fix: add circuit breaker to agent status polling to eliminate 404 spam on static hosting

Author: ijbo

changelogs/CHANGELOG-agent-polling.md

@@ -0,0 +1,19 @@
+# Changelog — Agent Status Polling Fix
+
+**Date:** 2026-03-25
+
+## Summary
+
+Added a circuit breaker to `getLocalStatus()` in `agent-cloud.js` to eliminate repeated `/api/agents/status` 404 errors on static hosting (GitHub Pages).
+
+## Problem
+
+The agent panel polls `getLocalStatus()` every 15 seconds to update the badge count. On GitHub Pages (where no backend exists), every poll resulted in a 404 error, spamming the browser console with dozens of `Failed to load resource: 404` messages.
+
+## Changes
+
+### Modified: `js/agent-cloud.js`
+- Added `_localStatusFailed` circuit breaker flag
+- After the first 404/network failure (when no custom agent URL is configured), all subsequent calls return `{ agents: [], docker: false }` immediately — zero network requests
+- Circuit breaker only activates on the default origin (not when `AGENT_CUSTOM_URL` is set by the user)
+- Resets on successful response, so local development with agent-runner still works normally

js/agent-cloud.js

@@ -11,6 +11,7 @@
     var IDLE_TIMEOUT_MS = 5 * 60 * 1000;            // Auto-stop after 5 min idle
     var CODESPACE_PREFIX = 'textagent-';             // Naming prefix for cleanup
     var idleTimer = null;
+    var _localStatusFailed = false;                   // Circuit breaker: stop polling after first 404
 
     // ── Public API ──
     M.agentCloud = {
@@ -136,16 +137,24 @@
 
         /** Get local Docker agent status */
         getLocalStatus: async function () {
+            // Circuit breaker: after the first failure on static hosting, stop polling
+            if (_localStatusFailed) return { agents: [], docker: false };
             var baseUrl = localStorage.getItem(M.KEYS.AGENT_CUSTOM_URL) || (window.location.origin);
             baseUrl = baseUrl.replace(/\/api\/exec$/, '');
             try {
                 var res = await fetch(baseUrl + '/api/agents/status', {
                     method: 'GET',
                     signal: AbortSignal.timeout(3000)
                 });
-                if (!res.ok) return { agents: [], docker: false };
+                if (!res.ok) {
+                    // On static hosts (GitHub Pages), this will always 404 — stop retrying
+                    if (!localStorage.getItem(M.KEYS.AGENT_CUSTOM_URL)) _localStatusFailed = true;
+                    return { agents: [], docker: false };
+                }
+                _localStatusFailed = false; // Reset on success
                 return await res.json();
             } catch (_) {
+                if (!localStorage.getItem(M.KEYS.AGENT_CUSTOM_URL)) _localStatusFailed = true;
                 return { agents: [], docker: false };
             }
         },