diff --git a/pyproject.toml b/pyproject.toml
index 1c5f009..dbc3ff8 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -22,7 +22,7 @@ classifiers = [
 ]
 
 [project.optional-dependencies]
-dev = ["pytest>=8", "ruff>=0.4", "flake8>=7"]
+dev = ["pytest>=8", "ruff>=0.4,<0.17", "flake8>=7"]
 
 [project.scripts]
 exact = "exact_linter.cli:main"
@@ -42,3 +42,11 @@ testpaths = ["tests"]
 [tool.ruff]
 line-length = 100
 target-version = "py310"
+
+[tool.ruff.lint]
+# State the rule set explicitly rather than inheriting ruff's default, which
+# is not stable across releases: 0.16 widened it to include isort, pylint,
+# flake8-simplify and flake8-blind-except, and CI started failing on code
+# that had not changed. The blind `except Exception` around eval()/pslq() is
+# deliberate - a linter must degrade to None, never crash on user input.
+select = ["E4", "E7", "E9", "F"]