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

Beyond the annotations, the description discloses the outbound side effect: it sends a sample payload to a configured URL and returns the result. It also adds operational traits such as scope, API mapping, and billing/rate-limit applicability. No contradiction with the annotations is present.

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?

The description is compact and front-loaded: the purpose is stated first, followed by scope, API mapping, and a guard against inventing paths. Each sentence contributes either operational clarity or constraint information without unnecessary filler.

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?

For a one-optional-parameter tool with annotations covering mutability and idempotency, the description is largely complete: it covers the action, scope, API path, and rate-limit context. The only minor gap is that 'returns the result' does not describe the result shape, but no output schema exists and the outcome is reasonably inferable.

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 coverage is 100%, and the only parameter, `x_app_id`, is fully described in the schema as an optional override defaulting to the MCP connection header. The description adds no parameter-specific detail, so the baseline score of 3 is appropriate.

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 states a specific action ('Sends a sample validation webhook payload') and a clear resource ('the configured URL'), then names the OpenAPI operation and HTTP path. This makes the tool's function unambiguous and distinct from sibling test tools like testAppleCertificates and testGoogleConnection.

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?

The description gives useful context: it is the validation-webhook test operation, requires `org:manage` scope, and shares PassFast HTTP API billing and rate limits. It does not explicitly list when to prefer this over alternatives such as listWebhookEvents, but the purpose is clear enough that the agent can infer the appropriate context.

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