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

Annotations already declare readOnlyHint, destructiveHint false and closed-world, so the safety profile is covered; the description reinforces it with "Read only" and adds genuinely new context: a 30-day retention window and the fact that options only appear "when ready", meaning partial responses are possible. It stops short of describing error behavior for expired or unknown trip ids.

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?

One sentence, front-loaded with the verb and resource, with the colon cleanly separating identity from payload. The retention clause is the only extra and it earns its place by preventing calls on expired trips.

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?

With no output schema, the description takes on the job of describing return values and does so adequately: status plus options with labelled prices and booking links, including the conditional "when ready". Only failure cases (not found, expired beyond 30 days) are left unstated.

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 0% for the single required tripId, so the description must carry the meaning; it does state the id identifies a trip "already planned on Trip720", implying the value originates from plan_trip. It adds no format or validity details (e.g. id shape or how to obtain it explicitly), so the compensation is only partial.

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?

"Reads a trip already planned on Trip720, by its trip id" names a specific verb and resource, and goes on to enumerate what comes back (status, options, prices, booking links). It does not explicitly contrast itself with siblings such as get_day_plan or trip_alternatives, so it falls short of full sibling differentiation.

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 phrase "a trip already planned" implies the tool is for retrieving something created by plan_trip rather than creating it, which gives an implicit usage context. There is no explicit when-not-to-use guidance and no named alternative for related lookups like day plans or swap candidates.

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