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

Adds substantial behavior the annotations cannot convey: partial update semantics, that eventTypes replaces rather than appends, that the HMAC secret is neither returned nor rotated, and the required `webhooks:write` API-key scope. For a destructive, non-idempotent, open-world tool these are exactly the details an agent needs before invoking.

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?

Four tight sentences, front-loaded with the verb and the biggest ambiguity (partial vs full update). Every clause carries a distinct fact — mutation model, pause idiom, replacement semantics, secret handling, auth scope — with no filler.

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?

Complete enough to call correctly: mutation semantics, secret behavior, and auth scope are all covered, and no output schema exists so return values need not be explained. The only omission is any note on failure modes or validation of url/eventTypes, which is minor given the schema's own descriptions for account/workspace.

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 71%, so the schema already documents most parameters. The description still adds meaning at the schema level: absent fields are left untouched, and eventTypes is a full replacement rather than a merge — the latter restated from the schema, but the partial-update rule is genuine added semantics.

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 and resource ("Partial-update a webhook subscription") and immediately qualifies the mutation model as pass-through PATCH-style. This clearly separates it from pm_create_webhook, pm_delete_webhook, and pm_get_webhook siblings without naming them.

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?

Gives actionable routing guidance: use `active: false` to pause deliveries instead of deleting, which points the agent away from pm_delete_webhook for a common intent. It does not mention pm_get_webhook for reading state first or pm_get_webhook_usage, so the alternative-selection story is incomplete but the key non-obvious case is covered.

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