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 adds one genuinely useful behavioral fact not in structured data: the output is returned as HEX and values are evenly spaced. It does not disclose how many values come back or how 'steps' interacts with output volume.

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?

Two tight sentences, front-loaded with the core operation and the output format, with the use-case hint appended. No filler or redundancy.

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 two-parameter read-only tool with no output schema, the description covers the output format (HEX) and typical use, which is decent. The remaining gap is the undocumented 'steps' parameter, whose meaning an agent must infer from the schema bounds alone.

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%: 'color' is well documented in the schema, but 'steps' has no description anywhere, and the tool description never explains that it controls the number of generated values or its 2-20 range. The phrase 'evenly spaced' gestures at it but adds no real semantic meaning over 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?

States a specific verb (get) and resource (tints/shades/tones of a color) and even defines each term parenthetically, so the operation is unambiguous. However, it does not differentiate itself from close siblings such as generate_scale, mix_colors or harmonies, which an agent might otherwise reach for.

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 second sentence gives implied usage context ('Good for hover states, borders and backgrounds') but never states when to choose this tool over generate_scale or mix_colors, nor any prerequisites or exclusions. Usage is suggested by scenario rather than by routing logic.

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