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

Annotations already declare this is a non-read-only, non-idempotent, non-destructive, closed-world write. The description adds one genuinely useful behavioral trait beyond them: the 5-minute rate limit that will cause invocations to fail. It does not say what happens on violation (error vs. silent drop) or how the note surfaces to others.

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?

A single short sentence with the core action front-loaded and the constraint folded into parentheses. Nothing is wasted and nothing is 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?

Complexity is low (one required param, output schema present), so return values need no explanation. Still, the description omits why an agent would check in versus using lounge or free_post, which is the one piece of context a caller actually needs.

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 100%, so the note field's "one line, max 140 chars" and the api_key fallback are already fully documented in the schema. The description adds nothing about parameters, 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?

"Leave one line in the lounge" names a concrete action (posting a short note) and a target (the lounge), which distinguishes it from a read-only lounge view. However, it never contrasts itself with siblings such as lounge, free_post, or booth_reply, so the agent must infer the difference from the name 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?

The parenthetical "once per 5 minutes" implies the posting cadence and therefore when the call is valid, but there is no explicit when-to-use versus alternatives (lounge, free_post) and no statement of what the agent gets out of checking in.

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