Peppol Directory Search

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

No annotations are present, so the description carries the burden of disclosing behavior. It usefully reveals that the operation is public and unauthenticated, and clarifies it is unrelated to SMP lookup. However, it does not mention return behavior, pagination beyond schema defaults, or any operational caveats, leaving a moderate transparency gap.

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. The first sentence states the operation, and the second sentence conveys access mode, scope exclusion, and an invocation requirement. Every sentence earns its place without unnecessary elaboration.

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?

For a search tool with a rich input schema and an output schema, the description provides the essential missing context: public access, unauthenticated use, non-relation to SMP lookup, and the required-filter condition. It could be slightly more complete by explicitly naming the SMP lookup sibling as the alternative, but it is otherwise sufficient.

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?

The input schema already documents all 8 parameters with 100% coverage, so the baseline is 3. The description adds value by stating a cross-parameter constraint: at least one of q/participant/name/country/doctype must be supplied. This is information not otherwise encoded per-parameter in the 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?

The description opens with a concrete verb and resource: 'Search the Peppol Directory for registered participants.' It also distinguishes itself from sibling tools by stating it is 'no relation to SMP lookup', which prevents confusion with peppol_lookup_participant and related 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 gives clear usage context: it is a public, unauthenticated search, and at least one of q/participant/name/country/doctype must be supplied. It also provides a when-not signal by disclaiming any relation to SMP lookup, though it does not explicitly name an alternative tool for SMP lookup.

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