---
title: "Inspector"
description: "Debug and inspect agent sessions with the Inspector UI."
icon: "magnifying-glass"
---

The Inspector is a web-based GUI for debugging and inspecting Sandbox Agent sessions. Use it to view events, send messages, and troubleshoot agent behavior in real-time.

<Frame>
  <img src="/images/inspector.png" alt="Sandbox Agent Inspector" />
</Frame>

## Open the Inspector

The Inspector UI is served at `/ui/` on your sandbox-agent server. For example, if your server is running at `http://localhost:2468`, open `http://localhost:2468/ui/` in your browser.

You can also generate a pre-filled Inspector URL with authentication from the TypeScript SDK:

```typescript
import { buildInspectorUrl } from "sandbox-agent";

const url = buildInspectorUrl({
  baseUrl: "http://127.0.0.1:2468",
  token: process.env.SANDBOX_TOKEN,
});
console.log(url);
// http://127.0.0.1:2468/ui/?token=...
```

## Features

- **Session list**: View all active sessions and their status
- **Event stream**: See events in real-time as they arrive (SSE or polling)
- **Event details**: Expand any event to see its full JSON payload
- **Send messages**: Post messages to a session directly from the UI
- **Agent selection**: Switch between agents and modes
- **Request log**: View raw HTTP requests and responses for debugging
- **Pi concurrent sessions**: Pi sessions run concurrently by default via per-session runtime processes

## When to Use

The Inspector is useful for:

- **Development**: Test your integration without writing client code
- **Debugging**: Inspect event payloads and timing issues
- **Learning**: Understand how agents respond to different prompts
