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

The description adds valuable behavioral context beyond the annotations: it clarifies append semantics (appends one note, never touches the athlete's own notes), and it explicitly warns that an empty string clears ALL notes on that day. This meaningfully expands on the destructiveHint annotation.

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 dense and uses strong front-loading ('ADD a SHORT note'), and every sentence carries useful information. It is slightly verbose in places (e.g., the long-form remark about the athlete's own impressions), but overall an efficient use of words.

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?

Given the simple three-parameter schema, no output schema, and the presence of a destructive annotation, the description covers the essentials: what to write, how much, what happens on empty, color usage, and the relevant alternative tool. Minor gaps like return value or success indication are not needed for basic invocation.

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 only 33% schema description coverage, the description compensates thoroughly. It explains the note parameter's purpose, length expectations, and the empty-string clearing behavior; it also details the optional color parameter's semantics and the condition for using it. This goes far beyond the schema's minimal details.

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 a specific verb ('ADD') and resource ('calendar day'), with an explicit scope ('a few words capturing the key thought, NOT an essay'). It distinguishes itself from sibling tools by emphasizing the day context and directly naming add_checklist as the alternative for checklists.

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 explicit when-to-use guidance (short note to a day), what to avoid (essays), and names a specific alternative tool (add_checklist) for list-type content. It also tells agents when to use colour tags, including the rule to only set a colour when the athlete has assigned its meaning.

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