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Agent skill

Sandbox Exec Fallback

by HKUDS in HKUDS/OpenSpace

Fallback pattern for executing Python code when executecodesandbox fails by writing to file and running via shell

MITAuto-check passedDocuments & Office

Install Sandbox Exec Fallback

skills CLI
$ npx skills add HKUDS/OpenSpace --skill sandbox-exec-fallback -a claude-code

Project install by default; add -g for ~/.claude/skills/.

GitHub CLI
$ gh skill install HKUDS/OpenSpace sandbox-exec-fallback --agent claude-code

Project scope by default; add --scope user for a personal install. Needs GitHub CLI 2.90.0 or later (public preview).

Manual copy
$ git clone --depth 1 https://github.com/HKUDS/OpenSpace.git skills-src && mkdir -p .claude/skills && cp -r skills-src/benchmarks/gdpval/skills/sandbox-exec-fallback .claude/skills/sandbox-exec-fallback && rm -rf skills-src

Use ~/.claude/skills/ instead of .claude/skills for a personal install. The folder must contain SKILL.md.

Claude Code skills documentation · loads skills from .claude/skills/

Facts

Skill name
sandbox-exec-fallback
GitHub stars
7.7k
Token cost
~617 tokens
SKILL.md length
249 words
Files
2
Skills in repo
199
Repo updated
First seen
Licence
MIT

At a glance

Fallback pattern for executing Python code when executecodesandbox fails by writing to file and running via shell

  • Works in 4 steps: Write Python Code to File → Execute via Shell → Verify Output → …
  • Tasks that involve Excel spreadsheets
  • SKILL.md covers When to Use, Recovery Pattern, Why This Works and Example: Spreadsheet Generation, plus 1 more section
  • Instructions only: no scripts, shell commands, URLs or credentials in SKILL.md

What it does

Sandbox Exec Fallback is an agent skill from HKUDS/OpenSpace. Fallback pattern for executing Python code when executecodesandbox fails by writing to file and running via shell

Its SKILL.md is about 620 tokens, which your agent loads only when the skill is triggered. The skill folder holds 1 other file.

It sits in Documents & Office, covering Excel spreadsheets. It works with Python. The repository describes itself as: "OpenSpace: The Skill Management Layer for AI Agents" -- https://open-space.cloud/. The licence is MIT.

When your agent uses it

  • Tasks that involve Excel spreadsheets

Example prompts

  • “/sandbox-exec-fallback”

Requirements

  • Python 3

Workflow steps

4 steps, taken from the step headings in SKILL.md.

  1. Write Python Code to File
  2. Execute via Shell
  3. Verify Output
  4. Access Generated Files

What it can do on your machine

Read from SKILL.md and the folder at commit 3827781. It shows what the files ask for, not the result of running them.

  • Tool permissions

    Pre-approves nothing: there is no allowed-tools line, so your agent's usual permission prompts apply.

    From allowed-tools in the SKILL.md frontmatter.

  • Runs code

    No scripts in the folder and no shell commands in SKILL.md (its code samples are python).

    From the folder's file list and the shell code blocks in SKILL.md.

  • Network

    No URLs in SKILL.md.

    From URLs in SKILL.md, links to its own repository left out.

  • Credentials

    Names no API keys, tokens, secrets or passwords.

    From names ending in _API_KEY, _TOKEN, _SECRET, _KEY or _PASSWORD in SKILL.md.

Context cost

Sandbox Exec Fallback loads about 617 tokens when it runs. Until then it costs about 34 tokens; SKILL.md has 249 words of instructions outside code blocks.

Always · name and description, kept in context so the agent knows when to use it
~34
When it runs · the whole SKILL.md, loaded when a task matches
~617

Estimates: characters ÷ 4, the usual rule of thumb; real counts depend on the model's tokenizer. Scripts and assets cost tokens only if the agent reads them.

Safety

Auto-check passed

The automated check found no risky patterns in SKILL.md.

Automated static check — not a guarantee. Review scripts before installing. It scans the text of SKILL.md for risky patterns (piping downloads into a shell, reading credential files, hidden Unicode, destructive commands); files beside SKILL.md are not scanned.

SKILL.md

The full file from HKUDS/OpenSpace at commit 3827781, republished under its MIT licence (© HKUDS). 249 words, ~617 tokens.

Download SKILL.mdSave it as .claude/skills/sandbox-exec-fallback/SKILL.md (or your agent's skills folder). This skill also uses 1 other file; get the full folder from GitHub.
name
sandbox-exec-fallback
description
Fallback pattern for executing Python code when execute_code_sandbox fails by writing to file and running via shell

Sandbox Execution Fallback

When to Use

Use this skill when execute_code_sandbox fails during Python code execution, particularly for tasks involving:

  • Spreadsheet generation (xlsx, csv)
  • Data processing and transformations
  • File output operations
  • Complex computations requiring libraries

Recovery Pattern

When execute_code_sandbox returns an error or fails to produce expected output:

Step 1: Write Python Code to File

Use write_file to save your Python script to a file:

# Use write_file tool with:
path: "script.py"
content: <your complete Python code as a string>
Step 2: Execute via Shell

Use run_shell to execute the script:

# Use run_shell tool with:
command: "python3 script.py"
timeout: <appropriate timeout, e.g., 300 for long-running tasks>
Step 3: Verify Output

Check the shell output for:

  • Success messages or printed results
  • Error messages (if any, diagnose and fix the script)
  • File creation confirmations
Step 4: Access Generated Files

If the script creates output files (e.g., spreadsheets), they will be in the current working directory. Use list_dir to confirm, then read_file to access if needed.

Why This Works

  • Same Python Environment: python3 in the shell uses the same environment as the sandbox
  • More Robust: Shell execution handles long-running or memory-intensive tasks better
  • Debuggable: Errors are captured in stdout/stderr for easier diagnosis
  • Identical Results: Produces the same output as sandbox execution when successful

Example: Spreadsheet Generation

Original code that failed in execute_code_sandbox:

python
import pandas as pd

data = {'A': [1, 2, 3], 'B': [4, 5, 6]}
df = pd.DataFrame(data)
df.to_excel('output.xlsx', index=False)
print("File created successfully")

Recovery Execution:

  1. write_file with path="generate_spreadsheet.py" and the code above as content
  2. run_shell with command="python3 generate_spreadsheet.py"
  3. Verify output.xlsx was created with list_dir

Tips

  • Increase timeout for complex operations (default 30s may be insufficient)
  • Add explicit print statements for debugging
  • Handle exceptions in your script and print error messages
  • Clean up temporary script files after successful execution if needed

© HKUDS, MIT. Rendered from Markdown: HTML in the file is shown as text, images as links, and headings moved down two levels. Raw file

Files

SKILL.md and 1 other file in benchmarks/gdpval/skills/sandbox-exec-fallback of HKUDS/OpenSpace.

  • SKILL.md
  • .skill_id

Open the folder on GitHubat commit 3827781

Compare with similar skills

Sandbox Exec Fallback next to the 5 skills that share the most tags, products or categories with it. Stars are the repository's; “used in” counts other GitHub owners with a copy.

Sandbox Exec Fallback compared with similar skills
SkillStarsUsed inTokensAuto-checkLicenceRepo updated
Sandbox Exec Fallback this skillHKUDS/OpenSpace7.7k—~617Automated safety check: PassMIT
Instrument Data To Allotropeaws-samples/amazon-bedrock-agents-healthcare-lifesciences2742 repos~2.7kAutomated safety check: PassApache-2.0
Doc Cleanernotoriouslab/doc-cleaner309—~712Automated safety check: PassMIT
MineruNebutra/MinerU-Skill122—~504Automated safety check: PassMIT
XLSXzzhonglei/GeoCode-Release187—~3.1kAutomated safety check: PassMIT
Python Bridgetmustier/pi-for-excel434—~820Automated safety check: PassMIT

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Works with

Categories

Questions about Sandbox Exec Fallback

What does Sandbox Exec Fallback do?

Fallback pattern for executing Python code when executecodesandbox fails by writing to file and running via shell. Sandbox Exec Fallback is an agent skill from HKUDS/OpenSpace.

When should I use Sandbox Exec Fallback?

Sandbox Exec Fallback fits situations like: tasks that involve Excel spreadsheets.

How do I install Sandbox Exec Fallback in Claude Code?

Run `npx skills add HKUDS/OpenSpace --skill sandbox-exec-fallback -a claude-code`. Or copy the skill folder (benchmarks/gdpval/skills/sandbox-exec-fallback in HKUDS/OpenSpace) into .claude/skills/sandbox-exec-fallback in your project. Claude Code loads it when a task matches its description.

How do I install Sandbox Exec Fallback in Codex?

Run `npx skills add HKUDS/OpenSpace --skill sandbox-exec-fallback -a codex`. Or copy the skill folder (benchmarks/gdpval/skills/sandbox-exec-fallback in HKUDS/OpenSpace) into .agents/skills/sandbox-exec-fallback in your project. Codex loads it when a task matches its description.

Can I use Sandbox Exec Fallback in Cursor, Gemini CLI or GitHub Copilot?

Cursor, Gemini CLI, GitHub Copilot and OpenCode also load SKILL.md folders. With the skills CLI, run `npx skills add HKUDS/OpenSpace --skill sandbox-exec-fallback -a cursor` (or -a gemini-cli, github-copilot or opencode for the others). To copy it by hand, put the folder in .cursor/skills/sandbox-exec-fallback, .gemini/skills/sandbox-exec-fallback, .github/skills/sandbox-exec-fallback and .opencode/skills/sandbox-exec-fallback in your project.

What does Sandbox Exec Fallback need to run?

SKILL.md names no scripts, command-line tools or credentials: Sandbox Exec Fallback is instructions for the agent only. Our summary lists: Python 3.

Does Sandbox Exec Fallback access the network?

SKILL.md contains no URLs. Any network use would come from the scripts or tools the agent runs. This is read from the text; nothing was executed.

Is Sandbox Exec Fallback safe to install?

Our automated static check of SKILL.md found no risky patterns, such as piping downloads into a shell, reading credential files or hidden Unicode. It is not a guarantee. Review the folder before installing.

What licence does Sandbox Exec Fallback use?

Sandbox Exec Fallback is published under the MIT licence (the repository's licence). It allows redistribution, so the full SKILL.md is shown on this page.

How many tokens does Sandbox Exec Fallback use?

About 617 tokens (SKILL.md is roughly 2.5k characters). Agents keep only the skill's name and description in context until a task matches; then they load SKILL.md in full.

What are the alternatives to Sandbox Exec Fallback?

Skills that share tags, products or a category with Sandbox Exec Fallback: Instrument Data To Allotrope (aws-samples/amazon-bedrock-agents-healthcare-lifesciences, 274 stars), Doc Cleaner (notoriouslab/doc-cleaner, 309 stars), Mineru (Nebutra/MinerU-Skill, 122 stars) and XLSX (zzhonglei/GeoCode-Release, 187 stars). The comparison table on this page puts their stars, adoption, token cost, safety result and licence side by side.

Who maintains Sandbox Exec Fallback?

HKUDS (a GitHub organization) maintains it in HKUDS/OpenSpace, which has 7,749 GitHub stars. The repository holds 199 skills in this directory. The repository was last updated on August 12, 2026.

Source: HKUDS/OpenSpace on GitHub. Facts on this page come from the repository at the commit we read; the author's words are quoted as theirs.