describe_fields

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

No annotations are provided, so the description must fully disclose behavior. It states this is a reference tool (implying read-only and no side effects), but lacks details on data freshness, output format, or whether it caches results. The minimal disclosure is insufficient for comprehensive transparency.

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 short sentences with key information front-loaded. No redundant or extraneous text, every word 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?

For a zero-parameter tool with no output schema, the description is somewhat complete but lacks clarity on the scope of fields described. Given the context of many sibling tools, it could specify which tool's fields it covers to be fully complete.

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 tool has zero parameters, and schema coverage is 100% (empty schema). The description does not need to explain parameters, and it correctly omits irrelevant details. This aligns with the baseline expectation.

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 it is a reference for field meanings and units, which clearly indicates the tool's purpose. However, it does not specify which fields, leaving some ambiguity. It distinguishes from sibling tools by being a documentation tool rather than a data retrieval or filter tool.

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 advises 'call once; don't repeat,' which is a clear usage instruction. However, it does not provide when-to-use or when-not-to-use guidance, nor does it mention alternative tools for similar tasks.

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