First request walkthrough

The typed MCP surface is verified over the real protocol in the isolated mcp==2.0.0 target: initialize, tools/list (all 30 tools), resources/ list (4 concrete resources + 6 templates), prompts/list (8 prompts), and a typed tool call.

Example sequence (raw JSON-RPC frames)

-> {"jsonrpc":"2.0","id":1,"method":"initialize","params":{
      "protocolVersion":"2025-03-26","capabilities":{},
      "clientInfo":{"name":"e2e","version":"1"}}}
<- {"jsonrpc":"2.0","id":1,"result":{"serverInfo":{
      "name":"backtrader-mcp","version":"0.2.0",...},...}}
-> {"jsonrpc":"2.0","method":"notifications/initialized"}   (no response)
-> {"jsonrpc":"2.0","id":2,"method":"tools/list","params":{}}
<- {"jsonrpc":"2.0","id":2,"result":{"tools":[...30 tools...]}}
-> {"jsonrpc":"2.0","id":3,"method":"tools/call","params":{
      "name":"get_catalog_snapshot","arguments":{}}}
<- {"jsonrpc":"2.0","id":3,"result":{"isError":false,"content":[{
      "type":"text","text":"{\"schema_version\":...,\"extensions\":{
        \"entry_count\":1155,...}}"}]}}

Error frames

A tool error is an isError=true result whose text starts with the stable error code:

Error executing tool preview_dataset: [invalid_request] preview limit must be
between 1 and 200
Suggestion: use a limit between 1 and 200

The server never writes anything but protocol frames to stdout; logs go to stderr.

Reproducing the protocol tests locally

python -m pip install -c constraints/requirements-v2.txt ".[test]"
PYTHONPATH=src python -m pytest tests/test_protocol_v2.py tests/test_stdio_transport.py -q

The stdio transport test spawns a real serve subprocess and asserts the frames above over the production pipe.