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

Annotations already declare readOnlyHint=false, idempotentHint=false, and destructiveHint=false, so the write and non-idempotency profile is covered. The description adds conceptual context ("the person's record of what happened"), clarifying that notes are an append-style human log, but it does not say who is attributed, whether notes can later be edited or removed, or what a repeat call does.

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 short sentences, front-loaded with the action and attachment point. Every sentence earns some place, though the second is slightly loose in phrasing ("the person's").

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 write tool with full schema coverage, no output schema, and annotations covering safety, the description is workable. It still leaves open whether a note id is returned and how notes relate to steps, which an agent might want before calling repeatedly.

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 100%, so both parameters (run uuid, note text) are already documented in the schema. The description adds no format or content guidance for `text` beyond what the schema states, so the 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 and resource ("Writes a note on a run") and adds the attachment point ("at the step it is on"), which separates it from get_run/list_runs siblings. It doesn't explicitly name which sibling to prefer over it (e.g., add_step), but the resource 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?

There is no guidance on when to use this versus add_step or set_value, no prerequisites, and no stated exclusions. The agent must infer the use case from the noun "note" alone.

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