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

Annotations already declare readOnlyHint=true and destructiveHint=false, so the safety profile is covered; the description reinforces this and adds scope ('owned' subscriptions) and the no-mutation guarantee. It stops short of describing return shape or count/pagination behavior, which for a list tool with no output schema would have been useful, but with annotations carrying safety this is solid.

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?

Three short sentences, front-loaded with the trigger condition, then the read-only guarantee, then the sibling redirect. Every sentence adds distinct value with no repetition.

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 parameterless read-only list tool with no output schema, the description covers purpose, trigger, and the nearest alternative tool. The only missing piece is any hint about the returned collection (size, pagination, fields), which is a minor gap given the absence of an output schema.

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?

Zero parameters, so the baseline is 4. There is nothing for the description to disambiguate and it makes no misleading claims about inputs; it simply omits any mention of parameterization, which is appropriate for a no-arg listing call.

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?

States a specific verb+resource (list webhook subscriptions) and anticipates the user's vocabulary with concrete synonyms (callback URLs, integration subscriptions, event endpoints). It differentiates from the closely named sibling by pointing to list-webhook-events for event keys, so an agent can pick it apart from the other webhook tools.

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?

Opens with an explicit trigger ('Use this when the user asks which webhooks... are configured') and names the alternative tool (list-webhook-events) for the distinct job of discovering valid event keys. Nothing is left to inference for when to select this tool.

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