Plan a GA4 key event

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

Annotations declare readOnlyHint=true/destructiveHint=false, which the description reinforces and enriches: nothing is written, a confirmation_token is returned, user agreement is a prerequisite, and there is no automatic rollback because deletion is not offered in this version. This is behavior beyond what the structured hints convey.

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?

Roughly three dense sentences, front-loaded with the PLAN/nothing-written constraint, then the apply path, then the rollback caveat. Every clause carries information an agent needs.

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 mutation-adjacent plan tool with no output schema, the description covers the write-free guarantee, the returned token, the apply handoff, and the missing rollback path. Nothing an agent needs to invoke and follow up correctly is absent.

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%, so all four parameters (client_id, event_name, property_id, counting_method) are already documented in the schema with defaults and enum values. The description adds no additional parameter semantics, so the baseline 3 applies.

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?

States a specific verb and resource ('mark an event as a key event of the client's GA4 property') and immediately clarifies the mode with 'PLAN (nothing is written)'. An agent can distinguish it from the sibling apply tools and from ga4_key_events without opening a schema.

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?

Explicit two-step workflow: plan here, then 'apply it with google_apply after the user agreed', plus what to do instead if the user wants removal (GA4 Admin > Key events). Names both the next step and the unavailable alternative.

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