diff --git a/engine/hooks/unverified-tag-ledger/claude.hook.json b/engine/hooks/unverified-tag-ledger/claude.hook.json
index fc42fd5..800014f 100644
--- a/engine/hooks/unverified-tag-ledger/claude.hook.json
+++ b/engine/hooks/unverified-tag-ledger/claude.hook.json
@@ -12,5 +12,9 @@
         ]
       }
     ]
+  },
+  "subagent_stop": {
+    "inherit": false,
+    "reason": "the ledger and its next-prompt reminder belong to the session owner; a subagent shares the parent's session id and would log its own tags against the parent's ledger, and it has no next user prompt to be reminded at"
   }
 }
diff --git a/engine/hooks/unverified-tag-ledger/install_claude_hook.py b/engine/hooks/unverified-tag-ledger/install_claude_hook.py
new file mode 100644
index 0000000..0986c73
--- /dev/null
+++ b/engine/hooks/unverified-tag-ledger/install_claude_hook.py
@@ -0,0 +1,74 @@
+#!/usr/bin/env python3
+"""Idempotently merge unverified-tag-ledger's Claude Code hooks into
+~/.claude/settings.json: the Stop hook (records tags and refuses a turn that
+tagged without checking) and the UserPromptSubmit hook (re-surfaces claims
+earlier turns deferred and never settled).
+
+Safe to rerun on every `install.sh`: each hook type is identified by whether
+any of its entries' "command" mentions that hook's own marker script,
+replaces just that hook type's unverified-tag-ledger entry with the current fragment
+file's content, and leaves every other key in settings.json (model, theme,
+other hooks, other hook types, ...) untouched. That means editing either
+fragment file and rerunning install.sh converges cleanly instead of
+appending a duplicate entry each time.
+"""
+import json
+import os
+
+HERE = os.path.dirname(os.path.abspath(__file__))
+SETTINGS_PATH = os.path.expanduser("~/.claude/settings.json")
+
+# (hook type in settings.json, marker script identifying "our" entry, fragment file)
+HOOK_SPECS = [
+    ("Stop", "claude_stop_check.py", os.path.join(HERE, "claude.hook.json")),
+    ("UserPromptSubmit", "claude_prompt_reminder.py", os.path.join(HERE, "claude.prompt.hook.json")),
+]
+
+
+def _is_ours(entry, marker):
+    return any(marker in h.get("command", "") for h in entry.get("hooks", []))
+
+
+def merge_hook(settings, hook_type, marker, fragment):
+    """Pure: returns (new_settings, changed). Replaces any existing
+    unverified-tag-ledger entry of this hook type with fragment's, appends if none
+    existed yet."""
+    settings = json.loads(json.dumps(settings))  # deep copy, no external dep
+    entry_list = settings.setdefault("hooks", {}).setdefault(hook_type, [])
+    new_entries = fragment["hooks"][hook_type]
+
+    before = json.dumps(entry_list, sort_keys=True)
+    entry_list[:] = [e for e in entry_list if not _is_ours(e, marker)] + new_entries
+    changed = json.dumps(entry_list, sort_keys=True) != before
+    return settings, changed
+
+
+def main():
+    settings = {}
+    if os.path.exists(SETTINGS_PATH):
+        with open(SETTINGS_PATH) as f:
+            settings = json.load(f)
+
+    any_changed = False
+    for hook_type, marker, fragment_path in HOOK_SPECS:
+        with open(fragment_path) as f:
+            fragment = json.load(f)
+        settings, changed = merge_hook(settings, hook_type, marker, fragment)
+        if changed:
+            any_changed = True
+            print(f"link    claude {hook_type} hook merged into settings.json")
+        else:
+            print(f"ok      claude {hook_type} hook already up to date")
+
+    if not any_changed:
+        return
+
+    os.makedirs(os.path.dirname(SETTINGS_PATH), exist_ok=True)
+    with open(SETTINGS_PATH, "w") as f:
+        json.dump(settings, f, indent=2)
+        f.write("\n")
+    print("        (restart Claude Code to pick up the change)")
+
+
+if __name__ == "__main__":
+    main()
diff --git a/install.sh b/install.sh
index c1360a0..a8acfac 100755
--- a/install.sh
+++ b/install.sh
@@ -335,6 +335,7 @@ fi
 # either file. See each script's docstring for exactly what it does.
 echo "--- claude Stop + UserPromptSubmit hooks (\$HOME/.claude/settings.json) ---"
 python3 "$REPO_DIR/engine/hooks/diu-stop/install_claude_hook.py"
+python3 "$REPO_DIR/engine/hooks/unverified-tag-ledger/install_claude_hook.py"
 python3 "$REPO_DIR/engine/hooks/bug-complaint-leak/install_claude_hook.py"
 python3 "$REPO_DIR/engine/hooks/reflect-on-thrash/install_claude_hook.py"
 python3 "$REPO_DIR/engine/hooks/scope-lock/install_claude_hook.py"