metadata": JSON.stringify({
+          "Client-Metadata": JSON.stringify(getOAuthClientMetadata())
-            ideType: "IDE_UNSPECIFIED",
-            platform: "PLATFORM_UNSPECIFIED",
-            pluginType: "GEMINI"
-          })
         },
         body: JSON.stringify({
-          metadata: {
+          metadata: getOAuthClientMetadata(),
-            ideType: "IDE_UNSPECIFIED",
+          mode: 1
-            platform: "PLATFORM_UNSPECIFIED",
-            pluginType: "GEMINI"
-          }
         })
       }
     );

src/mitm/server.js

@@ -6,6 +6,7 @@ const { promisify } = require("util");
 const os = require("os");
 
 // Configuration
+const INTERNAL_REQUEST_HEADER = { name: "x-request-source", value: "local" };
 const TARGET_HOST = "daily-cloudcode-pa.googleapis.com";
 const LOCAL_PORT = 443;
 const ROUTER_URL = "http://localhost:20128/v1/chat/completions";
@@ -174,7 +175,7 @@ const server = https.createServer(sslOptions, async (req, res) => {
   if (bodyBuffer.length > 0) saveRequestLog(req.url, bodyBuffer);
 
   // Anti-loop: requests from 9Router bypass interception
-  if (req.headers["x-9router-source"] === "9router") {
+  if (req.headers[INTERNAL_REQUEST_HEADER.name] === INTERNAL_REQUEST_HEADER.value) {
     return passthrough(req, res, bodyBuffer);
   }