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

Annotations already declare readOnly, non-destructive and open-world, so the safety profile is covered. The description adds that custom dimensions/metrics are included, which is useful scope information, but says nothing about result volume, pagination, or lookup cost against the live API.

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, purpose first, follow-up usage pointer second. No filler and nothing buried.

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 need not be described, and annotations cover safety. The description covers purpose, custom-field scope and the next step in the workflow; only result-size/pagination hints are absent, which is minor here.

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 both property_id and the search filter are documented in the schema. The description adds nothing about the search parameter's matching behavior; 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?

Specific verb 'List' with the resource 'dimensions and metrics a GA4 property supports', plus the qualifier 'including its custom ones'. It is distinguishable from ga4_list_properties and list_fields, though it doesn't explicitly contrast against them.

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 it to find the exact API names for `ga4_run_report`' gives a clear when-to-use and ties the tool to its downstream consumer. There is no explicit when-not guidance, but the intended workflow is unambiguous.

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