diff --git a/benches/README.md b/benches/README.md
index ceaab47..61b79ce 100644
--- a/benches/README.md
+++ b/benches/README.md
@@ -10,3 +10,9 @@ different SRC variants. They are grouped by the kind of workload exercised:
 - [`stack/`](stack/) — One-shot SRC over stacks of trains against sequential
   pairwise application, by stack depth: accuracy against dense references and
   wall time. See [`stack/README.md`](stack/README.md).
+
+The scripts need the `bench` dependency group (included in `dev`):
+
+```bash
+uv sync --group bench
+```
diff --git a/pyproject.toml b/pyproject.toml
index 317aae2..161c7c7 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -64,15 +64,19 @@ test = [
   "pytest>=9.1.0,<10.0",
   "pytest-benchmark>=5.2.3",
   "quimb>=1.14.0,<2",
+  # Not imported directly: without it, cotengra (via quimb) warns when it plans a
+  # contraction, which `filterwarnings = ["error"]` turns into a failure.
   "cmaes>=0.12.0",
 ]
+# Only the scripts under benches/ need these.
+bench = ["cyclopts>=3.20", "quimb>=1.14.0,<2", "cmaes>=0.12.0", "scipy"]
 dev = [
   "scalene",
   "prek>=0.2.6",
   "ruff==0.16.9",
-  "cyclopts>=3.20",
   "ty==0.0.82",
   { include-group = "test" },
+  { include-group = "bench" },
 ]
 interactive = [
   "ipykernel>=7.2.0",
diff --git a/uv.lock b/uv.lock
index e35a1dd..cae5c32 100644
--- a/uv.lock
+++ b/uv.lock
@@ -2911,6 +2911,12 @@ gpu-rocm = [
 ]
 
 [package.dev-dependencies]
+bench = [
+    { name = "cmaes" },
+    { name = "cyclopts" },
+    { name = "quimb" },
+    { name = "scipy" },
+]
 dev = [
     { name = "cmaes" },
     { name = "cyclopts" },
@@ -2921,6 +2927,7 @@ dev = [
     { name = "quimb" },
     { name = "ruff" },
     { name = "scalene" },
+    { name = "scipy" },
     { name = "ty" },
 ]
 docs = [
@@ -2970,6 +2977,12 @@ requires-dist = [
 provides-extras = ["gpu-nvidia", "gpu-rocm"]
 
 [package.metadata.requires-dev]
+bench = [
+    { name = "cmaes", specifier = ">=0.12.0" },
+    { name = "cyclopts", specifier = ">=3.20" },
+    { name = "quimb", specifier = ">=1.14.0,<2" },
+    { name = "scipy" },
+]
 dev = [
     { name = "cmaes", specifier = ">=0.12.0" },
     { name = "cyclopts", specifier = ">=3.20" },
@@ -2980,6 +2993,7 @@ dev = [
     { name = "quimb", specifier = ">=1.14.0,<2" },
     { name = "ruff", specifier = "==0.16.9" },
     { name = "scalene" },
+    { name = "scipy" },
     { name = "ty", specifier = "==0.0.82" },
 ]
 docs = [