diff --git a/.github/workflows/evals.yml b/.github/workflows/evals.yml
index 5400b19d4..40c775135 100644
--- a/.github/workflows/evals.yml
+++ b/.github/workflows/evals.yml
@@ -284,6 +284,27 @@ jobs:
             cp "$REPO/$s/SKILL.md" "$PROJ_SKILLS/$s/SKILL.md"
             cp -R "$REPO/$s/sections" "$PROJ_SKILLS/$s/sections"
           done
+          # Pre-seed every ONE-TIME preamble marker so no PTY child ever takes a
+          # first-run branch mid-test. On a fresh runner these are all missing, so
+          # each smoke's preamble fires feature discovery / telemetry / lake-intro
+          # prompts before the behavior under test — and touching the
+          # feature-discovery marker under ~/.claude/skills/gstack/ trips Claude
+          # Code's sensitive-file permission prompt, stalling the run before the
+          # scope gate renders (the documented intermittent
+          # scope-gate-question-NOT-observed failure: outcome=asked was the
+          # permission dialog, not the gate). Dev machines never hit this because
+          # the operator's markers already exist; CI must seed them explicitly.
+          mkdir -p "$HOME/.gstack"
+          touch "$HOME/.gstack/.activated" \
+                "$HOME/.gstack/.first-loop-tip-shown" \
+                "$HOME/.gstack/.telemetry-prompted" \
+                "$HOME/.gstack/.proactive-prompted" \
+                "$HOME/.gstack/.completeness-intro-seen" \
+                "$HOME/.gstack/.plan-tune-nudge-shown"
+          # These two resolve through the gstack root symlink into $REPO —
+          # untracked scratch in the CI checkout, exactly where the preamble looks.
+          touch "$SKILLS_DIR/gstack/.feature-prompted-continuous-checkpoint" \
+                "$SKILLS_DIR/gstack/.feature-prompted-model-overlay"
           echo "--- registry under $SKILLS_DIR ---"
           ls -la "$SKILLS_DIR/gstack" "$SKILLS_DIR/office-hours" "$SKILLS_DIR/plan-ceo-review"
           # Fail fast if any committed target moved/renamed — a dangling symlink