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

Annotations already declare readOnlyHint=true and openWorldHint=true, so safety is covered. The description adds a genuine behavioral rule not present in structured data: a property_id outside the workspace is rejected, and the workspace parameter is only optional when a single workspace exists.

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?

One line of purpose followed by two dense parameter clauses; front-loaded, no filler, every sentence carries information an agent needs.

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 explained, and both parameters plus the workspace/property constraint are covered. Minor gaps (ordering, pagination/limits for large dimension lists) are not addressed but are unlikely to block a correct call.

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 carries the full burden and does so for both parameters: property_id is scoped to the workspace's own property (others rejected) and workspace is the customer slug, optional with exactly one workspace. It lacks format hints (e.g. 'properties/123456'), which keeps it short of a 5.

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 custom dimensions of a GA4 property, and even names the returned fields (Name, Parameter, Scope). It does not distinguish itself from the near-identical sibling ga4_list_custom_metrics or from ga4_create_custom_dimension / ga4_archive_custom_dimension.

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 implied by the read-only listing verb plus the constraint that the property_id must belong to the caller's workspace (others are rejected), which is useful. However it never states when to choose this over ga4_list_custom_metrics or when this is not appropriate.

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