Accessibility 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, and it does disclose a meaningful trait: it is pure arithmetic that deliberately does not touch the site and works without Drush configured. This tells the agent the operation is side-effect-free and environment-independent. It does not, however, describe whether any network or auth is ever involved beyond that, so it stops short of full coverage.

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?

Two short sentences, front-loaded with the core action, and no filler. The second sentence earns its place by explaining the offline nature. It could arguably be condensed but nothing is wasted.

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?

An output schema exists, so return values need not be explained, and the behavioral note covers the key operational trait. The notable gap is color-format guidance for the two required inputs, which is needed to invoke the tool correctly. Adequate but with a clear, actionable omission.

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% and there are two required parameters, so the description must compensate but does not. It never states the accepted color format (hex, rgb, named) for foreground/background, which is exactly the ambiguity the schema leaves open. The parameter names are self-explanatory, but format guidance is missing.

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?

States a specific verb and resource ('Check color contrast ratio'), which is unambiguous and clearly distinct from its sibling scanning tools (axe_scan, wcag_check, aria_validate). The behavioral note 'does not touch the site' implicitly separates it from site-scanning siblings, though no sibling is named explicitly.

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?

There is no explicit when-to-use guidance, no prerequisites, and no named alternatives among the accessibility_* siblings. The usage is only inferable from the tool's purpose; an agent gets no routing signal for choosing this over accessibility_wcag_check.

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