diff --git a/.github/workflows/version-compat-ci.yml b/.github/workflows/version-compat-ci.yml
index 2fbdd15747..599b53df1d 100644
--- a/.github/workflows/version-compat-ci.yml
+++ b/.github/workflows/version-compat-ci.yml
@@ -127,6 +127,7 @@ jobs:
         run: |
           PYTHONPATH=. python -m pytest \
             tests/version_compat/test_peft_pinned_symbols.py \
+            tests/version_compat/test_unsloth_zoo_save_merged_pinned_symbols.py \
             -v --tb=short
 
   st-pinned-symbols:
diff --git a/tests/version_compat/test_unsloth_zoo_save_merged_pinned_symbols.py b/tests/version_compat/test_unsloth_zoo_save_merged_pinned_symbols.py
new file mode 100644
index 0000000000..19faa51119
--- /dev/null
+++ b/tests/version_compat/test_unsloth_zoo_save_merged_pinned_symbols.py
@@ -0,0 +1,128 @@
+# SPDX-License-Identifier: AGPL-3.0-only
+# Copyright 2026-present the Unsloth AI Inc. team.
+"""Pinned-symbol canary for unsloth-zoo save_pretrained_merged guards
+(unslothai/unsloth-zoo#647 / unslothai/unsloth#5410). Skips until #647
+lands, then becomes a hard gate. CPU-only static fetch."""
+
+from __future__ import annotations
+
+import re
+
+import pytest
+
+from tests.version_compat._fetch import fetch_text
+
+
+ZOO_TAG = "main"
+
+
+def _fetch_saving_utils() -> str:
+    src = fetch_text("unslothai/unsloth-zoo", ZOO_TAG, "unsloth_zoo/saving_utils.py")
+    if src is None:
+        pytest.skip("unsloth_zoo/saving_utils.py not fetchable")
+    return src
+
+
+def _fetch_merge_tests() -> str:
+    src = fetch_text(
+        "unslothai/unsloth-zoo",
+        ZOO_TAG,
+        "tests/test_unsloth_zoo_lora_merge.py",
+    )
+    if src is None:
+        pytest.skip("tests/test_unsloth_zoo_lora_merge.py not fetchable")
+    return src
+
+
+def _skip_until_pr_647_lands(src: str) -> None:
+    if not any(
+        m in src
+        for m in (
+            "_MOE_MERGE_STATE",
+            "_detect_moe_lora_layout",
+            "_resolve_num_experts_from_lora_stats",
+        )
+    ):
+        pytest.skip(
+            "unslothai/unsloth-zoo#647 has not yet merged into main; "
+            "tests auto-promote to hard gates once it lands."
+        )
+
+
+def test_zoo_saving_utils_has_moe_merge_state():
+    src = _fetch_saving_utils()
+    _skip_until_pr_647_lands(src)
+    for sym in (
+        "_MOE_MERGE_STATE",
+        "_reset_moe_merge_state",
+        "_record_moe_merge_fallback",
+    ):
+        assert sym in src, f"{sym} missing from saving_utils.py (issue #5410 guard)."
+    # zoo#647 wraps the fallback guard's message onto a second line;
+    # allow the regex to span newlines via re.DOTALL.
+    assert re.search(
+        r"raise\s+RuntimeError\b.*?MoE", src, re.IGNORECASE | re.DOTALL
+    ), "no `raise RuntimeError(...MoE...)`; post-loop guard weakened."
+
+
+def test_zoo_saving_utils_has_layout_detector():
+    src = _fetch_saving_utils()
+    _skip_until_pr_647_lands(src)
+    assert (
+        "_detect_moe_lora_layout" in src
+    ), "_detect_moe_lora_layout removed (issue #5410)."
+    assert (
+        '"swapped"' in src and '"standard"' in src
+    ), "one of the layout labels removed."
+
+
+def test_zoo_saving_utils_has_num_experts_resolver():
+    src = _fetch_saving_utils()
+    _skip_until_pr_647_lands(src)
+    assert "_resolve_num_experts_from_lora_stats" in src, "resolver removed (#5410)."
+    assert re.search(
+        r"for\s+_\s+in\s+range\s*\(\s*\d+\s*\)", src
+    ), "resolver walk no longer bounded by `for _ in range(N):`."
+
+
+def test_zoo_saving_utils_writes_generation_config():
+    src = _fetch_saving_utils()
+    _skip_until_pr_647_lands(src)
+    # zoo#647 binds the generation_config attr to a local var
+    # (`gen_cfg = getattr(model, "generation_config", ...); ...
+    # gen_cfg.save_pretrained(save_directory)`) so an exact
+    # `generation_config.save_pretrained(` substring no longer
+    # matches. Anchor on the conceptual operation: a `generation_config`
+    # mention plus a `.save_pretrained(` call nearby, which is what
+    # the canary actually cares about.
+    assert re.search(
+        r"generation_config[\s\S]{0,400}?\.save_pretrained\s*\(", src
+    ), "generation_config.json no longer saved (#5410)."
+
+
+def test_zoo_lora_merge_tests_have_standard_layout_coverage():
+    src = _fetch_merge_tests()
+    if "test_merge_moe_gate_expert_standard_layout" not in src:
+        pytest.skip("unslothai/unsloth-zoo#647 not yet merged; coverage appears later.")
+    for name in (
+        "test_merge_moe_gate_expert_standard_layout",
+        "test_merge_moe_up_expert_standard_layout",
+        "test_merge_moe_down_proj_expert_standard_layout",
+        "test_detect_moe_lora_layout_classifies_both_conventions",
+        "test_moe_merge_fallback_counter_records_bad_layout",
+        "test_resolve_num_experts_walks_base_layer_chain",
+    ):
+        assert name in src, f"regression test `{name}` removed."
+
+
+def test_unsloth_save_pretrained_merged_entry_point_exists():
+    import pathlib
+
+    save_py = pathlib.Path(__file__).resolve().parents[2] / "unsloth" / "save.py"
+    if not save_py.is_file():
+        pytest.skip(f"{save_py} not present")
+    text = save_py.read_text(encoding = "utf-8", errors = "replace")
+    assert "save_pretrained_merged" in text, "entry point removed from unsloth/save.py."
+    assert (
+        "merge_and_overwrite_lora" in text
+    ), "no dispatch into unsloth_zoo merge; #647 bypassed."