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

Annotations only declare mutation and open-world traits; the description supplies the operational detail those hints cannot: payload shape {event, at, data}, absence of client emails, HMAC-SHA256 signature verification via X-AIfa-Signature, the one-time secret disclosure, https-only on port 443 with a public domain, no redirect following, and a 3-second timeout. These are exactly the constraints an agent needs before calling and are not derivable from idempotentHint/destructiveHint.

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 with the outcome (what gets posted to your URL), then payload, then security, then constraints, then the disable switch. Dense but every clause carries unique operational information; nothing is repeated from the schema or annotations.

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 single-parameter configuration tool with no output schema, the description covers the return value (secret returned once), the delivered payload, authentication, network constraints, and teardown. Nothing needed to call it correctly or to consume the result is missing.

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 schema already documents url including the empty-string disable case, so the baseline would be 3. The description still adds real meaning: only https, only port 443, public domain names required, redirects not followed — constraints on the accepted value that the schema's "https URL of your endpoint" does not fully spell out.

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 concrete verb and resource plus the exact triggering conditions: a POST on every counted click (event "click") and every commission (event "commission"). An agent knows precisely what this tool configures and what the endpoint will receive, which distinguishes it from every sibling in this affiliate/payout toolset.

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 makes the invocation conditions clear (give an https URL to enable) and explicitly documents the off-path: "Pass an empty url to switch off." It does not name alternatives or state when not to use it, but no sibling offers overlapping webhook functionality, so there is little to differentiate.

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