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

Annotations already convey read-only, idempotent, and non-destructive behavior. The description adds behavioral context by specifying the source standard (CXS 193) and the output shape (contaminant, maximum level, unit), which goes beyond the structured annotations without contradicting them.

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?

The description is compact with two sentences and zero filler, and the core purpose is front-loaded. The phrasing 'Every Codex maximum level that applies to one food' is slightly awkward but still clear and efficient.

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?

For a single-parameter, read-only tool with full schema coverage, the description provides enough context: it names the source, the output fields, and gives user-facing examples. Minor gaps like handling unknown commodities or formatting details are not critical here.

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?

The input schema already fully describes the single 'commodity' parameter with examples, so schema coverage is 100%. The description reinforces that it refers to 'one food' but adds little meaning beyond the schema, so the baseline score of 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?

The description clearly states the tool returns each contaminant's maximum level and unit for a given commodity, sourced from CXS 193, with illustrative queries. It is specific about the resource and action, but it does not differentiate from the sibling tool 'contaminants_max_levels', so it misses full sibling distinction.

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?

No explicit guidance is given about when to use this tool versus alternatives such as 'contaminants_max_levels'. The examples imply a use case (look up limits for one food), but there are no conditions, exclusions, or references to sibling tools, leaving selection largely to inference.

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