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

Annotations only cover the safety profile (readOnlyHint=false, destructiveHint=false, openWorldHint=false). The description goes well beyond, disclosing the one-time signing secret that cannot be retrieved again, the Swop-Signature header format and HMAC construction, and a ~15 hour retry window for failed deliveries — exactly the behavioral context an agent needs.

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 ('Get notified the moment the user gets paid'), then layers in the one-time secret warning, signature format, and retry window. Every sentence carries operational value, including the user-confirmation instruction.

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?

No output schema exists, so the description correctly covers the return value (a signing secret shown ONCE) and delivery semantics (signature header, retries). Combined with annotations and full schema descriptions, an agent has everything needed to call and use the tool correctly.

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%, so the baseline is 3, and the description adds real meaning by explaining the event payloads and when they fire, which enriches the 'events' parameter beyond its bare enum. It does not restate the https/localhost rule or maxLength, which the schema already covers.

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 (register) and resource (an https webhook URL) plus the triggering events (checkout.paid, payout.released). An agent can distinguish it from swop_list_webhooks, swop_remove_webhook, and swop_test_webhook purely from the description.

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?

Gives clear context ('the moment the user gets paid') and a prerequisite workflow step ('Confirm the exact URL with the user first'). It does not explicitly name alternatives like swop_test_webhook or swop_remove_webhook, so an agent must infer lifecycle routing rather than being told.

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