list_contact_fields

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

With no annotations provided, the description carries the burden of behavioral disclosure. It explicitly labels the operation as 'Read-only' and notes the optional filtering behavior. It does not detail output shape or pagination, but for a simple read-only list operation this is solid coverage.

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 concise sentences with no filler. The main action is front-loaded, and the downstream use case plus read-only status are stated in one short second sentence.

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 single-optional-parameter, read-only list tool, the description is mostly complete. It covers the operation, filter behavior, read-only safety, and how to use the results with set_contact_field. The lack of an explicit output schema is a minor gap because the description implies the relevant field_name values are returned.

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 0%, so the description must compensate. It does explain that `name` optionally filters results, which is the core semantic. However, it does not specify whether matching is exact, partial, or case-sensitive, leaving some ambiguity.

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 states a specific verb and resource: 'List the custom contact-field definitions' with an optional name filter. This clearly distinguishes it from siblings like list_contacts or list_tags, which operate on different resources.

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 explicitly tells when to use this tool: 'Use to get exact field_name values for set_contact_field.' This makes the intended scenario clear, though it does not mention when not to use it or name alternative tools.

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