generate_verifactu_qr

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

Annotations already declare readOnly, idempotent, and closed-world behavior, so the bar is lower, and the description still adds real context: 'environment' selects the AEAT production versus test portal, the verifactu flag selects between ValidarQR and ValidarQRNoVerifactu endpoints, and the image uses error correction level M. It does not mention failure modes such as invalid NIF or malformed numserie, keeping it from a 5.

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 one-line purpose statement is front-loaded and the Args block is dense with zero filler; every line adds information an agent needs. The docstring-style 'Args:' formatting is slightly machine-unfriendly, but nothing is redundant.

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?

With an output schema present, the description does not need to enumerate return fields, and it still names URL and image plus the print_rules guidance. For an 8-parameter tool with rich format requirements, this is close to complete; only error behavior and the relationship to sibling validation tools are absent.

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%, so the description must carry all parameter meaning, and it does: date format conversions (AAAA-MM-DD and DD/MM/AAAA accepted), importe requiring a decimal point with an example, size_px bounds 100-2000, image_format png/svg, and the semantic distinction behind the verifactu boolean. This is meaningfully more than the bare schema titles.

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 opens with a specific verb and resource: 'Generate the AEAT tax QR (QR tributario) of an invoice: URL and image.' This tells the agent exactly what comes back. It does not explicitly contrast itself with the sibling 'check_qr_url', so it stops short of a 5.

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?

Usage is only implied: the agent can infer this is for producing the QR that must appear on an invoice, and the 'verifactu' flag hints at which system configuration applies. There is no explicit statement of when to use this versus check_qr_url or verifactu_hash, and no exclusion or prerequisite is named.

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