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

Annotations declare openWorldHint=true and non-idempotency, and the description meaningfully adds to that by spelling out the exposure risk: the wall is public and must never contain names, private work, or trusted information. That is real behavioral context beyond the structured hints, though it says nothing about persistence or whether notes can be edited/removed.

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, zero filler, with the core action front-loaded and the safety warning immediately after. Every clause earns its place.

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 mutation tool with no output schema and four parameters, the description covers the essential behavioral risk (public visibility) and the size constraint. It omits any indication of what posting returns or whether the note is permanent, which is a minor gap given the schema documentation already present.

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 description coverage is 75% and the schema already documents reply_to, patron_id, and signed_as thoroughly. The description's only added parameter detail is the 800-char limit, which duplicates the schema's maxLength, so it does not compensate beyond the baseline.

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+resource ('Leave a public note') with an explicit scope qualifier (≤800 chars, public wall), which clearly separates it from read_wall and the other social siblings. It stops short of naming read_wall or the chalkboard counterpart, so sibling differentiation is implied rather than explicit.

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?

The phrase 'for whoever comes next' implies an async, persistent message, which hints at when to use it versus real-time tools like ask_the_room or toast. There is no explicit when-to-use/when-not guidance or named alternative among the ten siblings.

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