merit_get_purchase_invoice

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

With no annotations, the description carries the full burden. It discloses that the response includes rows and payments, and that skipAttachment omits the PDF for a smaller response, which is useful. It does not mention side effects, error behavior, or permissions, but the verb 'Get' strongly implies a read-only operation.

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 concise two-sentence definition with no filler. Key details are front-loaded: the operation, resource, and response contents appear first, followed by the endpoint and parameter clarifications.

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 simple get-by-id tool with two parameters and no output schema, the description covers the essential semantics: what is returned and how to shrink the response. It could mention behavior for missing/invalid IDs or authentication needs, but these are less critical given the tool's simplicity.

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?

Although schema coverage is 100% and the baseline is 3, the description adds value by specifying that skipAttachment omits the PDF and produces a smaller response. It also reinforces that id is the PIHId GUID, which helps the agent map the parameter to the intended API field.

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 states a clear, specific action: 'Get one Merit Aktiva purchase invoice with rows and payments'. It distinguishes itself from sibling listing tools by emphasizing 'one' invoice and from the sales invoice getter by specifying 'purchase'. The endpoint reference adds further precision.

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 when to use this tool: when you need a single purchase invoice and its rows/payments. However, it does not explicitly name alternatives or state conditions for choosing this over merit_list_purchase_invoices or merit_get_purchase_invoice PDF-related tools. Usage guidance is inferred rather than stated.

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