GA4: Custom dimensions & metrics

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

Annotations already declare readOnlyHint=true and openWorldHint=true, so safety is covered, but the description adds nothing beyond them: it does not say whether archived or deleted custom definitions are included, whether results are paginated, or how many items are returned. Only one short clause of behavioral context is supplied for a listing tool.

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?

One front-loaded sentence with no filler or redundancy. It is efficient, though its brevity leaves little room for the guidance the tool lacks.

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 read-only listing with full schema coverage and a clear safety annotation, the definition is minimally sufficient. It falls short on whether custom dimensions and metrics are both always returned together, on pagination/result size, and on any property-format caveat an agent might need before invoking.

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% and the single property parameter already documents the accepted ID formats ('123456789' or 'properties/123456789'). The description's phrase 'of a property' merely restates the required parameter, 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?

States a specific verb and resource ('Lists all custom dimensions and custom metrics') and scopes it to a property, so an agent knows this is a read of custom definitions. It does not explicitly distinguish itself from the sibling write tools ga4_create_custom_dimension and ga4_create_custom_metric, though the verb 'lists' does much of that work.

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?

There is no guidance on when to call this versus alternatives such as ga4_get_metadata or ga4_list_key_events, and no stated prerequisites (permissions, property type). The agent must infer usage entirely from the name and the single required parameter.

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