diff --git a/src/context_engine/cli.py b/src/context_engine/cli.py
index 1db7cf7..1cb21c5 100644
--- a/src/context_engine/cli.py
+++ b/src/context_engine/cli.py
@@ -922,6 +922,19 @@ def init(ctx: click.Context, agent: str) -> None:
             section = _editor_section(editor, project_dir)
             click.echo(_dim(f"    ~/{editor['config_path']}  →  [{section}]"))
 
+    # In auto mode, show which agents weren't detected so the user knows
+    # they can use --agent <name> to force configuration.
+    if agent == "auto":
+        # Only mention agents that can be forced via --agent <name>
+        configurable_keys = set()
+        for _agent_name, editor_keys in _INIT_AGENT_TO_EDITORS.items():
+            configurable_keys.update(editor_keys)
+        skipped = configurable_keys - editor_targets
+        if skipped:
+            agent_names = [a for a, keys in _INIT_AGENT_TO_EDITORS.items() if keys & skipped]
+            names = ", ".join(sorted(agent_names))
+            click.echo(_dim(f"    Not detected: {names}. Use --agent <name> to configure manually."))
+
     # Write instruction files for the selected editors. In `auto` mode, also
     # pick up instruction files whose marker exists even if the editor itself
     # wasn't detected (e.g. an `AGENTS.md` checked in without a `~/.codex/`).
diff --git a/src/context_engine/editors.py b/src/context_engine/editors.py
index 8b056b8..195fe58 100644
--- a/src/context_engine/editors.py
+++ b/src/context_engine/editors.py
@@ -217,7 +217,12 @@ def _toml_quote(s: str) -> str:
 
 def detect_editors(project_dir: Path) -> list[str]:
     """Return list of editor keys detected for this project. Markers are
-    looked up under each editor's scope root (project dir or home dir)."""
+    looked up under each editor's scope root (project dir or home dir).
+
+    For Codex, also checks for the VS Code extension directory
+    (``~/.vscode/extensions/openai.*``) since the extension doesn't
+    create ``~/.codex`` until the CLI is run separately.
+    """
     found = []
     for key, editor in EDITORS.items():
         root = _scope_root(editor, project_dir)
@@ -225,9 +230,23 @@ def detect_editors(project_dir: Path) -> list[str]:
             if (root / marker).exists():
                 found.append(key)
                 break
+        else:
+            # Secondary detection for Codex: VS Code extension installed
+            if key == "codex" and _has_vscode_openai_extension():
+                found.append(key)
     return found
 
 
+def _has_vscode_openai_extension() -> bool:
+    """Check if any OpenAI VS Code extension is installed (as a proxy for Codex)
+    by looking for extension directories matching ``openai.*`` under
+    ``~/.vscode/extensions``. No subprocess needed, works cross-platform."""
+    ext_dir = Path.home() / ".vscode" / "extensions"
+    if not ext_dir.is_dir():
+        return False
+    return any(ext_dir.glob("openai.*"))
+
+
 def _codex_toml_block(command: str, project_dir: str, *, section: str) -> str:
     """Generate one TOML mcp_servers block. Section is the full dotted key
     rendered from the editor's section_template (e.g. `mcp_servers.cce-myapp-a3f2`).
diff --git a/tests/test_editors_codex.py b/tests/test_editors_codex.py
index d38785f..adbcbb5 100644
--- a/tests/test_editors_codex.py
+++ b/tests/test_editors_codex.py
@@ -130,6 +130,22 @@ def test_no_codex_detection_when_home_codex_absent(fake_home, project_dir):
     assert "codex" not in detect_editors(project_dir)
 
 
+def test_detect_codex_via_vscode_extension(fake_home, project_dir):
+    """Codex VS Code extension installed but ~/.codex doesn't exist yet.
+    Detection should still fire via the extension directory."""
+    ext_dir = fake_home / ".vscode" / "extensions" / "openai.openai-chatgpt-adhoc-1.0.0"
+    ext_dir.mkdir(parents=True)
+    # ~/.codex does NOT exist
+    assert not (fake_home / ".codex").exists()
+    detected = detect_editors(project_dir)
+    assert "codex" in detected
+
+
+def test_no_codex_detection_without_any_signal(fake_home, project_dir):
+    """Neither ~/.codex nor VS Code extension present — no detection."""
+    assert "codex" not in detect_editors(project_dir)
+
+
 # ── Configure: writes to ~/.codex/config.toml ────────────────────────────────
 
 def test_configure_writes_to_user_global_codex_config(fake_home, project_dir):