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

Goes well beyond the annotations: signing behavior, single-attempt/no-retry semantics, the 409 precondition with its remedy, and exactly what the response reports (2xx outcome, HTTP status, error, duration). This is consistent with idempotentHint=false and destructiveHint=false. No output schema exists, yet the return shape is still disclosed.

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 dense sentences, front-loaded with the action and its scope, followed by execution semantics and the failure precondition. The parenthetical REST mapping is compact and aids recognition; no sentence is wasted.

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?

A simple two-parameter tool with no output schema, and the description nonetheless covers execution behavior, refusal condition, remediation path, and return contents. An agent has everything needed to call it correctly on the first attempt.

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%, and both parameters are fully documented in the schema itself, so the baseline is 3. The description mentions the account ID and access token but adds no format, acquisition, or usage detail beyond what the schema already states.

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: send one webhook.test event to the follow-up's webhook address now. It distinguishes itself from the sibling payer_follow_up_webhook_set, which merely configures the address, and even maps to the equivalent REST endpoint.

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?

Explicitly says to use payer_follow_up_webhook_set when no address is configured, and that this call is refused with 409 in that state. It also sets the timing expectation ('now', 'one try, no retries'), so the agent knows this is a live, non-retryable probe.

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