Bug type

Regression (worked before, now fails)

Summary

After upgrading from 2026.3.8 to 2026.3.13, the agent's edit, write, and read file tools are completely broken inside the sandbox. Every attempt fails with: moltbot-sandbox-fs: 2: python3: not found

Steps to reproduce

1. Use the default openclaw-sandbox:bookworm-slim sandbox image
2. Upgrade to 2026.3.13 via npm i -g openclaw@latest
3. Have the agent attempt to edit or write any file

Expected behavior

Either the openclaw-sandbox:bookworm-slim image ships with python3 included, or the release notes for 2026.3.13 document this new dependency and the workaround.

Actual behavior

Environment

• openclaw version: 2026.3.13 (broken), 2026.3.8 (worked)
• Sandbox image: openclaw-sandbox:bookworm-slim
• Platform: Linux (Debian bookworm-slim container)

Root cause

moltbot-sandbox-fs (the file tool bridge, new or updated in 2026.3.13) depends on python3. The bookworm-slim base image does not include python3 — it's a deliberately minimal Debian variant. The container root filesystem is also read-only, so packages cannot be installed into a running container.

This dependency was absent or unused in 2026.3.8. It was not documented in the 2026.3.13 release notes.

Workaround

Rebuild the sandbox image with python3 added:

bash
docker build -t openclaw-sandbox:bookworm-slim - <<'EOF'
FROM openclaw-sandbox:bookworm-slim
USER root
RUN apt-get update && apt-get install -y --no-install-recommends python3 && rm -rf /var/lib/apt/lists/*
EOF

Then stop and remove the existing sandbox container and restart the gateway so a fresh container is created from the updated image. Note: this workaround is lost if a future upgrade replaces the base image.

OpenClaw version

2026.3.13

Operating system

Ubuntu 24.04.4 LTS

Install method

No response

Model

GPT5.3-Codex

Provider / routing chain

openclaw->openAI (using auth token)

Additional provider/model setup details

No response

Logs, screenshots, and evidence

Impact and severity

High severity: Agent is not able to update markdown files, preventing it from updating stkills or storing new memories

Additional information

No response