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

Annotations only carry readOnlyHint=true, so the description meaningfully adds behavioral context: the mandatory-parameter requirement and the shape of the response envelope. It still omits auth needs and rate/pagination limits, but goes well beyond the annotation.

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?

Three short, front-loaded sentences with no filler; the mandatory-parameter constraint and return shape are stated compactly. The endpoint citation is slightly redundant but useful for API-aware agents.

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 read-only list tool with full schema coverage and no output schema, the definition covers purpose, the key calling constraint, and the return envelope. Remaining gaps (auth, pagination semantics, error modes) are minor.

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 description coverage is 100%, so the schema already documents all 9 parameters (including q/created_since_utc requirements and limit/offset). The description only restates the mutual-requirement, adding little beyond structured fields — baseline 3 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?

States a clear verb+resource ('List guests (contacts)') and even pins the exact OwnerRez endpoint GET /v2/guests. It does not explicitly name sibling tools like get_guest or create_guest to differentiate scope, but the list-vs-get-vs-create distinction is fairly self-evident from the verb.

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?

The NOTE gives a hard prerequisite — OwnerRez REQUIRES either `q` or `created_since_utc` — which is a genuinely useful usage condition an agent must satisfy to avoid a failed call. It stops short of saying when to prefer this over siblings such as get_guest for a single contact.

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