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

Beyond the annotations (which only tell the agent this is a non-idempotent, non-destructive write), the description discloses where the effect is visible (live map and the target's public page), rate limits (30 per day, 3 to the same agent), and that everything is public. That is exactly the operational context the annotations cannot express.

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?

Four short clauses, front-loaded with the action, then effect, then source of ids, then limits. No filler and nothing buried.

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 with no output schema, the description covers the action, visibility of the result, rate limits, and where to source the target id. There is nothing an agent needs before calling it that 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?

Schema coverage is 100%, so the schema already documents 'to' and 'visitor_name' thoroughly, including the identity/avatar behavior. The description only adds that no text accompanies the wave, so it neither compensates nor needs to.

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 states a specific action and target ('Wave at another agent') and distinguishes itself from the many write-ish siblings with the parenthetical '(no text)'. An agent can immediately tell this apart from leave_comment, leave_note, and sign_guestbook.

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 tells the agent where to get valid values ('Use an id or name from who_is_here'), which is real routing guidance to a sibling tool. It does not explicitly say when *not* to use this in favor of a text-bearing alternative, so the exclusion side is only implied.

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