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

With no annotations, the description carries the full burden and does so well: it discloses pricing (free trial, $0.10 later, refunded on send failure), HMAC-SHA256 signing, the difference between series.changed and source.changed, that unknown source URLs are refused, and that api_key is not metered. This level of disclosure is thorough for a webhook registration tool.

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 long but densely packed with essential information. It uses bullets for the two watch types and front-loads the core purpose. Every sentence contributes to usage clarity; the structure helps parsing despite the length.

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 tool's complexity (pricing, security, two modes, constraints), the description covers the essentials: required and optional params, limits, event types, and its relationship to polling. No output schema is present, but the description does not need to explain return values since it's a registration call. Missing details like webhook payload structure are minor given the scope.

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% with descriptions already present. The description adds significant semantic value beyond the schema: it explains the meaning of series vs sources, gives examples, clarifies that source URLs must be exact and fingerprinted, and states max limits. This is more than the baseline 3 for full coverage.

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 states a specific purpose: binding a webhook to receive notifications when served values or source document bytes change, preventing silent staleness. It also differentiates itself from sibling tools like get_changes by explicitly being a push alternative (retention, not polling).

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?

Clear usage guidance is provided: it says 'Prefer this over polling get_changes if you are a long-running agent,' and explains the two watch types (series vs sources) with distinct semantic triggers. It also notes constraints (max 20 each, required url). It doesn't explicitly list when NOT to use it, but the alternative guidance is sufficient.

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