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

Annotations declare destructiveHint=true, openWorldHint=true, and idempotentHint=false, but not the actual consequence. The description adds real behavioral context beyond them: which automations will enroll the contact, how payload surfaces in condition steps, and a user-confirmation safeguard. It does not address auth failure modes or whether repeat fires duplicate enrollments.

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?

Three tight sentences, front-loaded with the action, then consequence, then the safety admonition. No filler or repetition of the title.

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?

There is no output schema, and annotations only convey safety flags. The description covers the side effect that matters most (automation enrollment), how payload is consumed, and a confirmation guardrail — everything an agent needs before invoking a non-idempotent, destructive event fire.

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 six parameters are already documented, and the description adds only the `event.<key>` payload-access convention. That is a modest addition over the schema's own parameter docs, matching the baseline 3.

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 ('Fire') and resource ('custom event for a contact') and describes the concrete downstream effect (matching automations enroll and run). This distinguishes it clearly from siblings like register_for_event, list_events, and get_event_insights.

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?

Gives clear usage context by explaining that only automations with a matching custom_event trigger will act, and includes an explicit caution to confirm with the user before firing events that could trigger an emailing automation. It does not name alternative tools or exclusion conditions, so it falls short of a 5.

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