diff --git a/.github/workflows/copilot-setup-steps.yml b/.github/workflows/copilot-setup-steps.yml
index a756b90..c8d602e 100644
--- a/.github/workflows/copilot-setup-steps.yml
+++ b/.github/workflows/copilot-setup-steps.yml
@@ -31,7 +31,8 @@ jobs:
       - name: Set up Go
         uses: actions/setup-go@4a3601121dd01d1626a1e23e37211e3254c1c06c # v6.4.0
         with:
-          go-version: "1.25.1"
+          # Track go.mod so the Copilot toolchain never drifts from the module floor.
+          go-version-file: go.mod
           cache: true
 
       - name: Set up Docker