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

Annotations already declare readOnlyHint=true, idempotentHint=true, destructiveHint=false and openWorldHint=false, so the safety profile is covered. The description adds nothing beyond that—no mention of pagination, result size, or whether archived/created-in-UI metrics are included—and the 'Tools revision' line is noise rather than behavior.

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 core sentence is front-loaded and wastes no words. The trailing 'Tools revision: 5c9bea8f.' adds no decision-relevant information and could be dropped.

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?

An output schema exists, so return values needn't be described, and the read-only annotations are complete. But for a one-parameter call whose only parameter is undocumented in the schema, the description leaves the critical identifier format unstated, making the definition incomplete for correct invocation.

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%, so the description must compensate for the single required 'property' parameter, but it never explains that this is a GA4 property identifier or what format (e.g., 'properties/123456789') to pass. Without that, agents are likely to pass a display name and fail.

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: list the custom metrics belonging to a GA4 property. It is clearly distinct from ga4_create_custom_metric and ga4_update_custom_metric by the 'list' verb, but the description never names those siblings or scoping conditions explicitly.

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 use this versus ga4_list_custom_dimensions, ga4_get_metadata, or the create/update counterparts, and no prerequisites such as permissions or required property ID format. The agent must infer usage from the verb alone.

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