Convert a color between HEX, RGB, and HSL formats. Use when translating design tokens between CSS notations, verifying color accessibility, or normalizing color values from user input. Accepts #rrggbb, #rgb, rgb(r,g,b), or hsl(h,s%,l%).
| Name | Required | Description | Default |
|---|---|---|---|
| input | Yes | Color value to convert, e.g. "#ff6b6b", "rgb(255,107,107)", "hsl(0,100%,71%)" |
| Name | Required | Description | Default |
|---|---|---|---|
| b | No | ||
| g | No | ||
| r | No | ||
| hex | No | ||
| hsl | No | ||
| rgb | No | ||
| input | No |
Changes observed during successful MCP inspections.
Input schema / examplesAdded value: +[
+ {
+ "input": "rgb(18, 52, 86)"
+ }
+]Output schema / propertiesAdded value: +{
+ "b": {},
+ "g": {},
+ "hex": {},
+ "hsl": {
+ "type": "string"
+ },
+ "input": {},
+ "r": {},
+ "rgb": {
+ "type": "string"
+ }
+}Output schema / (root)Previous value: -nullNew value: +{
+ "additionalProperties": true,
+ "type": "object"
+}Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint=true, idempotentHint=true, destructiveHint=false, and openWorldHint=false, so safety is covered. The description adds useful behavioral detail by listing accepted input notations, including shorthand #rgb and CSS rgb()/hsl() forms, though it does not discuss invalid-input handling.
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 three tight sentences: purpose first, then usage contexts, then accepted formats. Every sentence adds useful information, and there is no repetition or 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?
With one fully documented parameter, rich annotations, and an output schema, the description provides everything needed for correct invocation. Return-value behavior can be delegated to the output schema, so no important context is missing.
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 schema already documents the single input parameter and provides examples. The description still adds meaning by enumerating supported notations (#rrggbb, #rgb, rgb(...), hsl(...)), including the #rgb shorthand that the schema examples do not explicitly mention.
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 and resource: convert a color between HEX, RGB, and HSL. This clearly distinguishes it from other conversion siblings such as number_base_convert or timestamp_convert, since the resource is explicitly color formats.
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?
It gives clear when-to-use contexts: translating design tokens between CSS notations, verifying accessibility, and normalizing user input. It does not name alternatives or exclusions, but for this simple utility the intended usage is well specified.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
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