ga4_custom_metrics_list

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

Without annotations, the description only states 'Read-only,' indicating no side effects. It does not disclose pagination behavior, rate limits, or other operational characteristics, leaving the agent with limited behavioral insight.

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 sentence plus 'Read-only,' front-loading the action and key details. Every element serves a purpose with no redundancy.

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 operation with no output schema, the description is sparse. It mentions returned fields but does not specify that the response is a list, include pagination details, or confirm the structure of the output, leaving significant gaps.

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 100%, so the schema fully documents parameters. The description adds a list of returned fields but does not elaborate on parameter semantics beyond what the schema provides, meeting the baseline.

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 on a GA4 property'), and includes specific fields returned. It distinguishes from siblings like ga4_custom_dimensions_list by listing metric-specific attributes in parentheses.

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 no guidance on when to use this tool versus alternatives, no prerequisites beyond the property ID (which is in the schema), and no exclusions or context about when not to use it.

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