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

readOnlyHint=true already tells the agent this is a safe read, so the description's only added context is the underlying OwnerRez endpoint (GET /v2/guests/{id}). It adds nothing about behavior on a missing id, permissions, or rate limits, which keeps it at the baseline for an annotated tool.

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 compact sentences, the scoping information front-loaded, with zero filler. Nothing to trim.

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 simple one-id read with annotations covering safety, this is nearly adequate. With no output schema present, however, the description gives no hint of what a guest object contains or how a missing id behaves, leaving a small but real gap.

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?

There is a single parameter with 100% schema description coverage ('The guest id.'), so the schema already carries the semantics. The description restates the id-based lookup but adds no format, range, or sourcing detail beyond what is already documented.

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 ('Fetch a single guest (contact) by id') and the 'single' qualifier implicitly distinguishes it from the sibling list_guests. It never names an alternative explicitly, so it falls just short of a 5.

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?

'by id' implies the usage context (you must already know the guest id), which rules out lookup-by-name or bulk retrieval. However there is no explicit when-to-use statement, no mention of list_guests as the alternative when the id is unknown, and no prerequisites.

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