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

Annotations already cover read-only, idempotent, non-destructive behavior, so the bar is lower. The description still adds real context: a 30-day retention window, newest-first ordering, and the returned fields (status, attempts, response) that an agent needs to interpret results.

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 sentences, zero waste, with the scope and retention/ordering facts front-loaded before the use case. Every clause carries information.

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 read-only list tool with annotations and an output schema, the definition covers scope, time window, ordering, and typical use. Pagination and filter behavior are left entirely to the schema, which is acceptable here but keeps it just short of complete.

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 all seven parameters are already documented, and an output schema exists. The description adds only the implicit notion of filtering by failure, without explaining how the q, event, status, or pagination parameters shape results. Baseline 3.

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 and resource ('List the delivery log of one webhook endpoint') with scope and ordering, which separates it from get_webhook_delivery (single delivery) and list_webhooks (endpoints). It does not explicitly name those siblings, so differentiation is inferable rather than stated.

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 it to find failed deliveries' names one clear scenario, but there is no guidance on when not to use it or which sibling to pick for per-delivery detail or retrying (resend_webhook_delivery). Adequate but leaves alternative selection to inference.

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