a11y_check_contrast

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

With no annotations provided, the description carries the full burden of behavioral disclosure. It only says 'checks', which implies a read-only operation, but it does not disclose whether a URL is required, whether direct color values suffice, whether a network request is made, or what the tool returns. This is minimal behavior information.

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, direct sentence with no wasted words. It front-loads the main purpose and does not repeat information already present in the tool name.

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?

Given five undocumented parameters, no output schema, and no annotations, the description is too sparse to guide correct invocation. It does not clarify how 'url' relates to 'background' and 'foreground', whether WCAG AA/AAA levels are reported, or what response an agent should expect. The description is adequate only as a label, not as a complete tool contract.

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 the input schema has no descriptions for any of the five parameters. The description gives a high-level hint that foreground/background colors are involved and that isBold/fontSize may matter for WCAG thresholds, but it does not explain any parameter's meaning, syntax, or which combinations are valid.

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 states a specific verb ('Checks') and resource ('color contrast ratios for WCAG compliance'), which clearly identifies the tool's core function. It is distinguishable from siblings like a11y_audit and a11y_check_images, though it does not explicitly name them.

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 guidance on when to use this tool versus alternatives, such as a11y_audit or a11y_check_images. The description implies its purpose but provides no context about which scenarios warrant calling it or what the tool requires.

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