diff --git a/scripts/extract-knowledge.py b/scripts/extract-knowledge.py
new file mode 100755
index 0000000..3282905
--- /dev/null
+++ b/scripts/extract-knowledge.py
@@ -0,0 +1,174 @@
+#!/usr/bin/env python3
+"""Extract knowledge from Claude Code conversation transcripts and store in memory API.
+
+Runs as a background process triggered by a Stop hook. Reads the latest
+conversation JSONL, extracts facts/decisions/preferences, and stores them
+via the memory HTTP API.
+
+Usage:
+    python3 extract-knowledge.py <transcript_jsonl_path>
+
+Environment:
+    MEMORY_API_URL - Memory API base URL
+    MEMORY_API_KEY - Memory API key
+"""
+
+import json
+import os
+import re
+import sys
+import urllib.error
+import urllib.request
+from pathlib import Path
+
+API_URL = os.environ.get("MEMORY_API_URL", os.environ.get("CLAUDE_MEMORY_API_URL", ""))
+API_KEY = os.environ.get("MEMORY_API_KEY", os.environ.get("CLAUDE_MEMORY_API_KEY", ""))
+
+# Patterns that indicate something worth remembering
+KNOWLEDGE_PATTERNS = [
+    # User explicitly says "remember"
+    (r'\bremember\b.*?[:\-]\s*(.+)', "preferences", 0.9),
+    # Decisions made
+    (r'(?:decided|decision|we\'ll go with|let\'s use|agreed)\s+(?:to\s+)?(.+)', "decisions", 0.8),
+    # Preferences expressed
+    (r'(?:always|never|prefer|don\'t|do not)\s+(.+)', "preferences", 0.7),
+    # Project facts
+    (r'(?:deployed|running|hosted)\s+(?:at|on)\s+(.+)', "projects", 0.6),
+]
+
+SEEN_FILE = Path(os.environ.get("MEMORY_SEEN_FILE", Path.home() / ".claude" / "claude-memory" / "seen_lines.json"))
+
+
+def load_seen() -> set:
+    if SEEN_FILE.exists():
+        return set(json.loads(SEEN_FILE.read_text()))
+    return set()
+
+
+def save_seen(seen: set) -> None:
+    SEEN_FILE.parent.mkdir(parents=True, exist_ok=True)
+    # Keep only last 1000 entries to prevent unbounded growth
+    recent = sorted(seen)[-1000:]
+    SEEN_FILE.write_text(json.dumps(recent))
+
+
+def api_store(content: str, category: str, importance: float, keywords: str) -> bool:
+    if not API_URL or not API_KEY:
+        return False
+    data = json.dumps({
+        "content": content,
+        "category": category,
+        "importance": importance,
+        "expanded_keywords": keywords,
+    }).encode()
+    req = urllib.request.Request(
+        f"{API_URL}/api/memories",
+        data=data,
+        method="POST",
+        headers={
+            "Authorization": f"Bearer {API_KEY}",
+            "Content-Type": "application/json",
+        },
+    )
+    try:
+        with urllib.request.urlopen(req, timeout=10) as resp:
+            result = json.loads(resp.read().decode())
+            print(f"  Stored memory #{result.get('id', '?')}: {content[:60]}...", file=sys.stderr)
+            return True
+    except (urllib.error.URLError, urllib.error.HTTPError) as e:
+        print(f"  Failed to store: {e}", file=sys.stderr)
+        return False
+
+
+def extract_from_transcript(transcript_path: str) -> list[dict]:
+    """Extract knowledge candidates from conversation transcript."""
+    findings = []
+    seen = load_seen()
+
+    try:
+        with open(transcript_path) as f:
+            for line in f:
+                line = line.strip()
+                if not line:
+                    continue
+                # Create a hash for dedup
+                line_hash = str(hash(line))
+                if line_hash in seen:
+                    continue
+                seen.add(line_hash)
+
+                try:
+                    msg = json.loads(line)
+                except json.JSONDecodeError:
+                    continue
+
+                # Only look at user messages and assistant text
+                role = msg.get("role", "")
+                if role not in ("user", "assistant"):
+                    continue
+
+                # Extract text content
+                content = ""
+                if isinstance(msg.get("content"), str):
+                    content = msg["content"]
+                elif isinstance(msg.get("content"), list):
+                    for block in msg["content"]:
+                        if isinstance(block, dict) and block.get("type") == "text":
+                            content += block.get("text", "") + " "
+
+                if not content or len(content) < 20:
+                    continue
+
+                # Check for knowledge patterns
+                for pattern, category, importance in KNOWLEDGE_PATTERNS:
+                    matches = re.findall(pattern, content, re.IGNORECASE)
+                    for match in matches:
+                        match_text = match.strip()
+                        if len(match_text) > 15 and len(match_text) < 500:
+                            findings.append({
+                                "content": match_text,
+                                "category": category,
+                                "importance": importance,
+                                "keywords": " ".join(match_text.split()[:10]),
+                            })
+
+    except FileNotFoundError:
+        print(f"Transcript not found: {transcript_path}", file=sys.stderr)
+
+    save_seen(seen)
+    return findings
+
+
+def main():
+    if len(sys.argv) < 2:
+        # Try to find the latest transcript
+        projects_dir = Path.home() / ".claude" / "projects"
+        if projects_dir.exists():
+            transcripts = sorted(projects_dir.rglob("*.jsonl"), key=lambda p: p.stat().st_mtime, reverse=True)
+            if transcripts:
+                transcript_path = str(transcripts[0])
+            else:
+                print("No transcript found", file=sys.stderr)
+                return
+        else:
+            print("Usage: extract-knowledge.py <transcript.jsonl>", file=sys.stderr)
+            return
+    else:
+        transcript_path = sys.argv[1]
+
+    findings = extract_from_transcript(transcript_path)
+
+    if not findings:
+        return
+
+    print(f"Found {len(findings)} knowledge candidates", file=sys.stderr)
+    stored = 0
+    for finding in findings[:5]:  # Max 5 per run to avoid spam
+        if api_store(finding["content"], finding["category"], finding["importance"], finding["keywords"]):
+            stored += 1
+
+    print(f"Stored {stored}/{len(findings)} memories", file=sys.stderr)
+
+
+if __name__ == "__main__":
+    main()