diff --git a/CHANGELOG.md b/CHANGELOG.md
index c4a655c12..696203b9f 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -5,6 +5,8 @@
 ### Bug Fixes
 - **Empty result field handling:** Fixed bug where Claude CLI returning `result: ""` (empty string) would cause raw JSON to be sent to WhatsApp instead of being treated as valid empty output. Changed truthy check to explicit type check in `command-reply.ts`.
 - **Response prefix on heartbeat replies:** Fixed `responsePrefix` (e.g., `🦞`) not being applied to heartbeat alert messages. The prefix was only applied in the regular message handler, not in `runReplyHeartbeat`.
+- **User-visible error messages:** Command failures (non-zero exit, killed processes, exceptions) now return user-friendly error messages to WhatsApp instead of silently failing with empty responses.
+- **Test session isolation:** Fixed tests corrupting production `sessions.json` by mocking session persistence in all test files.
 
 ### Changes
 - **Auto-recovery from stuck WhatsApp sessions:** Added watchdog timer that detects when WhatsApp event emitter stops firing (e.g., after Bad MAC decryption errors) and automatically restarts the connection after 30 minutes of no message activity. Heartbeat logging now includes `minutesSinceLastMessage` and warns when >30 minutes without messages. The 30-minute timeout is intentionally longer than typical `heartbeatMinutes` configs to avoid false positives.