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

Annotations already declare readOnlyHint=true, idempotentHint=true, and openWorldHint=false, so the safety profile is covered. The description adds useful behavioral context: it states that each hook carries its public TripHook page and event page, that the reply includes a 'see_more' token, and that only public fields are returned. It does not mention rate limits or pagination behavior explicitly, which keeps it from a 5.

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?

The description is three sentences and front-loads the main use case. Every sentence contributes: the first states usage, the second explains the output structure, and the third gives a formatting rule. It is slightly dense but well-organized and avoids waste.

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?

Given 6 parameters, zero required, no output schema, and annotations that cover the safety profile, the description is fairly complete. It tells the agent what the tool returns (hooks with URLs and event pages) and that responses include a 'see_more' token, which helps with multi-turn interactions. It could be improved by noting that all filters are optional, but it is sufficient for correct invocation.

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 50%, with only city, limit, and month having explicit descriptions. The description mentions city slug, month (YYYY-MM), kind, budget, and mood, which adds some semantic context for the undocumented parameters (e.g., the notion of 'budget tier' and 'mood' as filter dimensions). However, it provides no additional syntax or format details beyond what the schema already says, so a baseline 3 is appropriate.

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 searches for open trips or day outs and enumerates multiple filter dimensions (city, month, kind, budget, mood). It effectively communicates the purpose of discovering joinable public hooks. However, it does not explicitly distinguish itself from sibling tools like search_destinations or events_and_company, so it falls short of a perfect score.

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 provides clear when-to-use guidance: 'Use for any question about open trips or day outs to join' with specific filter criteria. It does not, however, mention alternatives or exclusions—e.g., when to prefer events_and_company or search_destinations—so an agent still has to infer the boundaries between tools.

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