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

No annotations are provided, so the description carries full burden. It mentions AA/AAA compliance levels but does not clarify the return format (e.g., ratio value, pass/fail), error handling for invalid hex values, or other behavioral details. The description is insufficient for the agent to know exactly what to expect.

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 concise and front-loaded, conveying the essential purpose in a single sentence. No unnecessary words.

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?

Despite the tool's simplicity, the lack of output schema and param descriptions, combined with minimal behavioral transparency, leaves gaps. The agent may not know what the tool returns or how to provide valid input.

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%, yet the description only states 'two hex colors' without specifying which parameter is foreground (fg) or background (bg), nor the expected hex format (e.g., with or without '#'). The parameters are not individually explained.

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 the tool computes WCAG contrast ratio between two hex colors, specifying AA/AAA levels. It distinguishes from sibling tools like color_convert, which handles color space conversion, not contrast ratio.

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 includes a 'When:' clause that indicates the tool is for WCAG contrast ratio for UI color pairs, providing clear context. However, it does not specify when not to use it or mention alternatives.

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