fix: watch providers.jsonc for external edits so UI refreshes without restart

src/node/config.ts

@@ -1878,6 +1878,69 @@ export class Config {
     return null;
   }
 
+  /**
+   * Watch providers.jsonc for external edits. Fires callback (debounced 300 ms)
+   * on any create/modify/delete event. Returns a cleanup function.
+   *
+   * We watch the parent directory rather than the file directly so that
+   * creates (first-time manual edit) are also detected on all platforms.
+   */
+  watchProvidersFile(callback: () => void): () => void {
+    const filename = path.basename(this.providersFile);
+    let debounceTimer: ReturnType<typeof setTimeout> | null = null;
+
+    const fire = (): void => {
+      if (debounceTimer) clearTimeout(debounceTimer);
+      debounceTimer = setTimeout(() => {
+        debounceTimer = null;
+        callback();
+      }, 300);
+    };
+
+    // Anything inside this block can fail in restricted environments:
+    //   - ensurePrivateDirSync: read-only filesystem, unwritable MUX_ROOT
+    //   - fs.watch: ENOENT, network filesystems (NFS/SMB), watch-limit
+    //     exhaustion (ENOSPC on Linux), unsupported virtualized mounts.
+    // We degrade gracefully in every case: log once, return a no-op
+    // cleanup, and let the rest of provider config keep working. The UI
+    // just won't auto-refresh on manual edits in that environment (same
+    // as the pre-PR behaviour).
+    let watcher: fs.FSWatcher;
+    try {
+      // The mux home directory may not exist on a fresh install. Create it
+      // so fs.watch doesn't throw ENOENT; the directory being empty is fine.
+      if (!fs.existsSync(this.rootDir)) {
+        ensurePrivateDirSync(this.rootDir);
+      }
+
+      // persistent: false so the watcher doesn't prevent the process (or
+      // Jest) from exiting when nothing else is keeping the event loop alive.
+      watcher = fs.watch(this.rootDir, { persistent: false }, (_eventType, changedFilename) => {
+        // changedFilename can be null on some platforms/kernels (notably
+        // older macOS FSEvents). When we can't tell which file changed,
+        // assume providers.jsonc might have and let the consumer re-fetch
+        // — better an extra refresh than a missed one, since this is the
+        // exact scenario the feature is meant to fix.
+        if (changedFilename != null && changedFilename !== filename) return;
+        fire();
+      });
+    } catch (error) {
+      log.warn(
+        `Could not watch providers.jsonc for external edits (${this.rootDir}); manual edits will require a restart to take effect:`,
+        error
+      );
+      const noop = (): void => {
+        // Nothing to clean up — watcher setup never completed.
+      };
+      return noop;
+    }
+
+    return () => {
+      if (debounceTimer) clearTimeout(debounceTimer);
+      watcher.close();
+    };
+  }
+
   /**
    * Save providers configuration to JSONC file
    * @param config The providers configuration to save

src/node/services/providerService.ts

@@ -132,6 +132,7 @@ export class ProviderService {
   private readonly policyService: PolicyService | null;
   private readonly emitter = new EventEmitter();
   private lastWarnedShadowedCustomProviderIds: Set<string> | null = null;
+  private readonly stopWatchingProvidersFile: () => void;
 
   constructor(
     private readonly config: Config,
@@ -141,6 +142,19 @@ export class ProviderService {
     // The provider config subscription may have many concurrent listeners (e.g. multiple windows).
     // Avoid noisy MaxListenersExceededWarning for normal usage.
     this.emitter.setMaxListeners(50);
+    // Notify subscribers when providers.jsonc is edited externally (e.g. manual edits).
+    this.stopWatchingProvidersFile = this.config.watchProvidersFile(() =>
+      this.notifyConfigChanged()
+    );
+  }
+
+  /**
+   * Release long-lived OS handles (e.g. the providers.jsonc file watcher).
+   * Called by ServiceContainer.dispose() during shutdown and by tests.
+   */
+  dispose(): void {
+    this.stopWatchingProvidersFile();
+    this.emitter.removeAllListeners();
   }
 
   /**

src/node/services/serviceContainer.ts

@@ -543,6 +543,7 @@ export class ServiceContainer {
 
     this.copilotOauthService.dispose();
     this.serverAuthService.dispose();
+    this.providerService.dispose();
     await this.backgroundProcessManager.terminateAll();
   }
 }