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

Annotations already declare destructiveHint=true, readOnlyHint=false and openWorldHint=true, so the irreversible-send risk is known. The description adds real value beyond that by disclosing that the confirmation token is single-use and that the payload is transmitted unmodified, but it says nothing about what the send produces, whether it can be retried, or what happens on token expiry.

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 sentence with no filler, front-loaded on the action and immediately followed by the two gating conditions (exact prepared payload, one-use token). Nothing in it is redundant.

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 no explanation, and the annotations cover the safety profile. However, for a destructive three-parameter tool with zero schema descriptions, the definition leaves the idempotencyKey contract and the failure mode of a spent token undocumented, which is a meaningful gap.

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% for all three required parameters, so the description carries the full explanatory burden. It clarifies confirmationToken only as a one-use validation token, says nothing about variationId's origin, and completely omits idempotencyKey, whose retry semantics are exactly the non-obvious part an agent needs.

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 names a specific verb and resource ('Sends ... variation payload') and adds two distinguishing qualifiers: the payload must be exactly the one already prepared, and a one-use confirmation token is validated first. This separates it from draft-creation siblings, though it never names prepare_variation_send explicitly.

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?

Usage is only implied: the phrase 'exact prepared variation payload' signals that a preparation step must have happened first, which points an agent toward prepare_variation_send. There is no explicit when-to-use statement, no statement of what to do if the token was already consumed, and no named alternative.

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