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

Genuinely adds behavior beyond the annotations: replacing the webhook immediately invalidates the previous secret, the new secret is displayed only in this response, a signed POST fires on every status change, and the exact Licium-Signature scheme (t=<unix seconds>, v1=hex HMAC-SHA256 over "<t>.<raw body>") is spelled out. It also names the returned fields (url, updated_at, secret) even though no output schema exists, and the destructive/irreversible consequence is stated plainly.

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-loads the action and the URL constraints, then the response contract, then the signature verification recipe — a sensible order with no filler. Sentences are dense and slightly run-on with parenthetical stacking, but each one carries information an agent needs.

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 3-parameter mutation with no output schema, everything needed to call it correctly and to handle the result is present: address rules, secret rotation semantics, returned fields, and the signature format for verifying the callback. No meaningful gap remains.

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, but the description compensates for what the schema does not enforce: HTTPS only, port 443 or 8443, public host with private/loopback/link-local addresses explicitly banned. It also clarifies the provenance of account_id and access_token by tying them to payer_follow_up_request, adding meaning beyond the property descriptions.

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 ('Set the follow-up's webhook address') and pins it to a REST endpoint (PUT /v1/payer-follow-ups/{id}/webhook), so the operation is unambiguous. It does not differentiate from the near-identical sibling payer_follow_up_webhook_test, which an agent must still disambiguate on its own.

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 by the constraints on the url (public HTTPS host, ports 443/8443) and by the note that the returned secret is shown once. There is no statement of when to call this versus payer_follow_up_webhook_test, nor prerequisites such as needing a follow-up created by payer_follow_up_request first. Adequate but leaves routing to inference.

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