diff --git a/.github/workflows/tests.yml b/.github/workflows/tests.yml
index 091b9971..130021b9 100644
--- a/.github/workflows/tests.yml
+++ b/.github/workflows/tests.yml
@@ -306,8 +306,8 @@ jobs:
       - name: Tmate debugging session (self-hosted)
         if: ${{ failure() && inputs.tmate-debug && inputs.self-hosted-runner }}
         uses: canonical/action-tmate@main
-        timeout-minutes: ${{ inputs.tmate-timeout }}
+        timeout-minutes: ${{ fromJSON(inputs.tmate-timeout) }}
       - name: Tmate debugging session (gh-hosted)
         if: ${{ failure() && inputs.tmate-debug && !inputs.self-hosted-runner }}
         uses: mxschmitt/action-tmate@v3
-        timeout-minutes: ${{ inputs.tmate-timeout }}
+        timeout-minutes: ${{ fromJSON(inputs.tmate-timeout) }}