# Backend CLI Interface
## Requirements for Language Backends
For a CLI tool to be compatible with mcp-refactoring, it must implement:
### 1. Command Structure
```bash
{cli} {refactoring} {target} [--param value ...] [--dry-run] [--output=toon]
```
Example:
```bash
molting extract-method src/order.py::Order::calculate#L10-L15 \
--name calculate_tax \
--dry-run \
--output=toon
```
### 2. Required Flags
| Flag | Purpose |
|------|---------|
| `--dry-run` | Preview mode - show diff without modifying files |
| `--output=toon` | Return TOON-formatted structured output |
### 3. Exit Codes
| Code | Meaning |
|------|---------|
| 0 | Success |
| 1 | Refactoring failed (invalid target, parse error, etc.) |
| 2 | Invalid arguments |
### 4. Output Format (TOON)
**Preview output:**
```
preview:
refactoring: extract-method
status: success
files_affected: 1
changes[1]{file,action,diff}:
src/order.py,modified,"@@ -10,5 +10,10 @@..."
```
**Apply output:**
```
result:
refactoring: extract-method
status: success
files_modified: 1
files[1]{path,action}:
src/order.py,modified
```
**Error output:**
```
error:
message: "Could not find method 'calculate' in class 'Order'"
code: invalid_target
```
### 5. Introspection Commands
```bash
# List available refactorings
{cli} --list-refactorings --output=toon
# Inspect code structure
{cli} inspect {path} --depth=method --output=toon
# Analyze for smells (optional)
{cli} analyze {path} --output=toon
```
## Current molting-cli Status
**Implemented:**
- All 71+ refactoring commands
- Target syntax parsing (file.py::Class::method#L10-L15)
**Not yet implemented (needed for MCP):**
- `--dry-run` flag
- `--output=toon` flag
- `--list-refactorings` command
- `inspect` command
- `analyze` command
