sens-mcp

An MCP (Model Context Protocol) server and developer starter kit for the SENS Energy Data API — the Polish electricity market data API (distribution operators, tariffs, and composite price calculations).

It solves the "cold start" problem for LLMs and AI agents (Claude Desktop, Cursor, LangChain, n8n, ...) talking to the API: the Polish energy market has its own vocabulary (OSD vs. sprzedawca, tariff groups G11/G12/G12w/...) that models don't know out of the box, and raw REST responses are too large and too easy to miscalculate against by hand.

sens-mcp provides:

• Zero-shot discoverability — an MCP resource (sens://market/cheat-sheet) and discovery tools (resolve_operator, search_tariffs) that teach the model the market vocabulary in under ~400 tokens.
• Actionable self-correction — tool errors return structured JSON with suggestions (did you mean G12w?) instead of raw HTTP failures, so an agent in a ReAct loop can repair its own next call.
• Single source of truth calculations — all price/volume math happens on the SENS backend; the toolkit never re-derives totals client-side.
• Non-blocking startup — the server boots instantly with an embedded fallback market schema; live tariff metadata refreshes in the background.

Quickstart

Run via uvx (recommended, no install step)

export SENS_API_KEY=sens_live_your_key_here
uvx sens-mcp

Or install with pip

pip install sens-mcp
export SENS_API_KEY=sens_live_your_key_here
python -m sens_mcp

Environment variables

Using it with an AI agent

Claude Desktop

Add to claude_desktop_config.json (see configs/claude_desktop_config.json):

{
  "mcpServers": {
    "sens-energy": {
      "command": "uvx",
      "args": ["sens-mcp"],
      "env": {
        "SENS_API_KEY": "sens_live_your_key_here"
      }
    }
  }
}

Cursor

Add to .cursor/mcp.json (see configs/cursor_mcp.json) — same shape as above.

Tools exposed

Resource: sens://market/cheat-sheet — a Markdown cheat sheet of Polish electricity market vocabulary (OSDs, tariff groups, price component structure).

Developer examples (no MCP required)

Standalone snippets that hit the SENS REST API directly:

• examples/python/get_prices.py
• examples/python/list_tariffs.py
• examples/python/async_stream.py — delta sync via since
• examples/typescript/get_prices.ts
• examples/curl/api_requests.sh

API reference (essentials)

• Base URL: https://api.getsens.energy
• Auth: X-API-KEY: <your key> header (not Bearer, not a query param).
• GET /api/v1/prices — osd, sprzedawca, taryfa, market, date, annual_kwh, region, since, page, size (max 1000).
• GET /api/v1/tariffs — since/If-Modified-Since for delta queries, page, size.
• GET /api/v1/tariffs/components?tariff_id=... — component breakdown for a single tariff, also supports since.

Full Swagger/OpenAPI docs: https://api.getsens.energy/api/docs. Full developer documentation (quickstart, MCP integration guide, market vocabulary): docs.getsens.energy.

Development

python3 -m venv .venv
source .venv/bin/activate
pip install -e ".[dev]"
pytest

Tests mock all HTTP calls with respx — nothing in the default test suite hits the live API.

Live integration suite (opt-in)

tests/test_live_integration.py runs the real server as a subprocess over the real MCP stdio protocol against the real production SENS API, and checks byte-for-byte parity between MCP tool responses and raw httpx calls to the same endpoints. Excluded by default; run explicitly with a real key:

SENS_API_KEY=<a real key> pytest -m live tests/test_live_integration.py -v

License

MIT