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

Annotations already declare a non-destructive, non-open-world write, and the description adds the crucial behavioral detail that this action is what pushes the workout to the watch. It does not disclose what happens if a workout is already scheduled on that date, which is a meaningful gap for a scheduling mutation.

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?

Two tight sentences with the purpose and the key side effect front-loaded, followed by precisely the parameter information an agent needs. No filler.

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 two-parameter mutation with annotations and an output schema, this is nearly complete: purpose, side effect, and both parameters are covered. The missing piece is collision behavior when a date already holds a scheduled workout.

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 coverage is 0%, so the description carries the full burden and does well: it defines workout_id and gives concrete accepted formats for date (YYYY-MM-DD, 'today', 'tomorrow', '+3'). It leaves the integer-or-string flexibility of workout_id unaddressed, but the essentials are covered.

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 specific verb and resource ('Put a saved workout on a date in the user's Garmin calendar') and immediately explains the effect ('what sends it to the watch'), making it unmistakably distinct from unschedule_workout and other siblings.

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 conveys the context in which to use the tool (placing a saved workout onto the calendar) but never names an alternative or states exclusions, such as when to unschedule or update instead. The usage is implied rather than explicitly routed.

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