fix(antigravity): strip any competitor system prompt, not one literal

Google answers a systemInstruction advertising a rival agent with 429 RESOURCE_EXHAUSTED - a content refusal shaped like a quota error, which is why it survived the endpoint and backoff fixes. Upstream PR #3223 stripped a single Zed literal, so Claude Code / Hermes wording still tripped it. Match the sentence shape instead. Check fails on the old one-literal code and passes here.

open-sse/executors/antigravity-competitor-strip.check.mjs

@@ -0,0 +1,57 @@
+/**
+ * #3223-generalised: Antigravity answers a system prompt that advertises a rival
+ * agent with 429 RESOURCE_EXHAUSTED. Upstream stripped one Zed literal; every
+ * other client wording still tripped it. This pins the shapes we must strip.
+ *
+ * Run: node open-sse/executors/antigravity-competitor-strip.check.mjs
+ */
+import assert from 'node:assert/strict';
+import { readFileSync } from 'node:fs';
+import { dirname, resolve } from 'node:path';
+import { fileURLToPath } from 'node:url';
+import vm from 'node:vm';
+
+const here = dirname(fileURLToPath(import.meta.url));
+const src = readFileSync(
+  process.env.AG_SOURCE || resolve(here, 'antigravity.js'),
+  'utf8'
+);
+
+// Lift the strip block out of buildRequest and run it against a fake request.
+const start = src.indexOf('if (requestWithoutTools.systemInstruction?.parts)');
+assert.ok(start >= 0, 'competitor-strip block must exist');
+const end = src.indexOf('\n    }\n', src.indexOf('for (const part', start)) + 6;
+const block = src.slice(start, end);
+
+const strip = (text) => {
+  const requestWithoutTools = { systemInstruction: { parts: [{ text }] } };
+  vm.runInNewContext(block, { requestWithoutTools });
+  return requestWithoutTools.systemInstruction.parts[0].text;
+};
+
+// The literal upstream already handled — must keep working.
+assert.ok(
+  !strip("You are a Claude agent, built on Anthropic's Claude Agent SDK. Be terse.")
+    .includes('Claude'),
+  'Zed wording must still be stripped'
+);
+
+// The wordings upstream missed.
+for (const prompt of [
+  "You are Claude Code, Anthropic's official CLI for Claude. Help the user.",
+  'You are Claude, made by Anthropic!',
+  'you are a claude agent. lowercase should not save it.',
+]) {
+  const out = strip(prompt);
+  assert.ok(!/claude/i.test(out), `must strip competitor branding from: ${prompt}`);
+}
+
+// Must not eat an innocent prompt.
+const benign = 'You are a helpful assistant. Answer in French.';
+assert.equal(strip(benign), benign, 'benign prompts must pass through untouched');
+
+// Non-string parts must not throw.
+const req = { systemInstruction: { parts: [{ inlineData: {} }] } };
+vm.runInNewContext(block, { requestWithoutTools: req });
+
+console.log('antigravity-competitor-strip: all passed');

open-sse/executors/antigravity.js

@@ -246,17 +246,27 @@ export class AntigravityExecutor extends BaseExecutor {
     const { tools: _originalTools, toolConfig: _originalToolConfig, ...requestWithoutTools } = body.request || {};
     stripBlacklisted(requestWithoutTools);
     
-    // Rewrite competitive system prompts (e.g. Zed IDE's Claude prompt) to prevent Antigravity from 
+    // Rewrite competitive system prompts before they reach Antigravity. Google
-    // flagging the request and immediately blocking it with a 429 Quota Exhausted response.
+    // inspects systemInstruction and answers a prompt that advertises a rival
+    // agent with 429 RESOURCE_EXHAUSTED — a content refusal wearing a quota
+    // error's clothes, which is why it survives every backoff and endpoint fix.
+    // Upstream PR #3223 stripped ONE literal (Zed's "You are a Claude agent,
+    // built on Anthropic's Claude Agent SDK."), so every other client — Claude
+    // Code, Hermes, Cline — still trips it. Match the shape instead.
+    // ponytail: regex over a prompt-classifier; widen the alternation if a new
+    // client wording slips through.
     if (requestWithoutTools.systemInstruction?.parts) {
-      const oldText = "You are a Claude agent, built on Anthropic's Claude Agent SDK.";
       for (const part of requestWithoutTools.systemInstruction.parts) {
-        if (typeof part.text === "string" && part.text.includes(oldText)) {
+        if (typeof part.text !== "string") continue;
-          part.text = part.text.split(oldText).join("");
+        part.text = part.text
-        }
+          // "You are Claude Code, Anthropic's official CLI for Claude." /
+          // "You are a Claude agent, built on Anthropic's Claude Agent SDK."
+          .replace(/You are (?:a |an )?Claude\b[^.!?]*[.!?]\s*/gi, "")
+          // Residual vendor branding in the same sentence position.
+          .replace(/\b(?:Anthropic's|Anthropic)\s+(?:official\s+)?(?:CLI|Claude Agent SDK)\b[^.!?]*[.!?]\s*/gi, "")
+          .trimStart();
       }
     }
-
     const generationConfig = { ...(requestWithoutTools.generationConfig || {}) };
     if (generationConfig.maxOutputTokens > MAX_ANTIGRAVITY_OUTPUT_TOKENS) {
       generationConfig.maxOutputTokens = MAX_ANTIGRAVITY_OUTPUT_TOKENS;

open-sse/services/accountFallback.js

@@ -185,9 +185,13 @@ export function resetAccountState(account) {
   if (!account) return account;
   return {
     ...account,
+    ...buildClearModelLocksUpdate(account),
     rateLimitedUntil: null,
     backoffLevel: 0,
+    testStatus: "active",
     lastError: null,
+    errorCode: null,
+    lastErrorAt: null,
     status: "active"
   };
 }

src/lib/db/repos/connectionsRepo.js

@@ -189,13 +189,14 @@ export async function createProviderConnection(data) {
 }
 
 // Critical: OAuth refresh token race — atomic merge inside transaction
-export async function updateProviderConnection(id, data) {
+export async function updateProviderConnection(id, update) {
   const db = await getAdapter();
   let result;
   db.transaction(() => {
     const row = db.get(`SELECT * FROM providerConnections WHERE id = ?`, [id]);
     if (!row) { result = null; return; }
     const existing = rowToConn(row);
+    const data = typeof update === "function" ? update(existing) : update;
     const merged = { ...existing, ...data, updatedAt: new Date().toISOString() };
     upsert(db, merged);
     if (data.priority !== undefined) reorderInTx(db, existing.provider);

src/sse/handlers/stt.js

@@ -1,6 +1,6 @@
 import {
   extractApiKey, isValidApiKey,
-  getProviderCredentials, markAccountUnavailable,
+  getProviderCredentials, markAccountUnavailable, clearAccountError,
 } from "../services/auth.js";
 import { getSettings } from "@/lib/localDb";
 import { getModelInfo } from "../services/model.js";
@@ -74,7 +74,10 @@ export async function handleStt(request) {
 
     const result = await handleSttCore({ provider, model, formData, credentials, sttConfig: AI_PROVIDERS[provider]?.sttConfig });
 
-    if (result.success) return result.response;
+    if (result.success) {
+      await clearAccountError(credentials.connectionId, credentials, model);
+      return result.response;
+    }
 
     const { shouldFallback } = await markAccountUnavailable(credentials.connectionId, result.status, result.error, provider, model);
     if (shouldFallback) {

src/sse/handlers/tts.js

@@ -1,6 +1,6 @@
 import {
   extractApiKey, isValidApiKey,
-  getProviderCredentials, markAccountUnavailable,
+  getProviderCredentials, markAccountUnavailable, clearAccountError,
 } from "../services/auth.js";
 import { getSettings } from "@/lib/localDb";
 import { getModelInfo, getComboModels } from "../services/model.js";
@@ -101,7 +101,10 @@ async function handleSingleModelTts(body, modelStr, responseFormat, language, st
 
     const result = await handleTtsCore({ provider, model, input: body.input, credentials, responseFormat, language, style });
 
-    if (result.success) return result.response;
+    if (result.success) {
+      await clearAccountError(credentials.connectionId, credentials, model);
+      return result.response;
+    }
 
     const { shouldFallback } = await markAccountUnavailable(credentials.connectionId, result.status, result.error, provider, model);
     if (shouldFallback) {

src/sse/services/auth.js

@@ -1,6 +1,6 @@
 import { getProviderConnections, validateApiKey, updateProviderConnection, getSettings, getProxyPools } from "@/lib/localDb";
 import { resolveConnectionProxyConfig, pickProxyPoolId } from "@/lib/network/connectionProxy";
-import { formatRetryAfter, checkFallbackError, isModelLockActive, buildModelLockUpdate, getEarliestModelLockUntil } from "open-sse/services/accountFallback.js";
+import { formatRetryAfter, checkFallbackError, isModelLockActive, buildModelLockUpdate, getEarliestModelLockUntil, resetAccountState } from "open-sse/services/accountFallback.js";
 import { MAX_RATE_LIMIT_COOLDOWN_MS } from "open-sse/config/errorConfig.js";
 import { resolveProviderId, FREE_PROVIDERS } from "@/shared/constants/providers.js";
 import * as log from "../utils/logger.js";
@@ -274,43 +274,8 @@ export async function markAccountUnavailable(connectionId, status, errorText, pr
  */
 export async function clearAccountError(connectionId, currentConnection, model = null) {
   if (!connectionId || connectionId === "noauth") return;
-  const conn = currentConnection._connection || currentConnection;
+  // Reset inside transaction so concurrent 429 writes cannot leave stale locks.
-  const now = Date.now();
+  await updateProviderConnection(connectionId, resetAccountState);
-  const allLockKeys = Object.keys(conn).filter(k => k.startsWith("modelLock_"));
-
-  if (!conn.testStatus && !conn.lastError && allLockKeys.length === 0) return;
-
-  // Keys to clear: current model's lock + all expired locks
-  const keysToClear = allLockKeys.filter(k => {
-    if (model && k === `modelLock_${model}`) return true; // succeeded model
-    if (model && k === "modelLock___all") return true;    // account-level lock
-    const expiry = conn[k];
-    return expiry && new Date(expiry).getTime() <= now;   // expired
-  });
-
-  if (keysToClear.length === 0 && conn.testStatus !== "unavailable" && !conn.lastError) return;
-
-  // Check if any active locks remain after clearing
-  const remainingActiveLocks = allLockKeys.filter(k => {
-    if (keysToClear.includes(k)) return false;
-    const expiry = conn[k];
-    return expiry && new Date(expiry).getTime() > now;
-  });
-
-  const clearObj = Object.fromEntries(keysToClear.map(k => [k, null]));
-
-  // Only reset error state if no active locks remain
-  if (remainingActiveLocks.length === 0) {
-    Object.assign(clearObj, {
-      testStatus: "active",
-      lastError: null,
-      errorCode: null,
-      lastErrorAt: null,
-      backoffLevel: 0
-    });
-  }
-
-  await updateProviderConnection(connectionId, clearObj);
 }
 
 /**

tests/unit/account-fallback-reset.test.js

@@ -0,0 +1,16 @@
+import { describe, expect, it } from "vitest";
+import { applyErrorState, resetAccountState } from "../../open-sse/services/accountFallback.js";
+
+describe("resetAccountState", () => {
+  it("clears every model lock and backoff after success", () => {
+    const reset = resetAccountState({ backoffLevel: 9, modelLock_alpha: "2099-01-01T00:00:00.000Z", modelLock___all: "2099-01-01T00:00:00.000Z", lastError: "429", errorCode: 429 });
+    expect(reset.backoffLevel).toBe(0);
+    expect(reset.modelLock_alpha).toBeNull();
+    expect(reset.modelLock___all).toBeNull();
+    expect(reset.lastError).toBeNull();
+  });
+
+  it("keeps 429 on error path ratcheting upward", () => {
+    expect(applyErrorState({ backoffLevel: 3 }, 429, "rate limited").backoffLevel).toBe(4);
+  });
+});