ga4_custom_metrics_list

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

No annotations are provided, so the description must carry the full burden. It correctly notes the tool is read-only, but does not disclose pagination behavior, error conditions, or authorization needs beyond the schema.

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 a single concise sentence covering action, resource, return fields, and read-only nature. It is front-loaded and efficient, though slightly dense.

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 lists key return fields, which is helpful. It also notes read-only behavior. However, pagination is only implied via the schema, and the description could mention that results may be truncated.

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, including details for maxPages, property, and pageToken. The description does not add new meaning to the parameters beyond listing return fields.

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') and resource ('custom metrics configured on a GA4 property'), and enumerates specific return fields (parameter name, display name, etc.), distinguishing it from sibling tools like ga4_custom_dimensions_list.

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 mentions 'Read-only', implying safe usage, but lacks explicit guidance on when to use this tool versus other list tools or alternatives, nor does it specify prerequisites or context.

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