MissionBell — Claude Code sessions & alerts
Unofficial. This extension is a community tool and is not affiliated with or endorsed by Anthropic. "Claude" and "Claude Code" are trademarks of Anthropic, PBC, used here only to describe compatibility.
Run several Claude Code sessions across projects without babysitting any of them:
- 🖥️ Mission Control panel — every live session in one sidebar: which project, whether it's ⏳ working / ✅ done / 🙋 waiting for your answer, and for how long. Click a session to raise that project's window.
- 📈 Context Health (Session X-Ray) — a live gauge per session showing how full its context window is (with cache-hit rate and token headroom in the tooltip), and a warning before lossy autocompact hits (
contextWarnPercent, default 80%) — the moment to /compact on your terms or externalize state.
- 🌱 Memory health — flags the chronic context tax: an auto-memory index over its always-loaded budget, oversized CLAUDE.md chains, memories referencing files that no longer exist, and stale entries worth re-checking.
- 🔔 Native notifications from any window (Windows toasts / macOS notifications) — when a session finishes processing (only turns longer than a threshold, default 30 s — quick replies stay silent) and the moment one needs your answer (permission prompt / waiting for input).
- 📊 Status bar counts — a compact
⏳ 2 🙋 1 in every window; click it to open Mission Control.
- ⏰ "Still waiting" reminder — if a session sits on needs answer for more than 5 minutes (configurable), it nudges you again.
Notifications persist in the Windows Notification Center (Win + N) / macOS Notification Center, and because the hook fires them itself, they keep working even when VS Code is closed — Claude Code in a plain terminal notifies too.
How it works
Claude Code has a built-in hooks system that fires on session events. On Enable, this extension:
- copies a small, self-contained hook script to
~/.claude/hooks/claude-code-notifier.mjs,
- wires it into
~/.claude/settings.json for SessionStart, UserPromptSubmit, Stop, Notification, and SessionEnd (a timestamped backup of your settings is made first; your existing hooks are never touched),
- registers a per-user toast identity (
HKCU, no admin rights) so notifications show this extension's name and icon.
The hook maintains a tiny per-session state file (in your temp folder) that feeds the panel and status bar. Context Health reads only the tail of Claude Code's local session transcripts (they can reach hundreds of MB — MissionBell never loads them whole) and your memory files' metadata. Everything is local; no network requests, nothing collected. Token figures come from Claude Code's own recorded usage; window-size tiers (200K / 1M) are inferred, so treat the percentage as a close estimate, not gospel.
Requirements
- Windows 10/11 or macOS (Linux is on the roadmap)
- Node.js on your PATH (you have this — Claude Code requires it)
- Claude Code
macOS notes: notifications use the built-in osascript — no dependencies, but macOS attributes them to "Script Editor" (a custom name/icon would require a signed app bundle; on the roadmap). Allow them under System Settings → Notifications → Script Editor if you don't see any. Click-to-raise from the panel uses the code CLI — run "Shell Command: Install 'code' command in PATH" once from the Command Palette.
Getting started
- Install the extension — it asks once whether to enable notifications. (Or run MissionBell: Enable from the Command Palette.)
- Restart any already-running Claude Code sessions — hooks load when a session starts.
- Optional: run MissionBell: Send Test Notification to see a toast right away.
- Open the MissionBell icon in the activity bar to watch your sessions.
Upgrading from v0.1.x? The two new session-tracking events are wired automatically on first activation — nothing to do.
Settings
| Setting |
Default |
Meaning |
claudeCodeNotifier.minSeconds |
30 |
Only notify "done" when the turn took longer than this. 0 = every turn. |
claudeCodeNotifier.notifyOnNeedsInput |
true |
Toast immediately when Claude needs a permission/answer. |
claudeCodeNotifier.staleAnswerMinutes |
5 |
Re-notify when a session has waited this long for your answer. 0 = off. |
claudeCodeNotifier.contextWarnPercent |
80 |
Warn when a session's context window passes this %. 0 = off. |
Uninstalling
Run MissionBell: Disable first — it unwires the hook from ~/.claude/settings.json, removes the installed files, and deletes the registry identity. Then uninstall the extension normally. (If you uninstall without disabling, the hook entries remain in your settings but fail silently and never block Claude Code; you can remove them by hand or reinstall + Disable.)
Troubleshooting
- No notification appears — check Focus assist / Do Not Disturb (Windows) or Focus mode + Script Editor's notification permission (macOS); both suppress notifications system-wide. Also confirm the session was started after enabling.
- "Done" toast missing for a quick reply — that's the
minSeconds filter working as intended.
- Panel shows a session that's actually closed — sessions that end without a clean
SessionEnd are swept automatically within a day; right-click → Dismiss Session removes one instantly.
- Settings file worries — every Enable/Disable writes a
settings.json.bak-ccn-<timestamp> backup next to your ~/.claude/settings.json.
Privacy
Everything is local. The extension makes no network requests and collects nothing.
