Troubleshooting Angular apps

Diagnose Angular runtime connections, agent resolution, tools, threads, interrupts, SSR, and rendering failures.

Use this page for failures in the Angular application layer. Runtime and protocol diagnostics remain available in the shared troubleshooting pages, so you can investigate the complete request without switching frontend docs.

Start at the connection boundary#

Confirm that the browser is calling the same Copilot Runtime URL your server actually exposes:

src/app/app.config.ts

import { provideCopilotKit } from "@copilotkit/angular";

export const appConfig = {
  providers: [
    provideCopilotKit({
      runtimeUrl: "/api/copilotkit",
    }),
  ],
};

Then inspect GET {runtimeUrl}/info. A healthy response lists the expected agent ids. If the request fails:

verify the path, origin, proxy, and deployment base URL;
verify the runtime process is running and allows the Angular origin;
check authentication headers without logging their values;
try 127.0.0.1 when local localhost resolution is unreliable.

The CopilotKit service exposes runtimeConnectionStatus, runtimeUrl, and the resolved agents as signals. Use them in a temporary diagnostic component:

src/app/copilot-diagnostics.component.ts

import { Component, inject } from "@angular/core";
import { CopilotKit } from "@copilotkit/angular";

@Component({
  selector: "app-copilot-diagnostics",
  standalone: true,
  template: `
    <p>Runtime: {{ copilotKit.runtimeConnectionStatus() }}</p>
    <p>Agents: {{ agentIds().join(", ") || "none" }}</p>
  `,
})
export class CopilotDiagnosticsComponent {
  protected readonly copilotKit = inject(CopilotKit);
  protected readonly agentIds = () =>
    Object.keys(this.copilotKit.agents());
}

Remove diagnostics that expose topology or identifiers before production.

Agent id does not resolve#

injectAgentStore("support") and <copilot-chat agentId="support" /> must use an id returned by the runtime or registered through agents or selfManagedAgents. After the runtime finishes connecting, injectAgentStore throws an error that includes the requested id and known agents when no match exists.

If you intend to use the default agent, either register an agent named default or pass the real id explicitly everywhere the chat, state, tools, or interrupt controller selects an agent.

A frontend tool is missing or never runs#

Registrations are injector-scoped. Call registerFrontendTool, registerRenderToolCall, or registerHumanInTheLoop from a field initializer, constructor, provider factory, or another active injection context.

Check these in order:

The component or service that registers the tool is instantiated.
Its injector has not been destroyed by route or conditional-view changes.
The registered agentId matches the chat's agent.
The tool description tells the model when it should call the tool.
The input schema accepts the arguments emitted by the agent.
The handler catches expected application failures and returns a deliberate result instead of silently throwing.

For a source-backed registration, see Frontend tools and generative UI.

A thread list or mutation fails#

Use listError() for user-visible thread-list and mutation failures. The broader error() signal can also contain developer configuration errors such as a missing runtime URL or unavailable thread endpoints.

Mutation methods return promises. Handle rejection and confirm before permanent deletion:

await threads.renameThread(threadId, nextName).catch((error) => {
  console.error("Thread rename failed", error);
});

See injectThreads for loading, pagination, realtime, and optimistic-mutation behavior.

An interrupt cannot resume#

Read injectInterrupt().error() after a failed predicate, handler, or resume. Expired decisions use InterruptExpiredError. Resolve or cancel every pending interrupt id when the backend emits multiple simultaneous decisions.

The controller clears stale decisions when a thread changes or a new run starts. Do not cache it outside the injector that created it.

SSR, hydration, or zoneless problems#

Keep provider configuration and initial component inputs identical between the server render and first browser render.
Do not start agent runs, resume interrupts, or access browser APIs during server rendering.
Put application-owned DOM and media work behind an Angular platform guard or afterNextRender.
Read CopilotKit signals from templates or computed signals so zoneless change detection observes updates.

The complete contract is in Angular production and lifecycle.