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

Annotations already declare readOnly=false, idempotent=true, destructive=false and openWorld=true, so the safety profile is covered. The description adds genuinely useful semantics beyond that: 'Replaces' signals full overwrite of url and events rather than a partial patch, which changes how an agent must construct the call. It does not explain the effect of omitting status, keeping it from a 5.

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?

A single front-loaded sentence with no filler; the replacement semantics come first and the status toggle is appended as a secondary case. Nothing is wasted.

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 and 50% parameter coverage, the description leaves open whether status is optional, whether omitted fields are cleared, and what the response contains. It is adequate to call the tool but not fully self-sufficient.

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 50%, so the description must compensate, and it does name three of four parameters (url, events, status) with their roles. However, it never clarifies that status is optional or what happens when it is omitted, and endpoint_id is only explained in the schema itself.

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 ('Replaces') and resource ('url and events of an endpoint') plus the secondary status toggle, which clearly separates it from create_webhook and rotate_webhook_secret. It does not explicitly name a sibling, so it stops short of a 5.

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?

Usage is only implied by the verb 'Replaces' — an agent can infer this is for modifying an existing endpoint rather than creating one. There is no explicit guidance on when to use this versus rotate_webhook_secret, nor any note about prerequisites such as needing an endpoint_id from list_webhooks.

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