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

Goes well past the destructiveHint=true annotation: it specifies the exact endpoint (including the doubled path segment), the HTTP outcome (204/null), the second-call 404 behavior with the error text, and, most importantly, the blast radius — scheduled workouts are removed but completed activities remain. That side-effect specificity is exactly what an agent needs before a destructive call.

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?

The purpose and the IRREVERSIBLE warning are both front-loaded, and most sentences carry operational weight. It loses a point for incidental detail — the observed-date provenance and the aside that the path segment 'really is doubled' — which is useful trivia but dilutes the core message.

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 fully compensates by describing the return (null, 204), the failure mode (404 with message), and the data consequences. Nothing needed to call this destructive tool 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%, so planId's meaning is already documented as a numeric id. The description's mention of planId only shows its position in the URL template and does not add type, format, or sourcing guidance beyond the schema. 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?

States a specific verb+resource pair ('Quits an enrolled plan') and immediately describes the effect on the calendar. An agent can distinguish it from siblings like delete_workout, unschedule_workout, or get_training_plan_by_id 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?

Gives a clear directive on the required procedure ('confirm with the user before calling') and signals the irreversible nature, which strongly shapes when to invoke it. However, it never names an alternative such as unschedule_workout for removing a single workout instead of quitting the whole plan, so the routing guidance is contextual rather than explicit.

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