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

readOnlyHint=true already establishes the safe-read profile, and the description adds the API route plus the notion that results are scoped to a customer/product. It does not disclose anything about the caching behavior (from_cache defaults to true), freshness of results, or ordering/pagination, which are the real behavioral unknowns for a list tool.

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?

A single front-loaded sentence carries the substance, followed by a compact API path. Nothing is padded, though the trailing 'API: GET ...' line is metadata that contributes little to tool selection.

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?

A simple read-only list tool with fully documented parameters and a readOnly annotation needs little more. With no output schema, one would ideally know the return shape and ordering, but the omission is minor for this complexity level.

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 four parameters including defaults. The description only echoes the product and payment-status dimensions, adding no syntax, format, or default detail beyond the schema; 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 verb and resource ('List all invoices for a customer') and adds scope detail ('optionally for a specific product, with payment status'). It is distinguishable in practice from the singular sibling amberflo_get_customer_invoice, though that contrast is never made explicit.

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 optional product scoping and payment-status mention imply when this tool fits, but there is no explicit when-to-use vs. when-not guidance and no pointer to the sibling amberflo_get_customer_invoice for single-invoice lookups. Usage is left to inference.

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