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

Annotations already declare readOnlyHint, openWorldHint, idempotentHint, and destructiveHint=false, covering the safety profile. The description adds valuable behavioral context: the data source (openFDA CVM), the aggregation breakdowns, and the top-20 reaction limit. It does not mention data freshness, authentication needs, or rate limits, but adds enough beyond annotations for a solid score.

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?

Three sentences, front-loaded with the core action and resource, followed by concrete example questions and a parameter usage note. Every sentence contributes to understanding, with no redundancy or filler.

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?

Although there is no output schema, the description clearly specifies the return structure: counts broken down by reaction (top 20), outcome, and year. Annotations cover the safety profile, so the description provides sufficient context for an agent to call the tool correctly without additional explanation.

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?

With 100% schema description coverage, the schema already documents all three parameters, including the 'use this OR drug' note for active_ingredient. The description repeats that OR relationship and names the example values, but adds no new syntax, format, or constraint beyond what is in 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?

States a specific verb ('Count') and resource ('FDA animal adverse-event reports') with breakdown dimensions (reaction, outcome, year), making the aggregation nature clear. However, it does not explicitly differentiate from sibling tool vet_adverse_events, which likely lists individual reports, so the distinction relies on the verb 'Count' and the word 'summary' in the name.

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?

Provides three example questions that clearly illustrate when to use the tool, giving strong context for its intended purpose. It does not name any alternative tool or state when not to use it, so exclusions are absent.

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