diff --git a/.githooks/pre-push b/.githooks/pre-push
index cd6b5cd4..e9c7d8da 100755
--- a/.githooks/pre-push
+++ b/.githooks/pre-push
@@ -1,23 +1,18 @@
 #!/usr/bin/env bash
 set -euo pipefail
+# Pre-push hook: runs quality gate before pushing
+# Skip with: git push --no-verify
 
-# Pre-push hook: run clippy and tests before pushing.
-# Install: git config core.hooksPath .githooks
+REPO_ROOT="$(git rev-parse --show-toplevel)"
+SCRIPT_DIR="$REPO_ROOT/scripts/ci"
 
-echo "pre-push: running clippy..."
-if ! cargo clippy --all --benches --tests --examples --all-features -- -D warnings; then
-    echo ""
-    echo "Push blocked: clippy warnings found."
-    echo "To bypass: git push --no-verify"
-    exit 1
+# Default: baseline quality gate
+"$SCRIPT_DIR/quality_gate.sh"
+
+# Optional strict delta lint (env-gated)
+if [ "${IRONCLAW_STRICT_DELTA_LINT:-0}" = "1" ]; then
+    "$SCRIPT_DIR/delta_lint.sh" "$1"
+elif [ "${IRONCLAW_STRICT_LINT:-0}" = "1" ]; then
+    echo "==> clippy (strict: all warnings)"
+    cargo clippy --locked --all-targets -- -D warnings
 fi
-
-echo "pre-push: running tests..."
-if ! cargo test; then
-    echo ""
-    echo "Push blocked: tests failed."
-    echo "To bypass: git push --no-verify"
-    exit 1
-fi
-
-echo "pre-push: all checks passed."
diff --git a/scripts/ci/delta_lint.sh b/scripts/ci/delta_lint.sh
new file mode 100755
index 00000000..c64b91a7
--- /dev/null
+++ b/scripts/ci/delta_lint.sh
@@ -0,0 +1,216 @@
+#!/usr/bin/env bash
+set -euo pipefail
+# Delta lint: only fail on clippy warnings/errors that touch changed lines.
+# Compares the current branch against the merge base with the upstream default branch.
+
+CLIPPY_OUT=""
+DIFF_OUT=""
+CLIPPY_STDERR=""
+
+cleanup() {
+    [ -n "$CLIPPY_OUT" ] && rm -f "$CLIPPY_OUT"
+    [ -n "$DIFF_OUT" ] && rm -f "$DIFF_OUT"
+    [ -n "$CLIPPY_STDERR" ] && rm -f "$CLIPPY_STDERR"
+}
+trap cleanup EXIT
+
+# Verify python3 is available (needed for diagnostic filtering)
+if ! command -v python3 &>/dev/null; then
+    echo "ERROR: python3 is required for delta lint but not found"
+    exit 1
+fi
+
+# Accept optional remote name argument; default to dynamic detection
+REMOTE="${1:-}"
+
+# Determine the upstream base ref dynamically
+BASE_REF=""
+if [ -n "$REMOTE" ]; then
+    # Use the provided remote name
+    if [ -z "$BASE_REF" ]; then
+        BASE_REF=$(git symbolic-ref "refs/remotes/$REMOTE/HEAD" 2>/dev/null | sed 's|refs/remotes/||' || true)
+    fi
+    if [ -z "$BASE_REF" ] && git rev-parse --verify "$REMOTE/main" &>/dev/null; then
+        BASE_REF="$REMOTE/main"
+    fi
+    if [ -z "$BASE_REF" ] && git rev-parse --verify "$REMOTE/master" &>/dev/null; then
+        BASE_REF="$REMOTE/master"
+    fi
+else
+    # Try the remote HEAD symbolic ref (works for any default branch name)
+    if [ -z "$BASE_REF" ]; then
+        BASE_REF=$(git symbolic-ref refs/remotes/origin/HEAD 2>/dev/null | sed 's|refs/remotes/||' || true)
+    fi
+    # Fall back to common default branch names
+    if [ -z "$BASE_REF" ] && git rev-parse --verify origin/main &>/dev/null; then
+        BASE_REF="origin/main"
+    fi
+    if [ -z "$BASE_REF" ] && git rev-parse --verify origin/master &>/dev/null; then
+        BASE_REF="origin/master"
+    fi
+fi
+if [ -z "$BASE_REF" ]; then
+    echo "WARNING: could not determine upstream base branch, skipping delta lint"
+    exit 0
+fi
+
+# Compute merge base
+BASE=$(git merge-base "$BASE_REF" HEAD 2>/dev/null) || {
+    echo "WARNING: git merge-base failed for $BASE_REF, skipping delta lint"
+    exit 0
+}
+
+# Find changed .rs files
+CHANGED_RS=$(git diff --name-only "$BASE" -- '*.rs' || true)
+if [ -z "$CHANGED_RS" ]; then
+    echo "==> delta lint: no .rs files changed, skipping"
+    exit 0
+fi
+
+echo "==> delta lint: checking changed lines since $(echo "$BASE" | head -c 10)..."
+
+# Extract unified-0 diff for changed line ranges
+DIFF_OUT=$(mktemp "${TMPDIR:-/tmp}/ironclaw-diff.XXXXXX")
+git diff --unified=0 "$BASE" -- '*.rs' > "$DIFF_OUT"
+
+# Run clippy with JSON output (stderr shows compilation progress/errors)
+CLIPPY_OUT=$(mktemp "${TMPDIR:-/tmp}/ironclaw-clippy.XXXXXX")
+CLIPPY_STDERR=$(mktemp "${TMPDIR:-/tmp}/ironclaw-clippy-err.XXXXXX")
+cargo clippy --locked --all-targets --message-format=json > "$CLIPPY_OUT" 2>"$CLIPPY_STDERR" || true
+
+# Show compilation errors if clippy produced no JSON output
+if [ ! -s "$CLIPPY_OUT" ] && [ -s "$CLIPPY_STDERR" ]; then
+    echo "ERROR: clippy failed to produce output. Compilation errors:"
+    cat "$CLIPPY_STDERR"
+    exit 1
+fi
+
+# Get repo root for path normalization in Python
+REPO_ROOT="$(git rev-parse --show-toplevel)"
+
+# Filter clippy diagnostics against changed line ranges
+python3 - "$DIFF_OUT" "$CLIPPY_OUT" "$REPO_ROOT" <<'PYEOF'
+import json
+import re
+import sys
+import os
+
+def parse_diff(diff_path):
+    """Parse unified-0 diff to extract {file: [[start, end], ...]} changed ranges."""
+    changed = {}
+    current_file = None
+    with open(diff_path) as f:
+        for line in f:
+            # Match +++ b/path/to/file.rs or +++ /dev/null (deletion)
+            if line.startswith('+++ /dev/null'):
+                current_file = None
+                continue
+            m = re.match(r'^\+\+\+ b/(.+)$', line)
+            if m:
+                current_file = m.group(1)
+                if current_file not in changed:
+                    changed[current_file] = []
+                continue
+            # Match @@ hunk headers: @@ -old,count +new,count @@
+            m = re.match(r'^@@ .+ \+(\d+)(?:,(\d+))? @@', line)
+            if m and current_file:
+                start = int(m.group(1))
+                count = int(m.group(2)) if m.group(2) is not None else 1
+                if count == 0:
+                    continue
+                end = start + count - 1
+                changed[current_file].append([start, end])
+    return changed
+
+def normalize_path(path, repo_root):
+    """Normalize absolute path to relative (from repo root)."""
+    if os.path.isabs(path):
+        if path.startswith(repo_root):
+            return os.path.relpath(path, repo_root)
+    return path
+
+def in_changed_range(file_path, line_start, line_end, changed_ranges, repo_root):
+    """Check if file:[line_start, line_end] overlaps any changed range."""
+    rel = normalize_path(file_path, repo_root)
+    ranges = changed_ranges.get(rel)
+    if not ranges:
+        return False
+    return any(start <= line_end and line_start <= end for start, end in ranges)
+
+def main():
+    diff_path = sys.argv[1]
+    clippy_path = sys.argv[2]
+    repo_root = sys.argv[3]
+
+    changed_ranges = parse_diff(diff_path)
+
+    blocking = []
+    baseline = []
+
+    with open(clippy_path) as f:
+        for line in f:
+            line = line.strip()
+            if not line:
+                continue
+            try:
+                msg = json.loads(line)
+            except json.JSONDecodeError:
+                continue
+
+            if msg.get("reason") != "compiler-message":
+                continue
+
+            cm = msg.get("message", {})
+            level = cm.get("level", "")
+            if level not in ("warning", "error"):
+                continue
+
+            rendered = cm.get("rendered", "").strip()
+
+            # Errors are always blocking regardless of location
+            if level == "error":
+                blocking.append(rendered)
+                continue
+
+            # For warnings, only block if they overlap changed lines
+            spans = cm.get("spans", [])
+            primary = None
+            for s in spans:
+                if s.get("is_primary"):
+                    primary = s
+                    break
+            if not primary:
+                if spans:
+                    primary = spans[0]
+                else:
+                    baseline.append(rendered)
+                    continue
+
+            file_name = primary.get("file_name", "")
+            line_start = primary.get("line_start", 0)
+            line_end = primary.get("line_end", line_start)
+
+            if in_changed_range(file_name, line_start, line_end, changed_ranges, repo_root):
+                blocking.append(rendered)
+            else:
+                baseline.append(rendered)
+
+    if baseline:
+        print(f"\n--- Baseline warnings (not in changed lines, informational) [{len(baseline)}] ---")
+        for w in baseline[:10]:
+            print(w)
+        if len(baseline) > 10:
+            print(f"  ... and {len(baseline) - 10} more")
+
+    if blocking:
+        print(f"\n*** BLOCKING: {len(blocking)} issue(s) in changed lines ***")
+        for w in blocking:
+            print(w)
+        sys.exit(1)
+    else:
+        print("\n==> delta lint: passed (no issues in changed lines)")
+        sys.exit(0)
+
+if __name__ == "__main__":
+    main()
+PYEOF
diff --git a/scripts/ci/quality_gate.sh b/scripts/ci/quality_gate.sh
new file mode 100755
index 00000000..83a62e02
--- /dev/null
+++ b/scripts/ci/quality_gate.sh
@@ -0,0 +1,13 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+echo "==> fmt check"
+cargo fmt --all -- --check
+
+echo "==> clippy (correctness)"
+cargo clippy --locked --all-targets -- -D clippy::correctness
+
+if [ "${IRONCLAW_PREPUSH_TEST:-1}" = "1" ]; then
+    echo "==> tests (skip with IRONCLAW_PREPUSH_TEST=0)"
+    cargo test --locked --lib
+fi
diff --git a/scripts/dev-setup.sh b/scripts/dev-setup.sh
index faa5aa2c..4d272f49 100755
--- a/scripts/dev-setup.sh
+++ b/scripts/dev-setup.sh
@@ -56,6 +56,9 @@ if [ -n "$HOOKS_DIR" ]; then
     echo "  commit-msg hook installed (regression test enforcement)"
     ln -sf "$SCRIPTS_ABS/pre-commit-safety.sh" "$HOOKS_DIR/pre-commit"
     echo "  pre-commit hook installed (UTF-8, case-sensitivity, /tmp, redaction checks)"
+    REPO_ROOT="$(git rev-parse --show-toplevel)"
+    ln -sf "$REPO_ROOT/.githooks/pre-push" "$HOOKS_DIR/pre-push"
+    echo "  pre-push hook installed (quality gate + optional delta lint)"
 else
     echo "  Skipped: not a git repository"
 fi