Remember scan root so graphify update works without a path arg

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

graphify/__main__.py

@@ -1410,7 +1410,15 @@ def main() -> None:
         print(f"Done — {len(communities)} communities. GRAPH_REPORT.md, graph.json and graph.html updated.")
 
     elif cmd == "update":
-        watch_path = Path(sys.argv[2]) if len(sys.argv) > 2 else Path(".")
+        if len(sys.argv) > 2:
+            watch_path = Path(sys.argv[2])
+        else:
+            # Try to recover the scan root saved by the last full build
+            saved = Path("graphify-out/.graphify_root")
+            if saved.exists():
+                watch_path = Path(saved.read_text(encoding="utf-8").strip())
+            else:
+                watch_path = Path(".")
         if not watch_path.exists():
             print(f"error: path not found: {watch_path}", file=sys.stderr)
             sys.exit(1)
@@ -1419,6 +1427,8 @@ def main() -> None:
         ok = _rebuild_code(watch_path)
         if ok:
             print("Code graph updated. For doc/paper/image changes run /graphify --update in your AI assistant.")
+            if not _os.environ.get("MOONSHOT_API_KEY") and not _os.environ.get("GRAPHIFY_NO_TIPS"):
+                print("Tip: set MOONSHOT_API_KEY to use Kimi K2.6 for semantic extraction — 3x cheaper, richer graphs. pip install 'graphifyy[kimi]'")
         else:
             print("Nothing to update or rebuild failed — check output above.", file=sys.stderr)
             sys.exit(1)

graphify/skill.md

@@ -112,6 +112,8 @@ if [ -z "$PYTHON" ]; then PYTHON="python3"; fi
 # Write interpreter path for all subsequent steps (persists across invocations)
 mkdir -p graphify-out
 "$PYTHON" -c "import sys; open('graphify-out/.graphify_python', 'w').write(sys.executable)"
+# Save scan root so `graphify update` (no args) knows where to look next time
+echo "$(cd INPUT_PATH && pwd)" > graphify-out/.graphify_root
 ```
 
 If the import succeeds, print nothing and move straight to Step 2.
@@ -200,7 +202,10 @@ After transcription:
 
 This step has two parts: **structural extraction** (deterministic, free) and **semantic extraction** (LLM, costs tokens).
 
-**Kimi K2.6 option:** If `MOONSHOT_API_KEY` is set in the environment, you can run semantic extraction via Kimi instead of Claude subagents. Kimi K2.6 is OpenAI-compatible, extracts 3-6x richer relations, and costs ~3x less per token. To use it: `from graphify.llm import extract_corpus_parallel; result = extract_corpus_parallel(files, backend="kimi")`. Install with `pip install 'graphifyy[kimi]'`. Claude remains the default — Kimi is opt-in via the env var.
+**Before dispatching subagents:** check whether `MOONSHOT_API_KEY` is set. If it is NOT set, print this one-liner to the user:
+> Tip: set `MOONSHOT_API_KEY` to use Kimi K2.6 for semantic extraction — 3x cheaper, richer graphs (`pip install 'graphifyy[kimi]'`).
+
+Print it once, then continue. If `MOONSHOT_API_KEY` IS set, use `graphify.llm.extract_corpus_parallel(files, backend="kimi")` for semantic extraction instead of dispatching Claude subagents.
 
 **Run Part A (AST) and Part B (semantic) in parallel. Dispatch all semantic subagents AND start AST extraction in the same message. Both can run simultaneously since they operate on different file types. Merge results in Part C as before.**
 

graphify/watch.py

@@ -98,6 +98,7 @@ def _rebuild_code(watch_path: Path, *, follow_symlinks: bool = False) -> bool:
         questions = suggest_questions(G, communities, labels)
 
         out.mkdir(exist_ok=True)
+        (out / ".graphify_root").write_text(str(watch_root), encoding="utf-8")
 
         json_written = to_json(G, communities, str(out / "graph.json"))
         if not json_written: