List contact fields

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

Annotations already declare this a read-only, non-destructive operation. The description adds useful behavioral detail about the response: returned UUIDs are used to set values on contacts, and choice fields expose their selectable options. No contradiction with annotations.

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?

The description is compact, front-loaded with the core purpose, and every sentence adds value: context about custom fields, the update flow, and choice options. No redundant or filler wording.

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-parameter read-only list tool without an output schema, the description explains what is returned, how the returned UUIDs are used, and what choice fields offer. Nothing essential is missing for an agent to decide to call it.

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 coverage is 100% and the single required parameter profileUuid is documented as 'Profile uuid parameter'. The description reinforces that fields are scoped to a profile but adds no additional parameter-level semantics, matching the baseline for full schema coverage.

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 action and resource: get the custom contact fields defined in a profile. This clearly differentiates from siblings like reach_listContacts or reach_listContactGroups, and from field mutation tools such as reach_createAContactField.

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?

Provides clear context: custom fields store attributes on contacts, and the returned UUIDs are consumed by the contact update endpoint. It does not explicitly name alternatives or state when not to use the tool, but the intended use is clear enough for an agent.

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