diff --git a/bin/exec-constrained.py b/bin/exec-constrained.py
index cda6267..7cccb41 100755
--- a/bin/exec-constrained.py
+++ b/bin/exec-constrained.py
@@ -729,6 +729,27 @@ def _tmux_kill_build(a):
     return [sys.executable, os.path.join(BIN_DIR, 'muse-tmux.py'), 'kill', a['session']]
 
 
+def _tmux_prune_validate(raw):
+    if not isinstance(raw, dict):
+        raise OpError('args must be an object')
+    allowed = {'ttl'}
+    for k in raw:
+        if k not in allowed:
+            raise OpError(f'unknown arg: {k}')
+    ttl = raw.get('ttl', 7200)
+    try:
+        ttl = int(ttl)
+        if ttl < 60:
+            ttl = 60
+    except Exception:
+        ttl = 7200
+    return {'ttl': ttl}
+
+
+def _tmux_prune_build(a):
+    return [sys.executable, os.path.join(BIN_DIR, 'muse-tmux.py'), 'prune', '--ttl', str(a['ttl'])]
+
+
 def _vars_list_validate(raw):
     if raw not in ({}, None):
         raise OpError('vars.list takes no required args')
@@ -1174,6 +1195,11 @@ OPS = {
         'timeout': 15, 'side_effecting': True,
         'desc': 'Kill a session on shared Muse tmux socket (/tmp/tmux-muse.sock)',
     },
+    'tmux.prune': {
+        'validate': _tmux_prune_validate, 'build': _tmux_prune_build,
+        'timeout': 15, 'side_effecting': True,
+        'desc': 'Reap stale unattached sessions inactive for >TTL (default 2h)',
+    },
     'exec.ping': {
         'validate': _health_validate,
         'build': lambda a: ['/bin/echo', 'PONG'],
diff --git a/bin/muse-tmux.py b/bin/muse-tmux.py
index 675aab6..78e85d5 100755
--- a/bin/muse-tmux.py
+++ b/bin/muse-tmux.py
@@ -105,6 +105,40 @@ def cmd_kill(args):
         print(f"Error: {err.strip() or out.strip()}", file=sys.stderr)
         return rc
 
+def cmd_prune(args):
+    ttl_seconds = getattr(args, "ttl", 7200) or 7200
+    rc, out, err = _run_tmux("list-sessions", "-F", "#{session_name} #{session_activity} #{session_attached}")
+    if rc != 0:
+        if "no server running" in (err or "").lower() or rc == 1:
+            print(f"No active tmux server on {SOCKET_PATH}.")
+            return 0
+        print(f"Error listing sessions: {err.strip() or out.strip()}", file=sys.stderr)
+        return rc
+        
+    now = int(time.time())
+    reaped = []
+    kept = []
+    
+    for line in out.strip().splitlines():
+        parts = line.split()
+        if len(parts) >= 3:
+            s_name, s_activity, s_attached = parts[0], int(parts[1]), int(parts[2])
+            idle_time = now - s_activity
+            # Only prune if unattached and idle > TTL
+            if s_attached == 0 and idle_time > ttl_seconds:
+                _run_tmux("kill-session", "-t", s_name)
+                reaped.append((s_name, idle_time))
+            else:
+                kept.append((s_name, idle_time, s_attached))
+                
+    if reaped:
+        print(f"✔ Reaped {len(reaped)} stale unattached session(s) (idle > {ttl_seconds//3600}h):")
+        for s_name, idle in reaped:
+            print(f"  • {s_name} (idle: {idle//60}m)")
+    else:
+        print(f"No stale unattached sessions to reap (all active within {ttl_seconds//3600}h).")
+    return 0
+
 def cmd_attach(args):
     session = args.session
     cmd = [TMUX_BIN, "-S", SOCKET_PATH, "attach", "-t", session]
@@ -144,6 +178,11 @@ def main():
     p_kill.add_argument("session", help="Session name")
     p_kill.set_defaults(func=cmd_kill)
     
+    # prune
+    p_prune = subparsers.add_parser("prune", help="Reap stale unattached sessions inactive for >TTL (default: 7200s / 2h)")
+    p_prune.add_argument("--ttl", type=int, default=7200, help="Inactivity threshold in seconds (default: 7200)")
+    p_prune.set_defaults(func=cmd_prune)
+    
     # attach
     p_att = subparsers.add_parser("attach", help="Attach to a session interactively")
     p_att.add_argument("session", help="Session name")
diff --git a/bin/netvm-reaper.sh b/bin/netvm-reaper.sh
index e6db038..7a63d7c 100755
--- a/bin/netvm-reaper.sh
+++ b/bin/netvm-reaper.sh
@@ -22,3 +22,6 @@ done
 find /tmp -name "*-smoke.log" -mtime +7 -delete 2>/dev/null
 find /tmp -name "otp_*.py" -mtime +1 -delete 2>/dev/null
 find /tmp -name "check_*.py" -mtime +1 -delete 2>/dev/null
+
+# Prune unattached stale agent tmux sessions older than 2 hours (7200s)
+python3 "$(cd "$(dirname "$0")" && pwd)/muse-tmux.py" prune --ttl 7200 2>/dev/null || true
diff --git a/docs/AGENT-TOOLING.md b/docs/AGENT-TOOLING.md
index e47353b..9a8a886 100644
--- a/docs/AGENT-TOOLING.md
+++ b/docs/AGENT-TOOLING.md
@@ -89,6 +89,9 @@ muse <account> tmux capture <session> --lines 30
 
 # Kill a session
 muse <account> tmux kill <session>
+
+# Prune unattached sessions inactive for >2 hours (or custom --ttl in seconds)
+muse <account> tmux prune [--ttl 7200]
 ```
 
 ### Via Autonomous Agent Directives:
@@ -98,6 +101,7 @@ Agents can emit structured tool calls in sidechats:
 [TOOL tmux.send {"session": "build-worker", "keys": "ls -la"}]
 [TOOL tmux.capture {"session": "build-worker", "lines": 20}]
 [TOOL tmux.list {}]
+[TOOL tmux.prune {"ttl": 7200}]
 [TOOL tmux.kill {"session": "build-worker"}]
 ```