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

The description explicitly states that it REPLACES the coach notes by default and provides the append:true option to add instead, which aligns with the destructiveHint annotation. It also mentions that it fills the event's coach-notes section, giving a clear side-effect. This goes beyond the annotation by explaining how to control the destructive behavior.

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 concise and well-structured, with each sentence adding valuable information: purpose, id source, replace/append behavior, content guidance, and markdown support. There is no redundancy or filler; it is appropriately sized for the tool's complexity.

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?

The description is complete for an agent to call the tool correctly. It covers the effect (fills coach-notes), the required id, the append behavior, and the content expectations. Since there is no output schema, it doesn't need to describe return values. It also gives practical advice on content quality, making it comprehensive.

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 coverage, the description must compensate, and it does. It explains the 'id' (from list_events), the 'append' parameter (append:true), and gives detailed guidance on the 'notes' parameter content (concrete specifics, markdown, and examples like carbs g/h, fluid, etc.). This adds meaning well beyond the bare schema.

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 clearly states the tool's purpose: to write extended prep notes on a single event, specifying the resource (event) and the content (fueling, hydration, pacing, taper, kit, strategy). It differentiates from sibling note tools like set_activity_notes by explicitly targeting events and mentioning the coach-notes section. The action is unambiguous.

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 context: the event id should come from list_events, and the default behavior replaces notes unless append:true is passed. However, it doesn't explicitly compare with alternatives or state when not to use it (e.g., for activities). The instruction to use the event id implies the prerequisite, but a direct contrast with sibling note tools would make it fully explicit.

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