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

Annotations already declare readOnlyHint=true, so the description adds limited behavioral insight. It mentions the API endpoint and optional filters, but does not disclose caching behavior, pagination, authorization needs, or data freshness trade-offs beyond the schema parameter 'from_cache'.

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?

The description is a single, well-structured sentence that conveys the core functionality without extraneous words. It is front-loaded and efficient.

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?

The tool lacks an output schema, and the description does not specify the return format, pagination, or error handling. While the parameter details are covered in the schema, the description itself is too terse to fully inform an agent about expected results or limitations.

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 coverage is 100% with clear descriptions. The description echoes 'optionally for a specific product' and 'with payment status' but adds no new meaning beyond what the schema provides. Baseline 3 is appropriate as the description does not compensate for any gaps.

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 clearly states the action (list), resource (invoices for a customer), and optional filters (by product, payment status). It is specific and distinguishes from the sibling tool 'get_customer_invoice' which likely retrieves a single invoice.

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 implies listing all invoices, but does not explicitly guide when to use this tool over alternatives like 'get_customer_invoice'. It lacks when-to-use or when-not-to-use advice, and no prerequisites are mentioned.

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