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

Annotations already declare readOnly, openWorld, idempotent, and non-destructive behavior. The description adds valuable non-obvious details about the return shape: each commodity with its maximum level, the unit, and the source page of CXS 193. It does not mention potential pagination or limits, but the annotation coverage reduces the need for more safety disclosure.

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 two sentences, front-loads the core resource and contaminant categories, then states return fields and use cases. No word is wasted, and the structure guides the agent naturally from what to how to when.

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 simple two-parameter tool with no output schema, the description is complete: it identifies the resource, lists valid inputs, describes the returned fields, and gives concrete examples. An agent can select and invoke this tool correctly with no additional information.

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 description coverage is 100%, so the schema fully documents both parameters. The description adds a broad list of valid contaminant names and example commodities, but this largely repeats what the schema examples already show. It does not materially increase parametric clarity beyond the schema.

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 Codex Alimentarius maximum levels for a contaminant in food, enumerates supported contaminants, and specifies the return fields (commodity, maximum level, unit, CXS 193 page). It does not explicitly contrast itself with the sibling contaminants_for_commodity, but the scope is concrete enough that an agent can identify its purpose.

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?

The description gives two explicit example queries: "what is the Codex limit for lead in fish" and "which foods have cadmium maximum levels". This conveys intended usage well, though it does not state when to prefer the sibling contaminants_for_commodity or mention exclusions.

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