openclaw - 💡(How to fix) Fix Sandbox mutation helper rejects writes when python3 is available (v2026.5.7)

Summary

Sandbox write-helper rejects all file writes with sandbox pinned mutation helper requires python3 or python even when python3 is installed and on the gateway PATH. Affects every agent running v2026.5.7 with a Docker-style runtime sandbox.

Environment

• OpenClaw: v2026.5.7 (eeef486)
• OS: Debian 13 (linux 6.12.85+deb13-amd64)
• Node: 22.22.2
• Python: /usr/bin/python3 version Python 3.13.5 (installed, on PATH)

Repro

Any tools.write call from an agent running inside the sandbox:

[tools] write failed: sandbox pinned mutation helper requires python3 or python
raw_params={"path":"/path/inside/workspace","content":"..."}

Reproduced both pre-restart (under v2026.5.2 process) and post-restart (under fresh v2026.5.7 process). Identical error string across upgrade boundary, so this is not a v5.2 artifact persisting in memory — it is a v5.7 regression.

Verification python3 IS findable

$ which python3
/usr/bin/python3
$ echo "$PATH" | tr ":" "\n" | grep usr/bin
/usr/bin
$ echo "import sys; print(sys.version)" | python3
3.13.5 (main, Jun 25 2025, 18:55:22) [GCC 14.2.0]

Gateway PATH (from systemctl --user show openclaw-gateway --property=Environment) includes /usr/bin.

Impact

All LLM-driven workspace file authoring is blocked. Agent cannot:

• Persist plans, drafts, or session memory to workspace files
• Execute their own end-of-session memory-push rules
• Author SOPs, run docs, or any artifact-producing workflow

Workaround: route writes through an out-of-sandbox executor (e.g., SSH-shell with full filesystem access). Not a real fix; just shifts the work to a privileged process.

Suggested investigation

The "pinned" naming suggests the helper resolves python3 via a specific absolute path that differs from what is installed. Worth checking:

• Is the mutation helper compiled against a specific python3 path that does not match this distro?
• Is there an OPENCLAW_PYTHON3_PATH (or similar) env var the helper expects?
• Does the v5.7 release notes mention a sandbox-runtime change vs v5.6?

Happy to gather any additional diagnostics on request.