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

Annotations already declare readOnly, idempotent, non-destructive, and closed-world, so safety profile is covered. The description adds useful specifics: returns at most 20 results as links. It stops there, not covering ordering, matching semantics, or empty-result behavior beyond the schema hint.

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?

Two compact sentences that front-load purpose and result shape with no filler. Appropriately sized for a simple single-parameter lookup tool.

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 one-parameter read-only search with annotations and an output schema, the description covers purpose, scope, result count and form. Ordering/relevance behavior is unspecified but non-blocking given the richness of structured fields.

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 coverage is 100%, so the schema already fully documents the single query parameter including the empty-lists-recent behavior and length cap. The description adds the useful note that matching is by place or request, but does not go beyond the structured data in syntax or format.

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 (Find) and resource (calls) scoped to the owner, plus a stated purpose (mentioning in a message). Distinguishes scope via 'owner's calls', though none of the siblings are search tools so differentiation is less critical. Clear but not maximally precise.

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?

Conveys context ('for mentioning one in a message') which implies when to use it, but gives no explicit exclusions or alternatives. The schema reveals empty query lists recent calls, but the description itself offers only implied usage guidance.

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