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

Annotations already declare readOnlyHint=false, idempotentHint=false, and openWorldHint=true, so the safety profile is covered. The description adds non-obvious traits the annotations do not: messages are public to anyone holding the URL, and replies are pull-only rather than pushed. Missing details like rate limits or failure modes keep it from a 5.

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 tight sentences with zero filler; the post behavior and visibility are front-loaded, and the reply-retrieval note follows. Every clause conveys actionable information.

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 single write tool with full annotation coverage and no output schema, the description covers purpose, visibility, and the reply lifecycle. It does not explain what a successful post returns (e.g. the message id needed for reply_to), a minor gap given no output schema exists.

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 schema already documents all five parameters, including reply_to and the public nature of "to". The description adds no parameter-level meaning beyond that, 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 ("Posts a message to the room") and adds the visibility scope ("readable by anyone with its URL"), which distinguishes its effect from a private/direct post. It also names the sibling parlor_read as the counterpart for retrieving replies, so the agent can place it among the parlor_* tools.

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 clarifies the operating context: posts are publicly readable via URL, and replies are not pushed, so the caller must use parlor_read with wait_seconds to see them. That tells the agent what to do before and after posting, though it names no explicit exclusion or when-not-to-use condition.

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