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

With no annotations, the description must carry behavioral disclosure, and it does add useful facts: HMAC-SHA256 signing and that the secret is returned only once. However, it does not disclose that this creates a persistent subscription or what happens on repeated registration, leaving part of the behavioral surface unspecified.

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 a single compact sentence with no filler; the signing and one-time-secret caveat is high-value and placed after the core function. Every phrase earns its place.

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 no annotations and no output schema, the description should cover the essential call semantics. It handles URL and security, but it omits event_types semantics, response/return details, and any setup or validation requirements, so an agent cannot fully reason about the call.

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 0%, so the description has to explain the parameters, but it only clarifies that the URL must be HTTPS and vaguely refers to events. The event_types parameter is not explained at all, including its optionality or possible values.

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 conveys the core function: events will be pushed to a supplied HTTPS URL, and it adds the signature detail. It relies partly on the title for the 'register' action and does not contrast with siblings, but the resource and push behavior are clear enough.

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?

No guidance is given about when to use register_webhook instead of a sibling such as events or when not to use it. The only implicit cue is the HTTPS URL and webhook terminology, so an agent has to infer the intended use case.

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