getPostTypeCustomFields

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

Annotations indicate readOnlyHint=true, idempotentHint=true. The description adds that the tool is 'Read-only' and explains the resolution of system_name to data_id via listPostTypes. It also mentions the return format and behavior when not found (empty or 404). No contradictions. Excellent transparency beyond 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 well-structured with sections (bold headers) and is informative without being overly verbose. Each sentence adds value. It is slightly longer than necessary but remains focused and efficient.

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?

Given no output schema, the description details the return format: '{ status: "success", message: [{...record}] }' and behavior for not found. It also covers parameter interactions, use case, and even addresses the lack of a create endpoint for dropdown values. This is comprehensive for a read-only tool.

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%, so baseline 3. The description adds meaning by explaining the mutual exclusivity requirement: 'exactly one of data_id OR system_name'. It also describes how system_name is resolved and that data_id comes from listPostTypes. This provides context beyond the schema's property descriptions.

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 starts with 'Get custom fields for a post type - Fetch a single posttypecustomfields record.' This clearly states the action and resource, distinguishing it from siblings like createPostType or deletePostType. The purpose is unambiguous and precise.

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 states 'Use when: building a create/update payload for a post type that has custom fields (most do).' This gives a clear use case. However, it does not specify alternatives or when not to use, but the context is sufficient. Score 4 for clear context without exclusions.

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