diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 10a6640..629e64a 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -46,12 +46,16 @@ jobs:
       - uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
       - uses: astral-sh/ruff-action@278981a28ce3188b1e39527901f38254bf3aac89 # v4.1.0
         with:
-          args: check .
-          version: "0.11.4"
+          # Preserve the pre-0.16 default rule set; Ruff 0.16 expanded it substantially.
+          # New rules should be enabled in a separate, reviewed lint migration.
+          args: check --select E4,E7,E9,F .
+          version: "0.17.3"
       - uses: astral-sh/ruff-action@278981a28ce3188b1e39527901f38254bf3aac89 # v4.1.0
         with:
-          args: format --check .
-          version: "0.11.4"
+          # Ruff 0.16+ also formats Python code fences inside Markdown by default.
+          # Keep Markdown reformatting separate from this Python linter upgrade.
+          args: format --check --config=extend-exclude=["*.md"] --force-exclude .
+          version: "0.17.3"
 
   js-lint:
     name: JS Lint (Biome)