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

With readOnlyHint=true already covering the safety profile, the description adds real behavioral value by stating that results include the HTTP outcome of each delivery attempt, which is what makes the debugging framing actionable. It omits operational details such as delivery retention window or pagination defaults, but it is well above the annotation-provided floor.

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 compact sentences with the purpose and the use-case hook front-loaded before the API mapping. The trailing 'Polar: GET /v1/webhooks/deliveries' is informational rather than functional, a minor use of space, but nothing is bloated.

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 endpoint with zero required parameters and no output schema, the description covers what the tool does and why an agent would call it. It could note that all parameters are optional filters or mention pagination behavior, but no critical calling information 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% and all seven filters (page, limit, succeeded, event_type, endpoint_id, start/end_timestamp) are documented in the schema itself. The description adds no filter semantics beyond the schema, so the 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+resource ('List webhook delivery attempts') and qualifies it with what is actually returned ('with their HTTP results'), which separates it from polar_list_webhook_endpoints (configuration) and polar_redeliver_webhook_event (action). It does not name a sibling explicitly, so it stops just 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?

'the tool for "why did my webhook not arrive?"' gives a concrete diagnostic scenario that tells the agent when this list tool is the right pick over other list tools. No explicit when-not conditions or named alternatives are provided, so it is clear context rather than full routing guidance.

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