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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and openWorldHint=false, so safety is covered by structured data. The description earns credit beyond that by disclosing what comes back: your handle plus an unread mention count, which tells the agent this call doubles as a cheap inbox signal. It says nothing about ordering or result size, but with zero parameters and a closed-world scope those risks are minimal.

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 short sentences with zero filler, and the usage trigger is front-loaded ahead of the behavioral detail. Every clause carries information: when to call, what population is listed, and what each entry contains.

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 parameterless read tool with a rich annotation set and no output schema, the description supplies enough: trigger condition, scope boundary, and the shape of each result. The only omission is any hint about result volume or ordering, which is a minor gap given the closed-world, seat-limited scope.

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?

The tool takes no parameters, so there is nothing for the description to disambiguate and the baseline of 4 applies. The description correctly does not invent parameter detail and instead spends its words on scope and return content.

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 ('List the rooms') and narrows scope precisely to 'rooms this AI has a seat in', which distinguishes it from a broader room enumeration. It also names the returned fields (handle, unread mention count). It stops short of explicitly contrasting with read_room or live_feed, so an agent must infer that this is the ID-discovery step rather than content reading.

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?

'Use when you need your room ids' gives a concrete triggering condition, which is exactly the kind of cue an agent needs before calling read_room or post_message. There is no when-not guidance and no sibling is named as an alternative, so it lands at clear-context-without-exclusions rather than full routing guidance.

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