diff --git a/app/web/router.py b/app/web/router.py
index e204d7d..fdae031 100644
--- a/app/web/router.py
+++ b/app/web/router.py
@@ -974,6 +974,7 @@ async def admin_workspace_prompt_page(
 ):
     from src.repositories.claude_md_template import ClaudeMdTemplateRepository
     from src.claude_md import compute_default_claude_md
+    from app.api.claude_md import _scan_legacy_strings
 
     row = ClaudeMdTemplateRepository(conn).get()
     server_url = str(request.base_url).rstrip("/")
@@ -986,6 +987,7 @@ async def admin_workspace_prompt_page(
         updated_at=row["updated_at"],
         updated_by=row["updated_by"],
         is_override=row["content"] is not None,
+        legacy_strings_detected=_scan_legacy_strings(row["content"] or ""),
     )
     return templates.TemplateResponse(request, "admin_workspace_prompt.html", ctx)
 
diff --git a/app/web/templates/admin_workspace_prompt.html b/app/web/templates/admin_workspace_prompt.html
index e8c1d2b..51206be 100644
--- a/app/web/templates/admin_workspace_prompt.html
+++ b/app/web/templates/admin_workspace_prompt.html
@@ -271,6 +271,20 @@
         </div>
       </details>
 
+      {% if legacy_strings_detected %}
+      <div id="legacy-banner"
+           role="alert"
+           style="background:#fff3cd; border:1px solid #ffc107; padding:0.75rem 1rem; border-radius:8px; margin-bottom:14px; color:#664d03;">
+        <strong>This override references CLI verbs / paths that were renamed:</strong>
+        <ul style="margin:0.5rem 0 0 1.5rem; padding:0;">
+          {% for hit in legacy_strings_detected %}
+          <li><code>{{ hit }}</code></li>
+          {% endfor %}
+        </ul>
+        <p style="margin:0.5rem 0 0 0;">Re-author and Save to clear this warning. See <code>CHANGELOG.md</code> for the rename list.</p>
+      </div>
+      {% endif %}
+
       <div class="welcome-editor-row">
         <div class="welcome-pane">
           <h4 class="welcome-pane-label">Editor</h4>
diff --git a/tests/test_legacy_strings_scan.py b/tests/test_legacy_strings_scan.py
index 73937b9..4120327 100644
--- a/tests/test_legacy_strings_scan.py
+++ b/tests/test_legacy_strings_scan.py
@@ -121,3 +121,51 @@ def test_admin_get_template_returns_empty_when_clean(web_session):
     resp = web_session.get("/api/admin/workspace-prompt-template")
     assert resp.status_code == 200, resp.text
     assert resp.json()["legacy_strings_detected"] == []
+
+
+# ---------------------------------------------------------------------------
+# HTML banner tests — admin /admin/workspace-prompt page renders a yellow
+# warning banner above the editor when the saved override contains stale
+# CLI verbs / paths.
+# ---------------------------------------------------------------------------
+
+
+def test_admin_workspace_prompt_page_renders_banner_when_legacy_present(web_session):
+    """When the saved override contains legacy strings, the admin UI renders
+    a yellow warning banner above the editor listing the hits."""
+    web_session.put(
+        "/api/admin/workspace-prompt-template",
+        json={"content": "Run `da sync` and check data/parquet/."},
+    )
+    resp = web_session.get("/admin/workspace-prompt")
+    assert resp.status_code == 200
+    text = resp.text
+    # Banner is rendered (id, class, or distinctive styling)
+    assert "legacy-banner" in text or "renamed" in text.lower() or "warning" in text.lower()
+    # Specific hits appear in the banner content
+    assert "da sync" in text
+    assert "data/parquet" in text
+
+
+def test_admin_workspace_prompt_page_no_banner_when_clean(web_session):
+    """When the override has no legacy strings, the banner block is absent
+    (or rendered as empty/hidden)."""
+    web_session.put(
+        "/api/admin/workspace-prompt-template",
+        json={"content": "Use `agnes pull` and `server/parquet/`."},
+    )
+    resp = web_session.get("/admin/workspace-prompt")
+    assert resp.status_code == 200
+    text = resp.text
+    # The banner div should not appear (or its content should not list hits)
+    # Pin to the legacy-banner id; the {% if %} guard means absent when clean
+    assert "legacy-banner" not in text
+
+
+def test_admin_workspace_prompt_page_no_banner_when_no_override(web_session):
+    """No saved override at all → banner absent."""
+    # Reset to default by deleting any existing override
+    web_session.delete("/api/admin/workspace-prompt-template")
+    resp = web_session.get("/admin/workspace-prompt")
+    assert resp.status_code == 200
+    assert "legacy-banner" not in resp.text