food-mcp

lookup_barcode

Scan or enter any packaged food barcode to retrieve product details, nutrition facts, and ingredients from Open Food Facts.

Instructions

Instant lookup of any global packaged food barcode via Open Food Facts API.

Tool call template

Replace each placeholder with a value matching the input schema. Only required parameters are included; add optional parameters as needed.

{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "arguments": {
      "barcode": "<barcode>"
    },
    "name": "lookup_barcode"
  }
}

Input Schema

Name	Required	Description	Default
`barcode`	Yes

Output Schema

Name	Required	Description	Default
`result`	Yes

Schema Changelog

Changes observed during successful MCP inspections.

First observedv0.1.0Oct 17, 2026

TDQS

B3.1/5.0

Behavior3/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

With no annotations, the description carries the full disclosure burden, and it does add two useful behavioral facts: lookups hit an external API (Open Food Facts) and coverage is limited to packaged food products. It says nothing about unknown-barcode behavior, coverage gaps, rate limits, or offline failure modes, so it is only partially transparent for an unannotated tool.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

A single tight sentence with the capability front-loaded and no filler. Nothing to trim.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness3/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

An output schema exists, so return values are not the description's responsibility, and a one-parameter tool is low complexity. Still, for an unannotated tool the description omits barcode format and not-found behavior, leaving a real gap for correct invocation.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters2/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

The single barcode parameter has 0% schema description coverage, so the description must compensate and largely does not: no format guidance (EAN/UPC digits, checksum, leading zeros), no acceptance of multiple codes. 'Any global packaged food barcode' gives vague scope but no callable format detail.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose4/5

Does the description clearly state what the tool does and how it differs from similar tools?

States a specific verb (lookup) and resource (packaged food barcode) plus the backing data source (Open Food Facts API), so the agent knows exactly what it returns. It implicitly separates itself from lookup_food (name-based), though it never names that sibling explicitly.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines2/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

There is no when-to-use guidance, no statement of when to prefer lookup_food or get_food_chemistry instead, and no prerequisites. The agent can only infer usage from the word 'barcode' in the name and description.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

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