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

Annotations already declare read-only, idempotent, non-destructive and closed-world, so the safety profile needs no restating. The description adds genuinely new behavior: the ~180-night horizon, that values are aggregate counts with no personal data, and that `generated_at` reflects real staleness — a useful caching caveat. It stops short of saying anything about payload size, so not 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?

Front-loaded with the payload definition, then usage, then scope limits, then the freshness caveat — each sentence carries a distinct fact. The only slightly soft phrase is 'the semantics needed to read it', but it usefully signals a documentation field in the response.

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?

Output schema exists, so return shape needn't be explained, and annotations cover safety; what remains — coverage window, aggregation scope, privacy, freshness — is all stated. Nothing an agent needs to decide or call correctly is missing for a parameterless read 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?

Zero parameters, so there is nothing for the description to disambiguate and the baseline of 4 applies. The description correctly spends its words on scope and freshness instead of inventing parameter guidance.

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 concrete verb and resource plus the exact payload: free room counts per night by room type over ~180 nights. It also names the sibling it is not (check_room_availability), so an agent can separate the bulk-feed tool from the specific-stay tool without reading either schema.

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 an explicit positive use case ('overviews — when is there space in October?') and an explicit exclusion routing to check_room_availability for a specific stay. Both the when and the when-not are stated, not inferred.

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