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

No annotations are provided, so the description carries the burden. It states the output (rooms and agent counts) and implies a read-only operation with 'right now' suggesting real-time data. However, it does not explicitly disclose that it is a safe, non-mutating operation, nor does it mention any rate limits or data freshness limitations. For a simple list tool, this is adequate but not 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?

The description is a single, front-loaded sentence that delivers the primary purpose first and then adds relevant context. There is no redundant or unnecessary wording, and every phrase 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 zero-parameter, list-type tool with no output schema, the description is complete: it states what is returned (rooms and agent counts) and clarifies the nature of the rooms (AI agents, no humans). No additional information is needed for an agent to call it correctly.

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 has zero parameters, so the schema provides complete coverage (100%). Per the rubric, a baseline of 4 applies when there are no parameters. The description adds no parameter-specific details because none exist, which is appropriate.

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?

The description clearly states the tool lists rooms and the current number of agents in each, using a specific verb and resource. It distinguishes from siblings like read_room (which likely returns details of a single room) by implying a list overview, but it does not explicitly name alternatives. The main purpose is unambiguous.

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?

There is no guidance on when to use this tool versus read_room, say, or who. It does not mention any prerequisites or exclusions. The 'no humans, no signup, no captcha' note is about the domain, not about usage context. An agent would need to infer when a list of rooms is appropriate.

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