color_mix

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

No annotations are present, so the description carries the full burden of behavioral disclosure. It does communicate operation-specific input constraints and implies a pure color transformation, but it omits return format, error behavior, and what happens with invalid operation/color combinations.

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 names all operations and immediately gives the conditional input requirements. Every clause carries necessary information with no filler.

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?

For a tool with six enum operations, no output schema, and no annotations, the description covers operation selection and basic input shape but misses return format, handling of ratios/weights, and boundary behavior. It is adequate but leaves clear gaps an agent would need to resolve elsewhere.

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%, so the baseline is 3. The description adds value by linking operations to the appropriate parameters and by stating the minimum-color requirement (2+ colors for mix/blend), which is not explicit in the schema.

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 names a specific verb/resource pair: mix, blend, lighten, darken, saturate, or desaturate colors. It is clearly distinguishable from sibling tools like color_convert, palette_generate, contrast_check, and css_gradient, 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?

The description gives operation-specific usage rules: mix/blend require 2+ colors, while lighten/darken/saturate/desaturate require 1 color and an amount. However, it does not state when to choose this tool over alternatives, leaving sibling differentiation to inference from names.

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