fallback-python-execution

A fallback process for running Python when the usual code sandbox or shell tool fails.

In plain words
What is it for?
Use it to write a Python script to a file, run it from the shell, check that it worked, and optionally remove the temporary script.
Why use it?
It provides another way to run Python and create files when delegated execution repeatedly produces errors.

Skill for Claude CodeCodex

Install

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.

agentmods
npx agentmods add skills/hkuds/openspace/fallback-python-execution
Any agent
npx skills add HKUDS/OpenSpace --skill fallback-python-execution
Clone the repo
git clone --depth 1 https://github.com/HKUDS/OpenSpace

Made for: Claude Code, Codex.

Per session 18 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 615 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin original No closer match found in the catalogue.
Token cost

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.

ModelPer sessionOnce invoked
Fable 5 $0.00018 $0.00615
Opus 5 $0.00009 $0.00308
Sonnet 5 $0.00004 $0.00123
Haiku 4.5 $0.00002 $0.00061

Measured 2d ago against content hash b7cc2b24da5e, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

fallback-python-execution 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 2d 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.

benchmarks/gdpval/skills/fallback-python-execution/SKILL.md · 100 lines

How it starts

The opening of the file, as written. The whole thing — 100 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Fallback Python Execution Pattern

When to Use

Use this pattern when:

  • execute_code_sandbox returns unknown errors or fails repeatedly
  • shell_agent cannot successfully execute Python code
  • You need to create files (spreadsheets, documents, data files) via Python
  • Direct delegated approaches prove unreliable in the current environment

Core Technique

Instead of delegating Python execution to agents, use this two-step inline approach:

  1. Write Python code to a .py file using write_file
  2. Execute the file using run_shell with python <script.py>

Step-by-Step Instructions

Step 1: Write Python Code to File

Use write_file to create a Python script with all necessary code inline:

write_file
path: /path/to/script.py
content: |
    import pandas as pd
    # Your complete Python code here
    df = pd.DataFrame({...})
    df.to_excel('output.xlsx', index=False)

Step 2: Execute via run_shell

Run the script directly:

run_shell
command: python /path/to/script.py

Step 3: Verify and Clean Up

  • Check the output for success/errors
  • Verify the expected files were created
  • Optionally remove the temporary script if no longer needed

Why This Works

This approach is more reliable because:

  • Avoids agent interpretation layers that can introduce errors
  • Provides direct control over execution environment
  • Gives clear error output for debugging
  • Bypasses sandbox delegation issues

Example: Excel File Creation

# Step 1: Write the script
write_file:
  path: create_report.py
  content: |
    import pandas as pd
    from openpyxl import Workbook
    
    # Create data
    data = {'Column1': [1, 2, 3], 'Column2': ['A', 'B', 'C']}
    df = pd.DataFrame(data)
    
    # Save to Excel
    df.to_excel('report.xlsx', index=False)
    print('Excel file created successfully')

# Step 2: Execute
run_shell:
  command: python create_report.py

Tips

  • Include error handling in your Python code for better debugging
  • Use absolute paths when possible to avoid working directory issues
  • Add print statements to track execution progress
  • Keep scripts self-contained with all imports at the top
  • For complex tasks, break into multiple scripts if needed

Read the full file on GitHub · 100 lines

Files

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.

Changes

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.

  1. 2d ago First seen · 100 lines · 18 tokens per session scan A b7cc2b24da5e

Subscribe to this mod's changes

fallback-python-execution is a skill published in the GitHub repository HKUDS/OpenSpace (7,479 stars, last pushed 20d ago), licensed MIT. It adds 18 tokens to every session and 615 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 2026-08-30.

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