feat: add MCP server to expose Finary portfolio to LLMs

[nmathey]

Related to #265.

Introduces mcp_server.py, a Model Context Protocol server that wraps the existing finary_uapi functions and exposes them as MCP tools. This allows any MCP-compatible LLM client (Claude Desktop, Cursor…) to query a Finary portfolio in natural language.

18 read-only tools covering investments, cryptos, real estates, crowdlendings, precious metals, SCPIs, fonds euro, startups and generic assets
Session handled via the existing auth.prepare_session() and credentials.json — no extra auth setup required
Requires mcp >= 1.0.0 added to pyproject.toml
Updated README with setup instructions and usage examples

[lasconic]

I tested a couple calls and they don't work. get_portfolio doesn't work for generic_assets or scpis. The mapping needs to be changed and tested one by one.

For reference, I used the following file with LMstudio and Qwen3.5-9b (so everything running locally)

{
  "mcpServers": {
    "finary": {
      "command": "poetry",
      "args": [
        "-C",
        "{FINARY_UAPI_FULL_PATH}",
        "run",
        "python",
        "mcp_server.py"
      ]
    }
  }
}

[nmathey]

Working mapping:

Catégorie	Fonction associée
Immobilier physique	user_real_estates.get_user_real_estates
SCPI	user_scpis.get_user_scpis
Fonds euros	user_fonds_euro.get_user_fonds_euro
Startups & PME	user_startups.get_user_startups
Métaux précieux	user_precious_metals.get_user_precious_metals
Crowdlending	user_crowdlendings.get_user_crowdlendings
Actifs génériques	user_generic_assets.get_user_generic_assets

[nmathey]

I did fix some function calls but I'll need to install LMstudio and Qwen3.5-9b like you in order to test again as I'm getting size response limite form my free claude desktop account...

[lasconic]

It's a hint that the finary API is too verbose as it maybe ? The server could reduce the verbosity to limit the token usage ?

[nmathey]

Ok I did refactor responses handling to optimize token usage.
Looks good on my side now if you can try again on yours @lasconic