Submit to FACe (Spain B2G)

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

The description adds value beyond annotations by detailing the three modes and the requirement for DIR3 codes. Annotations are minimal (no readOnly, destructive, idempotent hints contradicted), so the description carries the burden but does not fully disclose potential side effects or idempotency behavior.

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 concise, front-loaded with English, and includes a Spanish translation. Each sentence adds value, though the bilingual format slightly increases length. No unnecessary fluff.

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?

Given the presence of an output schema and the tool's specific domain, the description covers prerequisites (DIR3), modes, return value, and references the sibling tool for subsequent status polling. It is sufficiently comprehensive for an agent to invoke correctly.

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% and both parameters have descriptions in the schema. The description provides additional context for the 'mode' parameter (e.g., default is production, mock is safe) but largely repeats schema information. Baseline 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 it submits a Facturae invoice to the Spanish FACe B2G portal, with specific prerequisites (DIR3 codes) and return value. It distinguishes itself from the sibling face_status by noting the returned reference can be used with that tool.

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 explains the three modes (mock, sandbox, production) with guidance on when each is appropriate, including that mock is safe for dev/test. However, it does not explicitly state when to use this tool versus alternatives (e.g., face_status for polling) or provide exclusions.

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