LSP Tools MCP Server

Instructions

Implementation Reference

• src/index.ts:96-118 (handler)

  The handler case block for the 'find_regex_position' tool. It parses input arguments, validates the file path against allowed directories, calls the helper function to find regex positions, and returns the JSON-stringified results or an error.
  case "find_regex_position": { try { // Validate input const parsed = FindRegexPositionArgsSchema.parse(args); // Validate path for security const validatedPath = await validatePath(parsed.path, allowedDirectories); // Find regex positions const positions = await findRegexPositionsInFile(validatedPath, parsed.regex); return { content: [{ type: 'text', text: JSON.stringify(positions), }] }; } catch (error) { return { error: error instanceof Error ? error.message : String(error), }; } }
• src/index.ts:42-46 (schema)

  Zod schema defining the input arguments for the 'find_regex_position' tool: path (absolute file path) and regex (pattern string). Used for validation and JSON schema generation.
  // Schema definitions for the find_regex_position tool const FindRegexPositionArgsSchema = z.object({ path: z.string().describe("Absolute path to the file to search in. Relative paths are not supported."), regex: z.string().describe("Regular expression pattern to search for"), });
• src/index.ts:68-78 (registration)

  Tool registration in the ListToolsRequest handler, including name, detailed description, and input schema reference.
  { name: "find_regex_position", description: "Find the positions (line and column) of regex pattern matches in a file. " + "Returns an array of matches with their positions. " + "Line and column numbers are 0-indexed (first line is 0). " + "Each match includes: match (matched text), line (starting line), column (starting column), " + "endLine (ending line), and endColumn (ending column, exclusive). " + "IMPORTANT: The path parameter must be an absolute path. Relative paths are not supported.", inputSchema: zodToJsonSchema(FindRegexPositionArgsSchema), },
• src/utils/regex-utils.ts:18-21 (helper)

  Helper function that reads the file content and delegates to findRegexPositionsInContent for processing. This is the entry point called by the handler.
  export async function findRegexPositionsInFile(filePath: string, regexStr: string): Promise<RegexMatchPosition[]> { const content = await fs.readFile(filePath, "utf-8"); return findRegexPositionsInContent(content, regexStr); }
• src/utils/regex-utils.ts:29-102 (helper)

  Core helper function that executes the regex search on content, calculates precise 0-indexed line/column positions for start and end of each match, and returns an array of RegexMatchPosition objects.
  export function findRegexPositionsInContent(content: string, regexStr: string): RegexMatchPosition[] { // Split content into lines for position calculation const lines = content.split("\n"); try { // Create regex with global flag to find all matches const regex = new RegExp(regexStr, "g"); const matches: RegexMatchPosition[] = []; let match: RegExpExecArray | null; // Process each match while ((match = regex.exec(content)) !== null) { const matchText = match[0]; const matchStartIndex = match.index; // Calculate line and column for start position let currentIndex = 0; let startLine = 0; let startColumn = 0; for (let i = 0; i < lines.length; i++) { const lineLength = lines[i].length + 1; // +1 for the newline character if (currentIndex + lineLength > matchStartIndex) { startLine = i; startColumn = matchStartIndex - currentIndex; break; } currentIndex += lineLength; } // Calculate line and column for end position let endLine = startLine; let endColumn = startColumn; let charsRemaining = matchText.length; while (charsRemaining > 0 && endLine < lines.length) { const lineRemainder = lines[endLine].length - endColumn + 1; // +1 for newline if (charsRemaining <= lineRemainder) { endColumn += charsRemaining; charsRemaining = 0; } else { charsRemaining -= lineRemainder; endLine++; endColumn = 0; } } // Adjust end column to be exclusive (pointing to the character after the match) if (endColumn > 0 && lines[endLine] && endColumn <= lines[endLine].length) { // No adjustment needed, end column already points to the character after the match } else { // End of line or beyond, set to 0 and increment line endColumn = 0; endLine++; } matches.push({ match: matchText, line: startLine, column: startColumn, endLine: endLine, endColumn: endColumn }); } return matches; } catch (error) { throw new Error(`Error processing regex: ${error instanceof Error ? error.message : String(error)}`); } }