MCP SmallEdit

Instructions

Implementation Reference

• src/index.ts:739-758 (handler)

  The handler function for the perl_edit tool. It executes a Perl one-liner script on the specified file, with options for backup and multiline processing.

  case 'perl_edit': {
    const { file, script, backup = true, multiline = false } = args;
    
    if (!existsSync(file)) {
      throw new Error(`File not found: ${file}`);
    }
    
    const backupExt = backup ? '.bak' : '';
    const multilineFlag = multiline ? '-0777 ' : '';
    const perlCmd = `perl -i${backupExt} ${multilineFlag}-pe '${script}' '${file}'`;
    
    await execAsync(perlCmd);
    
    return {
      content: [{
        type: 'text',
        text: `Successfully edited ${file} using Perl${backup ? ' (backup created as .bak)' : ''}`
      }]
    };
  }

• src/index.ts:175-202 (registration)

  Registers the perl_edit tool in the listTools response, including its name, description, and input schema.

  {
    name: 'perl_edit',
    description: 'Edit files using Perl one-liners (more powerful than sed, better cross-platform support)',
    inputSchema: {
      type: 'object',
      properties: {
        file: {
          type: 'string',
          description: 'File to edit'
        },
        script: {
          type: 'string', 
          description: 'Perl script (e.g., "s/old/new/g" or "$_ = uc" for uppercase)'
        },
        backup: {
          type: 'boolean',
          default: true,
          description: 'Create backup file'
        },
        multiline: {
          type: 'boolean',
          default: false,
          description: 'Enable multiline mode (-0777)'
        }
      },
      required: ['file', 'script']
    }
  },

• src/index.ts:178-200 (schema)

  Input schema definition for the perl_edit tool, specifying parameters and types.

  inputSchema: {
    type: 'object',
    properties: {
      file: {
        type: 'string',
        description: 'File to edit'
      },
      script: {
        type: 'string', 
        description: 'Perl script (e.g., "s/old/new/g" or "$_ = uc" for uppercase)'
      },
      backup: {
        type: 'boolean',
        default: true,
        description: 'Create backup file'
      },
      multiline: {
        type: 'boolean',
        default: false,
        description: 'Enable multiline mode (-0777)'
      }
    },
    required: ['file', 'script']

• src/index.ts:383-408 (helper)

  Help content and examples for the perl_edit tool.

    perl_edit: `perl_edit - Perl one-liner execution
  ===================================
  Direct access to perl's text processing power.
  
  Examples:
    // Simple substitution
    perl_edit({ file: "data.txt", script: "s/foo/bar/g" })
    
    // Delete lines
    perl_edit({ file: "log.txt", script: "$_ = '' if /DEBUG/" })
    
    // Transform to uppercase
    perl_edit({ file: "names.txt", script: "$_ = uc" })
    
    // Complex multiline operations
    perl_edit({ 
      file: "code.js", 
      script: "s/function\\s+(\\w+)\\s*\\(/const $1 = (/g",
      multiline: true 
    })
  
  Tips:
  - Use $_ for the current line
  - Escape backslashes in regex
  - multiline mode slurps entire file
  `,