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

Annotations already declare readOnly, idempotent, non-destructive, so safety is covered; the description adds real value beyond them by disclosing that results are ids needing 'fetch', that message text is not indexed, that results are permission-scoped, and that content involving minors is excluded. Minor omissions remain: no result count, pagination, or empty-result behavior.

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 dense sentences with the capability, the exclusion, the return shape, and the age restriction front-loaded; nothing is wasted. The final fragment 'Nothing with someone under 18 in it' is terse to the point of slight ambiguity about whether minors are excluded as subjects, authors, or both.

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, and the description compensates by saying results are ids to pass to fetch. Scope, exclusions, and the follow-up step are all present for a single-parameter tool. A note on result limits or ordering would be the only remaining gap.

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 only one parameter and 100% schema description coverage, the schema already explains the query field, its examples, the 200-character limit, and that empty means recent items. The description adds no additional syntax or matching-behavior detail for 'query', so the 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?

The description states the verb (search) plus an explicit resource list: chats by participant or room name, plans, public profiles. It also fences off message text, so the agent knows this is not a full-text search over conversations. It does not clarify how it relates to the sibling 'search_profiles', which overlaps with the 'public profiles' scope it claims.

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?

Usage is implied by 'Search what you may read' and by the explicit exclusion 'never message text', which tells the agent to go elsewhere for message content (read_chat, read_thread). There is no named alternative for people/profile lookups despite the presence of search_profiles and find_people as siblings, leaving the routing decision partly to inference.

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