check_color_contrast

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 reveals only that the tool checks a contrast ratio, but it doesn't state what the output is (e.g., numeric ratio, pass/fail), whether WCAG levels are considered, or any edge cases like invalid color formats. This is minimal behavioral disclosure.

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, front-loaded sentence that is appropriately concise for a simple function. Every word adds value, and it avoids unnecessary elaboration or visual clutter.

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 with no output schema, so the description should clarify what the tool returns. It only says 'check contrast ratio', leaving the result format ambiguous. With no alternatives or caveats mentioned, the description is incomplete for an agent expecting to act on results.

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 schema has 100% description coverage for both parameters (foreground and background), so the baseline is 3. The description doesn't add any meaning beyond what the schema already provides; it merely says 'two specific colors', which is implied by the parameters.

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's function: 'Check contrast ratio between two specific colors'. This is a specific verb (check) and resource (contrast ratio), and it distinguishes from siblings like analyze_color_scheme and analyze_accessibility by focusing on the contrast ratio between two explicit colors.

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 no guidance on when to use this tool versus alternatives such as analyze_accessibility or analyze_color_scheme. It doesn't mention any context, prerequisites, or exclusions, leaving the agent without direction for tool selection.

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