List registered field groups

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

The annotations already declare readOnlyHint=true and destructiveHint=false, so the safety profile is covered. The description adds that it returns fields and placement info, which is content rather than behavior. It doesn't disclose any additional side effects or requirements (e.g., permissions), but since annotations carry the behavioral burden, a 3 is appropriate.

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 two sentences with no redundancy. The primary purpose is front-loaded, and the usage hint is concise and actionable. Every word contributes value.

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 list tool with a single optional parameter and no output schema, the description adequately communicates what results to expect (fields and placement) and why to use it. It doesn't mention pagination or limits, but these are not critical for such a simple list operation. The openWorldHint annotation suggests data may change, which is fine.

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 only parameter, site_id, is already fully described in the schema with 100% coverage, including optionality, default behavior, and a reference to list_sites for valid IDs. The tool description adds no further parameter details, so the baseline 3 applies.

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 action: 'List the editable field groups registered on the site' with the added detail of 'their fields and where each appears.' This distinguishes it from sibling tools like register_fields and delete_field_group, making the tool's scope unambiguous.

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 second sentence provides explicit guidance: 'Check here before registering a group so you extend an existing one rather than duplicating it.' This tells the agent exactly when to use this tool (before registration) and implies that register_fields is the alternative for creating new groups. It does not explicitly mention when not to use it, but the stated use case is clear enough.

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