check_color_contrast

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

No annotations provided, so description carries full burden. It discloses the extraction process (CSS vars + dominant colors) and fallback behavior. No destructive actions or rate limits mentioned; sufficient for a check tool.

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?

Description is two sentences, front-loads the primary purpose, and efficiently conveys core behavior and conditional logic 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?

No output schema, so description should specify output. It mentions 'ratio + pass/fail' and 'suggests replacements' but lacks details on suggestion format. Adequate but not fully complete.

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% providing baseline 3. Description adds workflow context (how url and brandColors trigger suggestions, fallback without them) beyond schema definitions, aiding parameter selection.

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 that the tool checks a foreground/background color pair against WCAG contrast thresholds and optionally suggests brand-aligned replacements. It distinguishes itself from unrelated sibling tools.

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 when suggestions are provided (with url or brandColors) and when only ratio/pass-fail is returned. It does not explicitly mention alternatives but sibling tools are unrelated, so context is clear.

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