edit_file

Instructions

Implementation Reference

• index.js:749-824 (handler)

  Main execution logic for edit_file tool: validates path, checks file existence, ensures unique find text match, creates backup, performs string replacement, and returns detailed change info.

  case "edit_file": {
    const { path, find, replace_with } = args;
    
    if (!isPathAllowed(path)) {
      throw new Error(`Access denied: Path not in allowed directories`);
    }
  
    if (!fs.existsSync(path)) {
      throw new Error(`File not found: ${path}`);
    }
  
    // Read current content
    const content = fs.readFileSync(path, 'utf8');
    const lines = content.split('\n');
    
    // Count occurrences
    const occurrences = (content.match(new RegExp(find.replace(/[.*+?^${}()|[\]\\]/g, '\\$&'), 'g')) || []).length;
    
    if (occurrences === 0) {
      throw new Error(`Text not found in file. Search text: "${find.substring(0, 100)}..."`);
    }
    
    if (occurrences > 1) {
      throw new Error(`Text appears ${occurrences} times in file. Must be unique for safety. Search text: "${find.substring(0, 100)}..."`);
    }
  
    // Find the line numbers where the change occurs
    const findLines = find.split('\n');
    const changedLines = [];
    let foundAtLine = -1;
    
    for (let i = 0; i < lines.length; i++) {
      if (lines[i].includes(findLines[0])) {
        // Check if this is the full match
        let isMatch = true;
        for (let j = 0; j < findLines.length; j++) {
          if (i + j >= lines.length || !lines[i + j].includes(findLines[j])) {
            isMatch = false;
            break;
          }
        }
        if (isMatch) {
          foundAtLine = i + 1; // 1-indexed for humans
          for (let j = 0; j < findLines.length; j++) {
            changedLines.push(i + j + 1);
          }
          break;
        }
      }
    }
  
    // Create backup
    const backupPath = `${path}.backup-${Date.now()}`;
    fs.copyFileSync(path, backupPath);
    debugLog(`Created backup: ${backupPath}`);
  
    // Perform replacement
    const newContent = content.replace(find, replace_with);
    fs.writeFileSync(path, newContent, 'utf8');
  
    result = {
      success: true,
      path: path,
      changes: {
        linesModified: changedLines,
        totalLines: changedLines.length,
        startLine: changedLines[0],
        endLine: changedLines[changedLines.length - 1],
        before: find.substring(0, 200) + (find.length > 200 ? '...' : ''),
        after: replace_with.substring(0, 200) + (replace_with.length > 200 ? '...' : ''),
      },
      backupCreated: backupPath,
      message: `Successfully edited ${changedLines.length} line(s) at lines ${changedLines.join(', ')}`
    };
    break;
  }

• index.js:555-576 (registration)

  Tool registration in ListTools handler, including name, description, and input schema definition.

  {
    name: "edit_file",
    description: "Surgically edit a file by finding and replacing exact text. 50% more efficient than read+write. Use after read_file to ensure exact match. Errors if text not found or appears multiple times. Creates backup automatically.",
    inputSchema: {
      type: "object",
      properties: {
        path: { 
          type: "string", 
          description: "Full file path" 
        },
        find: {
          type: "string",
          description: "Exact text to find (must match exactly including whitespace)"
        },
        replace_with: {
          type: "string",
          description: "Text to replace it with"
        }
      },
      required: ["path", "find", "replace_with"]
    }
  },

• index.js:558-575 (schema)

  Input schema defining parameters for the edit_file tool: path, find, replace_with.

  inputSchema: {
    type: "object",
    properties: {
      path: { 
        type: "string", 
        description: "Full file path" 
      },
      find: {
        type: "string",
        description: "Exact text to find (must match exactly including whitespace)"
      },
      replace_with: {
        type: "string",
        description: "Text to replace it with"
      }
    },
    required: ["path", "find", "replace_with"]
  }

• index.js:58-63 (helper)

  Helper function to validate if a file path is within allowed directories, used in edit_file handler for security.

  function isPathAllowed(filePath) {
    const normalized = filePath.replace(/\//g, '\\');
    return ALLOWED_PATHS.some(allowedPath => 
      normalized.startsWith(allowedPath)
    );
  }