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

Annotations already declare readOnly, idempotent, non-destructive and closed-world, so the safety profile is covered. The description adds real behavioral value beyond that: it discloses exactly what data comes back (events, category filters, active state, signing-secret prefix) and that delivery history appears only in the id-scoped mode.

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 dense sentence with the primary scope front-loaded and the conditional mode appended. Efficient, though the field enumeration makes it somewhat list-heavy for one sentence.

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?

With no output schema, the description correctly carries the burden of describing return content, and it does so at both levels (destination list and delivery records). Combined with complete annotation coverage for a read-only tool, an agent has everything needed to call 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 50%: webhook_id is documented in the schema and the description reinforces its meaning (it switches the tool into recent-deliveries mode). The limit parameter is undocumented in both schema and description, and the description adds no syntax or range guidance for it.

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?

Names the resource (the account's webhook destinations) and enumerates the payload fields returned, making the verb effectively 'list with optional detail drill-down'. It is distinguishable from create_webhook/manage_webhooks, though it never names them explicitly.

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?

The conditional 'when a webhook id is given' implies two modes of use (overview vs single-destination with deliveries), which is useful implied guidance. However, there is no explicit statement of when to choose this over manage_webhooks or create_webhook, and no prerequisites or exclusions.

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