ga4_list_custom_metrics

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

Annotations already declare readOnlyHint=true and openWorldHint=true, so the description does not need to restate safety. It adds useful context by specifying the fields returned for each entry (parameter_name, display_name, measurement_unit, scope, restricted_metric_type), which sets expectations beyond the 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 and front-loaded: one clear purpose sentence followed by a concise list of returned fields. There is no fluff or redundant restatement of annotations.

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 list operation with one parameter, read-only annotations, and an output schema, the description covers the essential resource and result structure. It does not discuss pagination or limits, but those are lower-risk for a read-only list tool and are partially covered by the openWorldHint.

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 description coverage is 0% and the description never defines property_id or its expected format. The only clue is 'configured on a GA4 property,' which weakly connects the parameter to the tool but does not compensate for the missing schema documentation.

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 uses a specific verb and resource: 'List custom metrics configured on a GA4 property.' It clearly distinguishes from sibling tools such as ga4_list_custom_dimensions by naming the exact entity being listed.

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 intended use is implied by 'List custom metrics configured on a GA4 property,' but there is no explicit guidance about when to choose this over related siblings like ga4_list_custom_dimensions or ga4_get_metadata. No prerequisites or exclusions are stated.

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