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

Annotations indicate idempotent, non-destructive write. Description adds context: 'free control-plane write', re-registration updates/reactivates, auto-disable after delivery failures, and a security rule about secret handling. No contradictions with annotations.

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 and front-loaded with purpose. It packs essential details without verbosity. Could be slightly more structured (e.g., bullet points) but remains clear and efficient.

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 the presence of an output schema, not explaining return values is acceptable. The description covers all parameters, behavioral nuances, security notes, and re-registration logic. It is complete for a registration tool with this complexity.

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 0%, but the description compensates fully. It details event_types (lists allowed values with explanation), url (requires https), and secret (HMAC-SHA256, length 8-128, not stored by platform). It also explains the behavior for the wallet_address+url pair.

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 states the tool's purpose: 'Register (or reactivate) a lifecycle-event webhook for a wallet'. It specifies the resource (webhook) and action (register/reactivate), and distinguishes itself from siblings like list_webhooks and delete_webhook.

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 provides specific guidance on event_types, url, and secret requirements, including constraints like 'non-empty subset' and 'https(s)'. It explains re-registration behavior. However, it does not explicitly state when not to use the tool or compare with other webhook tools beyond mentioning reactivation.

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