MCP tools
mastercss_lint_content
Run Master CSS class-list diagnostics on an in-memory source buffer without writing files.
Contract
Check an unsaved source buffer with the native class diagnostics and the connected workspace’s manifest.
Input
Complete input schema
{ "$schema": "http://json-schema.org/draft-07/schema#", "type": "object", "properties": { "context": { "type": "string", "enum": [ "project", "preset" ] }, "content": { "type": "string" }, "filePath": { "type": "string" }, "rules": { "type": "string" } }, "required": [ "content", "filePath" ]}Example
Call mastercss_lint_content from a connected MCP client with these arguments:
{ "content": "<button class=\"p-md flex\">Save</button>", "filePath": "src/button.html", "rules": "sort-classes"}The virtual HTML path selects the source language; no file is written.
Output
files includes the buffer’s diagnostics and fix proposals, with a diagnostic summary and manifest status. Fix proposals are data in the result, not applied edits. Manifest-loading failures return the error envelope without selecting a preset.
Every tool returns an object with version: 3, metadata, diagnostics and result. Success payload fields described above live in result.data; failure has result.status: "error" and a required { code, message } error. JSON text equals structuredContent. Tool errors set isError. Metadata records actual context, package/language/binding versions, manifest fingerprint, entries and dependencies; unavailable information is null or an empty array.
Complete output schema
{ "$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": { "root": { "type": "string" }, "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": {} }, "files": { "type": "array", "items": { "type": "object", "properties": { "filePath": { "type": "string" }, "languageId": { "type": "string" }, "sourceKind": { "type": "string", "enum": [ "source", "stylesheet", "manifest" ] }, "diagnostics": { "type": "array", "items": { "type": "object", "properties": { "code": { "type": "string" }, "phase": { "type": "string" }, "severity": { "type": "string", "enum": [ "error", "warning" ] }, "message": { "type": "string" }, "notes": { "type": "array", "items": { "type": "string" } }, "alternatives": { "type": "array", "items": { "type": "string" } }, "source": { "type": "string", "const": "Master CSS" }, "range": { "type": "object", "properties": { "start": { "type": "number" }, "end": { "type": "number" } }, "required": [ "start", "end" ], "additionalProperties": false }, "loc": { "type": "object", "properties": { "start": { "type": "object", "properties": { "line": { "type": "integer", "minimum": 0, "maximum": 9007199254740991 }, "column": { "type": "integer", "minimum": 0, "maximum": 9007199254740991 } }, "required": [ "line", "column" ], "additionalProperties": false }, "end": { "type": "object", "properties": { "line": { "type": "integer", "minimum": 0, "maximum": 9007199254740991 }, "column": { "type": "integer", "minimum": 0, "maximum": 9007199254740991 } }, "required": [ "line", "column" ], "additionalProperties": false } }, "required": [ "start", "end" ], "additionalProperties": false }, "sourceKind": { "type": "string" }, "fixes": { "type": "array", "items": { "type": "object", "properties": { "kind": { "type": "string", "enum": [ "class-list", "directive" ] }, "safety": { "type": "string", "enum": [ "safe", "structural" ] }, "range": { "type": "object", "properties": { "start": { "type": "number" }, "end": { "type": "number" } }, "required": [ "start", "end" ], "additionalProperties": false }, "text": { "type": "string" }, "description": { "type": "string" }, "requiresFormatting": { "type": "boolean" } }, "required": [ "kind", "safety", "range", "text", "description", "requiresFormatting" ], "additionalProperties": false } } }, "required": [ "code", "severity", "message", "source", "range", "loc", "sourceKind" ], "additionalProperties": {} } } }, "required": [ "filePath", "languageId", "sourceKind", "diagnostics" ], "additionalProperties": false } }, "summary": { "type": "object", "properties": { "files": { "type": "integer", "minimum": 0, "maximum": 9007199254740991 }, "diagnostics": { "type": "integer", "minimum": 0, "maximum": 9007199254740991 }, "errors": { "type": "integer", "minimum": 0, "maximum": 9007199254740991 }, "warnings": { "type": "integer", "minimum": 0, "maximum": 9007199254740991 }, "fixable": { "type": "integer", "minimum": 0, "maximum": 9007199254740991 }, "safeFixes": { "type": "integer", "minimum": 0, "maximum": 9007199254740991 }, "structuralFixes": { "type": "integer", "minimum": 0, "maximum": 9007199254740991 } }, "required": [ "files", "diagnostics", "errors", "warnings", "fixable", "safeFixes", "structuralFixes" ], "additionalProperties": false } }, "required": [ "root", "manifest", "files", "summary" ], "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.