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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive, closed-world). The description goes beyond them by disclosing output semantics (exact vs approximate relation, sources, documented path) and a meaningful behavioral rule about not chaining non-exact relations and requiring expert validation for approximate matches.

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?

Two tightly written sentences with the scope front-loaded and a critical caveat second. No filler, no restatement of the title, and every clause carries information an agent needs.

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?

With no output schema, the description does the work of describing the return contents (relation type, sources, documented path) and its reliability caveat. It is nearly complete for a 3-parameter lookup tool; only the directionality and self-mapping rules for source/target are left unspecified.

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 only 33%: the 'code' parameter is documented with format examples in the schema, and the two enum parameters are self-describing. The description adds value by enumerating the classification families and their geographic origin (Swiss/EU/UN), but says nothing about directionality of the mapping, whether source and target may coincide, or how ambiguity is resolved.

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 states a specific verb ('Find correspondences') and names the exact resources involved (NOGA 2008, NOGA 2025, NACE 2.0, NACE 2.1, ISIC 4), plus clarifying them as Swiss, EU and UN classifications. An agent immediately understands this is a cross-classification code mapping tool and can distinguish it from kyc_check and tariff_lookup.

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?

It provides an important operating constraint ('Never chains two non-exact relations; a non-exact correspondence needs expert validation'), which guides how to interpret and act on results. However, it never states when to reach for this tool versus the sibling tools, nor any prerequisites such as whether source and target may be identical.

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