List custom dimensions

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

Annotations already declare readOnlyHint=true and openWorldHint=true, so the safety profile is covered. The description adds genuinely useful context — the three backing field types (parameter name, display name, scope) and the customEvent:/customUser:/customItem: report reference syntax — but says nothing about pagination or result limits for an open-world listing.

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 tightly packed sentences, front-loaded with the listing purpose followed by the reference syntax. No filler or redundancy.

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 single-optional-parameter read tool with annotations covering safety and a fully documented schema, the description covers purpose and return content adequately. Only the absence of any guidance on result volume/pagination for an open-world listing keeps it from a 5.

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 is fully documented in the schema (ID, resource name, display name, default fallback), so the description need not compensate. Baseline 3 applies since the description adds no parameter detail beyond what the schema already provides.

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+resource (list a property's custom dimensions) and even names the returned fields, so an agent knows exactly what it produces. It does not, however, explicitly distinguish itself from the sibling list_custom_metrics, which an agent might confuse it with.

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?

Usage is only implied: the mention of how custom dimensions are referenced in reports hints this is a discovery step, but there is no explicit when-to-use or when-not-to-use guidance and no alternative named. Adequate minimum viability, not more.

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