/code-transfer

name: code-transfer
description: 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.

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