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

Annotations already declare readOnlyHint and openWorldHint, but the description adds valuable context: it notes the 404 pitfall of the sibling endpoint and describes the returned content (segments, steps, estimatedTrainingEffect). It does not cover error behavior for this endpoint itself or rate limits, but the disclosure is strong for a read-only fetch.

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 tightly packed sentences, front-loaded with the core purpose and followed by the endpoint and the UUID sourcing. Every clause earns its place, and there is no redundancy.

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?

Given no output schema, the description adequately covers what is returned (segments, steps, estimatedTrainingEffect), why the tool exists (sibling cannot fetch coach workouts), and where the UUID comes from. This is complete for a single-parameter read-only fetch.

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?

With 0% schema description coverage, the description must compensate. It explains that the workoutUuid comes from getTrainingPlanWorkouts or getScheduledWorkoutSummaries, which adds meaning beyond the bare parameter name. It does not specify the UUID format, but the source guidance is substantial.

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 (GET) and resource (Garmin Coach workout by workoutUuid), and explicitly distinguishes it from the sibling getWorkoutById, which cannot fetch these workouts. An agent can immediately tell this apart from get_workout_by_id without opening either 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?

Explicitly states when to use this tool (for Garmin Coach workouts that getWorkoutById returns 404 for) and where to obtain the required workoutUuid (from getTrainingPlanWorkouts or getScheduledWorkoutSummaries). No ambiguity remains about the alternative or the prerequisite.

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