How to Debug Errors

CopilotKit provides visual error display for local development and debugging. This feature is completely free and requires no API keys.

Quick Setup

export default function App() {
  return (
    <CopilotKit
      runtimeUrl="<your-runtime-url>"
      showDevConsole={true} // [!code highlight]
    >
      {/* Your app */}
    </CopilotKit>
  );
}

When to Use Development Debugging

• Local development - See errors immediately in your UI
• Quick debugging - No setup required, works out of the box
• Testing - Verify error handling during development

Programmatic Error Handling (v2)

The v2 API provides an onError callback on both CopilotKitProvider and CopilotChat for programmatic error handling. No publicApiKey is required.

Provider-Level Error Handling

Catches all errors across the entire application:

<CopilotKitProvider
  runtimeUrl="/api/copilotkit"
  onError={(event) => {
    // event.code — error type (e.g. "runtime_info_fetch_failed", "agent_run_failed")
    // event.error — the Error object
    // event.context — additional context (agentId, toolName, etc.)
    console.error(`[CopilotKit ${event.code}]`, event.error.message);
    errorTracker.capture(event);
  }}
>
  <App />
</CopilotKitProvider>;

Chat-Level Error Handling

Scoped to a specific chat's agent — fires in addition to the provider-level handler:

<CopilotChat
  agentId="my-agent"
  onError={(event) => {
    showToast(`Agent error: ${event.error.message}`);
  }}
/>;

Error Codes

Code	Description
runtime_info_fetch_failed	Could not reach the runtime /info endpoint
agent_connect_failed	Agent connection (thread setup) failed
agent_run_failed	Agent run rejected (e.g. network error)
agent_run_failed_event	Agent's onRunFailed subscriber fired
agent_run_error_event	Agent sent a RUN_ERROR event
tool_argument_parse_failed	Tool call arguments were not valid JSON
tool_handler_failed	A frontend tool handler threw an error

Troubleshooting

Development Debugging Issues

• Dev console not showing:
  • Confirm showDevConsole={true}
  • Check for JavaScript errors in the browser console
  • Ensure no CSS is hiding the error banner