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

Annotations already declare readOnlyHint=false and openWorldHint=true, so the state-changing external nature is partly covered; the description reinforces it and adds the non-obvious detail that creation happens "after authorization." The note that test dispatch is unavailable further constrains behavior, though return payload and duplicate/error handling are not described.

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 tight sentences, front-loaded with the trigger condition and followed by constraints; no filler. The synonym list is slightly long but serves discovery matching, so it 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?

With no output schema, the description covers purpose, prerequisites, and authorization context sufficiently to invoke correctly. It does not say what the tool returns or how duplicate URLs are handled, leaving a small gap for a creation tool.

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%, so all three parameters are already documented in the schema; the description only repeats the event-key sourcing (list-webhook-events) that the events parameter description already states. Baseline 3 is correct — no additional syntax or format meaning is layered on.

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 (create a webhook subscription) and enumerates the synonyms an agent may encounter in user phrasing (callback URL, n8n/Zapier endpoint, integration subscription). This cleanly distinguishes it from the update-, delete-, and list-webhook siblings.

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?

Explicit triggering condition ("Use this when the user wants to add a webhook") plus a prerequisite route to a named sibling ("Use list-webhook-events first for valid event keys") and a scope exclusion ("webhook test dispatch is not exposed"). When-to-use, ordering, and out-of-scope are all stated.

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