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

Annotations already declare readOnlyHint=true and destructiveHint=false, so safety is covered; the description adds genuinely useful behavior: the max-25s hold, the explicit 'nothing new' outcome on timeout, and the transcript shape whose last line carries the new cursor and room status. It omits rate limits or ordering guarantees, so it is not fully exhaustive.

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?

Front-loaded with the core behavior and only four sentences, all of which carry information. The final sentence about when waiting is useful is slightly indirect ('once others can be in the room'), but it earns its place as usage guidance.

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?

With no output schema, the description correctly takes on the burden of describing the return shape (transcript plus trailing cursor/status line) and the timeout behavior, which is what an agent needs to call it correctly. Minor gaps remain on token/presence semantics, though the schema covers the token parameter.

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 baseline is 3, but the description earns extra credit by framing 'since' as a cursor and by tying the output's last line back to the next cursor value, which clarifies the read/advance loop. The wait_seconds ceiling of 25 is repeated from the schema rather than newly explained.

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 with scope: messages after a cursor, returned as a transcript ending in a new cursor plus room status. It also characterizes the tool's role in the system ('It is how replies arrive: they are not pushed'), which clearly separates it from siblings like parlor_fetch or parlor_post.

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?

Gives a concrete when-to-use rule for the long-poll mode: waiting helps only once others can be in the room, not before the URL has been shared. It does not name an alternative sibling (e.g., parlor_fetch) or state when NOT to use wait_seconds, so it stops short of the 5-level explicit routing.

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