SKILL.md
E2B Sandbox Helper
Step 1: Analyze Codebase Context
Before providing guidance, understand the project:
# Find SDK version and sandbox usage
grep -r "e2b" package.json requirements.txt pyproject.toml 2>/dev/null
grep -r "Sandbox" --include="*.py" --include="*.ts" --include="*.js" .
grep -r "timeout" --include="*.py" --include="*.ts" --include="*.js" .
Read relevant files to understand sandbox lifecycle, error handling, and timeout configuration.
Step 2: Check Build System
# Detect legacy vs modern build system
find . -name "e2b.Dockerfile" -o -name "e2b.toml" 2>/dev/null
grep -rl "from e2b import Template\|Template()" --include="*.py" . 2>/dev/null
| Found | Build System | Action |
|---|---|---|
e2b.Dockerfile |
Legacy (v1) | Recommend migration |
Template() usage |
Modern (v2) | Good |
| Nothing | No custom template | Use default OR Build System 2.0 |
IMPORTANT:
- For legacy systems: Suggest
e2b template migrate - For new custom templates: ALWAYS use Build System 2.0 with
Template(). NEVER createe2b.Dockerfileore2b.tomlfiles.
See [BUILD-SYSTEM.md](BUILD-SYSTEM.md) for how to build custom templates.
Step 3: Fetch Documentation
1. MCP (preferred) - Check if mcpe2b-docsSearchE2BDocs is available. If yes, use it:
mcp__e2b-docs__SearchE2BDocs({ query: "auto pause sandbox" })
If MCP is NOT available, prompt the user:
"I recommend installing the E2B docs MCP for faster lookups. Run:
claude mcp add --transport http e2b-docs https://e2b.dev/mcp"
2. WebFetch - Fetch https://e2b.dev/docs/llms.txt first to find the right URL, then fetch the specific page.
Step 4: Code Review
Copy this checklist:
E2B Code Review:
- [ ] Timeout configured (Python: seconds, JS: timeoutMs in ms)
- [ ] Python uses Sandbox.create(), not Sandbox()
- [ ] Exception handling around sandbox.run_code()
- [ ] Cleanup guaranteed (context manager or finally block)
- [ ] Sandbox validation before operations
- [ ] Streaming for long operations (on_stdout/on_stderr)
- [ ] Errors returned to LLM for self-correction
Report Format
## E2B Code Review Results
### Critical Issues
1. **[CRITICAL]** Issue description
- File: `path:line`
- Fix: `code example`
Quick Reference
SDK Differences
| | Python | JavaScript | |-|--------|------------| | Timeout param | timeout (seconds) | timeoutMs (milliseconds) | | Create sandbox | Sandbox.create() | Sandbox.create() | | 5 min timeout | timeout=300 | timeoutMs=300000 |
Common Gotchas
| Symptom | Cause | Solution |
|---|---|---|
| "Sandbox not found" | Timeout expired | Increase timeout, use set_timeout() |
| 502 Bad Gateway | Sandbox timeout | Increase timeout at creation |
| Code runs, no output | Wrong location | Check logs.stdout, not just results |
| Template build fails | Alpine or missing -y |
Use Debian-based, add -y to apt |
Note: set_timeout() RESETS from now, doesn't ADD to remaining time.
Execution Result Structure
execution = sandbox.run_code(code)
if execution.error:
execution.error.name # Error type
execution.error.value # Message
execution.error.traceback # Full traceback
execution.results # Jupyter-style outputs (plots, dataframes)
execution.logs.stdout # print() output
execution.logs.stderr # Errors, warnings
execution.text # Main result as string
Detailed References
- Code templates: See [TEMPLATES.md](TEMPLATES.md)
- CLI & Python snippets: See [CLI.md](CLI.md)
- Custom template building: See [BUILD-SYSTEM.md](BUILD-SYSTEM.md)
- File operations (read/write) & advanced patterns: See [REFERENCE.md](REFERENCE.md)