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

Annotations already declare destructiveHint=true, so the 'Behavior: destructive' line adds nothing on its own. The description does add value beyond structured fields: it discloses the state-machine firing semantics, requires a state pre-check, and states that workspace_id/user_id are injected from request headers, which is auth/context information an agent cannot get from the schema or annotations.

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?

Front-loaded purpose, then labelled 'Use when:' and 'Behavior:' sections that make scanning easy, with no filler sentences. Slightly long for the information conveyed, but every paragraph carries distinct content.

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?

An output schema exists, so return values need not be described, and annotations cover the safety profile, freeing the description to cover domain and workflow — which it does. The remaining gap is parameter disambiguation for the five optional identifiers, which is a real omission for a 5-param tool.

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% across five parameters, so the description carries the full burden and largely fails: the three identifier parameters (referrer_id, referrer_request_id, intro_request_id) are indistinguishable and referrer_request_state_meta is never explained. The one genuinely useful hint — consult GetStateMachineTransitions to learn valid 'event' values — only partially compensates for the single most important parameter.

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 opening sentence names a specific verb and resource — 'Transition a referrer request to a new state by firing a state machine event' — and the second sentence defines the domain object (per-connector leg of a warm intro request for a SUPER_CONNECTOR member), which distinguishes it from the sibling intro_request_send_state_change_event. An agent can tell what this does 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 'Use when: Use when you need to advance a referrer request' plus a concrete prerequisite workflow ('Call GetCurrentState first... then GetStateMachineTransitions if unsure which event is valid') that names the exact sibling tools to consult. It stops short of stating when NOT to use this tool (e.g. versus the intro_request equivalent), so it is clear context rather than full exclusion guidance.

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