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

Annotations already declare readOnlyHint=false, idempotentHint=false, destructiveHint=false, and openWorldHint=false, so the basic safety profile is covered. The description adds only that creation targets a GA4 property; it does not explain whether new dimensions become immediately active, whether names must be unique, or what happens on duplicate creation attempts.

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 first sentence is front-loaded and efficient, but the second sentence is a revision tag that adds no invocation value. The overall definition is concise but under-specified rather than optimally structured.

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 four-parameter mutation tool with zero schema description coverage, the description is too thin. Even with an output schema handling return values, an agent lacks enough context to confidently supply parameter_name, display_name, and scope.

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% for all four parameters, so the description must carry the burden. It only mentions 'property' and says nothing about parameter_name, display_name, or the scope default of EVENT, leaving critical parameter meaning undocumented.

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 states a specific verb and resource: create a custom dimension on a GA4 property. It distinguishes the tool from siblings like ga4_create_custom_metric and ga4_update_custom_dimension by naming the resource and operation, though it does not explicitly route away from alternatives.

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?

The description gives no indication of when to use this tool versus alternatives such as ga4_create_custom_metric or ga4_update_custom_dimension, nor does it mention prerequisites like required GA4 permissions or property readiness.

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