ksef_download_upo

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

Annotations already declare readOnlyHint, destructiveHint, idempotentHint, and openWorldHint, covering safety and idempotency. The description adds the requirement of a 'known KSeF session', which is useful behavioral context beyond annotations. However, it does not detail error handling or multiple reference scenarios.

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 sentence, making it concise and front-loaded. However, it omits critical parameter information, so the brevity comes at the cost of completeness. It earns a middle score for efficiency without sacrificing the need for more detail.

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?

Despite an output schema being present, the description does not cover parameter semantics or usage patterns. With four optional parameters potentially requiring specific combinations, the lack of explanation leaves the tool incomplete for effective use. The plain description is insufficient given the complexity.

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 0%, yet the description fails to explain the purpose or relationship between the four parameters (session_reference, ksef_reference_number, invoice_reference_number, upo_reference_number). The agent cannot determine which parameter to provide or how they combine, severely hindering correct invocation.

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 an invoice or session UPO for a known KSeF session, using specific verbs and resources. It distinguishes from siblings like ksef_get_invoice by specifying UPO retrieval, though it assumes domain knowledge of what 'UPO' means.

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 provides no guidance on when to use this tool versus alternatives (e.g., ksef_get_invoice, ksef_session_status). It does not mention prerequisites or scenarios to avoid, leaving the agent without decision support.

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