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

Annotations already declare readOnlyHint=true and openWorldHint=false, so safety is covered. The description adds useful output context (retry state, last error) but says nothing about ordering, default page size behavior, or what 'dead_letter' or 'skipped_suspended' statuses imply operationally.

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 tight sentences: what the tool returns first, then the debugging use case. No filler and nothing buried.

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 small read-only list tool with full schema coverage and no output schema, the description covers purpose, scope and returned fields adequately. Minor gaps (ordering of deliveries, how paging interacts with a filtered status) remain but are not blocking.

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 status enum values, pagination cursor, and webhook_id are all documented in the schema. The description adds no syntax or filtering guidance beyond that, so baseline 3 is appropriate.

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 resource and scope: delivery attempts for one webhook, and enumerates the returned fields (status, attempt count, last HTTP status/error, next retry). The 'one webhook' scoping implicitly separates it from list_webhooks, though no sibling is named 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?

'Use to debug why events are not arriving' gives a clear situational trigger for reaching for this tool. It stops short of stating when not to use it or pointing at an alternative such as list_webhooks when the subscription itself is the question.

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