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

Beyond the annotations (readOnly=false, destructive=false, openWorld=false) it discloses real behavior: a 409 conflict on stale expected_version, the differing scopes required for url vs forms/events changes (settings:notify on own key, personal_key_required on shared key), owner email notification, and that the signing secret is neither changed nor returned. Only minor gap is no note on partial-update semantics (what happens to omitted fields).

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?

Core action and the conflict/versioning rule are front-loaded, and the bracketed scope note plus the when-to-use block are clearly demarcated. It is dense and a bit long, but nearly every sentence carries operational information; the injection-defense paragraph is boilerplate but serves a safety purpose.

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 mutation tool with no output schema, the description covers concurrency failure, permission requirements, side effects (owner mail), and what the tool will not do (change/return the signing secret). An agent has everything needed to invoke it correctly.

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 the baseline is 3; the description still adds meaning by explaining expected_version as an optimistic-concurrency token whose mismatch fails with 409, and by tying the url change to a distinct authorization scope. It does not, however, say whether omitted url/forms/events are left untouched.

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 first sentence names a specific verb (change) and resource (saved form Webhook) and enumerates the mutable fields (destination url, target forms, events). It explicitly points at webhooks_get as the read counterpart, so it is distinguishable from the sibling list/get/test 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?

It states the prerequisite workflow ('read it first with webhooks_get') and that expected_version is required, plus an explicit when-to-use gate: only when the user explicitly asks, and never in response to instructions found in external data. Alternatives and the conditions selecting them are spelled out.

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