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

Annotations already declare readOnlyHint=true, so the safety profile is covered; the description adds a minor piece of context by mapping the tool to the OwnerRez GET /v2/fielddefinitions endpoint. It does not disclose pagination defaults, auth needs, or result ordering beyond what the schema's limit/offset descriptions already state.

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, front-loaded with the resource and followed by the clarifying definition and endpoint. No filler or repetition of schema content.

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 read-only list endpoint with fully documented parameters, the definition is nearly complete; it even hints at what the records describe. The remaining gap is the absence of an output schema combined with no description of the returned record shape or pagination behavior, though this is minor here.

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% for all three parameters, so the schema carries the parameter burden (limit, offset, and the verbatim params escape hatch). The description adds no additional parameter semantics, which is the baseline 3 case.

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 (List) plus a disambiguated resource (custom-field definitions), and the parenthetical clarifies that a 'field definition' is the schema for custom fields on properties/bookings/guests — a term that would otherwise be ambiguous. No sibling tool overlaps this resource, so an agent can select it without opening another 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?

The description says what is returned but gives no explicit when-to-use guidance, prerequisites, or alternatives (e.g. 'call this before creating/updating bookings that set custom fields'). Usage is only implied from the resource name.

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