# Review by Staff Security Engineer (Round 1)

## Review Complete — Staff Security Engineer

**VERDICT: approve**

### Summary

This is a clean, tightly-scoped UI bugfix with **zero security impact**. I reviewed the full diff (8 files, ~530 lines added) against the PRD. All 95 TUI tests pass. No secrets in the diff.

**What changed:**
- **CSS fix** (`styles.py`): Dead selector `TranscriptView RichLog` → `TranscriptView`; `overflow: hidden` on Screen
- **Scroll logic** (`transcript.py`): `auto_scroll=False` on RichLog base class, 3-line re-engagement threshold, async flag clearing via `_pending_programmatic_clear`, unread-lines counter with one-shot notification
- **Hints** (`hint_bar.py`, banners): "Shift+drag select" added to HintBar and both banners
- **Tests**: 26 new tests across `test_transcript.py`, `test_app.py`, `test_composer.py`

**Security assessment:** No new user inputs parsed, no file/network I/O introduced, no new dependencies, no permission escalation. All new code paths use hardcoded strings and internal state only. The notification uses a static string (no injection risk) and is rate-limited to the 0→1 unread transition (no spam vector).

FINDINGS:
- [src/colonyos/tui/widgets/transcript.py]: Notification correctly rate-limited to 0→1 transition only — no spam risk
- [src/colonyos/tui/widgets/transcript.py]: Scroll threshold is hardcoded constant — safe; would need validation if ever made configurable
- [tests/tui/test_app.py]: `asyncio.sleep(0.2)` in integration tests could cause flakiness in slow CI but is not a security concern

SYNTHESIS:
This is pure presentation-layer work: CSS fixes, internal scroll-tracking state, and static hint strings. No new security boundaries are modified, no new capabilities are granted, and no user-controlled data enters the new code paths. From a supply-chain and least-privilege perspective, the change is inert — it adds zero new dependencies and zero new subprocess/file/network calls. Approved without reservations.
