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

Annotations already declare readOnlyHint, idempotentHint and openWorldHint, so safety is covered. The description adds genuinely non-structured context: that it is a lightweight lookup, that trustScore is a published formula composed of identity verification, official records, completeness and source consistency, and that reviews are auxiliary only — useful for interpreting the result.

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 capability and the return fields, followed by usage routing. The trust-score formula clause is slightly dense but earns its place by explaining the tool's headline output.

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?

There is no output schema, so the description must describe the return values, and it does enumerate them (existence, public status, verification level, trustScore) plus how the score is derived. For a single-parameter read-only lookup, nothing an agent needs to call it correctly is missing.

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% with a single well-documented agentId parameter, so the schema carries the burden. The description adds no syntax, format, or scoping detail about the identifier beyond what the schema already states; baseline 3 applies.

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 (verify/lookup) and resource (AgentID) and enumerates exactly what is returned: existence, public status, verification level, and trustScore. It implicitly contrasts with search results, but never names the closest sibling get_agent, so the differentiation from a plain agent-fetch tool is left to inference.

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?

"Prefer this before citing or recommending an Agent Card from search results" gives a concrete when-to-use trigger tied to a workflow (citing/recommending). It offers no when-not guidance or named alternative, so it stops short of full routing instructions.

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