list_formats

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

No annotations are provided, so the description bears the full burden. It discloses that the operation is a list (read-only) and that no API key is needed, which is valuable. However, it does not mention whether data is cached or any rate limits; for a simple list operation, this is acceptable but not exhaustive.

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 extremely concise—two sentences with no wasted words. It front-loads the core purpose and then adds the no-API-key detail. Every sentence adds value.

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 no output schema, the description should explain return values. It states what is listed but not the format (e.g., array of strings) or any pagination. For a simple tool, this is adequate but incomplete; the agent lacks full information about the expected response structure.

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?

There are zero parameters, and the input schema is fully covered. The description adds meaning beyond the schema by specifying that the list includes both current formats and roadmap items, giving context to the output. Baseline for 0 params is 4.

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 verb 'List' and the resource 'EU e-invoice formats', including both current validation capabilities and roadmap items. It is specific and distinguishes itself from sibling tools (explain_error_code and validate_einvoice) by focusing on listing supported formats.

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 usage for discovering supported e-invoice formats and mentions no API key required, but does not explicitly compare to sibling tools or provide when-not-to-use guidance. It lacks explicit context on when to choose this tool over alternatives.

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