fix: replace subshell bridge supervisor with tmux session

[baudbot-agent]

Problem

The Slack bridge ran as a subshell (( ... ) &) child of startup-cleanup.sh. Three issues:

1. Bridge doesn't survive restarts — when pi is restarted independently (not through start.sh), the bridge subshell dies with no recovery
2. Script hangs — the subshell keeps the script's process group alive, so startup-cleanup.sh never returns when called from pi's bash tool
3. EADDRINUSE crash loops — PID-file cleanup misses orphaned bridge processes, so the new bridge can't bind port 7890 and crash-loops

Fix

Replace the subshell supervisor with a slack-bridge tmux session — same pattern as sentry-agent, which has been rock solid.

• tmux session with a 5-second restart loop replaces the subshell ( ... ) &
• lsof -ti :7890 | xargs kill -9 replaces PID-file tracking — kills whatever is on the port, guaranteed
• tmux kill-session cleans up any existing bridge session before starting fresh
• Script completes immediately — tmux new-session -d detaches, no hang
• Backward compat: still cleans up old-style PID files from previous deploys

Also removes the bridge-restart-policy.sh dependency — the tmux restart loop is simpler and sufficient.

Testing

• Tested live on the running agent — bridge starts, no hang, survives script completion
• Pre-existing test failures (heartbeat, memory) unrelated to this change (13/15 pass, same on main)

[greptile-apps]

Greptile Summary

Replaces the subshell-based Slack bridge supervisor with a tmux session pattern (matching sentry-agent), fixing three issues: bridge survival across pi restarts, script hanging, and EADDRINUSE crash loops from orphaned processes.

Major changes:

• Removes bridge-restart-policy.sh dependency and bb_bridge_supervise function
• Uses lsof -ti :7890 | xargs kill -9 for guaranteed port cleanup instead of PID-file tracking
• Bridge now runs in detached tmux session with 5-second restart loop
• Backward compatible cleanup for old PID files from previous deploys

Issues found:

• Hardcoded node path ~/opt/node-v22.14.0-linux-x64/bin will break if node version changes or runtime overrides are configured (differs from start.sh which uses bb_resolve_runtime_node_bin_dir)

Confidence Score: 3/5

• Safe to merge with one fix needed: node path resolution
• The tmux-based approach is sound and matches the proven sentry-agent pattern. Port cleanup via lsof is more reliable than PID files. However, the hardcoded node version path creates a maintenance risk and breaks the abstraction used in start.sh. This should be fixed to use ~/opt/node/bin or source runtime-node.sh for dynamic resolution.
• Fix the hardcoded node path in pi/skills/control-agent/startup-cleanup.sh:128

Important Files Changed

Filename	Overview
pi/skills/control-agent/startup-cleanup.sh	Replaces subshell bridge supervisor with tmux session; hardcoded node path differs from start.sh pattern

Sequence Diagram

sequenceDiagram
    participant S as startup-cleanup.sh
    participant P as Port 7890
    participant T as tmux session
    participant B as slack-bridge

    Note over S,P: Old approach: subshell supervisor
    S->>P: Check PID file, kill old supervisor
    S->>S: Start subshell background
    S->>S: Track supervisor PID in file
    Note over S: Script hangs if called from pi

    Note over S,B: New approach: tmux session
    S->>P: lsof -ti :7890 and kill -9
    S->>T: tmux kill-session if exists
    S->>T: tmux new-session -d detached
    loop Restart loop in tmux
        T->>B: varlock run -- node bridge.mjs
        B-->>T: exit with code
        T->>T: sleep 5 seconds
    end
    Note over S: Script returns immediately
    Note over T,B: Bridge restarts automatically

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_{Last reviewed commit: c1110d5}

[greptile-apps]

_{1 file reviewed, 1 comment}

_{Edit Code Review Agent Settings | Greptile}

[greptile-apps]

Hardcoded node path $HOME/opt/node-v22.14.0-linux-x64/bin differs from start.sh which uses bb_resolve_runtime_node_bin_dir to dynamically locate node.

This will break if:

• Node version is upgraded
• BAUDBOT_RUNTIME_NODE_BIN_DIR override is set
• Installation uses ~/opt/node/bin symlink pattern

Suggested change

	export PATH=\$HOME/.varlock/bin:\$HOME/opt/node-v22.14.0-linux-x64/bin:\$PATH; \
	export PATH=\$HOME/.varlock/bin:\$HOME/opt/node/bin:\$PATH; \

Or source runtime-node.sh and use bb_resolve_runtime_node_bin_dir to match start.sh behavior.

Prompt To Fix With AI

This is a comment left during a code review.
Path: pi/skills/control-agent/startup-cleanup.sh
Line: 128

Comment:
Hardcoded node path `$HOME/opt/node-v22.14.0-linux-x64/bin` differs from `start.sh` which uses `bb_resolve_runtime_node_bin_dir` to dynamically locate node.

This will break if:
- Node version is upgraded
- `BAUDBOT_RUNTIME_NODE_BIN_DIR` override is set
- Installation uses `~/opt/node/bin` symlink pattern

```suggestion
  export PATH=\$HOME/.varlock/bin:\$HOME/opt/node/bin:\$PATH; \
```

Or source `runtime-node.sh` and use `bb_resolve_runtime_node_bin_dir` to match `start.sh` behavior.

How can I resolve this? If you propose a fix, please make it concise.

[baudbot-agent]

Fixed in 4ec7393 — node path is now resolved dynamically (~/opt/node/bin with fallback to versioned glob). Good catch from the drift check.