{
  "openapi": "3.1.1",
  "info": {
    "title": "Two-Color Ramp Mixer API",
    "version": "1.0.0",
    "summary": "Mix two colors into an sRGB or linear-light ramp for drawing and pixel art.",
    "description": "Every endpoint performs the same calculation as the human page and returns inputs, result, units, assumptions, sources, warnings and computedAt. MCP endpoint: /mcp."
  },
  "servers": [
    {
      "url": "https://fliplinecolorramp.usefulweb.app"
    }
  ],
  "paths": {
    "/api/v1/calculate": {
      "post": {
        "operationId": "calculate",
        "summary": "Mix two colors into an sRGB or linear-light ramp for drawing and pixel art.",
        "description": "Interpolate 2–24 opaque colors between two HEX endpoints. Compare encoded sRGB and linear-light mixing, then download HEX, GIMP GPL, JASC-PAL and CSS palettes for your drawing workflow.\n\nMethodology:\n- Sample progress at index/(count-1), including both endpoints. Interpolate RGB components independently.\n- Encoded sRGB mixes channel values directly. Linear-light mixing decodes the sRGB transfer function, interpolates, then re-encodes and rounds to eight bits.\n- Order and duplicate colors are preserved in HEX, GPL, JASC-PAL and CSS. This is additive color interpolation, not physical pigment mixing.",
        "tags": [
          "apps"
        ],
        "x-mcp-tool": "flipline_color_ramp",
        "requestBody": {
          "required": true,
          "content": {
            "application/json": {
              "schema": {
                "$ref": "#/components/schemas/FliplineColorRampInput"
              },
              "examples": {
                "example1": {
                  "summary": "Seven drawing colors",
                  "value": {
                    "from": "#30585D",
                    "to": "#EBC17E",
                    "count": 7,
                    "space": "linear"
                  }
                },
                "example2": {
                  "summary": "Black-to-white linear-light midpoint",
                  "value": {
                    "from": "#000000",
                    "to": "#FFFFFF",
                    "count": 3,
                    "space": "linear"
                  }
                }
              }
            }
          }
        },
        "responses": {
          "200": {
            "description": "Calculation result envelope.",
            "content": {
              "application/json": {
                "schema": {
                  "$ref": "#/components/schemas/FliplineColorRampResult"
                }
              }
            }
          },
          "400": {
            "description": "Malformed JSON body.",
            "content": {
              "application/problem+json": {
                "schema": {
                  "$ref": "#/components/schemas/Problem"
                }
              }
            }
          },
          "422": {
            "description": "Invalid input (see errors[]).",
            "content": {
              "application/problem+json": {
                "schema": {
                  "$ref": "#/components/schemas/Problem"
                }
              }
            }
          },
          "429": {
            "description": "Rate limit exceeded (see Retry-After).",
            "content": {
              "application/problem+json": {
                "schema": {
                  "$ref": "#/components/schemas/Problem"
                }
              }
            }
          }
        }
      }
    },
    "/api/v1/tool": {
      "get": {
        "operationId": "getToolDefinition",
        "summary": "Inputs, output schema and examples for this tool",
        "responses": {
          "200": {
            "description": "Tool definition.",
            "content": {
              "application/json": {
                "schema": {
                  "type": "object"
                }
              }
            }
          }
        }
      }
    }
  },
  "components": {
    "schemas": {
      "Problem": {
        "type": "object",
        "description": "RFC 9457 problem details. 422 responses include per-field `errors`.",
        "required": [
          "type",
          "title",
          "status",
          "detail"
        ],
        "properties": {
          "type": {
            "type": "string"
          },
          "title": {
            "type": "string"
          },
          "status": {
            "type": "integer"
          },
          "detail": {
            "type": "string"
          },
          "code": {
            "type": "string"
          },
          "errors": {
            "type": "array",
            "items": {
              "type": "object",
              "required": [
                "field",
                "message"
              ],
              "properties": {
                "field": {
                  "type": "string"
                },
                "message": {
                  "type": "string"
                }
              }
            }
          }
        }
      },
      "FliplineColorRampInput": {
        "type": "object",
        "additionalProperties": false,
        "properties": {
          "from": {
            "title": "First HEX color",
            "type": "string",
            "maxLength": 7,
            "default": "#30585D"
          },
          "to": {
            "title": "Second HEX color",
            "type": "string",
            "maxLength": 7,
            "default": "#EBC17E"
          },
          "count": {
            "title": "Ramp colors",
            "type": "integer",
            "minimum": 2,
            "maximum": 24,
            "default": 7
          },
          "space": {
            "title": "Mixing space",
            "type": "string",
            "enum": [
              "linear",
              "srgb"
            ],
            "default": "linear"
          }
        },
        "required": []
      },
      "FliplineColorRampResult": {
        "type": "object",
        "additionalProperties": false,
        "required": [
          "schemaVersion",
          "tool",
          "computedAt",
          "inputs",
          "summary",
          "result",
          "units",
          "assumptions",
          "sources",
          "warnings",
          "presentation",
          "links"
        ],
        "properties": {
          "schemaVersion": {
            "type": "string",
            "const": "1.0"
          },
          "tool": {
            "type": "object",
            "additionalProperties": false,
            "required": [
              "id",
              "name",
              "version"
            ],
            "properties": {
              "id": {
                "type": "string"
              },
              "name": {
                "type": "string"
              },
              "version": {
                "type": "string"
              }
            }
          },
          "computedAt": {
            "type": "string",
            "format": "date-time"
          },
          "inputs": {
            "type": "object",
            "description": "Normalised inputs actually used, including applied defaults."
          },
          "summary": {
            "type": "string"
          },
          "result": {
            "type": "object",
            "additionalProperties": false,
            "required": [
              "colors",
              "hex",
              "gpl",
              "jasc",
              "css"
            ],
            "properties": {
              "colors": {
                "type": "array",
                "items": {
                  "type": "string"
                }
              },
              "hex": {
                "type": "string"
              },
              "gpl": {
                "type": "string"
              },
              "jasc": {
                "type": "string"
              },
              "css": {
                "type": "string"
              }
            }
          },
          "units": {
            "type": "object",
            "additionalProperties": {
              "type": "string"
            }
          },
          "assumptions": {
            "type": "array",
            "items": {
              "type": "string"
            }
          },
          "sources": {
            "type": "array",
            "items": {
              "type": "object",
              "additionalProperties": false,
              "required": [
                "title"
              ],
              "properties": {
                "title": {
                  "type": "string"
                },
                "url": {
                  "type": "string"
                },
                "publisher": {
                  "type": "string"
                },
                "retrievedAt": {
                  "type": "string"
                },
                "note": {
                  "type": "string"
                }
              }
            }
          },
          "warnings": {
            "type": "array",
            "items": {
              "type": "string"
            }
          },
          "presentation": {
            "type": "array",
            "items": {
              "type": "object"
            },
            "description": "Display blocks used by the human page (same data)."
          },
          "links": {
            "type": "object",
            "additionalProperties": false,
            "required": [
              "human",
              "api",
              "openapi",
              "methodology"
            ],
            "properties": {
              "human": {
                "type": "string",
                "format": "uri"
              },
              "api": {
                "type": "string",
                "format": "uri"
              },
              "openapi": {
                "type": "string",
                "format": "uri"
              },
              "methodology": {
                "type": "string",
                "format": "uri"
              }
            }
          }
        }
      }
    }
  }
}