diff --git a/README.md b/README.md
index afdc9888..514c5bf5 100644
--- a/README.md
+++ b/README.md
@@ -154,7 +154,7 @@ sidemantic migrator --queries legacy/ --generate-models output/
 
 **Workbench** (TUI with SQL editor + charts):
 ```bash
-uvx sidemantic workbench --demo
+uvx --from "sidemantic[workbench]" sidemantic workbench --demo
 ```
 
 **PostgreSQL server** (connect Tableau, DBeaver, etc.):
diff --git a/sidemantic/cli.py b/sidemantic/cli.py
index 3e1f088f..f0a81948 100644
--- a/sidemantic/cli.py
+++ b/sidemantic/cli.py
@@ -739,13 +739,17 @@ def tree(
     """
     Alias for 'workbench' command (deprecated).
     """
-    from sidemantic.workbench import run_workbench
+    from sidemantic.workbench import WorkbenchDependencyError, run_workbench
 
     if not directory.exists():
         typer.echo(f"Error: Directory {directory} does not exist", err=True)
         raise typer.Exit(1)
 
-    run_workbench(directory)
+    try:
+        run_workbench(directory)
+    except WorkbenchDependencyError as e:
+        typer.echo(f"Error: {e}", err=True)
+        raise typer.Exit(1)
 
 
 @app.command()
@@ -762,13 +766,17 @@ def validate(
       sidemantic validate
       sidemantic validate ./models --verbose
     """
-    from sidemantic.workbench import run_validation
+    from sidemantic.workbench import WorkbenchDependencyError, run_validation
 
     if not directory.exists():
         typer.echo(f"Error: Directory {directory} does not exist", err=True)
         raise typer.Exit(1)
 
-    run_validation(directory, verbose=verbose)
+    try:
+        run_validation(directory, verbose=verbose)
+    except WorkbenchDependencyError as e:
+        typer.echo(f"Error: {e}", err=True)
+        raise typer.Exit(1)
 
 
 @app.command()
@@ -790,9 +798,9 @@ def workbench(
       sidemantic workbench --demo
       sidemantic workbench ./models --db data/warehouse.db
       sidemantic workbench ./models --connection "postgres://localhost:5432/db"
-      uvx sidemantic workbench --demo
+      uvx --from 'sidemantic[workbench]' sidemantic workbench --demo
     """
-    from sidemantic.workbench import run_workbench
+    from sidemantic.workbench import WorkbenchDependencyError, run_workbench
 
     if demo:
         import sidemantic
@@ -813,7 +821,11 @@ def workbench(
                 raise typer.Exit(1)
 
         directory = demo_dir
-        run_workbench(directory, demo_mode=True, connection=None)
+        try:
+            run_workbench(directory, demo_mode=True, connection=None)
+        except WorkbenchDependencyError as e:
+            typer.echo(f"Error: {e}", err=True)
+            raise typer.Exit(1)
     elif not directory.exists():
         typer.echo(f"Error: Directory {directory} does not exist", err=True)
         raise typer.Exit(1)
@@ -831,10 +843,14 @@ def workbench(
             connection_str = build_connection_string(_loaded_config)
 
         # Only pass connection if it's not None
-        if connection_str:
-            run_workbench(directory, connection=connection_str)
-        else:
-            run_workbench(directory)
+        try:
+            if connection_str:
+                run_workbench(directory, connection=connection_str)
+            else:
+                run_workbench(directory)
+        except WorkbenchDependencyError as e:
+            typer.echo(f"Error: {e}", err=True)
+            raise typer.Exit(1)
 
 
 # Pre-aggregation recommendation commands
diff --git a/sidemantic/workbench/__init__.py b/sidemantic/workbench/__init__.py
index cdf26164..57b3ce57 100644
--- a/sidemantic/workbench/__init__.py
+++ b/sidemantic/workbench/__init__.py
@@ -2,17 +2,50 @@
 
 from pathlib import Path
 
-from sidemantic.workbench.app import SidequeryWorkbench
-from sidemantic.workbench.validation_app import ValidationApp
+WORKBENCH_EXTRA_INSTALL = "uvx --from 'sidemantic[workbench]' sidemantic workbench --demo"
+WORKBENCH_EXTRA_ADD = "uv add 'sidemantic[workbench]'"
+
+
+class WorkbenchDependencyError(RuntimeError):
+    """Raised when optional workbench dependencies are not installed."""
+
+
+def _is_optional_workbench_dependency(module_name: str | None) -> bool:
+    if not module_name:
+        return False
+    return module_name == "plotext" or module_name.startswith("textual")
+
+
+def _missing_dependency_message(module_name: str | None, command: str) -> str:
+    missing = module_name or "required package"
+    return (
+        f"Missing optional dependency for `sidemantic {command}`: {missing}. "
+        "Install the workbench extra or run it with uvx, for example: "
+        f"`{WORKBENCH_EXTRA_INSTALL}`. In a project, use `{WORKBENCH_EXTRA_ADD}`."
+    )
 
 
 def run_workbench(directory: Path, demo_mode: bool = False, connection: str | None = None):
     """Run the interactive workbench application."""
+    try:
+        from sidemantic.workbench.app import SidequeryWorkbench
+    except ModuleNotFoundError as exc:
+        if _is_optional_workbench_dependency(exc.name):
+            raise WorkbenchDependencyError(_missing_dependency_message(exc.name, "workbench")) from exc
+        raise
+
     workbench_app = SidequeryWorkbench(directory, demo_mode=demo_mode, connection=connection)
     workbench_app.run()
 
 
 def run_validation(directory: Path, verbose: bool = False):
     """Run the validation UI application."""
+    try:
+        from sidemantic.workbench.validation_app import ValidationApp
+    except ModuleNotFoundError as exc:
+        if _is_optional_workbench_dependency(exc.name):
+            raise WorkbenchDependencyError(_missing_dependency_message(exc.name, "validate")) from exc
+        raise
+
     app = ValidationApp(directory, verbose=verbose)
     app.run()
diff --git a/sidemantic/workbench/app.py b/sidemantic/workbench/app.py
index 333e2ef5..06c79cba 100644
--- a/sidemantic/workbench/app.py
+++ b/sidemantic/workbench/app.py
@@ -12,14 +12,7 @@
 from textual_plotext import PlotextPlot
 
 from sidemantic import SemanticLayer, load_from_directory
-
-# Example queries
-EXAMPLE_QUERIES = {
-    "Timeseries": "-- Timeseries revenue by month and region\nSELECT \n  orders.created_month,\n  customers.region,\n  orders.total_revenue,\n  orders.order_count\nFROM orders\nORDER BY created_month DESC, region",
-    "Top Customers": "-- Top customers by revenue\nSELECT \n  customers.name,\n  customers.region,\n  orders.total_revenue,\n  orders.order_count\nFROM orders\nORDER BY orders.total_revenue DESC\nLIMIT 10",
-    "Aggregates": "-- Revenue metrics by region\nSELECT \n  customers.region,\n  orders.total_revenue,\n  orders.avg_order_value,\n  orders.order_count\nFROM orders\nGROUP BY customers.region\nORDER BY orders.total_revenue DESC",
-    "Custom": "-- Write your custom query here\nSELECT \n  \nFROM ",
-}
+from sidemantic.workbench.examples import EXAMPLE_QUERIES
 
 
 class SidequeryWorkbench(App):
diff --git a/sidemantic/workbench/examples.py b/sidemantic/workbench/examples.py
new file mode 100644
index 00000000..1356a665
--- /dev/null
+++ b/sidemantic/workbench/examples.py
@@ -0,0 +1,34 @@
+"""Example semantic SQL queries for the workbench."""
+
+EXAMPLE_QUERIES = {
+    "Timeseries": """-- Timeseries revenue by month and region
+SELECT
+  orders.created_month,
+  customers.region,
+  orders.total_revenue,
+  orders.order_count
+FROM orders
+ORDER BY created_month DESC, region""",
+    "Top Customers": """-- Top customers by revenue
+SELECT
+  customers.name,
+  customers.region,
+  orders.total_revenue,
+  orders.order_count
+FROM orders
+ORDER BY orders.total_revenue DESC
+LIMIT 10""",
+    "Aggregates": """-- Revenue metrics by region
+SELECT
+  customers.region,
+  orders.total_revenue,
+  orders.avg_order_value,
+  orders.order_count
+FROM orders
+GROUP BY customers.region
+ORDER BY orders.total_revenue DESC""",
+    "Custom": """-- Write your custom query here
+SELECT
+
+FROM """,
+}
diff --git a/tests/test_cli_commands.py b/tests/test_cli_commands.py
index 0e9b2efe..820416bc 100644
--- a/tests/test_cli_commands.py
+++ b/tests/test_cli_commands.py
@@ -49,6 +49,26 @@ def fake_run_workbench(directory, demo_mode=False, connection=None):
     assert called["connection"] is None
 
 
+def test_workbench_missing_extra_prints_install_hint(monkeypatch, tmp_path):
+    from sidemantic.workbench import WorkbenchDependencyError
+
+    def fake_run_workbench(directory, demo_mode=False, connection=None):
+        raise WorkbenchDependencyError(
+            "Missing optional dependency for `sidemantic workbench`: textual. "
+            "Install the workbench extra or run it with uvx, for example: "
+            "`uvx --from 'sidemantic[workbench]' sidemantic workbench --demo`."
+        )
+
+    monkeypatch.setattr("sidemantic.workbench.run_workbench", fake_run_workbench)
+
+    _write_min_model(tmp_path)
+    result = runner.invoke(app, ["workbench", str(tmp_path)])
+
+    assert result.exit_code == 1
+    assert "Missing optional dependency" in result.output
+    assert "uvx --from 'sidemantic[workbench]' sidemantic workbench --demo" in result.output
+
+
 def test_validate_calls_runner(monkeypatch, tmp_path):
     pytest.importorskip("textual")
     called = {}
diff --git a/tests/test_workbench_demo.py b/tests/test_workbench_demo.py
new file mode 100644
index 00000000..5251fcbd
--- /dev/null
+++ b/tests/test_workbench_demo.py
@@ -0,0 +1,54 @@
+"""Tests for bundled workbench demo behavior."""
+
+import importlib.util
+import sys
+from pathlib import Path
+
+from sidemantic import SemanticLayer, load_from_directory
+from sidemantic.sql.query_rewriter import QueryRewriter
+from sidemantic.workbench.examples import EXAMPLE_QUERIES
+
+
+def _load_demo_data_module():
+    demo_data_path = Path(__file__).resolve().parent.parent / "examples" / "multi_format_demo" / "demo_data.py"
+    spec = importlib.util.spec_from_file_location("demo_data", demo_data_path)
+    module = importlib.util.module_from_spec(spec)
+    sys.modules["demo_data"] = module
+    spec.loader.exec_module(module)
+    return module
+
+
+def _load_demo_layer():
+    demo_dir = Path(__file__).resolve().parent.parent / "examples" / "multi_format_demo"
+    demo_data = _load_demo_data_module()
+
+    layer = SemanticLayer(connection="duckdb:///:memory:")
+    demo_conn = demo_data.create_demo_database()
+
+    for table in ["customers", "products", "orders"]:
+        rows = demo_conn.execute(f"SELECT * FROM {table}").fetchall()
+        columns = [desc[0] for desc in demo_conn.execute(f"SELECT * FROM {table} LIMIT 0").description]
+        create_sql = demo_conn.execute(f"SELECT sql FROM duckdb_tables() WHERE table_name = '{table}'").fetchone()[0]
+        layer.adapter.execute(create_sql)
+
+        if rows:
+            placeholders = ", ".join(["?" for _ in columns])
+            layer.adapter.executemany(f"INSERT INTO {table} VALUES ({placeholders})", rows)
+
+    load_from_directory(layer, str(demo_dir))
+    return layer
+
+
+def test_workbench_demo_starter_queries_execute():
+    layer = _load_demo_layer()
+    rewriter = QueryRewriter(layer.graph, dialect=layer.dialect)
+
+    for name, sql in EXAMPLE_QUERIES.items():
+        if name == "Custom":
+            continue
+
+        rendered_sql = rewriter.rewrite(sql)
+        result = layer.adapter.execute(rendered_sql)
+
+        assert result.description, name
+        assert result.fetchall(), name