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

readOnlyHint=true already establishes this as a safe read. The description adds the age-grouping behavior and the API mapping, but says nothing about pagination behavior, sorting, or what the aging buckets look like, and the schema exposes page/per_page that go unmentioned.

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 terse sentences with the core purpose front-loaded and the endpoint as a secondary detail. No filler.

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 report the safety profile and parameters are covered, but with no output schema the description should hint at the aging bucket structure or returned fields. As written an agent knows what the tool conceptually returns but not its shape.

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 three parameters (date, page, per_page) are fully documented in-schema. The description adds no parameter 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?

States a specific resource ('unpaid vendor bills') and transformation ('grouped by age'), plus the underlying endpoint. 'Vendor bills' implicitly distinguishes it from the aged receivable sibling, though it never names that alternative 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?

Usage is implied by the report nature and the 'unpaid vendor bills' scope, but there is no explicit when-to-use guidance, no mention of the aged-receivable alternative, and no note on defaults or prerequisites.

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