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
One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.
npx skills add HKUDS/OpenSpace --skill sandbox-fallback-pythongit clone --depth 1 https://github.com/HKUDS/OpenSpaceWrote 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-python)<a href="https://agentmods.dev/skills/hkuds/openspace/sandbox-fallback-python"><img src="https://agentmods.dev/badge/skills/hkuds/openspace/sandbox-fallback-python.svg" alt="Measured on agentmods" height="20"></a>- NVIDIA SkillSpector warn
SkillSpector: 1 finding, up to medium
These are SkillSpector’s own severities. On a checked sample its high-severity flags on skills were ~96% false positives — a documented command, a public API, a “never do X” rule — so we show them as a caution to read, not a verdict. Why →
- medium Data Exfiltration · line 82 Data is being sent to an external URL. This could be legitimate telemetry or data exfiltration. Manual review is recommended.Fix: Verify the destination URL is trusted and necessary. Remove or replace with documented APIs. Ensure no secrets, tokens, or PII are transmitted.
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 | $0.00025 | $0.00732 |
| Opus 5 | $0.00013 | $0.00366 |
| Sonnet 5 | $0.00005 | $0.00146 |
| Haiku 4.5 | $0.00003 | $0.00073 |
Grade A, and why
sandbox-fallback-python scanned grade A with 1 finding 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.
Makes network callslowCapability
Not a fault in itself. Listed so you know the mod talks to something, and to what.
response = requests.get("https://api.example.com/data") How it starts
The opening of the file, as written. The whole thing — 121 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Sandbox Fallback: Python via run_shell
When to Use This Skill
Apply this skill when execute_code_sandbox fails with errors indicating:
- e2b service unavailability
- Sandbox timeout or connection issues
- Code execution environment not accessible
This fallback allows you to execute Python code directly via shell, bypassing the sandbox infrastructure.
Fallback Procedure
Step 1: Detect Sandbox Failure
Identify fallback necessity from error messages like:
- "e2b unavailable"
- "sandbox connection failed"
- "execution environment error"
- Timeout errors during code execution
Step 2: Switch to run_shell with Embedded Python
Instead of execute_code_sandbox, use run_shell with a Python heredoc or inline script:
python3 << 'EOF'
# Your Python code here
print("Hello from fallback execution")
EOF
Step 3: Install Dependencies First
If your Python code requires packages not guaranteed to be installed:
pip install package_name package_name2 && python3 << 'EOF'
# Your Python code here
import package_name
print("Code with dependencies executed")
EOF
Step 4: Handle File I/O
For scripts that need to read/write files:
- Use absolute or explicit relative paths
- Files persist in the workspace directory
- List directory contents with
lsto verify file operations
python3 << 'EOF'
import os
# Write output to file
with open("output.txt", "w") as f:
f.write("Results here")
# Verify
print(f"Working directory: {os.getcwd()}")
EOF
Code Examples
Simple Calculation
python3 << 'EOF'
result = sum(range(100))
print(f"Sum: {result}")
EOF
With Package Installation
pip install requests -q && python3 << 'EOF'
import requests
response = requests.get("https://api.example.com/data")
print(response.json())
EOF
With JSON Processing
python3 << 'EOF'
import json
data = {"key": "value", "count": 42}
output = json.dumps(data, indent=2)
print(output)
# Save to file
with open("data.json", "w") as f:
f.write(output)
EOF
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 · 121 lines · 25 tokens per session scan A 4d22779a9daa
sandbox-fallback-python is a skill published in the GitHub repository HKUDS/OpenSpace (7,534 stars, last pushed 26d ago), licensed MIT. It adds 25 tokens to every session and 732 once invoked, about $0.0001 per session on Opus 5. A static security scan graded it A with 1 finding (makes network calls). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-09-03.
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