describe_type

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

With no annotations, the description carries the behavioral disclosure burden. It does disclose the output substance—all fields with units and meaning—which implies a read-only introspection operation. It does not mention error behavior, naming requirements, or whether inherited/nested fields are included, but the core behavior is reasonably conveyed.

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 a single compact sentence with no filler. The first clause states the core value, and the dash clause provides a concrete example. Slightly redundant, but efficient and well-sized for a one-parameter tool.

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 compensates by saying what is returned: all fields, with units and meaning. However, it does not describe the return structure, ordering, or any limitations, and the lack of an explicit verb leaves some ambiguity. It is adequate for a simple tool but not fully specified.

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 100% for the single 'name' parameter, so the description is not required to document it in depth. The phrase 'derived type' and the aqu_d example add domain context for what kind of type name is expected, but this is marginal beyond the schema's 'Type name, e.g. aquifer_dynamic'.

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 indicates the tool enumerates every field of a derived type, including units and meaning, and grounds it with a concrete example (aqu_d). The verb is implicit but recoverable from the tool name and phrasing. It does not explicitly name sibling tools, but the resource and output are specific enough to distinguish it from procedure-, I/O-, and scope-oriented siblings.

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 it: when you need to know what fields and units a state object/derived type contains. It does not explicitly contrast against alternatives like search_fields or scope_at, nor state when not to use it, so the guidance is left to inference.

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