ga4_update_calculated_metric

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

No annotations provided, so description carries full burden. It explains the updateMask derivation from supplied fields and the use of body for nested fields. However, it does not disclose whether the update is atomic, what happens on success/failure, or any side effects. Some behavioral context is present but incomplete.

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 a single, two-sentence paragraph with no filler. It front-loads the purpose and essential requirements (writes flag, confirm flag) and explains updateMask derivation efficiently. Every word earns its place.

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?

Given no output schema, the description is fairly complete for a write operation: it covers required flags, updateMask logic, and the body parameter for advanced cases. It lacks details on return values or error handling, but the core behavior (update a calculated metric with partial updates) is well-covered.

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 57%; description adds significant context: explains that only changed fields need to be passed, that updateMask is auto-derived (but can be overridden), and that body parameter is for nested fields. It groups key parameters (formula, displayName, unit) implicitly. This adds meaning beyond the schema, though each parameter could be described in more detail.

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 starts with '[GA4 WRITE] Update a calculated metric' which clearly identifies the action and resource. It lists the updatable fields (formula, displayName, unit) and distinguishes from sibling create/delete tools by specifying it's an update operation.

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 explicitly requires GA4_MCP_ENABLE_WRITES=true and confirm=true, providing clear conditions for use. However, it does not explicitly contrast with sibling tools like ga4_create_calculated_metric or ga4_delete_calculated_metric, which would help an agent decide when to choose this tool.

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