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

Annotations already declare readOnlyHint=true and openWorldHint=false, so the safety profile is covered. The description goes beyond them by disclosing the computational basis — OKLCH with even lightness — which is a genuine behavioral trait that shapes what the returned colors look like.

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 sentence, front-loaded with the verb and resource, then the computation method, then the enumerated outputs. No filler and nothing that fails to earn its place.

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 read-only tool with full schema coverage, the description covers purpose, method, and output categories. The only gap is the shape of the return value (e.g. whether each harmony is a list of color strings), which is not described and there is no output schema to fall back on — minor for this tool class.

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 100%, so both parameters (color formats, kind enum with 'all harmonies when omitted') are fully documented in the schema. The description's enumeration of harmony names merely restates the enum and adds no syntax or semantics beyond it; baseline 3 applies.

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 (get) and resource (color harmonies) and enumerates the eight harmony types it computes. This distinguishes it cleanly from siblings like generate_palette, mix_colors, and tints_shades without needing to open a schema.

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 by the purpose statement — the agent can infer it is for deriving a harmony set from one base color. There is no explicit when-to-use, when-not-to-use, or pointer to a sibling (e.g. generate_palette) that might overlap, so an agent must guess at the boundary.

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