GA4 dimensions & metrics metadata

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

Annotations already declare readOnlyHint, openWorldHint, idempotentHint, and destructiveHint=false, covering safety and side effects. The description adds the behavior that it includes custom dimensions/metrics and that the output can be large without a search filter, which are useful non-obvious details. No contradiction with 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 two short sentences with no filler. It front-loads the core action and then provides a practical filtering tip. Every word earns its place.

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 metadata listing tool with a required propertyId and optional kind/search, the description covers the essential purpose and filtering behavior. It does not detail the return structure, but the absence of an output schema and the simplicity of the tool make that less critical. Annotations cover the safety profile, so nothing critical is missing.

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 67% (propertyId and search have descriptions; kind does not). The description reinforces the search parameter's purpose and implies kind through 'dimensions and metrics', but it does not add substantial semantics beyond what the schema already provides. Baseline of 3 is appropriate given high schema coverage.

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 verb ('List') and the resource ('dimensions and metrics available for a GA4 property'), and adds specificity with 'including custom ones'. It is distinct from siblings like ga_list_properties (which lists properties) and ga_run_report (which runs reports), so an agent can immediately tell what this tool does.

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 gives clear context (listing available dimensions/metrics for a property) and even hints at usage by advising to filter with a search string to keep output small. However, it does not explicitly mention when to prefer this over alternatives, nor does it state exclusions. The context is sufficient for most agents to select it appropriately.

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