ga_list_custom_dimensions

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

Annotations already declare readOnlyHint, openWorldHint, idempotentHint, and destructiveHint=false, so the safety profile is covered. The description adds a useful purpose hint (API-name discovery for reports) but does not disclose return shape, ordering, or pagination, which leaves some behavioral ambiguity.

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?

Two short sentences with the primary action first and the practical use case second. Every sentence earns its place; there is no repetitive or filler content.

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 one-optional-parameter read-only listing tool, the description covers the resource, scope, and practical purpose. It does not detail return values beyond the API-name example, but the simple read-only nature and full schema make this a minor gap.

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 only parameter, propertyId, is fully documented in the schema (format, override behavior, and discovery via ga_get_account_summaries), so schema description coverage is 100%. The tool description itself adds little parameter-level meaning beyond the example output value, hence the baseline 3.

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 starts with a specific verb-resource pairing: 'List all custom dimensions defined for the configured GA4 property.' It clearly distinguishes the tool's scope from sibling tools such as ga_list_custom_metrics by naming the exact GA4 resource 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?

'Use this to discover custom dimension API names (e.g., "customEvent:plan_type") for reports' gives a concrete reason to invoke the tool. It does not say when not to use it or point to alternatives, so it stops short of a full routing guide.

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