add_webhook

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

No annotations are provided, so the description carries the full behavioral burden and largely drops it. It does not say whether duplicate URLs are rejected, whether the endpoint is verified/challenged, what secret or signing key (if any) is returned, whether the call is idempotent, or what permissions are needed for a mutating operation.

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?

A single front-loaded sentence with no filler or redundancy. It is efficient, though its brevity is partly the cause of the missing behavioral detail rather than optimal density.

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-parameter create call the description is minimally sufficient to invoke the tool. But with no annotations and no output schema, it leaves open what the call returns (webhook ID, signing secret) and how the registered endpoint is meant to be used — meaningful gaps for a registration/mutation tool in a payment API.

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% for the single `url` parameter, so the baseline is 3. The description adds only a hint of payload context ("payment notifications") beyond the schema's "webhook URL to call when events occur" — no format, validation, or HTTPS constraints are added.

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?

Specific verb + resource: "Register a new webhook callback endpoint" says exactly what is created, and "to receive payment notifications" adds the reason. It is distinguishable from remove_webhook and list_webhooks by implication, but never names them or states the contrast explicitly.

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: an agent can infer this is the create-side counterpart to list_webhooks/remove_webhook. There is no statement of when to prefer this over subscribe_invoice_status (push webhooks vs. subscription streams), nor any prerequisites, exclusions, or limits on how many webhooks may exist.

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