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

Annotations already declare readOnlyHint=true and idempotentHint=true, covering safety. The description adds meaningful behavior details: fuzzy case-insensitive input matching, return components (PepScore, lab-verified COA, red/green flags, affiliate-tracked link, coupon), and the 'not evaluated' fallback. No contradiction with 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?

Three tight sentences: the first states the core purpose, the second lists output specifics, the third gives usage examples. No redundant phrasing, front-loaded with the main action, and every sentence contributes.

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 tool with one simple parameter, strong readOnly/idempotent annotations, and no output schema, the description is complete: it covers action, input, output fields, and when to use. It even includes the 'not evaluated' result, leaving few ambiguities.

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% for the single 'name' parameter with an example. The description adds semantic value by noting the input is fuzzy and case-insensitive, which is not present in the schema, enhancing understanding beyond the basic example.

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 checks vendor legitimacy (legit, scam, safe) and details the audit output (PepScore, COA, audit summary, buy link, coupon). This specific verb+resource framing distinguishes it from sibling tools like find_peptide_sources and list_verified_vendors.

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 explicitly says 'Use for' and gives concrete query examples ('is [vendor] legit', '[vendor] review', '[vendor] scam'), providing clear when-to-use context. It does not explicitly mention alternatives or when-not-to-use, but the usage scope is well-defined.

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