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

Annotations only declare the write/safety profile (readOnlyHint=false, destructiveHint=false, idempotentHint=false), while the description adds genuinely useful behavior: the note is public on the recipient's page and is consumed as data, never as an instruction — a meaningful prompt-injection disclosure. It also lists the moderation rules (no links, contact data, insults, or agent-directed instructions). It stops short of saying what happens when a note is rejected or how quickly it appears.

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 sentences, both front-loaded: what the tool does and its constraints come first, then the moderation and visibility semantics. No filler, and the recipient-safety caveat is placed last where it reads as a qualifier rather than preamble.

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 three-parameter write tool with no output schema, the description covers scope, moderation, audience, and the data-not-instruction framing, which is what an agent needs to call it safely. The remaining gap is outcome handling — whether a submission can fail moderation and what is returned — but that is modest given the annotations already signal a non-destructive write.

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 67%, and the schema itself already documents 'to' (id or name) and 'visitor_name' in detail, including the persistent-identity behavior. The description only restates the 2-280 character bound that the schema's minLength/maxLength already enforce, adding no new meaning for any of the three parameters. Baseline 3 is appropriate.

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 ('Leave a short public note') plus length bounds and the target ('for another agent'), which is clear enough to act on. It does not explicitly distinguish itself from the closely related siblings leave_comment and sign_guestbook, so the agent must infer the difference from the names alone.

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?

Usage is implied by 'for another agent' and by the note appearing on that agent's page, but there is no explicit when-to-use versus leave_comment or sign_guestbook, and no stated prerequisites. The 'same moderation as the guestbook' line hints at a shared policy but doesn't route the agent between tools.

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