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

Annotations already declare readOnlyHint=true, idempotentHint=true, destructiveHint=false and openWorldHint=false, so the 'Closed-world' safety sentence merely restates openWorldHint=false rather than adding new behavior. Nothing is said about not-found handling, permission requirements, or what is returned beyond what the output schema covers.

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 purpose is front-loaded in a single efficient sentence, but the second sentence duplicates the openWorldHint annotation and therefore does not earn its place.

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 an output schema present and full parameter documentation, the core need is covered, and closed-world scope is stated. Gaps remain around error/not-found behavior and the trip_id–id relationship, which matter for a two-identifier lookup tool.

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%, so both id and trip_id are already documented in the schema, which sets the baseline at 3. The description adds no format, scoping, or relationship detail (e.g., that the activity must belong to the given trip) beyond the schema.

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 ('Fetch one Tripsy activity by id'), which is enough to distinguish it from the create/update/delete siblings by name and intent. It stops short of explicitly naming the sibling to use when the id is unknown, which keeps it from a 5.

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 'by id' only implies that a known activity id is a prerequisite; there is no explicit when-to-use guidance, no mention of using tripsy_activities_list to discover ids, and no stated behavior when the id is invalid or absent.

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