Create Webhook

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

With no annotations, the description carries the full behavioral burden, and it discloses a high-value non-obvious trait: secret_key is returned only once and must be stored immediately. It also names the verification header (X-Up-Authenticity-Signature), which tells the agent what the secret is for. It stops short of stating auth requirements, duplicate-URL behavior, or retry semantics.

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?

Two sentences, no filler, with the core action front-loaded and the one-time secret warning immediately after. Every clause carries information the agent cannot get elsewhere.

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 two-parameter creation tool with full schema coverage and an output schema, the description covers the critical operational fact (one-time secret) that a schema cannot express. It is nearly complete; a note on authorization or duplicate registrations would close the remaining gap given the absence of annotations.

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%, so 'url' (publicly reachable HTTPS) and the optional 64-character 'description' are fully documented in the schema. The description adds no parameter-level detail beyond that, so the baseline 3 applies.

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 ('Register a webhook') plus the event scope ('for transaction events'), which cleanly separates it from the list/get/delete/ping webhook siblings. An agent needs no schema inspection to know this creates a new subscription.

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?

There is no explicit when-to-use guidance, no prerequisites (e.g. required plan or permissions), and no mention of when to prefer this over ping_webhook or list_webhooks as a next step. The only usage-adjacent content concerns verifying deliveries after the fact, not selecting this tool.

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