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

Annotations already declare this a safe, idempotent, read-only, non-open-world operation, so the safety burden is covered. The description adds genuinely useful behavioral context beyond that: a consent requirement and email-confirmation step. However, it says nothing about what the search returns or matching behavior, so it adds only moderate value on top of the 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?

Two tight sentences with the purpose front-loaded and the workflow guidance following. Every clause earns its place, though the second sentence bundles several instructions (sequencing, consent, email confirmation) fairly densely.

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 single-parameter read-only search with no output schema, the description covers purpose, sequencing relative to traveler_add, and a consent precondition. The main remaining gap is that it never indicates what the search returns, which would help an agent act on the result.

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 'names' parameter, and the schema documents that it is the names matched against prior participants. The description adds no syntax, format, or matching detail beyond the schema, so the baseline 3 for full coverage 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 and resource: 'Search people the authenticated user previously added to trips.' An agent can immediately tell this queries prior trip participants. It does not explicitly differentiate from similarly named siblings like trip_travelers or friends_list, but the purpose itself is unambiguous.

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?

Explicitly positions the tool in a workflow: 'Use before traveler_add,' which names the alternative/next step and when to invoke it. It also adds a precondition (obtain explicit invitation consent). It stops short of stating when NOT to use it, so it is clear context rather than full routing guidance.

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