get_activity

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

With no annotations provided, the description carries the full burden. It discloses the return shape ('same shape as a list_activities entry') and an important limitation: 'does not currently surface fields list_activities omits'. This is meaningful behavioral context, though it does not address errors, authentication, or side effects.

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?

Three tight sentences, each earning its place: one for what it returns, one for when to use it, and one for what it intentionally does not return. The key usage guidance is front-loaded, and there is zero filler.

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 tool with no output schema and no annotations, the description is complete enough. It specifies the return shape via reference to list_activities, explains when to use it, and clarifies the limitation on additional fields. Nothing essential is missing 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?

The schema only defines activity_id as a required string, with 0% description coverage. The description compensates by explaining that the id is the identifier already obtained from list_activities, an event, or the athlete. It provides provenance but does not give format or example values.

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 identifies the operation: 'One activity by id', naming the resource and the lookup key. It also distinguishes itself from list_activities by specifying 'same shape as a list_activities entry' and that it retrieves a single activity rather than a whole window.

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?

It explicitly states when to use the tool: when you 'already have an id (from list_activities, an event, or the athlete)' and want that one activity 'without re-listing a whole window'. This gives clear context and implies the alternative case where list_activities would be more appropriate.

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