Description

### [Environment]
OS:            station gb300
Architecture:  arm64
Node.js:       v22.x
npm:           10.x
Docker:        Docker Desktop
OpenShell CLI: openshell 0.0.32
NemoClaw:      v0.0.23
Hermes Agent:  v0.9.0 (2026.4.13)
Provider:      NVIDIA Endpoints (nvidia/nemotron-3-super-120b-a12b)
Brave Search:  enabled during onboard, preset applied, api.search.brave.com in egress

### [Steps to Reproduce]

Run nemoclaw onboard --agent hermes (any provider)
Complete onboard normally
Run nemoclaw test1 connect
Run hermes
Send any message (e.g. "hello")
Observe error traceback after the response
Try typing /exit to leave the chat

[Expected Behavior]

TUI accepts input and displays responses without errors
/exit cleanly exits the Hermes chat

[Actual Behavior]
After every interaction, a full Python traceback is displayed:

Unhandled exception in event loop: File "/usr/local/lib/python3.11/dist-packages/prompt_toolkit/history.py", line 299, in store_string with open(self.filename, "ab") as f: ^^^^^^^^^^^^^^^^^^^^^^^^^ Exception [Errno 13] Permission denied: '/sandbox/.hermes/.hermes_history'

Followed by `Press ENTER to continue...` which must be dismissed before the next input prompt appears. This creates a loop where:
- User types `/exit` → error triggers → "Press ENTER" appears → user presses Enter → `/exit` gets concatenated to the next input line instead of being processed as a command
- Ctrl-C does not break the loop
- Exiting requires Ctrl-U to clear input, then carefully typing `/exit`

### [Logs]
Full traceback:

File "/usr/local/lib/python3.11/dist-packages/prompt_toolkit/buffer.py", line 311, in reset self.append_to_history() File "/usr/local/lib/python3.11/dist-packages/prompt_toolkit/buffer.py", line 1365, in append_to_history self.history.append_string(self.text) File "/usr/local/lib/python3.11/dist-packages/prompt_toolkit/history.py", line 76, in append_string self.store_string(string) File "/usr/local/lib/python3.11/dist-packages/prompt_toolkit/history.py", line 299, in store_string with open(self.filename, "ab") as f: Exception [Errno 13] Permission denied: '/sandbox/.hermes/.hermes_history'

### [Suspected Root Cause / Notes]
During sandbox image build (Dockerfile step 28), `/sandbox/.hermes` is set to `root:root` ownership:

RUN chown root:root /sandbox/.hermes

This makes the directory read-only for the `sandbox` user. However, Python's `prompt_toolkit` library attempts to write command history to `/sandbox/.hermes/.hermes_history` at runtime. Since the sandbox runs as the `sandbox` user, the write fails with EACCES.

Fix options:
- Make `/sandbox/.hermes/.hermes_history` writable by the sandbox user (e.g. `chown sandbox:sandbox`)
- Or redirect history to a writable path like `/sandbox/.hermes-data/.hermes_history`
- Or disable file-based history in the Hermes CLI configuration

### [Regression?]
Unknown — first time testing Hermes Agent TUI.

DevTest task: 489841

Bug Details

Field	Value
Priority	Unprioritized
Action	Dev - Open - To fix
Disposition	Open issue
Module	Machine Learning - NemoClaw
Keyword	NemoClaw, NemoClaw_Agent&Skills, NEMOCLAW_GH_SYNC_APPROVAL, NemoClaw_Inference

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[NVB#6107559]