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

Annotations already declare idempotentHint=true and destructiveHint=false, so safety is covered structurally. The description adds genuinely useful behavior beyond them: it is a partial update ('Only the provided fields are changed') and disabling has a side effect on delivery without removing the resource. It does not cover permissions or delivery-timing implications.

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?

Two short sentences, front-loaded with the mutation scope, with zero filler. Each sentence carries distinct information (what changes vs. the disable-without-delete behavior).

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 5-parameter update tool with full schema coverage and no output schema or contradictions, the description supplies the extra semantics an agent needs: partial update and non-destructive disable. Only a note on required 'id' provenance or auth expectations 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 description coverage is 100%, so every parameter (id, url, name, type enum, isEnabled) is already documented in the schema. The description restates which fields are updatable but adds no format, constraint or default detail beyond what the schema provides, so baseline 3 applies.

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 description names a specific verb ('Updates') and resource ('a registered webhook'), and even enumerates the mutable fields (name, URL, event type, enabled state). That is enough for an agent to distinguish it from create_webhook, delete_webhook and list_webhooks, though it never explicitly references a sibling to reinforce the contrast.

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 gives clear operational context: only supplied fields change (partial/PATCH semantics), and disabling stops deliveries without deletion — effectively steering the agent toward isEnabled=false instead of delete_webhook. It stops short of naming that alternative or stating prerequisites, so it is clear context without explicit exclusions.

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