OpenSpace is a skill-management layer for AI agents that stores, retrieves, evaluates, shares, and improves reusable workflows. It is intended for people using multiple coding agents who want skills to be reused and refined based on task outcomes. The catalogue provides 200 skills for use with OpenSpace and the agents it supports.
Getting it into your agent
It runs from inside its repository, so the clone comes first — what it calls does not travel with the file alone.
git clone --depth 1 https://github.com/HKUDS/OpenSpacenpx agentmods add skills/hkuds/openspace/sandbox-fallback-execution-048d5aWrote this? Show the measurements
A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.
[](https://agentmods.dev/skills/hkuds/openspace/sandbox-fallback-execution-048d5a)<a href="https://agentmods.dev/skills/hkuds/openspace/sandbox-fallback-execution-048d5a"><img src="https://agentmods.dev/badge/skills/hkuds/openspace/sandbox-fallback-execution-048d5a.svg" alt="Measured on agentmods" height="20"></a>- NVIDIA SkillSpector pass
What it costs to keep this loaded
Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00028 | $0.00614 |
| Opus 5 | $0.00014 | $0.00307 |
| Sonnet 5 | $0.00006 | $0.00123 |
| Haiku 4.5 | $0.00003 | $0.00061 |
Grade A, and why
sandbox-fallback-execution-048d5a scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 4d ago.
A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.
Nothing flagged
None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.
How it starts
The opening of the file, as written. The whole thing — 97 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Sandbox Fallback Execution
When execute_code_sandbox repeatedly fails with e2b sandbox errors, use this fallback pattern to execute Python code directly on the host system.
When to Use
Use this skill when:
execute_code_sandboxfails with e2b-related errors- Multiple retry attempts (3+) have not resolved the issue
- The code does not require sandbox isolation
Steps
Step 1: Write Python Script to File
Use write_file to save your Python code as a .py file:
Tool: write_file
path: /workspace/script_name.py
content: |
# Your Python code here
import pandas as pd
# ... rest of code
Step 2: Execute via Shell
Use run_shell with explicit python3 path:
Tool: run_shell
command: python3 /workspace/script_name.py
timeout: 120
Step 3: Verify Output
Check the stdout/stderr from run_shell for:
- Successful execution messages
- Expected output or file creation confirmations
- Any errors that need debugging
Complete Example
# Instead of this (failing):
Tool: execute_code_sandbox
code: |
import pandas as pd
df = pd.DataFrame({'a': [1,2,3]})
df.to_excel('output.xlsx')
# Use this fallback:
Tool: write_file
path: /workspace/generate_report.py
content: |
import pandas as pd
# Create sample data
df = pd.DataFrame({'a': [1,2,3], 'b': [4,5,6]})
# Save to Excel
df.to_excel('/workspace/output.xlsx', index=False)
print('File created successfully')
Tool: run_shell
command: python3 /workspace/generate_report.py
timeout: 120
Tips
- Use absolute paths in your Python script when reading/writing files
- Add print statements for debugging since you won't get interactive output
- Increase timeout if the script performs heavy computation
- Check working directory - scripts run from the workspace root by default
- Handle errors explicitly with try/except blocks and meaningful error messages
Common e2b Errors That Trigger This Fallback
E2B execution errorSandbox timeoutConnection refusedSandbox initialization failed- Repeated retry failures (3+ attempts)
What ships with it
1 file beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.
What this file has done since we first saw it
Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.
- 4d ago First seen · 97 lines · 28 tokens per session scan A 1a5bd85c97f0
sandbox-fallback-execution-048d5a is a skill published in the GitHub repository HKUDS/OpenSpace (7,534 stars, last pushed 26d ago), licensed MIT. It adds 28 tokens to every session and 614 once invoked, about $0.0001 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-09-03.
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