code-execution-fallback

A workflow for recovering when code execution fails and keeping commands tied to the correct project folder.

In plain words
What is it for?
It is for retrying code with simpler commands, switching to shell execution when needed, and checking the active workspace path.
Why use it?
It reduces failures caused by complex execution methods and prevents files from being written to an unexpected location.

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

Made for: Claude Code, Codex.

Per session 17 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,014 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 $0.00017 $0.01014
Opus 5 $0.00009 $0.00507
Sonnet 5 $0.00003 $0.00203
Haiku 4.5 $0.00002 $0.00101

Measured yesterday against content hash e7a7d0d684e3, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

code-execution-fallback 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 yesterday.

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/code-execution-fallback/SKILL.md · 156 lines

How it starts

The opening of the file, as written. The whole thing — 156 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Code Execution Fallback & Workspace Anchoring

This skill provides a robust pattern for executing code when the primary method fails, combined with proper workspace path management to prevent file location errors.

Core Techniques

1. Workspace Path Anchoring

Always establish and verify your working directory at the start of any task:

# At the beginning of any code execution
import os
workspace_path = os.getcwd()
print(f"Working directory: {workspace_path}")
# In shell scripts
pwd
echo "Current directory: $(pwd)"

Why: Prevents files from being written to unexpected locations when agents switch between tools.

2. Execution Fallback Ladder

When execute_code_sandbox fails, follow this escalation pattern:

Level 1: Retry with Simpler Code
  • Simplify the code structure
  • Remove complex dependencies
  • Add explicit error handling
Level 2: Use run_shell with Heredoc

When sandbox execution repeatedly fails, switch to shell execution:

python3 << 'EOF'
import os
import pandas as pd

# Your code here
data = {"col1": [1, 2, 3], "col2": ["a", "b", "c"]}
df = pd.DataFrame(data)
df.to_csv("output.csv", index=False)
print("File written successfully")
EOF

Key points:

  • Use << 'EOF' (quoted) to prevent variable expansion
  • Include all imports and dependencies inline
  • Add explicit success/failure messages
Level 3: Delegate to shell_agent

For complex multi-step tasks with error recovery needs:

Task: Create a data processing pipeline that reads CSV, transforms data, and outputs Excel
Requirements:
- Handle missing values
- Apply transformations
- Write to ./output/ directory
- Retry on transient errors

3. Explicit Path Management

Always use absolute or explicitly relative paths:

# BAD - relies on implicit working directory
df.to_csv("output/data.csv")

# GOOD - explicit path anchoring
import os
base_path = os.getcwd()
output_dir = os.path.join(base_path, "output")
os.makedirs(output_dir, exist_ok=True)
df.to_csv(os.path.join(output_dir, "data.csv"))

Read the full file on GitHub · 156 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. yesterday First seen · 156 lines · 17 tokens per session scan A e7a7d0d684e3

Subscribe to this mod's changes

code-execution-fallback is a skill published in the GitHub repository HKUDS/OpenSpace (7,479 stars, last pushed 19d ago), licensed MIT. It adds 17 tokens to every session and 1,014 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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