# Automatic File Transfer Improvements

## Summary

Enhanced the cremote MCP server to automatically handle file transfers between the host machine and the container, eliminating the need for separate manual file transfer steps in most common workflows.

## Changes Made

### 1. Automatic File Upload for Web Forms

**Tool:** `web_interact_cremotemcp` with action "upload"

**Before:**
```yaml
# Step 1: Manually upload file to container
file_upload_cremotemcp:
  local_path: "/home/user/document.pdf"
  container_path: "/tmp/document.pdf"

# Step 2: Upload to web form using container path
web_interact_cremotemcp:
  action: "upload"
  selector: "input[type='file']"
  value: "/tmp/document.pdf"
```

**After:**
```yaml
# Single step - automatic transfer!
web_interact_cremotemcp:
  action: "upload"
  selector: "input[type='file']"
  value: "/home/user/document.pdf"  # Local path - auto-transferred
```

**How it works:**
- Detects if the file path is a local host path (doesn't start with `/tmp/` or `/var/`)
- Automatically uploads the file to the container using `UploadFileToContainer`
- Then performs the web form upload using the container path
- Falls back gracefully if the path is already a container path

### 2. Automatic Screenshot Download

**Tools:** 
- `web_screenshot_cremotemcp`
- `web_screenshot_element_cremotemcp`
- `web_screenshot_enhanced_cremotemcp`

**Before:**
```yaml
# Step 1: Take screenshot in container
web_screenshot_cremotemcp:
  output: "/tmp/screenshot.png"

# Step 2: Manually download from container
file_download_cremotemcp:
  container_path: "/tmp/screenshot.png"
  local_path: "/home/user/screenshots/screenshot.png"
```

**After:**
```yaml
# Single step - automatic download!
web_screenshot_cremotemcp:
  output: "/home/user/screenshots/screenshot.png"  # Local path - auto-downloaded
```

**How it works:**
- Detects if the output path is a local host path (doesn't start with `/tmp/` or `/var/`)
- Takes the screenshot in the container using a temporary path
- Automatically downloads the screenshot to the specified host path using `DownloadFileFromContainer`
- Returns the host path in the success message

### 3. Updated Documentation

**Files Updated:**
- `mcp/main.go` - Tool implementations
- `mcp/LLM_USAGE_GUIDE.md` - Usage examples and workflows
- `mcp/QUICK_REFERENCE.md` - Quick reference examples
- `docs/llm_instructions.md` - LLM agent instructions

**Key Documentation Changes:**
- Added notes about automatic file transfer capabilities
- Updated file upload workflow examples to show simplified approach
- Clarified when manual file transfer tools are still needed
- Updated tool descriptions to mention automatic transfer behavior

## Benefits

1. **Simplified Workflows**: Reduced multi-step operations to single-step operations
2. **Better UX**: Users can work with local paths directly without thinking about container paths
3. **Fewer Errors**: Eliminates the need to remember intermediate container paths
4. **Backward Compatible**: Still supports explicit container paths for advanced use cases
5. **Token Efficient**: Reduces the number of tool calls needed for common operations

## When to Use Manual File Transfer Tools

The manual file transfer tools (`file_upload_cremotemcp` and `file_download_cremotemcp`) are still useful for:

1. **Pre-staging files**: When you need to upload files to the container before using them
2. **Explicit control**: When you want to control the exact container path
3. **Bulk operations**: Using `file_operations_bulk_cremotemcp` for multiple files
4. **Browser downloads**: Files downloaded by the browser still need manual transfer

## Technical Implementation

### Path Detection Logic

```go
// For uploads and screenshots
if strings.HasPrefix(path, "/tmp/") || strings.HasPrefix(path, "/var/") {
    // Treat as container path
    containerPath = path
    hostPath = generateDefaultHostPath(path)
} else {
    // Treat as host path
    hostPath = path
    containerPath = generateTempContainerPath()
}
```

### Error Handling

- If automatic upload fails, the tool attempts to use the path as-is (might be a valid container path)
- If automatic download fails, returns an error message indicating the screenshot was taken but not downloaded
- Both approaches provide clear error messages to help users understand what went wrong

## Testing

Build successful with no compilation errors. The changes maintain backward compatibility with existing workflows while providing the new automatic transfer functionality.

## Future Enhancements

Potential improvements for future consideration:

1. **Browser Download Detection**: Automatically detect when the browser downloads a file and transfer it to the host
2. **Configurable Default Paths**: Allow users to configure default download directories
3. **Progress Indicators**: For large file transfers, show progress information
4. **Batch Screenshot Downloads**: Optimize multiple screenshot operations with batch downloads

