Convert a colour between hex, RGB, HSL and CMYK. Pure CPU, instant.
Replace each placeholder with a value matching the input schema. Only required parameters are included; add optional parameters as needed.
{
"id": 1,
"jsonrpc": "2.0",
"method": "tools/call",
"params": {
"arguments": {
"color": "<color>"
},
"name": "color"
}
}| Name | Required | Description | Default |
|---|---|---|---|
| color | Yes | Colour such as #3366ff |
Changes observed during successful MCP inspections.
Input schema / properties / colorAdded value: +{
+ "description": "Colour such as #3366ff",
+ "type": "string"
+}Input schema / requiredAdded value: +[
+ "color"
+]Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
No annotations exist, so the description carries the full behavioural burden. "Pure CPU, instant" usefully signals a local, deterministic, no-network operation, but the description never says what the call returns — whether all four representations come back or only one — which is the single most important behavioural fact for a conversion tool.
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 short sentences, zero filler, with the capability front-loaded ahead of the performance note. Nothing could be removed without losing information.
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 single-parameter utility with no output schema, the definition is serviceable but leaves the critical unknown unresolved: what the response contains and how the target format is chosen given that no such parameter exists. A brief clause on return shape would make it complete.
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% for the single "color" parameter, so the baseline is 3. The description adds no syntax detail beyond the schema's own example, and it leaves a real semantic hole: it advertises conversion between four formats but the schema exposes no target-format parameter, nor does the text explain that the input notation is auto-detected or that all formats are returned.
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 gives a specific verb ("Convert") plus the resource (a colour) and enumerates the four formats involved (hex, RGB, HSL, CMYK), which separates it from siblings like color_contrast, color_harmony, and color_palette. It falls short of a 5 only because it never explicitly states what it is not for, leaving the agent to infer the boundary from the format list alone.
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 implied by the task itself: an agent holding a colour string in one notation and needing another will recognise this tool. There is no explicit when-to-use or when-not-to-use statement, and the neighbouring colour tools (color_name_lookup, color_harmony, color_contrast) are never named as alternatives, so routing is left to inference.
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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