ga4_update_event_create_rule

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

No annotations are provided, so the description carries the full burden. It discloses that the operation is a write, requires an environment variable and confirm flag, and explains the updateMask derivation. It does not detail side effects or reversal, but covers essential behavioral traits.

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 two sentences long, with no redundant information. The first sentence states the purpose, and the second provides critical usage instructions. 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 4 parameters with 100% schema coverage, no output schema, and one nested object, the description covers the key aspects: purpose, usage, prerequisites, and updateMask behavior. It could mention the return value or confirmation, but overall it is complete enough for agent invocation.

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 100%. The description adds value by explaining that 'body' is for nested/advanced fields not exposed as flat args, and that updateMask can be omitted to derive from supplied fields. This goes beyond the schema.

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 clearly states '[GA4 WRITE] Update an event-create rule', specifying the verb (update) and the resource (event-create rule). It distinguishes itself from sibling tools like ga4_create_event_create_rule and ga4_delete_event_create_rule.

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 provides explicit usage guidance: 'Pass only the fields to change; updateMask is derived from them' and requires 'GA4_MCP_ENABLE_WRITES=true and confirm=true'. It implies this tool is for modifying existing rules, not creating or deleting them.

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