register_webhook

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

With no annotations, the description carries the full burden. It discloses that the tool returns a signing secret, which is a useful behavioral detail. However, it does not mention mutability, idempotency, authentication needs, or potential side effects like overwriting an existing webhook.

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?

The description is concise (two sentences) and front-loads the purpose. Every sentence adds value: first defines action and resource, second states the return value. No redundant or vague phrases.

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?

Given two simple parameters and no output schema, the description covers the primary return value (signing secret). However, it lacks details on error handling, confirmation, or idempotency behavior, leaving moderate gaps for an agent.

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 50%; the description adds context for the events parameter by listing values, but for the required url parameter, it provides no additional meaning beyond the schema. The description does not explain URI format, validation, or behavior when omitted.

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?

The description clearly identifies the action ('Register an HTTPS endpoint'), the resource ('outbound events'), and lists specific event types (transaction, balance, issued, card_status, kyc). It distinguishes from sibling tools like list_webhooks by focusing on creation.

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 implies usage for registering webhooks but provides no explicit guidance on when to use this tool versus alternatives (e.g., when to list or delete webhooks). No prerequisites or exclusions are mentioned.

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