check_color_contrast

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

No annotations are provided, so the description must disclose behavioral traits. It does not confirm the tool is read-only, mention any side effects, or explain authentication requirements. The description only states the output, missing important behavioral context.

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 two sentences long, front-loaded with the core purpose, and contains no extraneous information. Every word adds value.

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 no output schema, the description mentions return values. However, it does not specify the output format (e.g., JSON structure) nor provide context for optional parameters like apiKey. The tool's behavior is adequately described for simple use, but lacks depth for complex scenarios.

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 input schema has 100% description coverage for all three parameters (selector, tabId, apiKey). The description adds no additional meaning beyond the schema, merely restating the return value. A score of 3 is appropriate as schema covers parameter semantics adequately.

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 checks color contrast ratios against WCAG AA and AAA standards, specifying it returns contrast ratios and pass/fail status. This is a specific action on a resource, but it does not explicitly differentiate itself from sibling tools like run_accessibility_audit, which may also evaluate contrast.

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 get_computed_styles or run_accessibility_audit. It does not mention prerequisites, limitations, or contexts where this tool is preferred.

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