Submit to FACe (Spain B2G)

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

Annotations show readOnlyHint=false, so write operation is implied. Description adds that it returns a submission reference, explains modes (mock is safe), and mentions DIR3 requirement. No contradiction with annotations. Could mention side effects or authentication needs.

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?

Front-loaded with main action. Mode list is clearly structured. Bilingual but not excessive. Each sentence adds value. Could remove Spanish repetition, but still efficient.

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?

Covers purpose, prerequisites, modes, return value. Output schema exists so return details are covered. Adequate for a simple submission tool. Lacks error handling or rate limits, but not critical.

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% with descriptions for both parameters. Description enriches with domain context: DIR3 codes requirement, mode explanations (mock, sandbox, production), and return value (registration reference). Adds value beyond schema.

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?

Clearly states verb (Submit), resource (Facturae-formatted invoice), and target (Spanish FACe B2G portal). Includes return value and prerequisite (DIR3 codes). Distinguishes from sibling tools like face_status and ksef_submit.

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?

Explains when to use (submitting to Spanish government) and prerequisite (DIR3 codes). Describes three modes with context (mock for dev/test, sandbox for pre-prod, production default). No explicit not-to-use guidance, but context is clear.

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