delete_training_plan

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

Annotations already declare destructiveHint=true and readOnlyHint=false, and the description still adds substantial value beyond them: the exact side effects (scheduled workouts leave the calendar, completed activities remain), the return shape (null/204), the 404 error string on repeat calls, and an explicit irreversibility warning. This is precisely the extra context the structured fields cannot convey.

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?

One dense paragraph with no filler sentences, and the operation itself is front-loaded. The doubled-path aside and the observation date are minor implementation trivia that slightly dilute the message, but the critical warning is clearly emphasized.

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 no output schema, the description compensates by documenting the successful response (null/204), the failure mode (404 with message), and the second-order effects on calendar and completed activities. Nothing an agent needs to call this destructive operation safely 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?

Schema description coverage is 100% for the single planId parameter, so the schema already carries the semantics. The description only echoes planId inside the raw path template and quotes the 404 message containing the id, adding no format or lookup guidance (e.g. where to obtain a planId). Baseline 3 applies.

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?

Names a specific verb (DELETE) and resource (training plan), and even quotes the exact Garmin Connect UI action it corresponds to ("Quit Plan"), which disambiguates it from the many other delete_* siblings (delete_workout, delete_activity, delete_gear). An agent knows exactly what is being removed without opening the 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?

Provides clear usage context: it states the operation is irreversible and instructs the agent to confirm with the user before calling. It also warns that a second call returns 404, which implicitly tells the agent not to retry. It stops short of naming an alternative sibling tool or a when-not-to-use condition, so it is clear context rather than explicit routing.

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