feat: UserPromptSubmit hook for encounter announcements

Bash PostToolUse additionalContext is silently dropped by CC — encounters
are written to state but never surfaced. Fix with a two-phase approach:

- PostToolUse (Bash): detects error, writes encounter with announced:false
- UserPromptSubmit: fires on next user message, checks for unannounced
  encounter, surfaces it once, marks announced:true so dedup loop breaks

Removes debug scaffolding and the format_encounter_message call from the
Bash hook (announcement is now fully owned by user-prompt-submit.py).

hooks-handlers/post-tool-use.py

@@ -281,7 +281,6 @@ def main():
     if tool_name == "Bash":
         output = ""
         if isinstance(tool_response, dict):
-            # CC may use any of these keys; combine all text fields
             parts = [
                 tool_response.get("output", ""),
                 tool_response.get("content", ""),
@@ -292,7 +291,6 @@ def main():
         elif isinstance(tool_response, str):
             output = tool_response
         elif isinstance(tool_response, list):
-            # Array of content blocks: [{"type": "text", "text": "..."}]
             output = "\n".join(
                 b.get("text", "") for b in tool_response
                 if isinstance(b, dict) and b.get("type") == "text"
@@ -325,10 +323,9 @@ def main():
                         "defeatable": monster.get("defeatable", True),
                         "xp_reward": monster.get("xp_reward", 50),
                         "weakened_by": [],
+                        "announced": False,
                     }
                     set_active_encounter(encounter)
-                    msg = format_encounter_message(monster, strength, buddy_display)
-                    messages.append(msg)
 
         # Commit detection
         command = tool_input.get("command", "")

hooks-handlers/user-prompt-submit.py

@@ -0,0 +1,113 @@
+#!/usr/bin/env python3
+"""
+Buddymon UserPromptSubmit hook.
+
+Fires on every user message. Checks for an unannounced active encounter
+and surfaces it exactly once via additionalContext, then marks it announced
+so the dedup loop breaks. Exits silently if nothing is pending.
+"""
+
+import json
+import os
+import sys
+from pathlib import Path
+
+PLUGIN_ROOT = os.environ.get("CLAUDE_PLUGIN_ROOT", str(Path(__file__).parent.parent))
+BUDDYMON_DIR = Path.home() / ".claude" / "buddymon"
+CATALOG_FILE = Path(PLUGIN_ROOT) / "lib" / "catalog.json"
+
+
+def load_json(path):
+    try:
+        with open(path) as f:
+            return json.load(f)
+    except Exception:
+        return {}
+
+
+def save_json(path, data):
+    try:
+        with open(path, "w") as f:
+            json.dump(data, f, indent=2)
+    except Exception:
+        pass
+
+
+def main():
+    try:
+        json.load(sys.stdin)
+    except Exception:
+        pass
+
+    roster = load_json(BUDDYMON_DIR / "roster.json")
+    if not roster.get("starter_chosen", False):
+        sys.exit(0)
+
+    enc_file = BUDDYMON_DIR / "encounters.json"
+    enc_data = load_json(enc_file)
+    enc = enc_data.get("active_encounter")
+
+    if not enc or enc.get("announced", False):
+        sys.exit(0)
+
+    # Mark announced FIRST — prevents re-announce even if output delivery fails
+    enc["announced"] = True
+    enc_data["active_encounter"] = enc
+    save_json(enc_file, enc_data)
+
+    # Resolve buddy display name
+    active = load_json(BUDDYMON_DIR / "active.json")
+    buddy_id = active.get("buddymon_id")
+    buddy_display = "your buddy"
+    if buddy_id:
+        catalog = load_json(CATALOG_FILE)
+        b = (catalog.get("buddymon", {}).get(buddy_id)
+             or catalog.get("evolutions", {}).get(buddy_id))
+        if b:
+            buddy_display = b.get("display", buddy_id)
+    else:
+        catalog = load_json(CATALOG_FILE)
+
+    monster = catalog.get("bug_monsters", {}).get(enc.get("id", ""), {})
+    rarity = monster.get("rarity", "common")
+    rarity_stars = {
+        "very_common": "★☆☆☆☆", "common": "★★☆☆☆",
+        "uncommon": "★★★☆☆", "rare": "★★★★☆", "legendary": "★★★★★",
+    }
+    stars = rarity_stars.get(rarity, "★★☆☆☆")
+    strength = enc.get("current_strength", 50)
+    defeatable = enc.get("defeatable", True)
+    catchable = enc.get("catchable", True)
+    flavor = monster.get("flavor", "")
+
+    catchable_str = "[catchable · catch only]" if not defeatable else f"[{rarity} · {'catchable' if catchable else ''}]"
+
+    lines = [
+        f"\n💀 **{enc['display']} appeared!**  {catchable_str}",
+        f"   Strength: {strength}%  ·  Rarity: {stars}",
+    ]
+    if flavor:
+        lines.append(f"   *{flavor}*")
+    if not defeatable:
+        lines.append("   ⚠️  CANNOT BE DEFEATED — catch only")
+    lines += [
+        "",
+        f"   **{buddy_display}** is ready to battle!",
+        "",
+        "   `[FIGHT]` Fix the bug → `/buddymon fight` to claim XP",
+        "   `[CATCH]` Weaken first (test/repro/comment) → `/buddymon catch`",
+        "   `[FLEE]`  Ignore → monster grows stronger",
+    ]
+
+    msg = "\n".join(lines)
+    print(json.dumps({
+        "hookSpecificOutput": {
+            "hookEventName": "UserPromptSubmit",
+            "additionalContext": msg,
+        }
+    }))
+    sys.exit(0)
+
+
+if __name__ == "__main__":
+    main()

hooks/hooks.json

@@ -12,6 +12,17 @@
         ]
       }
     ],
+    "UserPromptSubmit": [
+      {
+        "hooks": [
+          {
+            "type": "command",
+            "command": "python3 ${CLAUDE_PLUGIN_ROOT}/hooks-handlers/user-prompt-submit.py",
+            "timeout": 5
+          }
+        ]
+      }
+    ],
     "PostToolUse": [
       {
         "matcher": "Bash|Edit|Write|MultiEdit",