# Testing with the MCP Inspector — Agent Frameworks and MCP Basics

Source: https://www.geekswithgeeks.com/en/agent-frameworks-mcp/srv-inspector

> Use the Inspector to list and call your tools interactively before connecting a real host.

## Try it without a model

The **MCP Inspector** is a developer tool with a web UI. It connects to your server, lists tools, resources and prompts, and lets you call them with sample inputs. Testing here separates server bugs from model behaviour: if it works in the Inspector, any remaining problem is in how the model uses it.

## Launch the Inspector

Either command opens the UI against your script. Requires Node.js for the npx form.

```bash
mcp dev server.py
# or
npx @modelcontextprotocol/inspector python server.py
```

**Quiz:** Why test a server in the Inspector first?

- [ ] To train the model
- [x] To separate server bugs from model behaviour
- [ ] It is required by Python
- [ ] To avoid writing tools

*Answer:* To separate server bugs from model behaviour. If a tool works when called directly, model-related problems are easier to isolate.