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

Goes well beyond the annotations: explains patch semantics ('only the fields you send change'), that 'events' is a lossy full replacement rather than a merge, and the auth/workspace preconditions including the specific 403 failure mode. This is exactly the destructive/idempotent nuance the destructiveHint and idempotentHint flags cannot convey.

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 sentences, front-loaded with the action and fields before prerequisites. Dense but every clause carries information; the workspace-claim sentence is slightly long but explains a concrete rejection case an agent would otherwise hit blind.

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, it covers what changes, what is preserved, replacement semantics, and permission gates. It omits what the response contains and whether an accidental events replacement can be recovered, but nothing essential to correct invocation is missing.

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 meaningful semantics by framing the call as a partial update, clarifying that status is the on/off switch, and reinforcing that events replaces rather than appends. It does not add anything about webhook_id resolution beyond what the schema says.

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 (Change) and resource (webhook endpoint) plus the exact mutable fields (url, events, status). An agent can distinguish it from create_webhook/delete_webhook/list_webhooks without opening the schema, since those verbs are semantically disjoint and the description scopes it to modifying an existing endpoint.

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 the operative context for using it: owner/admin role required, key must have no scope limits or be a person's sign-in, and a claimed workspace is required or the call returns 403. It does not explicitly name alternatives (e.g., delete_webhook to remove, create_webhook to add), so it stops short of full alternative routing.

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