# Tracerlab

MCP server for Cisco Packet Tracer 9. Lets Claude Code (or any MCP client) build networks in a running Packet Tracer: add devices, cable them, push IOS configs, address everything, set up routing, ping, and find what's broken. It can also read and write .pkt files without Packet Tracer open.

![Building a 3 router OSPF ring, cabling it, addressing it and pinging across it](https://raw.githubusercontent.com/atharv-santosh/tracerlab/main/docs/demo.gif)

Twelve devices, twelve cables, OSPF across the ring and 6/6 pings, from one prompt.

There are also some ready-made labs (router on a stick, OSPF/EIGRP/RIP topologies, NAT, HSRP, EtherChannel, IPv6) that build in one call.

## Install

Needs [uv](https://docs.astral.sh/uv/) and Packet Tracer 9.

Register the server with your MCP client:

```
claude mcp add packet-tracer -- uvx --from tracerlab packet-tracer-mcp
```

Cursor (`~/.cursor/mcp.json`), VS Code (`.vscode/mcp.json`) and Codex take the same command:

```json
{
  "mcpServers": {
    "packet-tracer": { "command": "uvx", "args": ["--from", "tracerlab", "packet-tracer-mcp"] }
  }
}
```

Then install the Packet Tracer side once:

```
uvx tracerlab install-extension
```

Restart Packet Tracer and answer Yes when it asks about the new script module. A small "PT-MCP Bridge"
window shows up and goes green once the MCP server is running.

If something isn't connecting, run `uvx tracerlab doctor`.

## Use

Open Packet Tracer, start Claude Code and ask for things like:

- build a 3 router OSPF ring with a PC on each LAN and ping everything
- set up router on a stick with VLANs 10, 20, 30 and DHCP
- what's wrong with this network
- show me the running config on R1

`examples/enterprise-two-site.pkt` is a bigger network built entirely through the tools.

## Tests

```
uv run pytest
```

mcp-name: io.github.atharv-santosh/tracerlab