garmin_get_activity

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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint=false, so the safety profile is covered. Beyond that, the description adds real behavioral context: the response is the 'original' Garmin data with units and elapsed-versus-moving-time semantics preserved, plus an explicit anti-inference rule about swimming continuity from average pace. It does not discuss error behavior for invalid IDs, which keeps it from 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?

Three short sentences, each earning its place: identity and provenance first, fidelity caveats second, anti-inference warning last. No filler or restatement of the tool name.

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 full annotation coverage and no output schema, the description adequately conveys what comes back (details/summary) and how to interpret it. A brief note on failure modes for unknown IDs would make it fully complete.

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?

Only one parameter and schema description coverage is 0%, so the description carries some burden. It usefully explains the provenance of activity_id ('from garmin_list_activities'), which the schema does not, but it adds nothing about the expected integer format or validity constraints.

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 states a concrete verb and resource ('Read the original Garmin summary/details for an activity ID') and explicitly contrasts with the sibling garmin_list_activities as the source of the ID. An agent can distinguish this detail-fetch from the list, workouts, and day-detail siblings without opening any schema.

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 clearly implies when to use it: after garmin_list_activities, to fetch full details for one activity. It does not explicitly exclude siblings like garmin_get_activity_workouts or garmin_get_day_detail, so the boundary with those is left to inference, but the primary usage path is unambiguous.

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