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

Annotations already declare readOnly, idempotent, openWorld and non-destructive, so the safety profile is covered. The description adds real context beyond that: the data source (EFSA OpenFoodTox 3.0), the coverage ceiling, and the fact that a partial name resolves to the closest substance with the response disclosing which one — useful for interpreting results.

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

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

Front-loaded with the core purpose, then usage examples, then coverage bounds — a sensible ordering with little waste. The coverage sentence is arguably long but it carries the important scoping limit, so nearly every clause earns its place.

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

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

With no output schema, the description compensates by enumerating the returned fields and their metadata, and it clarifies the substance population covered. It is silent on result size, pagination, or what an empty/no-reference-value response looks like, which is a minor remaining gap for a lookup tool.

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

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

Schema coverage is 100% and the schema description already documents the case-insensitive, partial-match resolution behavior for the single 'substance' parameter. The description's examples overlap with the schema's own examples and add no new syntax or format constraints, so baseline 3 is appropriate.

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

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

States a specific verb ('Get') and resource (EFSA derived toxicological reference values) and enumerates exactly what comes back — ADI, ARfD, tolerable intakes, operator exposure — plus the accompanying metadata (assessment body, critical endpoint). This is distinguishable from the generic sibling openfoodtox_search without opening either schema.

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

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

Gives concrete usage context via example questions ('what is the ADI for glyphosate', 'what tolerable intake has EFSA set for cadmium') and scopes coverage to the 3,437 substances with at least one reference value. It does not, however, name when to prefer the sibling openfoodtox_search instead, so the exclusion half of the guidance is missing.

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