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

Annotations flag destructiveHint=true, and the description goes further by disclosing that the default behavior REPLACES the coach note and that append:true is required to add instead. It also reveals the grade badge behavior, markdown rendering, and separation from the athlete's own note – all valuable context beyond the raw annotation flags. No contradiction exists between the description and readOnlyHint=false/destructiveHint=true.

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 description is long but front-loaded: the one-line purpose comes first, followed by id source, append semantics, grade, content grounding, and markdown rules in a logical order. Every sentence carries a functional requirement, but the lengthy grade scale and formatting guidance prevent a perfect conciseness score.

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 4-parameter write tool with no output schema, the description covers every angle an agent needs: input derivation, mutation behavior, optional parameters, content quality bar, rendering rules, and separation from other note types. No critical operational detail 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?

With 0% schema description coverage, the description fully compensates: id is tied to list_activities, notes receive content and style guidance, append is explained as the additive alternative to replacement, and grade carries a detailed A–E scale with execution-based interpretation. This is far more than the schema's type/enum declarations provide.

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 opening sentence names the exact action ('Write a coach summary / opinion'), the target resource ('one completed activity'), and where the result appears ('activity card in Blocks, labelled Coach read'). It also differentiates from sibling note tools by emphasizing it is a coach note separate from the athlete's own note and tied to a completed activity, not a planned workout or day.

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 gives clear operational context: pass the activity `id` from list_activities, default replaces the note, append:true adds, and grade is optional. It does not explicitly name sibling tools or state when not to use this tool, but the 'completed activity' criterion sufficiently routes away from set_workout_note, set_day_note, and set_event_notes.

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