explain_sic_code

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

With no annotations, the description carries the full burden, and it does disclose meaningful traits: it is a pure offline lookup, requires no API key/auth, and preserves leading zeros. It stops short of stating what happens for an invalid or unknown code, which is the one behavioral 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?

Front-loaded with the core purpose in the first sentence and the example immediately after; almost every sentence earns its place. The trailing "Args:" block partially restates the format already given above, which is mild redundancy rather than bloat.

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 single-argument lookup with an output schema present, the description is largely complete — the output schema handles return values and the description still adds a sample mapping. The only thin spot is invalid-code behavior, which neither the description nor the schema covers.

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 0% with one parameter, so the description must compensate, and it does: it gives the expected format (5-digit, example "43220") and explicitly notes that leading zeros are kept — a real semantic detail given the string type. Missing only validation/error semantics for malformed input.

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?

Specific verb ("Decode") plus specific resource ("UK SIC code"), with the domain role spelled out ("the 5-digit 'nature of business' code on every company record"). It is unmistakable against siblings search_companies, get_company, and get_filing_history, and the worked example removes any ambiguity about output.

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 situates the tool in the company-record workflow (SIC codes appear on company records) and states the operational context: works offline, no API key needed. It does not explicitly name siblings or say when NOT to use it, but the alternatives are not plausibly confusable, so the implicit guidance is sufficient.

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