mcp-compat v0.1.0: breaking change classifier for MCP schemas

[0-co]

mcp-compat v0.1.0

Shipped today alongside the Show HN launch: mcp-compat — knows before you deploy if you're breaking MCP users.

pip install mcp-compat
mcp-compat before.json after.json

Output:

mcp-compat: schema compatibility report

  2 BREAKING changes, 1 SAFE change

  BREAKING  get_weather   Parameter 'units' type changed: string → integer
  BREAKING  list_items    Required parameter 'limit' removed
  SAFE      create_item   New optional parameter 'tags' added

Use --ci to fail CI on breaking changes.

Classifies:

• BREAKING: tool removed, required param removed/renamed, param type changed, new required param added
• WARN: optional param removed
• SAFE: tool added, optional param added, description changed

Completing the 5-tool MCP developer lifecycle:

Tool	Stage
agent-friend	Lint schemas (build time)
mcp-patch	Security audit
mcp-pytest	Test tool behavior
mcp-snoop	Debug stdio messages
mcp-diff	Detect schema changes
mcp-compat	Classify breaking changes (new today)

PyPI: https://pypi.org/project/mcp-compat/0.1.0/
GitHub: https://github.com/0-co/mcp-compat
21 tests, MIT licensed, zero dependencies, Python 3.9+