feat(browser): add maxActionsPerTask for browser agent setting (#23216)

packages/core/src/agents/browser/browserAgentDefinition.ts

@@ -112,6 +112,7 @@ Some errors are unrecoverable and retrying will never help. When you see ANY of
 - "Could not connect to Chrome" or "Failed to connect to Chrome" or "Timed out connecting to Chrome" — Include the full error message with its remediation steps in your summary verbatim. Do NOT paraphrase or omit instructions.
 - "Browser closed" or "Target closed" or "Session closed" — The browser process has terminated. Include the error and tell the user to try again.
 - "net::ERR_" network errors on the SAME URL after 2 retries — the site is unreachable. Report the URL and error.
+- "reached maximum action limit" — You have performed too many actions in this task. Stop immediately and report this limit to the user.
 - Any error that appears IDENTICALLY 3+ times in a row — it will not resolve by retrying.
 Do NOT keep retrying terminal errors. Report them with actionable remediation steps and exit immediately.
 

packages/core/src/agents/browser/browserManager.test.ts

@@ -697,4 +697,28 @@ describe('BrowserManager', () => {
       expect(injectAutomationOverlay).not.toHaveBeenCalled();
     });
   });
+
+  describe('Rate limiting', () => {
+    it('should terminate task when maxActionsPerTask is reached', async () => {
+      const limitedConfig = makeFakeConfig({
+        agents: {
+          browser: {
+            maxActionsPerTask: 3,
+          },
+        },
+      });
+      const manager = new BrowserManager(limitedConfig);
+
+      // First 3 calls should succeed
+      await manager.callTool('take_snapshot', {});
+      await manager.callTool('take_snapshot', { some: 'args' });
+      await manager.callTool('take_snapshot', { other: 'args' });
+      await manager.callTool('take_snapshot', { other: 'new args' });
+
+      // 4th call should throw
+      await expect(manager.callTool('take_snapshot', {})).rejects.toThrow(
+        /maximum action limit \(3\)/,
+      );
+    });
+  });
 });

packages/core/src/agents/browser/browserManager.ts

@@ -97,6 +97,10 @@ export class BrowserManager {
   private mcpTransport: StdioClientTransport | undefined;
   private discoveredTools: McpTool[] = [];
 
+  /** State for action rate limiting */
+  private actionCounter = 0;
+  private readonly maxActionsPerTask: number;
+
   /**
    * Whether to inject the automation overlay.
    * Always false in headless mode (no visible window to decorate).
@@ -108,6 +112,8 @@ export class BrowserManager {
     const browserConfig = config.getBrowserAgentConfig();
     this.shouldInjectOverlay = !browserConfig?.customConfig?.headless;
     this.shouldDisableInput = config.shouldDisableBrowserUserInput();
+    this.maxActionsPerTask =
+      browserConfig?.customConfig.maxActionsPerTask ?? 100;
   }
 
   /**
@@ -151,6 +157,16 @@ export class BrowserManager {
       throw signal.reason ?? new Error('Operation cancelled');
     }
 
+    // Hard enforcement of per-action rate limit
+    if (this.actionCounter > this.maxActionsPerTask) {
+      const error = new Error(
+        `Browser agent reached maximum action limit (${this.maxActionsPerTask}). ` +
+          `Task terminated to prevent runaway execution. To config the limit, use maxActionsPerTask in the settings.`,
+      );
+      throw error;
+    }
+    this.actionCounter++;
+
     const errorMessage = this.checkNavigationRestrictions(toolName, args);
     if (errorMessage) {
       return {