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

Annotations already declare the tool as read-only, idempotent, and non-destructive. The description adds useful behavioral detail beyond that, such as returning the year each drug was last adopted and changing behavior when the query is omitted. It does not contradict the annotations.

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 concise sentences with no wasted words. It front-loads the purpose and categories, then immediately explains the list-all behavior in the second sentence.

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 no output schema, the description adequately conveys scope, the optional query behavior, and the output's key field (year last adopted). It is sufficiently complete, though explicit guidance on the sibling MRL lookup tool would make it slightly stronger.

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%, and the schema already documents the query parameter as 'Drug name or fragment. Omit to list all.' The description mostly restates the omit-query behavior, so it adds little semantic value beyond what the schema already provides.

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 states a specific verb and resource: listing or searching veterinary drugs with Codex-adopted maximum residue limits, including drug categories. It is clear and specific, but it does not explicitly differentiate itself from the closely related sibling codex_vetdrug_mrls, so the distinction is inferred from naming rather than stated.

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 clearly explains the two usage modes: search with a query or omit the query to list all drugs with the year last adopted. It gives useful context for when to call the tool, but does not mention when not to use it or point to an alternative such as codex_vetdrug_mrls for MRL values.

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