safe-script-execution

# Safe Script Execution Fallback ## When to Use This Skill Use this pattern when `execute_code_sandbox` or `shell_agent` repeatedly fails to produce expected outputs. This manual fallback provides explicit control over script creation and execution with built-in verification. ## Step-by-Step Instructions ### Step 1: Verify Working Directory Before creating any scripts, confirm your current location and permissions: ```bash pwd ls -la ``` Document the absolute path. All subsequent file operations should use explicit paths from this point. ### Step 2: Create Script via Heredoc Use shell heredoc syntax to create scripts. This avoids issues with multi-line string escaping: ```bash cat > /full/path/to/script.py << 'HEREDOC_END' #!/usr/bin/env python3 # Your script content here # Single quotes around delimiter prevent variable expansion print("Hello from script") HEREDOC_END ``` **Key escaping rules:** - Use single quotes around heredoc delimiter (`'EOF'`) to prevent shell variable expansion - If script contains the delimiter string, choose a different unique delimiter - For bash scripts containing special characters, escape `$`, backticks, and `!` ### Step 3: Make Executable and Run with Explicit Path ```bash chmod +x /full/path/to/script.py /full/path/to/script.py ``` Always use the full absolute path, never rely on `.` or relative paths. ### Step 4: Verify Output Confirm files were created and inspect their properties: ```bash # Check file exists with size ls -lh /full/path/to/output.file # For PDFs, inspect metadata pdfinfo /full/path/to/output.pdf 2>/dev/null || file /full/path/to/output.pdf # For Word docs, check file type file /full/path/to/output.docx ``` ### Step 5: Error Handling If execution fails: 1. Check script syntax: `python3 -m py_compile /path/to/script.py` 2. Check permissions: `ls -l /path/to/script.py` 3. Check available disk space: `df -h .` 4. Review stderr output carefully ## Example: PDF Generation Fallback ```bash # Step 1: Verify directory pwd ls -la # Step 2: Create Python script cat > /workspace/generate_pdf.py << 'SCRIPT_END' from reportlab.lib.pagesizes import letter from reportlab.pdfgen import canvas c = canvas.Canvas("/workspace/output.pdf", pagesize=letter) c.drawString(100, 750, "Generated PDF") c.save() SCRIPT_END # Step 3: Execute chmod +x /workspace/generate_pdf.py python3 /workspace/generate_pdf.py # Step 4: Verify ls -lh /workspace/output.pdf pdfinfo /workspace/output.pdf 2>/dev/null || echo "PDF created, pdfinfo unavailable" ``` ## Anti-Patterns to Avoid - ❌ Don't use relative paths like `./script.py` - always use absolute paths - ❌ Don't rely on unquoted heredoc delimiters if script contains variables - ❌ Don't skip verification steps - always confirm output exists and has expected size - ❌ Don't assume working directory - always `pwd` first ## Troubleshooting Checklist - [ ] Working directory confirmed with `pwd` - [ ] Script file exists after heredoc creation (`ls -l`) - [ ] Script has execute permissions (`chmod +x`) - [ ] Output file exists with non-zero size (`ls -lh`) - [ ] File type verified (`file` command or type-specific inspection)