diff --git a/.claude/commands/commit.md b/.claude/commands/commit.md
index 0033015..15ced9a 100644
--- a/.claude/commands/commit.md
+++ b/.claude/commands/commit.md
@@ -1,6 +1,6 @@
 ---
 description: Create a git commit following project standards and safety protocols
-allowed-tools: Bash(git status:*), Bash(git log:*), Bash(git add:*), Bash(git diff:*), Bash(git commit:*), Bash(make test:*), Read, Edit
+allowed-tools: Bash(git *), Bash(make test*), Bash(make foundation*), Read, Edit, Task
 ---
 
 # commit
@@ -34,8 +34,11 @@ Create a git commit following all project standards and safety protocols for pgx
    - Run in background so we can continue with analysis
    - Tests will be checked before committing
 
-2. **While tests run**, gather information in parallel:
-   - `git status`, `git diff --stat`, `git log -10 --oneline` for both repos
+2. **While tests run**, gather repo state:
+   - Combine all git queries into a single Bash call per repo to minimize approvals:
+     `git status && git diff --stat && git log -10 --oneline`
+   - If conversation context already makes clear that only one repo has changes
+     (e.g., "test-only change", no pgxntool files modified), skip the unchanged repo entirely
 
 3. **Check if HISTORY.asc needs updating** (for pgxntool changes only):
    - Read `../pgxntool/HISTORY.asc`
diff --git a/test/CLAUDE.md b/test/CLAUDE.md
index efc6413..43066cb 100644
--- a/test/CLAUDE.md
+++ b/test/CLAUDE.md
@@ -366,6 +366,17 @@ cd "$TEST_REPO" || error "Failed to cd to TEST_REPO"  # Error visible immediatel
 
 ## Shell Error Handling Rules
 
+### BATS Runs With `set -eET`
+
+BATS executes test files via `bats-exec-file`, which starts with `set -eET` (errexit, errtrace, trace). This means:
+
+- **All functions** — `setup_file()`, `setup()`, `@test` blocks, `teardown()`, `teardown_file()` — run under errexit.
+- **Any failing command** will abort the current function. In `setup_file`, this causes BATS to report `"setup_file failed"` with a stack trace and skip all tests in the file.
+- **Subshells** `( ... )` also run under errexit. A failure inside a subshell exits the subshell non-zero, which errexit in the parent catches.
+- **`local var=$(cmd)` masks exit status** — the `local` builtin always returns 0, hiding failures in the command substitution. Split these into two lines: `local var` then `var=$(cmd)`.
+
+**Implication for setup code**: You do not need explicit exit status checks on every command in `setup_file` — errexit handles that. But if this isn't obvious in a given context, add a comment explaining the reliance on `set -e`.
+
 ### Never Use BATS `skip` Unless Explicitly Told
 
 **CRITICAL RULE:** You should never use BATS `skip` unless explicitly told to do so by the user.
diff --git a/test/standard/pgxntool-sync.bats b/test/standard/pgxntool-sync.bats
new file mode 100644
index 0000000..3a6fe6f
--- /dev/null
+++ b/test/standard/pgxntool-sync.bats
@@ -0,0 +1,138 @@
+#!/usr/bin/env bats
+
+# Test: make pgxntool-sync end-to-end
+#
+# This test validates the full `make pgxntool-sync` flow:
+#   git subtree pull → update-setup-files.sh
+#
+# Unlike the unit tests in update-setup-files.bats (which test 3-way merge
+# scenarios in isolation), this test exercises the complete sync pipeline
+# including the Makefile target and git subtree pull mechanics.
+#
+# A dedicated source repo is needed because git subtree pull requires the
+# initial add to have been done via `git subtree add`. During normal test
+# runs, pgxntool may be dirty (uncommitted changes), causing
+# build_test_repo_from_template to use rsync instead. This test creates
+# its own clean source repo to guarantee git subtree add is used.
+
+load ../lib/helpers
+load ../lib/assertions
+
+setup_file() {
+  # Note: BATS runs with set -eET, so any command failure here (including
+  # inside subshells) will abort setup_file and BATS will report the failure.
+  setup_topdir
+
+  # Always start fresh - this test creates its own repos from scratch
+  clean_env "pgxntool-sync"
+  load_test_env "pgxntool-sync"
+
+  # =========================================================================
+  # Step 1: Create a clean pgxntool source repo
+  # =========================================================================
+  local source_repo="$TEST_DIR/pgxntool-source"
+  mkdir "$source_repo"
+  (
+    cd "$source_repo"
+    git init
+    # Copy current pgxntool files (excluding .git)
+    rsync -a --exclude='.git' "$PGXNREPO/" ./
+    git add .
+    git commit -m "Initial pgxntool"
+    git tag v1
+
+    # Modify _.gitignore with a marker line for sync detection
+    echo "# pgxntool-sync-test-marker" >> _.gitignore
+    git add _.gitignore
+    git commit -m "Update gitignore"
+    git tag v2
+  )
+
+  # =========================================================================
+  # Step 2: Create test extension repo using subtree add from source at v1
+  # =========================================================================
+  mkdir "$TEST_REPO"
+  (
+    cd "$TEST_REPO"
+    git init
+
+    # Copy template files and commit
+    rsync -a --exclude='.DS_Store' "$TEST_TEMPLATE"/ ./
+    git add .
+    git commit -m "Initial extension files"
+
+    # Add pgxntool via git subtree (forces subtree path, not rsync)
+    git subtree add -P pgxntool --squash "$source_repo" v1
+
+    # Run setup.sh to generate Makefile, .gitignore, etc.
+    ./pgxntool/setup.sh
+
+    # Fix META.in.json placeholders
+    sed -i.bak -e 's/DISTRIBUTION_NAME/pgxntool-test/g' -e 's/EXTENSION_NAME/pgxntool-test/g' META.in.json
+    rm -f META.in.json.bak
+
+    # Regenerate META.json from updated META.in.json (make auto-rebuilds this
+    # as an included file prerequisite, which would dirty the tree during sync)
+    ./pgxntool/build_meta.sh META.in.json META.json
+
+    # Ignore generated files so repo stays clean
+    echo "*.html" >> .gitignore
+    echo "meta.mk" >> .gitignore
+
+    # Commit everything
+    git add .
+    git commit -m "Add pgxntool setup"
+  )
+
+  # Store source repo path in env file for test access
+  echo "export SOURCE_REPO=\"$source_repo\"" >> "$TEST_DIR/.env"
+
+  # Wait for filesystem timestamps to settle, then refresh git index cache.
+  # git subtree pull internally uses 'git diff-index --quiet HEAD' which can
+  # fail due to filesystem timestamp granularity causing stale index entries.
+  (cd "$TEST_REPO" && sleep 1 && git update-index --refresh)
+}
+
+setup() {
+  load_test_env "pgxntool-sync"
+  cd "$TEST_REPO"
+}
+
+# =============================================================================
+# Tests
+# =============================================================================
+
+@test "pgxntool subtree was added correctly" {
+  assert_file_exists "pgxntool/base.mk"
+
+  # Verify git log shows the subtree merge commit
+  run git log --oneline -- pgxntool/
+  assert_success
+  assert_contains "$output" "pgxntool"
+}
+
+@test ".gitignore does not have v2 marker before sync" {
+  ! grep -q "pgxntool-sync-test-marker" .gitignore
+}
+
+@test "make pgxntool-sync pulls new changes" {
+  run make pgxntool-sync-test "pgxntool-sync-test=$SOURCE_REPO v2"
+  assert_success
+  assert_contains "$output" "Checking setup files for updates"
+}
+
+@test ".gitignore was auto-updated after sync" {
+  grep -q "pgxntool-sync-test-marker" .gitignore
+}
+
+@test "pgxntool files reflect v2 after sync" {
+  grep -q "pgxntool-sync-test-marker" pgxntool/_.gitignore
+}
+
+@test "sync created a merge commit" {
+  run git log --oneline -1
+  assert_success
+  assert_contains "$output" "Pull pgxntool from"
+}
+
+# vi: expandtab sw=2 ts=2