Ga4.Admin.Create Key Event

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

With no annotations at all, the description carries the full burden. It does disclose the single most important behavior — a preview/confirm guard against accidental creation — which is genuine value not present in the schema. But it omits permissions required, whether the operation is idempotent, whether unconfirmed calls have side effects, and how the token is obtained or how long it is valid.

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?

A single front-loaded sentence with no filler; the guard caveat is correctly placed at the end of the main clause. It is terse rather than padded, though that terseness is where the missing operational detail would have gone.

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?

This is a mutation tool with zero annotations, zero schema descriptions, and a three-parameter contract including a token parameter — the description is far too thin for that profile. The existence of an output schema means return values needn't be covered, but the confirm workflow and parameter formats remain unexplained.

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 compensate and does not: none of property_id, event_name, or confirm is explained. The opaque `anyOf [string, null]` confirm parameter is never tied to the mention of 'confirm token', and the expected property_id format (e.g. 'properties/123') is unstated.

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?

Specific verb+resource: 'Create a key event (conversion) on a property' — and it helpfully glosses 'key event' as 'conversion', which removes GA4 jargon ambiguity. It does not name or contrast with siblings like ga4.admin.list_key_events or ga4.admin.create_audience, but the create/list distinction is self-evident from the name.

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?

'(guarded: preview + confirm token)' implies a two-step call pattern, which is real usage guidance, but it is stated as a parenthetical rather than an instruction — the agent must infer that it should call without confirm first, then repeat with the token. No exclusions or prerequisites are given.

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