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

Annotations already declare readOnlyHint=true, idempotentHint=true, and openWorldHint=false, so safety is covered. The description adds useful context that computation happens in OKLCH and results are gamut-mapped into sRGB, but says nothing about the return shape (e.g., array of colors) or how many colors each harmony type yields.

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?

A single front-loaded sentence with no filler. Appropriately sized for a two-parameter tool, though the brevity contributes to the semantic gaps noted elsewhere.

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 simple two-param tool with annotations covering the safety profile, the essentials are nearly there, but with no output schema the description should state what is returned (one color per type? list of hex values?) and it does not.

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 only 50%: 'base' is documented as 'Base color hex' while 'type' has an enum but no description. The description does not compensate by explaining the harmony types or the relationship between base color and each mode.

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 (Build) and resource (color harmony) with the OKLCH input space and sRGB gamut-mapping detail. It implicitly distinguishes itself from siblings like convert_color and roll_palette, though it never names them 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?

Usage is only implied: an agent can infer you call this when you have a base color and want a harmony, but there is no explicit when-to-use, when-not, or comparison to alternatives such as roll_palette or convert_color.

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