# MCP Local Server

Minimal **Model Context Protocol (MCP)** server written in Python.

## Features
- Implements JSON-RPC stdio transport.
- Tools:
  - `sum`: safely sum a list of numbers.
  - `grep_lines`: filter lines containing a substring.
  - `sha256`: compute SHA-256 hash of text.
  - `json_validate`: validate data against a JSON Schema.

## Usage

### Run locally
```bash
python main.py
```
### Test with jq or PowerShell

```bash
echo '{"jsonrpc":"2.0","id":1,"method":"initialize","params":{"protocolVersion":"2025-06-18","capabilities":{},"clientInfo":{"name":"Test","version":"0.1"}}}' | python main.py
```

### Example tool call
```bash
echo '{"jsonrpc":"2.0","id":2,"method":"tools/call","params":{"name":"sum","arguments":{"values":[1,2,3.5]}}}' | python main.py
```

### Logging
Setea `MCP_LOG_FILE` para escribir JSONL además de `stderr`:

```powershell
$env:MCP_LOG_FILE="D:\ruta\log.jsonl"
python .\main.py
```