code-transfer

mhattingpete's avatarfrom mhattingpete

Transfer code between files with line-based precision. Use when users request copying code from one location to another, moving functions or classes between files, extracting code blocks, or inserting code at specific line numbers.

⭐126stars🔀16forks📁View on GitHub🕐Updated Dec 19, 2025
[Developer Tools]

When & Why to Use This Skill

The Code Transfer skill is a high-precision utility designed for seamless code manipulation and file reorganization. It enables developers to move, copy, or extract functions, classes, and code blocks between files with line-based accuracy. By offering dual-mode operation—native tools for small-scale edits and an execution mode for large-scale migrations—it significantly reduces token consumption and manual overhead during complex refactoring tasks.

Use Cases

  • Codebase Refactoring: Effortlessly move functions or classes from monolithic files into dedicated modules to improve maintainability and architectural clarity.
  • Modularization & Extraction: Quickly isolate specific logic or utility functions into new files, automatically handling line-specific insertions and structural updates.
  • Large-Scale Code Migration: Use Execution Mode to process 10+ files simultaneously, achieving up to 90% token savings when reorganizing extensive projects.
  • Precise Code Injection: Insert imports, decorators, or boilerplate code at exact line numbers or relative to existing code blocks without disrupting the surrounding syntax.
  • Automated Dependency Management: Streamline the process of updating imports and references across multiple files after moving core components.
namecode-transfer
descriptionTransfer code between files with line-based precision. Use when users request copying code from one location to another, moving functions or classes between files, extracting code blocks, or inserting code at specific line numbers.

Code Transfer

Transfer code between files with precise line-based control. Dual-mode operation: native tools (1-10 files) or execution mode (10+ files, 90% token savings).

Operation Modes

Basic Mode (Default)

Use Read, Edit, Bash scripts for 1-10 file operations. Works immediately, no setup required.

Execution Mode (10+ files)

from api.filesystem import batch_copy
from api.code_analysis import find_functions

functions = find_functions('app.py', pattern='handle_.*')
operations = [{
    'source_file': 'app.py',
    'start_line': f['start_line'],
    'end_line': f['end_line'],
    'target_file': 'handlers.py',
    'target_line': -1
} for f in functions]
batch_copy(operations)

When to Use

  • "copy this code to [file]"
  • "move [function/class] to [file]"
  • "extract this to a new file"
  • "insert at line [number]"
  • "reorganize into separate files"

Core Operations

1. Extract Source Code

Read(file_path="src/auth.py")                              # Full file
Read(file_path="src/auth.py", offset=10, limit=20)         # Line range
Grep(pattern="def authenticate", -n=true, -A=10)           # Find function

2. Insert at Specific Line

Use line_insert.py script for line-based insertion:

python3 skills/code-transfer/scripts/line_insert.py <file> <line_number> <code> [--backup]

Examples:

# Insert function at line 50
python3 skills/code-transfer/scripts/line_insert.py src/utils.py 50 "def helper():\n    pass"

# Insert with backup
python3 skills/code-transfer/scripts/line_insert.py src/utils.py 50 "code" --backup

# Insert at beginning
python3 skills/code-transfer/scripts/line_insert.py src/new.py 1 "import os"

When to use:

  • User specifies exact line number
  • Inserting into new/empty files
  • Inserting at beginning/end without context

3. Insert Relative to Content

Use Edit when insertion point is relative to existing code:

Edit(
  file_path="src/utils.py",
  old_string="def existing():\n    pass",
  new_string="def existing():\n    pass\n\ndef new():\n    return True"
)

Workflow Examples

Copy Function Between Files

  1. Find: Grep(pattern="def validate_user", -n=true, -A=20)
  2. Extract: Read(file_path="auth.py", offset=45, limit=15)
  3. Check target: Read(file_path="validators.py")
  4. Insert: Use line_insert.py or Edit based on context

Extract Class to New File

  1. Locate: Grep(pattern="class DatabaseConnection", -n=true, -A=50)
  2. Extract: Read(file_path="original.py", offset=100, limit=50)
  3. Create: Write(file_path="database.py", content="<extracted>")
  4. Update imports: Edit in original file
  5. Remove old class: Edit with replacement

Insert at Specific Line

  1. Validate: Read(file_path="main.py", offset=20, limit=10)
  2. Insert: python3 skills/code-transfer/scripts/line_insert.py main.py 25 "logger.info('...')" --backup
  3. Verify: Read(file_path="main.py", offset=23, limit=5)

Reorganize Into Modules

  1. Analyze: Read(file_path="utils.py")
  2. Identify groups: Grep(pattern="^def |^class ", -n=true)
  3. Extract each category: Write new files
  4. Update original: Re-export or redirect

Best Practices

Planning:

  • Understand dependencies (imports, references)
  • Identify exact start/end of code block
  • Check target file structure
  • Ensure necessary imports included

Preservation:

  • Include docstrings and comments
  • Transfer related functions together
  • Update imports in both files
  • Maintain formatting/indentation

Validation:

  • Verify insertion placement
  • Check syntax
  • Test imports
  • Suggest running tests

Backups:

  • Use --backup for significant changes
  • Critical file operations
  • Large deletions

Integration

  • code-refactor: Refactor after transferring
  • test-fixing: Run tests after reorganizing
  • feature-planning: Plan large reorganizations