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

Annotations already cover the safety profile (readOnly, non-destructive, open-world), and the description adds real behavioral context: newest-first ordering, 100-per-page paging, empty due dates when no payment plan exists, and an auth requirement. Balance/due-date semantics go beyond the structured fields.

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?

Purpose and ordering are front-loaded, then field semantics, then paging constraints, then auth. Every sentence carries information; only the field list borders on restating the schema.

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 usefully explains the key return fields (total, amount paid, balance, due date) and their derivation, plus cursor paging and the auth requirement. Adequate for a filtered list tool whose annotations already cover safety.

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 the schema already documents all five parameters including the status enum. The description adds semantic detail about output fields (balance, due date) but nothing extra about parameter usage, so the baseline of 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 verb and resource ("Lists invoices") plus the returned fields, so the agent knows exactly what it retrieves. It does not explicitly distinguish itself from siblings like dubsado_create_invoice or dubsado_send_invoice, but the verb is unambiguous.

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 description never says when to use this tool versus alternatives, nor does it state prerequisites beyond the API-key note. It gives ordering and page-size facts but no usage conditions or exclusions.

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