MCP Search Auto LBC

An MCP server that estimates used-car market values from comparable Leboncoin listings. It gives the model each retained listing's title, description, raw attributes, images, price, and URL, along with the reasons why other listings were excluded.

Endpoints

• Local MCP endpoint: http://127.0.0.1:3100/mcp

• Health check: http://127.0.0.1:3100/health

• Suggested production endpoint: https://mcp.your-domain.com/mcp

The server uses the MCP Streamable HTTP transport. POST /mcp accepts MCP JSON-RPC messages. GET /mcp and DELETE /mcp intentionally return HTTP 405 because the server operates without sessions.

Related MCP server: Polovnjak MCP

Installation

Requirements: Node.js 20 or newer and Python 3.11. All Leboncoin network traffic goes through a persistent Python worker backed by lbc; the TypeScript process only exposes MCP and computes the valuation. By default the worker pairs curl_cffi's chrome_android TLS profile with a matching Leboncoin Android User-Agent so Datadome sees one coherent client fingerprint. Both lbc and curl-cffi are pinned to the versions covered by the live integration test.

npm install
python3.11 -m venv .venv
.venv/bin/python -m pip install -r requirements.txt
npm start

The server then exposes http://127.0.0.1:3100/mcp.

On Windows, install the Python dependencies with .venv\Scripts\python.exe -m pip install -r requirements.txt.

Commands

npm start
npm run dev
npm test
npm run typecheck

Available environment variables:

• MCP_HOST: defaults to 127.0.0.1

• MCP_PORT: defaults to 3100

• MCP_API_TOKEN: required Bearer token when listening outside localhost

• MCP_ALLOWED_HOSTS: comma-separated list of allowed hostnames

• LBC_PYTHON_PATH: explicit path to a Python executable with lbc>=1.1.5

• LBC_MAX_PAGES: maximum number of pages fetched per search; defaults to 3

• LBC_PAGE_DELAY_MS: base delay between pages; defaults to 1500 ms and includes randomized jitter

• LBC_MAX_RETRIES: Datadome retries inside the Python client; defaults to 1

• LBC_REQUEST_TIMEOUT_SECONDS: timeout for each Python HTTP request; defaults to 30

• LBC_WORKER_TIMEOUT_MS: maximum duration of a complete worker search; defaults to 90000

• LBC_PROXY_URL: optional proxy URL, including credentials when required

• LBC_IMPERSONATE: optional browser profile supported by curl_cffi; defaults to the tested chrome_android profile

• LBC_CATALOG_CACHE_SECONDS: lifetime of the Leboncoin brand/model/trim catalog cache; defaults to 24 hours

• LBC_CATALOG_CACHE_PATH: catalog cache file; defaults to .cache/leboncoin-vehicle-catalog.json

• VALUATION_CACHE_TTL_MS: in-memory cache lifetime; defaults to 15 minutes

Tool: resolve_leboncoin_vehicle

This tool converts natural vehicle names into exact Leboncoin filter IDs. It first checks the local catalog and can then confirm an unknown model from one page of live listings.

Example input:

{
  "brand": "Renault",
  "model": "Clio III",
  "fuel": "diesel",
  "engine": "1.5 dCi 90"
}

Example output:

{
  "resolved": true,
  "brand": "Renault",
  "model": "Clio",
  "leboncoinBrand": "RENAULT",
  "leboncoinModel": "RENAULT_Clio",
  "generation": "3",
  "fuel": "diesel",
  "leboncoinFuel": "2",
  "confidenceScore": 98,
  "source": "catalog",
  "warnings": [],
  "alternatives": []
}

Tool: estimate_used_vehicle

Example input:

{
  "brand": "Renault",
  "model": "Clio",
  "leboncoinBrand": "RENAULT",
  "leboncoinModel": "RENAULT_Clio",
  "generation": "3",
  "year": 2010,
  "yearMin": 2010,
  "yearMax": 2010,
  "mileage": 100000,
  "fuel": "diesel",
  "engine": "1.5 dCi 90",
  "gearbox": "manual",
  "trim": "Dynamique",
  "excludeCompanyVehicles": true,
  "excludeProfessionalSellers": true,
  "location": {
    "city": "Saintes",
    "latitude": 45.746,
    "longitude": -0.633,
    "radiusKm": 200
  },
  "maxComparables": 20,
  "includeDescriptions": true,
  "includeImages": true
}

year is exact by default: when yearMin and yearMax are omitted, only ads whose registration year equals year are retained. Set both bounds only when the user explicitly requests a range, for example year: 2021, yearMin: 2020 and yearMax: 2022. The reference year must be inside that range. The MCP also rejects ads with a missing year or a year outside the requested bounds before calculating the valuation.

Leboncoin's exact filter IDs are different from the labels displayed to users:

• u_car_brand: RENAULT, PEUGEOT, BMW, MERCEDES-BENZ, and so on

• u_car_model: the brand ID, an underscore, and the case-sensitive model label, such as RENAULT_Clio, PEUGEOT_208, VOLKSWAGEN_Golf, or TESLA_Model 3

• The generation (Clio 3) and engine (1.5 dCi 90) are not part of u_car_model; they are checked against the manufacturer version, title, attributes, and description.

• Main fuel codes are 1 for petrol, 2 for diesel, 4 for electric, 6 for hybrid, and 8 for plug-in hybrid. Gearbox codes are 1 for manual and 2 for automatic.

When leboncoinBrand or leboncoinModel is omitted, the server retains a text search as a fallback.

Condensed output example:

{
  "request": {},
  "valuation": {
    "estimatedPrice": 5000,
    "lowPrice": 4600,
    "highPrice": 5400,
    "quickSalePrice": 4500,
    "currency": "EUR",
    "confidence": "high",
    "confidenceScore": 82
  },
  "market": {
    "adsFetched": 25,
    "comparablesUsed": 14,
    "excludedCount": 11
  },
  "comparables": [
    {
      "title": "Renault Clio III 1.5 dCi 90",
      "price": 5100,
      "description": "Full listing description...",
      "characteristics": {
        "regdate": "2010",
        "mileage": "103000",
        "fuel": "Diesel"
      },
      "images": ["https://..."],
      "url": "https://www.leboncoin.fr/...",
      "similarityScore": 0.92,
      "matchedCriteria": ["brand", "model", "year", "mileage", "fuel", "engine"]
    }
  ],
  "excludedAds": [
    {
      "title": "Damaged Clio sold for parts",
      "reasons": ["damaged, non-running, or parts-only vehicle"]
    }
  ],
  "warnings": []
}

Live vehicle catalog

Brands and models are synchronized by the Python worker from the same frontend configuration currently used by Leboncoin. Trims are fetched lazily for a selected model. The compact catalog is cached locally for 24 hours and a stale cache remains usable during a temporary upstream failure.

The MCP exposes three targeted tools so an LLM never needs to load the full catalog into its context:

• list_leboncoin_vehicle_brands

• list_leboncoin_vehicle_models

• list_leboncoin_vehicle_trims

resolve_leboncoin_vehicle uses this catalog automatically before falling back to observed listing attributes. The catalog structure is also published as an MCP resource at vehicle://catalog/schema.

Connecting an MCP client

The server uses Streamable HTTP. A typical client configuration looks like this:

{
  "mcpServers": {
    "mcp-search-auto-lbc": {
      "url": "http://127.0.0.1:3100/mcp"
    }
  }
}

The ready-to-use agent skill is available in skills/leboncoin-vehicle-valuation.

Disclaimer

This project uses an unofficial API and is neither affiliated with nor endorsed by Leboncoin. A valuation is an estimate based on advertised asking prices, not a guaranteed appraisal of a vehicle.