custom_fields

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

With no annotations provided, the description must carry the full burden of behavioral disclosure. It mentions 'delete' and 'update' without warning about side effects, irreversibility, permission requirements, or response behavior. It essentially restates the action enum from the schema without adding meaningful behavioral context.

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 sentences long, front-loaded with the resource and actions, no wasted words. It is concise and structured well.

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?

The tool is a multi-action CRUD with 8 parameters, and there is no output schema. The description covers the high-level operations but omits behavioral details like error cases, scope requirements, or return values. The input schema compensates somewhat by fully documenting parameters, making the description minimally adequate.

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?

The input schema has 100% description coverage for all 8 parameters, so the baseline is 3. The description adds minimal value beyond the schema by linking 'list' to 'field schemas,' but it does not explain conditional requirements or parameter relationships that aren't already in the schema.

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 clearly states the tool's purpose: 'List, create, update, or delete custom field definitions.' It uses specific verbs and identifies the resource, distinguishing it from the sibling tool 'custom_fields_values' which handles values rather than definitions.

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 provides sub-action guidance ('Use list to get field schemas, create to add a field, etc.'), giving clear context for internal actions. However, it offers no explicit guidance on when to choose this tool over alternatives like custom_fields_values or other mutation tools, and no exclusions are mentioned.

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