convert_units

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

No annotations are provided, so the description carries the full burden. It discloses that the tool returns the converted value with its new unit and rejects mismatches. It does not discuss potential failures beyond mismatches, but for a pure conversion tool this is adequate.

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 remarkably concise: two sentences plus a line of examples, all front-loaded with the core purpose. Every sentence adds value without redundancy.

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?

Given the tool's simplicity and the presence of an output schema (not shown but noted), the description covers the essential behavior: conversion, return format, and rejection of mismatches. It could mention supported unit systems or unit syntax, but overall is sufficient.

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%, meaning the description must compensate for parameter meaning. The description gives examples of unit strings (mas, pc, ly) but does not specify the exact format or range of allowed units. This leaves ambiguity for the agent. Baseline 3 is appropriate as the schema itself is minimal.

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 it converts a value between physical units using astropy, and provides concrete examples (mas, pc to ly, km/s), making the tool's purpose specific and distinct from sibling tools like convert_frame.

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 explains the conversion action and explicitly notes that unit mismatches are rejected. While it does not compare with alternatives like convert_frame, the context of sibling tools makes the usage context clear.

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