MCP tools

mastercss_trace_class

Trace one class from project extraction through generated CSS, missing CSS classification, and engine inspection.

Contract

Trace a class through source discovery, scanner state, and generated CSS to explain why it is present or missing.

Input

context
stringOptional

Semantic context. Defaults to project; entry discovery or compilation failures are reported without falling back. Select preset explicitly for standalone preset queries. Values: project, preset.

className
stringRequired

One complete Master CSS class, including any selector or condition suffix. Minimum length: 1.

patterns
string[]Optional

Source paths or glob patterns relative to the server root. Omit to use the tool’s default source scope. Absolute patterns and parent traversal are rejected.

includeCss
booleanOptional

Include the full generated stylesheet text in css.text. Omitted by default.

mode
stringOptional

Mode passed to class inspection. Omit to use the active manifest’s default behavior.

Complete input schema
JSON
{  "$schema": "http://json-schema.org/draft-07/schema#",  "type": "object",  "properties": {    "context": {      "type": "string",      "enum": [        "project",        "preset"      ]    },    "className": {      "type": "string",      "minLength": 1    },    "patterns": {      "type": "array",      "items": {        "type": "string"      }    },    "includeCss": {      "type": "boolean"    },    "mode": {      "type": "string"    }  },  "required": [    "className"  ]}

Example

Call mastercss_trace_class from a connected MCP client with these arguments:

Arguments
{  "className": "p-md",  "patterns": [    "src/button.html"  ],  "includeCss": true}

The file must exist under the server root and contain the class you want to trace.

Output

Read status, reason, and detected together, then inspect occurrences, inspection, scanner, and diagnostics. css describes the scan output. A matched inspection and a detected source occurrence answer different questions.

Every tool returns an object with version: 3, metadata, diagnostics and result. Success payload fields described above live in result.data; failure has result.status: "error" and a required { code, message } error. JSON text equals structuredContent. Tool errors set isError. Metadata records actual context, package/language/binding versions, manifest fingerprint, entries and dependencies; unavailable information is null or an empty array.

Complete output schema
JSON
{  "$schema": "http://json-schema.org/draft-07/schema#",  "type": "object",  "properties": {    "version": {      "type": "number",      "const": 3    },    "metadata": {      "type": "object",      "properties": {        "versions": {          "anyOf": [            {              "type": "object",              "properties": {                "languageVersion": {                  "type": "number"                },                "bindingAbiVersion": {                  "type": "number"                },                "packageVersion": {                  "type": "string"                }              },              "required": [                "languageVersion",                "bindingAbiVersion",                "packageVersion"              ],              "additionalProperties": {}            },            {              "type": "null"            }          ]        },        "context": {          "anyOf": [            {              "type": "string",              "enum": [                "project",                "preset"              ]            },            {              "type": "null"            }          ]        },        "manifestFingerprint": {          "type": [            "string",            "null"          ]        },        "entries": {          "type": "array",          "items": {            "type": "string"          }        },        "dependencies": {          "type": "array",          "items": {            "type": "string"          }        }      },      "required": [        "versions",        "context",        "manifestFingerprint",        "entries",        "dependencies"      ],      "additionalProperties": false    },    "diagnostics": {      "type": "array",      "items": {        "type": "object",        "properties": {          "code": {            "type": "string"          },          "phase": {            "type": "string"          },          "severity": {            "type": [              "string",              "number"            ]          },          "message": {            "type": "string"          },          "notes": {            "type": "array",            "items": {              "type": "string"            }          },          "alternatives": {            "type": "array",            "items": {              "type": "string"            }          },          "source": {            "type": "string"          },          "range": {            "anyOf": [              {                "type": "object",                "properties": {                  "start": {                    "type": "number"                  },                  "end": {                    "type": "number"                  }                },                "required": [                  "start",                  "end"                ],                "additionalProperties": false              },              {                "type": "object",                "properties": {                  "start": {                    "type": "object",                    "properties": {                      "line": {                        "type": "number"                      },                      "character": {                        "type": "number"                      }                    },                    "required": [                      "line",                      "character"                    ],                    "additionalProperties": false                  },                  "end": {                    "type": "object",                    "properties": {                      "line": {                        "type": "number"                      },                      "character": {                        "type": "number"                      }                    },                    "required": [                      "line",                      "character"                    ],                    "additionalProperties": false                  }                },                "required": [                  "start",                  "end"                ],                "additionalProperties": false              }            ]          }        },        "required": [          "message"        ],        "additionalProperties": {}      }    },    "result": {      "oneOf": [        {          "type": "object",          "properties": {            "status": {              "type": "string",              "const": "success"            },            "data": {              "type": "object",              "properties": {                "manifest": {                  "type": "object",                  "properties": {                    "context": {                      "type": "string",                      "enum": [                        "project",                        "preset"                      ]                    },                    "status": {                      "type": "string",                      "enum": [                        "loaded",                        "error"                      ]                    },                    "fingerprint": {                      "type": [                        "string",                        "null"                      ]                    },                    "entries": {                      "type": "array",                      "items": {                        "type": "string"                      }                    },                    "dependencies": {                      "type": "array",                      "items": {                        "type": "string"                      }                    },                    "versions": {                      "type": "object",                      "properties": {                        "languageVersion": {                          "type": "number"                        },                        "bindingAbiVersion": {                          "type": "number"                        },                        "packageVersion": {                          "type": "string"                        }                      },                      "required": [                        "languageVersion",                        "bindingAbiVersion",                        "packageVersion"                      ],                      "additionalProperties": {}                    }                  },                  "required": [                    "context",                    "status",                    "fingerprint",                    "entries",                    "dependencies"                  ],                  "additionalProperties": {}                },                "inspection": {                  "type": "object",                  "properties": {                    "className": {                      "type": "string"                    },                    "matchStatus": {                      "type": "string",                      "enum": [                        "matched",                        "unmatched",                        "ambiguous",                        "syntax-error"                      ]                    },                    "cssSyntaxStatus": {                      "type": "string",                      "enum": [                        "valid",                        "invalid",                        "unknown",                        "not-checked"                      ]                    },                    "cssValueStatus": {                      "type": "string",                      "enum": [                        "valid",                        "invalid",                        "unknown",                        "not-checked"                      ]                    },                    "browserSupport": {                      "type": "string",                      "enum": [                        "supported",                        "unsupported",                        "unknown",                        "not-checked"                      ]                    },                    "checks": {                      "type": "array",                      "items": {                        "type": "object",                        "properties": {                          "name": {                            "type": "string"                          },                          "version": {                            "type": "string"                          },                          "phase": {                            "type": "string"                          },                          "scope": {                            "type": "string"                          }                        },                        "required": [                          "name",                          "version",                          "phase",                          "scope"                        ],                        "additionalProperties": false                      }                    },                    "declarations": {                      "type": "array",                      "items": {                        "type": "object",                        "properties": {                          "property": {                            "type": "string"                          },                          "value": {                            "type": "string"                          },                          "status": {                            "type": "string",                            "enum": [                              "valid",                              "invalid",                              "unknown",                              "not-checked"                            ]                          },                          "range": {                            "type": "object",                            "properties": {                              "start": {                                "type": "number"                              },                              "end": {                                "type": "number"                              }                            },                            "required": [                              "start",                              "end"                            ],                            "additionalProperties": false                          },                          "error": {                            "type": "string"                          }                        },                        "required": [                          "property",                          "value",                          "status"                        ],                        "additionalProperties": {}                      }                    },                    "rules": {                      "type": "array",                      "items": {                        "type": "object",                        "properties": {                          "className": {                            "type": "string"                          },                          "key": {                            "type": "string"                          },                          "layer": {                            "type": "string",                            "enum": [                              "base",                              "defaults",                              "components",                              "utilities"                            ]                          },                          "type": {                            "type": "number"                          },                          "sortTier": {                            "type": "number"                          },                          "text": {                            "type": "string"                          },                          "selectorText": {                            "type": "string"                          },                          "priority": {                            "type": "object",                            "properties": {                              "features": {                                "type": "array",                                "items": {                                  "type": "object",                                  "properties": {                                    "domain": {                                      "type": "string"                                    },                                    "feature": {                                      "type": "string"                                    },                                    "unit": {                                      "type": "string"                                    },                                    "lower": {                                      "anyOf": [                                        {                                          "type": "object",                                          "properties": {                                            "value": {                                              "type": "number"                                            },                                            "inclusive": {                                              "type": "boolean"                                            }                                          },                                          "required": [                                            "value",                                            "inclusive"                                          ],                                          "additionalProperties": false                                        },                                        {                                          "type": "null"                                        }                                      ]                                    },                                    "upper": {                                      "anyOf": [                                        {                                          "type": "object",                                          "properties": {                                            "value": {                                              "type": "number"                                            },                                            "inclusive": {                                              "type": "boolean"                                            }                                          },                                          "required": [                                            "value",                                            "inclusive"                                          ],                                          "additionalProperties": false                                        },                                        {                                          "type": "null"                                        }                                      ]                                    }                                  },                                  "required": [                                    "domain",                                    "feature",                                    "unit",                                    "lower",                                    "upper"                                  ],                                  "additionalProperties": false                                }                              },                              "selector": {                                "type": "number"                              },                              "conditions": {                                "type": "array",                                "items": {                                  "type": "string"                                }                              },                              "sortKey": {                                "type": "string"                              },                              "valuePriority": {                                "type": "number"                              }                            },                            "required": [                              "features",                              "selector"                            ],                            "additionalProperties": false                          },                          "nodes": {                            "type": "array",                            "items": {                              "type": "object",                              "properties": {                                "text": {                                  "type": "string"                                }                              },                              "required": [                                "text"                              ],                              "additionalProperties": false                            }                          },                          "variableNames": {                            "type": "array",                            "items": {                              "type": "string"                            }                          },                          "animationNames": {                            "type": "array",                            "items": {                              "type": "string"                            }                          }                        },                        "required": [                          "className",                          "key",                          "layer",                          "type",                          "sortTier",                          "priority"                        ],                        "additionalProperties": false                      }                    },                    "variables": {                      "type": "array",                      "items": {                        "type": "object",                        "properties": {                          "key": {                            "type": "string"                          },                          "variable": {                            "type": "object",                            "properties": {                              "key": {                                "type": "string"                              },                              "name": {                                "type": "string"                              },                              "namespace": {                                "type": "string"                              },                              "type": {                                "type": "string"                              },                              "value": {                                "anyOf": [                                  {                                    "type": "string"                                  },                                  {                                    "type": "number"                                  },                                  {                                    "type": "boolean",                                    "const": false                                  },                                  {                                    "type": "array",                                    "items": {                                      "type": [                                        "string",                                        "number"                                      ]                                    }                                  }                                ]                              },                              "numeric": {                                "type": "object",                                "properties": {                                  "value": {                                    "type": "number"                                  },                                  "unit": {                                    "type": "string"                                  }                                },                                "required": [                                  "value"                                ],                                "additionalProperties": false                              },                              "dependencies": {                                "type": "array",                                "items": {                                  "type": "string"                                }                              },                              "modes": {                                "type": "object",                                "propertyNames": {                                  "type": "string"                                },                                "additionalProperties": {                                  "type": "object",                                  "properties": {                                    "type": {                                      "type": "string",                                      "enum": [                                        "string",                                        "number"                                      ]                                    },                                    "value": {                                      "type": [                                        "string",                                        "number"                                      ]                                    },                                    "numeric": {                                      "type": "object",                                      "properties": {                                        "value": {                                          "type": "number"                                        },                                        "unit": {                                          "type": "string"                                        }                                      },                                      "required": [                                        "value"                                      ],                                      "additionalProperties": false                                    }                                  },                                  "required": [                                    "type",                                    "value"                                  ],                                  "additionalProperties": false                                }                              },                              "inline": {                                "type": "boolean"                              },                              "static": {                                "type": "boolean"                              },                              "mode": {                                "type": "string"                              }                            },                            "required": [                              "key",                              "name",                              "type",                              "dependencies"                            ],                            "additionalProperties": false                          }                        },                        "required": [                          "key",                          "variable"                        ],                        "additionalProperties": false                      }                    },                    "diagnostics": {                      "type": "array",                      "items": {                        "type": "object",                        "properties": {                          "code": {                            "type": "string"                          },                          "phase": {                            "type": "string"                          },                          "severity": {                            "type": [                              "string",                              "number"                            ]                          },                          "message": {                            "type": "string"                          },                          "notes": {                            "type": "array",                            "items": {                              "type": "string"                            }                          },                          "alternatives": {                            "type": "array",                            "items": {                              "type": "string"                            }                          },                          "source": {                            "type": "string"                          },                          "range": {                            "anyOf": [                              {                                "type": "object",                                "properties": {                                  "start": {                                    "type": "number"                                  },                                  "end": {                                    "type": "number"                                  }                                },                                "required": [                                  "start",                                  "end"                                ],                                "additionalProperties": false                              },                              {                                "type": "object",                                "properties": {                                  "start": {                                    "type": "object",                                    "properties": {                                      "line": {                                        "type": "number"                                      },                                      "character": {                                        "type": "number"                                      }                                    },                                    "required": [                                      "line",                                      "character"                                    ],                                    "additionalProperties": false                                  },                                  "end": {                                    "type": "object",                                    "properties": {                                      "line": {                                        "type": "number"                                      },                                      "character": {                                        "type": "number"                                      }                                    },                                    "required": [                                      "line",                                      "character"                                    ],                                    "additionalProperties": false                                  }                                },                                "required": [                                  "start",                                  "end"                                ],                                "additionalProperties": false                              }                            ]                          }                        },                        "required": [                          "message"                        ],                        "additionalProperties": {}                      }                    }                  },                  "required": [                    "className",                    "matchStatus",                    "cssSyntaxStatus",                    "cssValueStatus",                    "browserSupport",                    "checks",                    "declarations",                    "rules",                    "variables"                  ],                  "additionalProperties": {}                },                "occurrences": {                  "type": "array",                  "items": {                    "type": "object",                    "properties": {                      "filePath": {                        "type": "string"                      },                      "source": {                        "type": "string"                      },                      "statuses": {                        "type": "array",                        "items": {                          "type": "string"                        }                      }                    },                    "required": [                      "filePath",                      "source",                      "statuses"                    ],                    "additionalProperties": false                  }                },                "status": {                  "type": "string"                },                "css": {                  "type": "object",                  "properties": {                    "bytes": {                      "type": "number"                    },                    "text": {                      "type": "string"                    }                  },                  "required": [                    "bytes"                  ],                  "additionalProperties": {}                }              },              "required": [                "manifest",                "inspection",                "occurrences",                "status",                "css"              ],              "additionalProperties": {}            }          },          "required": [            "status",            "data"          ],          "additionalProperties": false        },        {          "type": "object",          "properties": {            "status": {              "type": "string",              "const": "error"            },            "error": {              "type": "object",              "properties": {                "code": {                  "type": "string"                },                "message": {                  "type": "string"                }              },              "required": [                "code",                "message"              ],              "additionalProperties": false            }          },          "required": [            "status",            "error"          ],          "additionalProperties": false        }      ]    }  },  "required": [    "version",    "metadata",    "diagnostics",    "result"  ],  "additionalProperties": false}

Project context and lifecycle

This operation does not write workspace files.

The local stdio server uses the workspace passed to --root. Confirm the root and intended CSS entries with mastercss_workspace_info before relying on project-dependent values.

See the MCP workflow guide for client setup and the preview/apply workflow.


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