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

Annotations only declare readOnlyHint=true; the description goes well beyond that by disclosing the shared-trip access asymmetry, the meaning of statsSource, the provenance rule for weather fields, and the exact units/conventions (knots, meteorological degrees, Douglas sea state) of the returned data. This is rich behavioral context that structured fields do not carry.

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?

Well front-loaded: purpose, then the access quirk, then data semantics. Every sentence carries information, but the trailing block of unit/format facts reads as a dense dump rather than a structured list, which slows scanning slightly.

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, so the description correctly takes on return-value explanation (field provenance, units, ID/timestamp formats) while also covering the access edge case for shared trips. Nothing needed to invoke or interpret the response is missing.

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% and the anyOf structure already encodes the action/tripId vs action/id split, so the baseline is 3. The description still adds meaning beyond it: the action values are illustrated ('list them, or get one by id'), the access rule is attached to the action choice, and ID semantics ('6-character case-sensitive') are spelled out even where the regex only implies them.

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 ('Read a trip's ordered legs') and immediately splits the two modes ('list them, or get one by id'), so an agent knows exactly what the tool returns. It also implicitly distinguishes itself from trip_read by describing the shared-trip case, which is where the two overlap.

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?

Provides an explicit when-to-use rule for get vs list, plus a when-NOT/alternative: on a trip shared with the caller, list will not return the legs and the agent should use trip_read's get instead. That is exactly the routing decision an agent needs and it is not derivable from the schema.

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