get_activity

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

Annotations already cover read-only, idempotent, non-destructive safety, but the description adds genuinely non-obvious semantics: missing fields read as 'not recorded' rather than zero, and results are informational not medical. Both prevent real misinterpretation of the returned data. It does not discuss rate limits or payload size, so not a 5.

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?

Front-loaded with the core action, then the field inventory, then two short caveats that each earn their place. The leading 'T7.' tag is unexplained internal notation that adds no meaning for an agent calling the tool.

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, the description needn't restate return structure, yet it helpfully signals the field categories and, critically, how to interpret absent values. Combined with read-only/idempotent annotations and a fully documented single parameter, nothing needed to call this correctly 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?

One parameter at 100% schema coverage, and the schema itself explains the id comes from list_activities. The description's 'by id' adds nothing beyond the schema, so this sits at the baseline 3 for well-documented schemas.

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 ('Details of one activity by id') and enumerates exactly what comes back (duration, pace, heart rate, splits, workout steps), which clearly separates it from the sibling list_activities. An agent knows immediately this is the single-record detail fetch.

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 'one activity by id' phrasing plus the schema note tying the id to list_activities gives clear usage context: list first, then fetch details here. It stops short of naming alternatives explicitly or stating when not to use it (e.g., for aggregate ranges), so it is not a full 5.

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