> ## Documentation Index
> Fetch the complete documentation index at: https://docs.pwno.io/llms.txt
> Use this file to discover all available pages before exploring further.

# Transports and Runtime

> HTTP, stdio, health checks, attach sidecar behavior, and runtime defaults.

`pwno-mcp` supports two main runtime modes.

<Tabs>
  <Tab title="HTTP">
    * Main MCP endpoint defaults to `http://127.0.0.1:5500/mcp`
    * Health endpoint defaults to `http://127.0.0.1:5500/healthz`
    * Local attach helper API defaults to `http://127.0.0.1:5501/attach`
    * Best when your client wants a `url` or you want the server process to stay alive outside the client
  </Tab>

  <Tab title="stdio">
    * The client launches `python -m pwnomcp --stdio` or the equivalent Docker command
    * No HTTP endpoint is involved
    * Best when your client expects a local `command` and `args`
    * The attach sidecar is not started in stdio mode
  </Tab>
</Tabs>

## CLI defaults

| Flag            | Default     | Purpose                          |
| --------------- | ----------- | -------------------------------- |
| `--host`        | `0.0.0.0`   | main HTTP bind host              |
| `--port`        | `5500`      | main HTTP port                   |
| `--attach-host` | `127.0.0.1` | attach API bind host             |
| `--attach-port` | `5501`      | attach API port                  |
| `--http-path`   | `/mcp`      | HTTP transport path              |
| `--stdio`       | disabled    | switches runtime into stdio mode |

## Example launches

<CodeGroup>
  ```bash HTTP theme={null}
  python -m pwnomcp
  ```

  ```bash Custom HTTP theme={null}
  python -m pwnomcp --host 0.0.0.0 --port 6600 --http-path /mcp
  ```

  ```bash stdio theme={null}
  python -m pwnomcp --stdio
  ```
</CodeGroup>

## Runtime surfaces

* `/mcp` is the main FastMCP transport path in HTTP mode
* `/healthz` returns a simple JSON status payload for health checks
* `/attach` is a helper API for process-attach workflows driven by the local Python helper or external automation

<Info>
  The attach API is separate from the main MCP transport. It exists to make some attach workflows simpler for local helper scripts and integrations.
</Info>

## Which mode should you use?

* choose HTTP for persistent local servers, remote clients, and easy health checks
* choose stdio for clients that only support local process-based MCP servers
* keep the Docker capability and security flags the same in both modes