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pyproject declares `mcp>=1.27.0` unbounded, so `uv tool install` / pip
resolve to mcp 2.x, where `mcp.server.fastmcp` no longer exists
(FastMCP was renamed to MCPServer). The server then crashes on import:
ModuleNotFoundError: No module named 'mcp.server.fastmcp'. This is
mcp 2.x, where FastMCP was renamed to MCPServer ... or pin 'mcp<2'
to keep running v1 code.
uv.lock already pins mcp==1.27.0, so in-repo `uv sync`/`uv run` was
unaffected — this only broke installs that resolve from pyproject.
Cap the dependency at <2.0.0 until the codebase migrates to the MCP 2.x
API (https://py.sdk.modelcontextprotocol.io/v2/migration/).
Author
|
All checks green and approved — ready to merge whenever convenient. Anything else needed on my end? |
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Summary
mcpdependency at<2.0.0. Fresh installs viauv tool install/ pip resolvemcp>=1.27.0to mcp 2.x, which removedmcp.server.fastmcp(FastMCPrenamed toMCPServer), so the server crashes on import:uv.lockalready pinsmcp==1.27.0, so in-repouv sync/uv runwas unaffected; this only broke installs that resolve dependencies fresh frompyproject.toml.Test plan
uv tool install+mcp_massivebefore fix: import crash (mcp 2.x resolved)uv tool install --with 'mcp<2': server initializes and responds to MCPinitialize/tools/listover both stdio and streamable-http