.codex-plugin— mcp server

<div align="center"> <h1>@cyanheads/openfoodfacts-mcp-server</h1> <p><b>Look up food products by barcode, search by ingredient or nutrition filter, compare products side-by-side, and browse the canonical tag vocabulary via MCP. STDIO or Streamable HTTP.</b> <div>4 Tools</div> </p> </div>

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Public Hosted Server: https://openfoodfacts.caseyjhand.com/mcp

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Tools

Four tools for working with Open Food Facts — a free, crowd-sourced database of 3M+ packaged food products:

off_get_product

Fetch a packaged food product by barcode (EAN-13 or UPC).

• Accepts 8–14 digit barcodes (EAN-13, EAN-8, UPC-A, UPC-E)
• Returns ingredients (raw text and parsed list with percent estimates, vegan/vegetarian flags), all 14 major allergens as tag IDs, E-number additives, Nutri-Score a–e, NOVA 1–4, Green-Score/Eco-Score, full nutriments per 100g and per serving, categories/labels/packaging/origins as canonical tag IDs, front image URL, and data completeness score (0–1)
• Optional fields parameter restricts the response to a subset (e.g., scores only, or nutrition only)
• Open Food Facts is crowd-sourced — a missing field means "not yet entered by contributors," not that the attribute is absent from the actual product
• found: false means no contributor has recorded this barcode yet — not a product defect

off_search_products

Search Open Food Facts by text and/or structured tag filters.

• Full-text search across product names, brands, and ingredients
• Structured filters: categories_tag, brands_tag, labels_tag, nutrition_grade (a–e), nova_group (1–4), countries_tag
• All filter values are canonical tag IDs — use off_browse_taxonomy to resolve human terms (e.g., "organic" → en:organic)
• Pagination via page (1-based) and page_size (1–50, default 20); response includes total count for computing total pages
• Returns summary rows (barcode, name, brand, Nutri-Score, NOVA, categories) — use off_get_product for full label data
• Result counts reflect contributed products, not total products on the market
• Search rate-limited to ~10 requests/min by the Open Food Facts API

off_compare_products

Side-by-side nutrition and scoring comparison for 2–10 barcodes.

• Fetches all products in parallel
• Returns a normalized comparison table: energy (kcal/100g), fat, saturated fat, sugars, salt, protein, fiber, Nutri-Score, NOVA group, and Green-Score
• Missing nutrition data is preserved as null — comparisons are not imputed or estimated
• not_found list identifies barcodes with no contributor record (partial results are not an error)

off_browse_taxonomy

Browse the canonical Open Food Facts tag vocabulary before building off_search_products filters.

• Facets: categories, labels, allergens, additives, countries, nova_groups, nutrition_grades
• Optional search parameter: case-insensitive substring match against tag ID or display name (e.g., "gluten" → en:gluten, en:no-gluten, en:no-added-gluten)
• Taxonomy is embedded (not fetched live) because the OFF taxonomy API is unavailable to anonymous bot clients at current traffic levels
• Categories facet has 200K+ entries — always include a search term when browsing categories
• limit controls results returned (1–100, default 20)

Features

Built on @cyanheads/mcp-ts-core:

• Declarative tool definitions — single file per tool, framework handles registration and validation
• Unified error handling — handlers throw, framework catches, classifies, and formats
• Pluggable auth: none, jwt, oauth
• Swappable storage backends: in-memory, filesystem, Supabase, Cloudflare KV/R2/D1
• Structured logging with optional OpenTelemetry tracing
• STDIO and Streamable HTTP transports

Open Food Facts-specific:

• No API key required — the identifying User-Agent header (required by OFF terms) is baked into the service layer
• Token-bucket rate limiting per endpoint class: product reads (~100/min), search (~10/min)
• Automatic retry (3 attempts, 500ms base) with HTML error page detection for 503 during high load
• Nutriments normalized from raw hyphenated keys (energy-kcal_100g) to underscore form — only the _100g and _serving variants are returned
• Embedded tag taxonomy for off_browse_taxonomy — curated 200+ category subset, full allergen/label/additive vocabularies

Agent-friendly output:

• found field on every product response — explicit false when a barcode has no contributor record, not a thrown error
• Missing fields signal incomplete crowd-sourced data, not product attribute absence — surfaced in descriptions and format output
• Computed scores (Nutri-Score, NOVA, Green-Score) returned as-is with regional caveat notes — not interpreted or normalized to health claims
• not_found list in off_compare_products allows partial batch comparisons without request failure

Getting started

Public Hosted Instance

A public instance is available at https://openfoodfacts.caseyjhand.com/mcp — no installation required. Point any MCP client at it via Streamable HTTP:

{
  "mcpServers": {
    "openfoodfacts-mcp-server": {
      "type": "streamable-http",
      "url": "https://openfoodfacts.caseyjhand.com/mcp"
    }
  }
}

Self-Hosted / Local

No API key is required. Add the following to your MCP client configuration file.

{
  "mcpServers": {
    "openfoodfacts-mcp-server": {
      "type": "stdio",
      "command": "bunx",
      "args": ["@cyanheads/openfoodfacts-mcp-server@latest"],
      "env": {
        "MCP_TRANSPORT_TYPE": "stdio",
        "MCP_LOG_LEVEL": "info"
      }
    }
  }
}

Or with npx (no Bun required):

{
  "mcpServers": {
    "openfoodfacts-mcp-server": {
      "type": "stdio",
      "command": "npx",
      "args": ["-y", "@cyanheads/openfoodfacts-mcp-server@latest"],
      "env": {
        "MCP_TRANSPORT_TYPE": "stdio",
        "MCP_LOG_LEVEL": "info"
      }
    }
  }
}

Or with Docker:

{
  "mcpServers": {
    "openfoodfacts-mcp-server": {
      "type": "stdio",
      "command": "docker",
      "args": [
        "run", "-i", "--rm",
        "-e", "MCP_TRANSPORT_TYPE=stdio",
        "ghcr.io/cyanheads/openfoodfacts-mcp-server:latest"
      ]
    }
  }
}

For Streamable HTTP, set the transport and start the server:

MCP_TRANSPORT_TYPE=http MCP_HTTP_PORT=3010 bun run start:http
# Server listens at http://localhost:3010/mcp

Prerequisites

• Bun v1.3.0 or higher (or Node.js v24+).
• No API key needed. The server sends an identifying User-Agent to comply with Open Food Facts' terms of service — this is baked in and requires no configuration.

Installation

1. Clone the repository:

git clone https://github.com/cyanheads/openfoodfacts-mcp-server.git

1. Navigate into the directory:

cd openfoodfacts-mcp-server

1. Install dependencies:

bun install

1. Configure environment:

cp .env.example .env
# edit .env if you need to override rate limits or the base URL

Configuration

All configuration is validated at startup via Zod schemas in src/config/server-config.ts.

See .env.example for the full list of optional overrides.

Attribution: Open Food Facts data is released under the Open Database License (ODbL) 1.0. Downstream use must cite Open Food Facts.

Running the server

Local development

• Build and run:

  # One-time build
  bun run rebuild

  # Run the built server
  bun run start:stdio
  # or
  bun run start:http

• Run checks and tests:

  bun run devcheck   # Lint, format, typecheck, security
  bun run test       # Vitest test suite
  bun run lint:mcp   # Validate MCP definitions against spec

Docker

docker build -t openfoodfacts-mcp-server .
docker run --rm -p 3010:3010 openfoodfacts-mcp-server

The Dockerfile defaults to HTTP transport, stateless session mode, and logs to /var/log/openfoodfacts-mcp-server. OpenTelemetry peer dependencies are installed by default — build with --build-arg OTEL_ENABLED=false to omit them.

Project structure

Development guide

See CLAUDE.md for development guidelines and architectural rules. The short version:

• Handlers throw, framework catches — no try/catch in tool logic
• Use ctx.log for request-scoped logging, ctx.state for tenant-scoped storage
• Register new tools via the barrel in src/mcp-server/tools/definitions/index.ts
• Wrap external API calls: validate raw → normalize to domain type → return output schema; never fabricate missing fields

Contributing

Issues and pull requests are welcome. Run checks and tests before submitting:

bun run devcheck
bun run test

License

Apache-2.0 — see LICENSE for details.