length_converter

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

With no annotations provided, the description carries the full burden of behavioral disclosure, but it only states the conversion operation and input fields. It does not mention any constraints, error handling, edge cases (e.g., unknown units, case sensitivity, rounding), or the output format. For a simple converter this might be implied, but the description adds no behavioral detail beyond the schema, leaving the agent to infer the behavior.

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 sentences covering the purpose, the units, and the input parameters. It is front-loaded with the main action and includes no fluff or redundancy. Every word adds value, making it appropriately sized for a simple conversion 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?

The tool is simple (a unit converter) with no output schema or annotations. The description provides the essential information: the units and the parameter names. However, it does not describe the return value (e.g., the converted number), error behavior for invalid units, or any formatting details. For a minimal tool this is adequate, but it could be more complete by stating that the output is the converted numeric value and that unsupported units will cause an error.

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 description coverage is 0%, so the description must compensate. It lists the valid unit strings (mm, cm, m, km, in, ft, yd, mi) and states the input order (value, from, to), which helps an agent understand that 'from' and 'to' take these unit strings and 'value' is numeric. However, it does not explicitly state that these are the only acceptable values for from/to, nor does it clarify case sensitivity or aliases, leaving some ambiguity.

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 states 'Convert length' and lists the specific units (mm/cm/m/km ↔ in/ft/yd/mi), making the tool's purpose unambiguous. It distinguishes itself from sibling converters like weight_converter or temperature_converter by naming the unit types, so an agent can immediately identify this as the length-specific 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 provides clear context by naming the units and the input pattern ('value, from, to'), implying the agent should use this tool for length conversions. While it doesn't explicitly mention alternatives or exclusions, the sibling tool names (weight_converter, temperature_converter, etc.) make the usage context obvious, and the description's specificity removes ambiguity about when to select it.

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