get_purchase_invoices

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

With no annotations provided, the description carries the full burden. It discloses that the tool returns specified fields and optionally filters by due date, which is helpful. However, it does not mention any side effects, pagination behavior, default sort order, or limitations, leaving some behavioral aspects undisclosed.

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 two sentences long, front-loaded with the primary purpose. The second sentence efficiently lists the return fields and the optional filter without extraneous details. Every sentence earns its place, making it concise and well-structured.

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 description lists the key return fields (creditor name, reference, due date, open amount, currency) which is valuable since there is no output schema. It also explains the optional filter. However, it does not mention pagination, defaults (e.g., sort order), or the behavior of includeBankTransactions, which are covered by the schema but not the description, leaving slight gaps in completeness.

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 fully documents all four parameters. The description adds little beyond referencing dateOutstanding as an optional filter, but this is redundant with the schema. Therefore, a baseline score of 3 is appropriate.

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 tool retrieves outstanding (unpaid) purchase invoices from Yuki, specifying the resource (purchase invoices), status (unpaid), and source (Yuki). It distinguishes itself from sibling tools like get_sales_invoices by explicitly mentioning purchase invoices and outstanding status.

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 usage when outstanding purchase invoices are needed, and the optional dateOutstanding filter provides a clear context. However, it does not explicitly mention when not to use this tool or suggest alternatives, such as get_missing_invoices or get_transactions, so the guidance is implied rather than stated.

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