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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, covering the safety profile. The description adds value by noting the use of OKLab perceptual space, that the result is evenly spaced, and that it returns an audit with the caveat that pairwise separation is not judged for ramps. This enriches behavioral understanding without contradicting annotations.

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 with no fluff, front-loading the core purpose and including essential output details. Every word contributes value, making it highly efficient.

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?

The description covers the primary function and what is returned, but does not detail the exact structure of the steps or the audit. Given the lack of an output schema and the moderate parameter count, a bit more detail on the return format would improve completeness, but the annotations and schema cover safety and parameter constraints adequately.

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 description clarifies the semantic roles of start, end, mid (sequential vs diverging) and background (used for the contrast audit), which adds meaning beyond the schema's terse descriptions. Given a schema coverage of 50%, this compensation is helpful, though steps is not explicitly described (though schema provides default and range).

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 (build), a clear resource (color scale/ramp), and explicitly defines the two variants (sequential from start to end, diverging from start through mid to end). It also mentions the output (steps and a background-contrast audit), making the tool's purpose unambiguous and distinguishing it from the sibling audit/simulate/solve 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 does not provide any guidance on when to use this tool versus the sibling tools (audit_palette, simulate_palette, solve_palette). There is no mention of conditions or alternatives, leaving the agent to infer the appropriate context from the tool name alone.

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