Add MCP Client Support

[mconflitti-pbc]

Issue #21

Adds ability to register an SSE or stdio MCP server with any Chat provider.

Tests provide contained examples of these MCP servers that the tests interact with to register tools remotely.

Slightly modifies how tools are created: Tool.from_func (maintains existing behavior) and Tool.from_mcp static methods.

The use of MCP does mean that Python 3.9 support would be dropped. If this is a major problem, happy to brainstorm ways to make MCP an extra and conditionally import it when needing it.

TODOs:

• More docs
• Updating Readme(s)
• Verify tests

[wch]

It's great to see MCP support for Chatlas. A few thoughts about dependencies and requirements: The mcp dependency could be conditional on Python version, like "mcp>=1.2.1;python_version>='3.10'", and then the imports could be done conditional on Python version. But it might also make sense to make mcp an optional dependency, in a group named mcp.

[mconflitti-pbc]

It's great to see MCP support for Chatlas. A few thoughts about dependencies and requirements: The mcp dependency could be conditional on Python version, like "mcp>=1.2.1;python_version>='3.10'", and then the imports could be done conditional on Python version. But it might also make sense to make mcp an optional dependency, in a group named mcp.

Sure thing! Out of curiosity, is there something that would require us to keep py3.9 support? I suppose that would be considered a breaking change.

[schloerke]

Out of curiosity, is there something that would require us to keep py3.9 support?

Posit Open Source tries to support all python versions that are receiving security updates. Py3.9 will end its support in Oct '25.

Similarly, given the mcp is a non-critical code path, the mcp requirements shouldn't hinder the core functionality from running on an earlier python versions.

[cpsievert]

Overall, this is looking great, thank you! I think we'll have some additional suggestions for code changes/improvements, but also excited to see what you come up with for docs.

[schloerke]

This should be restored?

Let's skip the test files/funcs when using py3.9

[schloerke]

I'd like to have this as a subclass to the Tool class.

I'd also like to restructure the Tool class to be an ABC class. Then ToolFunction, ToolMcp, ToolMcpSse, and ToolMcpStdio would all spawn from Tool.

---

• Tool
  • ToolFunction
  • ToolMcp
    • ToolMcpSse
    • ToolMcpStdio

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I'm happy to implement this early next week.