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

Annotations already disclose that this is not read-only, is destructive, and is idempotent, so the description could focus on added behavioral context. Instead it adds almost nothing beyond saying the resource is addressed by name; it does not explain what update behavior is destructive or what permissions or effects are involved.

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 description is short and front-loads the core action, but the second sentence about the tools revision does not help an agent decide or invoke the tool. It is concise but includes non-functional metadata.

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 destructive update tool with three parameters and no schema descriptions, the description is too thin. The output schema may cover return values, but the input semantics and update effects are insufficiently explained.

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 needs to compensate but only clarifies that the 'name' parameter identifies the resource. It does not explain 'display_name' or the 'update_mask' default behavior, leaving most 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: 'Update a data stream,' and adds that it is identified 'by resource name.' This distinguishes it reasonably well from sibling tools like ga4_create_data_stream and ga4_list_data_streams, though it does not explicitly name 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?

There is no guidance on when to use this tool versus alternatives such as ga4_create_data_stream or ga4_list_data_streams, and no prerequisites or conditions are described. The update intent is implied only by the verb and tool name.

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