validate_mls_message

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

With no annotations, the description carries the behavioral disclosure burden. It reveals that Schematron validation is performed, that the optional xslt2 extra is required, and that full XSD validation is not covered. This is meaningful transparency beyond the schema, though it does not describe output details or error 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 compact and front-loaded with the primary purpose. The additional sentences about Schematron rules and validation scope are informative without fluff, and every sentence earns its place.

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?

The tool has a single parameter and an output schema, so the description does not need to detail return values. It adequately covers prerequisites and limitations, making it largely complete. It could be slightly stronger by noting typical usage context or alternatives, but not critically.

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 100%, with mls_xml_base64 already documented as Base64-encoded MLS XML. The description adds context about Schematron validation but does not add parameter-specific semantics beyond the schema, so the baseline score applies.

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 validates a Peppol Message Level Status (MLS) document, with a specific verb and resource. It also distinguishes the scope by noting Schematron validation and explicitly excluding full UBL XSD validation, which helps separate it from sibling validation tools.

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 when to use the tool: to validate MLS documents via bundled Schematron rules. It notes that full UBL XSD validation is out of scope, which is a useful exclusion, but it does not explicitly name alternatives or state when to prefer sibling tools like validate_eusr_report or invoice_validate.

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