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

Annotations already declare readOnlyHint=false, destructiveHint=true, idempotentHint=true, and openWorldHint=false. The description adds little beyond the mutation nature and an example field, but it does not contradict the annotations and provides some context for a destructive update.

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 concise and front-loaded. The appended 'Tools revision' sentence adds little value and is the only unnecessary element.

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?

Although annotations and an output schema reduce the need to explain safety and returns, the description is too thin for a 3-parameter mutation tool with 0% schema description coverage. It does not explain update_mask, allowed counting_method values, or practical update behavior.

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 explain parameters. It only hints at 'name' via 'by resource name' and at 'counting_method' via the example, leaving update_mask and valid counting-method values 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: 'Update a conversion event' and adds the scoping mechanism 'by resource name.' It is clearly distinct from ga4_create_conversion_event and ga4_list_conversion_events, though it does not explicitly name those siblings.

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?

It implies the tool is for updating an existing conversion event and requires a resource name, but it gives no explicit when-to-use guidance, prerequisites, or comparison against alternatives such as create or list operations.

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