feat(installer): skip embedding-model step on graph-only installs

java_codebase_rag/installer.py

@@ -1799,7 +1799,19 @@ def run_install(
         return e.code
 
     # Stage 2: Embedding model
-    resolved_model = resolve_model(model, non_interactive=non_interactive)
+    from java_codebase_rag.pipeline import vector_stack_installed
+
+    if not vector_stack_installed():
+        # Graph-only install (macOS Intel): no torch/lancedb, so there is no vector
+        # index to embed into — the embedding-model choice is inert here. Skip the
+        # prompt and let init build the graph (vectors phase auto-skipped).
+        print(
+            "Skipping embedding model selection: vector stack not installed on this "
+            "platform (graph-only mode)."
+        )
+        resolved_model = "auto"
+    else:
+        resolved_model = resolve_model(model, non_interactive=non_interactive)
 
     # Stage 3-4: Agent host + scope + surface selection
     prior_surface = _prior_surface_from_marker(cwd)

java_codebase_rag/pipeline.py

@@ -2,6 +2,7 @@
 from __future__ import annotations
 
 import asyncio
+import importlib.util
 import os
 import shutil
 import subprocess
@@ -200,6 +201,19 @@ def is_graph_preflight_blocker(proc: subprocess.CompletedProcess[str]) -> bool:
     return bool(proc.returncode in (126, 127) and len(getattr(proc, "args", ()) or ()) <= 1)
 
 
+def vector_stack_installed() -> bool:
+    """True when the optional vector stack (cocoindex/lancedb/sentence-transformers) is importable.
+
+    False on graph-only installs (macOS Intel), where PEP 508 markers exclude the trio.
+    Used to skip vector-only wizard steps (e.g. embedding-model selection) and to preflight
+    branching without spawning cocoindex. Probes all three since they are gated together.
+    """
+    return all(
+        importlib.util.find_spec(m) is not None
+        for m in ("cocoindex", "lancedb", "sentence_transformers")
+    )
+
+
 def _run_cocoindex_update_impl(
     env: dict[str, str],
     *,

tests/test_graph_only_boot.py

@@ -78,3 +78,25 @@ def test_preflight_blocker_detects_graph_only_install() -> None:
     # non-zero exit is a failure, not a skip.
     assert is_cocoindex_preflight_blocker(_completed(1, (exe, "update", "t", "-f"))) is False
     assert is_cocoindex_preflight_blocker(_completed(0, (exe, "update", "t", "-f"))) is False
+
+
+def test_vector_stack_installed_reports_absent_when_blocked() -> None:
+    # The installer wizard gates its embedding-model step on vector_stack_installed().
+    # Deterministic across platforms: blocking the modules in a fresh subprocess must
+    # report False (this is the macOS Intel reality).
+    proc = subprocess.run(
+        [
+            sys.executable,
+            "-c",
+            "import sys\n"
+            "for m in ('lancedb','pylance','torch','sentence_transformers','cocoindex'):\n"
+            "    sys.modules[m] = None\n"
+            "from java_codebase_rag.pipeline import vector_stack_installed\n"
+            "print('INSTALLED:' + str(vector_stack_installed()))",
+        ],
+        capture_output=True,
+        text=True,
+        timeout=60,
+    )
+    assert proc.returncode == 0, proc.stderr
+    assert "INSTALLED:False" in proc.stdout