fix(sse): match the native Antigravity CLI wire image

.env.example

@@ -1737,7 +1737,12 @@ GITHUB_OAUTH_CLIENT_ID=Iv1.b507a08c87ecfe98
 # Optional override; leave unset to follow the shared Codex client version.
 # CODEX_USER_AGENT="codex-cli/0.155.0 (Windows 10.0.26200; x64)"
 GITHUB_USER_AGENT="GitHubCopilotChat/0.54.0"
-ANTIGRAVITY_USER_AGENT="antigravity/2.0.1 linux/arm64 google-api-nodejs-client/10.3.0"
+# Optional override for the Antigravity CLI (`agy`) build changelist reported as `cl=` in
+# the CLI User-Agent. Google's Piper changelist is not derivable from the version and is not
+# exposed by the public auto-updater manifests, so it is seeded from a live capture per
+# version (1.4.4 -> 1003595037). Unset on an unknown version omits `cl=` entirely rather
+# than advertising another build's changelist.
+# ANTIGRAVITY_CLI_CL=1003595037
 KIRO_USER_AGENT="AWS-SDK-JS/3.0.0 kiro-ide/1.0.0"
 # KIRO_VERIFY_FULL_CRC=false           # opt-in: full per-frame message CRC validation on the Kiro event stream (debug corrupted streams; prelude CRC + TLS already protect framing)
 # Optional override for the Kiro social device-code OAuth clientId. Kiro's

changelog.d/fixes/17913-antigravity-cli-wire-image-fidelity.md

@@ -0,0 +1 @@
+- **fix(sse):** the Antigravity CLI profile now matches the native `agy` wire image — the User-Agent reports the real host in Go's `windows`/`amd64` dialect plus the build changelist (`cl=`) instead of the pinned `darwin/arm64`, `streamGenerateContent` no longer sends `Accept: text/event-stream` or `x-goog-user-project` on the consumer path, and `loadCodeAssist` sends the native 38-byte `{"metadata":{"ideType":"ANTIGRAVITY"}}` body. The IDE profile keeps its `darwin/arm64` pin and numeric protobuf enums. Also drops the never-read `ANTIGRAVITY_USER_AGENT` env knob.

docs/reference/ENVIRONMENT.md

@@ -725,7 +725,7 @@ process.env[`${PROVIDER_ID}_USER_AGENT`]
 | `CLAUDE_CODE_CLIENT_BUILD_REVISION` | `1e2` | Override the 3-character suffix OmniRoute appends to `cc_version=` in the Claude billing block. Bump alongside `CLAUDE_CODE_CLIENT_VERSION` — pinning only the version advertises a `version.revision` pair no real binary emits. |
 | `GITHUB_COPILOT_CLI_VERSION` | `1.0.91` | Override advertised Copilot CLI version independently of `GITHUB_USER_AGENT` |
 | `GITHUB_USER_AGENT` | `GitHubCopilotChat/0.54.0` | When GitHub Copilot Chat updates |
-| `ANTIGRAVITY_USER_AGENT` | `antigravity/2.0.1 darwin/arm64` | When Antigravity IDE updates |
+| `ANTIGRAVITY_CLI_CL` | _(unset)_ | Override the Antigravity CLI (`agy`) Piper changelist reported as `cl=` in the CLI User-Agent. Not derivable from the version nor exposed by the public manifests; seeded per version from a live capture (1.4.4 → `1003595037`). Unset on an unknown version omits `cl=` instead of advertising another build's changelist. |
 | `KIRO_USER_AGENT` | `AWS-SDK-JS/3.0.0 kiro-ide/1.0.0` | When Kiro IDE updates |
 | `KIRO_OAUTH_CLIENT_ID` | `kiro-cli` | Override the Kiro social device-code `clientId` (public id) |
 | `KIRO_VERIFY_FULL_CRC` | `false` | Opt-in: full per-frame message CRC validation on the Kiro event stream (debug corrupted streams) |

docs/security/STEALTH_GUIDE.md

@@ -251,7 +251,6 @@ All MITM endpoints require management auth (`requireCliToolsAuth`). The sudo pas
 | `CLAUDE_USER_AGENT`      | `claude-cli/2.1.280 (external, cli)`                            |
 | `CODEX_USER_AGENT`       | `codex-cli/0.155.0 (Windows 10.0.26200; x64)`                   |
 | `GITHUB_USER_AGENT`      | `GitHubCopilotChat/0.54.0`                                      |
-| `ANTIGRAVITY_USER_AGENT` | `antigravity/2.0.1 linux/arm64 google-api-nodejs-client/10.3.0` |
 | `KIRO_USER_AGENT`        | `AWS-SDK-JS/3.0.0 kiro-ide/1.0.0`                               |
 | `QODER_USER_AGENT`       | `Qoder-Cli`                                                     |
 | `CURSOR_USER_AGENT`      | `Cursor/3.4`                                                    |

open-sse/config/cliFingerprints.ts

@@ -172,19 +172,16 @@ export const CLI_FINGERPRINTS: Record<string, CliFingerprint> = {
     userAgent: getGitHubCopilotChatUserAgent,
   },
   antigravity: {
+    // Native capture of the Go CLI (agy 1.4.4, Windows): streaming is requested by the
+    // `?alt=sse` query param, so there is no Accept header, and the consumer path carries
+    // no x-goog-* identity headers at all.
     headerOrder: [
-      "Accept",
-      "Accept-Encoding",
-      "Authorization",
+      "Host",
       "Content-Type",
+      "Authorization",
       "User-Agent",
-      "x-goog-api-client",
-      "x-client-name",
-      "x-client-version",
-      "x-machine-id",
-      "x-vscode-sessionid",
-      "Host",
-      "Connection",
+      "Accept-Encoding",
+      "Transfer-Encoding",
     ],
     bodyFieldOrder: [
       "project",

open-sse/executors/antigravity.ts

@@ -623,10 +623,14 @@ export class AntigravityExecutor extends BaseExecutor {
 
   buildHeaders(credentials: AntigravityCredentials, _stream = true): Record<string, string> {
     const clientProfile = getAntigravityClientProfile(credentials);
-    const raw = {
+    const raw: Record<string, string> = {
       ...getAntigravityContentHeaders(clientProfile, credentials.accessToken),
-      Accept: "text/event-stream",
     };
+    // The native Go CLI requests SSE through `?alt=sse` alone and sends no Accept header;
+    // only the IDE/Electron profile advertises `text/event-stream`.
+    if (clientProfile !== "cli") {
+      raw.Accept = "text/event-stream";
+    }
     // Scrub proxy/fingerprint headers that reveal non-native traffic
     return scrubProxyAndFingerprintHeaders(raw);
   }

open-sse/services/antigravityClientProfile.ts

@@ -83,7 +83,9 @@ export function applyAntigravityClientProfileHeaders(
 
   const project = getProjectHeaderValue(body);
   removeHeaderCaseInsensitive(headers, "x-goog-user-project");
-  if (project) {
+  // The native Go CLI (consumer auth) sends no quota-project header at all; only the IDE
+  // profile does. sendAntigravityRequest still retries once without it on a 403.
+  if (project && profile !== "cli") {
     headers["x-goog-user-project"] = project;
   }
 

open-sse/services/antigravityHeaders.ts

@@ -52,13 +52,66 @@ function resolveAntigravityPlatformEnum(): number {
 export const ANTIGRAVITY_IDE_NODE_API_CLIENT = "google-api-nodejs-client/10.3.0";
 export const ANTIGRAVITY_IDE_NODE_X_GOOG_API_CLIENT = "gl-node/22.21.1";
 
-// Antigravity presents the native macOS desktop client fingerprint: the upstream
-// backend expects the Mac build, so the OS/arch token is pinned to darwin/arm64
-// regardless of the host OmniRoute happens to run on (#8098). The IDE / CLI /
-// IDE-Node User-Agent split (#8013) is preserved — only the platform token is fixed.
+// Antigravity presents the native macOS desktop client fingerprint on the IDE path:
+// the upstream backend expects the Mac build, so the OS/arch token is pinned to
+// darwin/arm64 regardless of the host OmniRoute happens to run on (#8098). The IDE /
+// CLI / IDE-Node User-Agent split (#8013) is preserved — only the platform token is fixed.
+//
+// The CLI path (agy, a Go binary) has no such constraint: it reports the real host in
+// Go's runtime.GOOS/GOARCH dialect, captured live from `agy 1.4.4` on Windows x64 as
+// `os_type=windows; arch=amd64`. Node's own names ("win32"/"x64") are a giveaway.
 const ANTIGRAVITY_OS_TYPE = "darwin";
 const ANTIGRAVITY_ARCH = "arm64";
 
+const ANTIGRAVITY_GO_OS: Record<string, string> = {
+  win32: "windows",
+  darwin: "darwin",
+  linux: "linux",
+  freebsd: "freebsd",
+  openbsd: "openbsd",
+  sunos: "solaris",
+  aix: "aix",
+};
+
+const ANTIGRAVITY_GO_ARCH: Record<string, string> = {
+  x64: "amd64",
+  ia32: "386",
+  arm64: "arm64",
+  arm: "arm",
+  ppc64: "ppc64",
+  s390x: "s390x",
+};
+
+/** Map a Node `process.platform`/`process.arch` pair onto Go's GOOS/GOARCH tokens. */
+export function resolveAntigravityGoPlatform(
+  platform: string = process.platform,
+  arch: string = process.arch
+): { osType: string; arch: string } {
+  return {
+    osType: ANTIGRAVITY_GO_OS[platform] ?? platform,
+    arch: ANTIGRAVITY_GO_ARCH[arch] ?? arch,
+  };
+}
+
+// `cl` is Google's internal Piper changelist for the build that shipped a given CLI
+// version — not derivable from the version, and not exposed by the public manifests
+// (only version/url/sha512 are). Seeded from the native capture; refresh when bumping.
+const ANTIGRAVITY_KNOWN_CHANGELISTS: Record<string, string> = {
+  "1.4.4": "1003595037",
+};
+
+/**
+ * Resolve the CLI build changelist: explicit override, then the known-version table.
+ * Returns `null` when the version has no recorded changelist, so the caller omits `cl=`
+ * entirely — a stale changelist paired with a newer version is a worse fingerprint than
+ * no changelist at all.
+ */
+export function resolveAntigravityCliChangelist(version: string): string | null {
+  const override = process.env.ANTIGRAVITY_CLI_CL?.trim();
+  if (override) return override;
+  return ANTIGRAVITY_KNOWN_CHANGELISTS[version] ?? null;
+}
+
 function withOptionalBearerAuth(
   headers: Record<string, string>,
   accessToken?: string | null
@@ -75,9 +128,12 @@ export function antigravityIdeUserAgent(version = getCachedAntigravityIdeVersion
 
 export function antigravityCliUserAgent(
   version = getCachedAntigravityCliVersion(),
-  authMethod = "consumer"
+  authMethod = "consumer",
+  changelist = resolveAntigravityCliChangelist(version),
+  platform = resolveAntigravityGoPlatform()
 ): string {
-  return `antigravity/cli/${version} (aidev_client; os_type=${ANTIGRAVITY_OS_TYPE}; arch=${ANTIGRAVITY_ARCH}; auth_method=${authMethod})`;
+  const clToken = changelist ? `cl=${changelist}; ` : "";
+  return `antigravity/cli/${version} (aidev_client; os_type=${platform.osType}; arch=${platform.arch}; ${clToken}auth_method=${authMethod})`;
 }
 
 export function antigravityIdeNodeUserAgent(version = getCachedAntigravityIdeVersion()): string {
@@ -112,8 +168,16 @@ export function getAntigravityIdeNodeHeaders(accessToken?: string | null): Recor
   );
 }
 
-/** Native loadCodeAssist body metadata captured from both official clients. */
-export function getAntigravityLoadCodeAssistMetadata(): Record<string, number> {
+/** Native loadCodeAssist body metadata, per client profile. */
+export function getAntigravityLoadCodeAssistMetadata(
+  profile: AntigravityClientProfile = "ide"
+): Record<string, number> | { ideType: string } {
+  // The Go CLI sends the bare string form — 38 bytes, 200 OK, captured live. The numeric
+  // enum shape below is what the IDE build needs; sending it from the CLI path would be
+  // an identity mismatch.
+  if (profile === "cli") {
+    return { ideType: "ANTIGRAVITY" };
+  }
   return {
     ideType: ANTIGRAVITY_IDE_TYPE_ENUM,
     platform: resolveAntigravityPlatformEnum(),

open-sse/services/antigravityProjectBootstrap.ts

@@ -136,7 +136,9 @@ async function tryLoadCodeAssist(
       const response = await fetchImpl(url, {
         method: "POST",
         headers,
-        body: JSON.stringify({ metadata: getAntigravityLoadCodeAssistMetadata() }),
+        body: JSON.stringify({
+          metadata: getAntigravityLoadCodeAssistMetadata(clientProfile),
+        }),
         signal: signal ? AbortSignal.any([signal, timeoutSignal]) : timeoutSignal,
       });
 
@@ -222,7 +224,7 @@ async function tryOnboardUser(
   const headers = getAntigravityContentHeaders(clientProfile, accessToken);
   const body = JSON.stringify({
     tier_id: tierId,
-    metadata: getAntigravityLoadCodeAssistMetadata(),
+    metadata: getAntigravityLoadCodeAssistMetadata(clientProfile),
   });
 
   for (const url of urls) {

open-sse/services/usage/antigravity.ts

@@ -824,7 +824,7 @@ async function getAntigravitySubscriptionInfo(
     const response = await fetch(ANTIGRAVITY_CONFIG.loadProjectApiUrl, {
       method: "POST",
       headers: getAntigravityContentHeaders(profile, accessToken),
-      body: JSON.stringify({ metadata: getAntigravityLoadCodeAssistMetadata() }),
+      body: JSON.stringify({ metadata: getAntigravityLoadCodeAssistMetadata(profile) }),
     });
 
     if (!response.ok) return null;

src/lib/oauth/providers/antigravity.ts

@@ -165,7 +165,7 @@ async function postExchangeAntigravity(
   tokens: AntigravityTokenPayload
 ): Promise<AntigravityPostExchange> {
   const headers = getPostExchangeHeaders(clientProfile, tokens.access_token);
-  const metadata = getAntigravityLoadCodeAssistMetadata();
+  const metadata = getAntigravityLoadCodeAssistMetadata(clientProfile);
   const userInfoResponse = await fetch(`${config.userInfoUrl}?alt=json`, {
     headers: { Authorization: `Bearer ${tokens.access_token}` },
     signal: AbortSignal.timeout(POSTEXCHANGE_TIMEOUT_MS),
@@ -297,9 +297,7 @@ export function createAntigravityOAuthProvider(
         // env-level custom client later on. Compare by value against the
         // embedded default: `config` may be the very same object as
         // ANTIGRAVITY_CONFIG when no runtime override exists.
-        oauthClient: isCustomAntigravityClient(config)
-          ? `custom:${config.clientId}`
-          : "builtin",
+        oauthClient: isCustomAntigravityClient(config) ? `custom:${config.clientId}` : "builtin",
       })),
     mapTokens: (tokens, extra) => mapAntigravityTokens(clientProfile, tokens, extra),
   };

src/lib/oauth/utils/agyAuthImport.ts

@@ -145,7 +145,7 @@ export async function enrichWithAntigravityBackend(
   const loadTimer = setTimeout(() => loadController.abort(), 8000);
   try {
     const headers = getAntigravityContentHeaders("cli", parsed.accessToken);
-    const metadata = getAntigravityLoadCodeAssistMetadata();
+    const metadata = getAntigravityLoadCodeAssistMetadata("cli");
     for (const endpoint of AGY_CONFIG.loadCodeAssistEndpoints) {
       try {
         const res = await fetch(endpoint, {

tests/fixtures/antigravity/native-wire.json

@@ -0,0 +1,45 @@
+{
+  "_comment": "Golden capture of the native Antigravity CLI (agy 1.4.4) on Windows x64. Values are copied verbatim from a mitmproxy capture except Authorization, which is replaced with a placeholder — never store a real bearer token here.",
+  "endpoint": "https://daily-cloudcode-pa.googleapis.com/v1internal:streamGenerateContent?alt=sse",
+  "requestHeaderOrder": [
+    "Accept-Encoding",
+    "Authorization",
+    "Content-Type",
+    "Host",
+    "Transfer-Encoding",
+    "User-Agent"
+  ],
+  "requestHeaders": {
+    "Accept-Encoding": "gzip",
+    "Authorization": "Bearer <redacted>",
+    "Content-Type": "application/json",
+    "Host": "daily-cloudcode-pa.googleapis.com",
+    "Transfer-Encoding": "chunked",
+    "User-Agent": "antigravity/cli/1.4.4 (aidev_client; os_type=windows; arch=amd64; cl=1003595037; auth_method=consumer)"
+  },
+  "forbiddenHeaders": ["Accept", "x-goog-user-project", "x-goog-api-client", "Client-Metadata"],
+  "envelopeFieldOrder": [
+    "project",
+    "requestId",
+    "request",
+    "model",
+    "userAgent",
+    "requestType"
+  ],
+  "requestFieldOrder": [
+    "contents",
+    "systemInstruction",
+    "tools",
+    "labels",
+    "generationConfig",
+    "sessionId"
+  ],
+  "loadCodeAssistMetadata": {
+    "ideType": "ANTIGRAVITY"
+  },
+  "platformTokens": {
+    "win32": { "osType": "windows", "arch": "amd64" },
+    "darwin": { "osType": "darwin", "arch": "arm64" },
+    "linux": { "osType": "linux", "arch": "amd64" }
+  }
+}

tests/unit/antigravity-client-profile.test.ts

@@ -111,14 +111,16 @@ test("content header application emits IDE and CLI identities and strips fake he
 
   assert.match(ideHeaders["User-Agent"], /^antigravity\/ide\/2\.1\.1 /);
   assert.match(ideHeaders["User-Agent"], / darwin\/arm64$| windows\/amd64$| linux\/[^ ]+$/);
+  // 1.1.1 has no recorded changelist, so `cl=` is omitted rather than borrowed from 1.4.4.
   assert.match(
     cliHeaders["User-Agent"],
     /^antigravity\/cli\/1\.1\.1 \(aidev_client; os_type=.+; arch=.+; auth_method=consumer\)$/
   );
   assertIdentityHeadersAbsent(ideHeaders);
   assertIdentityHeadersAbsent(cliHeaders);
+  // The Go CLI (consumer auth) sends no quota-project header; only the IDE profile does.
   assert.equal(ideHeaders["x-goog-user-project"], "project-1");
-  assert.equal(cliHeaders["x-goog-user-project"], "project-1");
+  assert.equal(cliHeaders["x-goog-user-project"], undefined);
 });
 
 test("public request envelopes never infer the internal jetski identity from email", () => {