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

With no annotations, the description carries the full burden of behavioral disclosure. It mentions persistent storage, the 'only way back in' property, and wallet-derived room mapping, but these are cryptic and incomplete. It does not disclose side effects, permission requirements, reversibility, or what happens when no key is provided.

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 dense paragraph that lacks a front-loaded purpose statement. It opens with an ambiguous imperative ('Take a day pass and a room.') rather than a clear verb+object summary. While not overly long, the structure buries the key functional details and forces the reader to parse metaphorical language.

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?

Given the tool's moderate complexity (one optional parameter, no output schema), the description should clearly explain its function, but it leaves too much to inference. Key terms like 'day pass' and 'room' are undefined, and the exact outcome of calling the tool (e.g., returning a room key string) is never explicitly stated. An agent would struggle to determine how and when to call this tool.

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 single parameter 'renew' is already described in the schema ('An old room key, to return to the same room.'), covering 100% of parameters. The description adds minimal context by mentioning expired keys, but this largely mirrors the schema description. The description does not significantly enhance parameter understanding beyond the schema.

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 is metaphorical and unclear. It says 'Take a day pass and a room' but never defines what a day pass or room means in the tool's context. It implies creating a key that grants persistent access, but the core action (e.g., 'create', 'issue', 'renew') is missing. It does not distinguish itself from sibling tools like 'room' or 'key'.

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 explicit guidance on when to use this tool versus alternatives. The only usage hint is that presenting an expired key returns to the same room, implying a renewal use case, but no conditions, prerequisites, or exclusions are stated. Sibling tools are not referenced.

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