diff --git a/cosmos_framework/configs/toml_config/sft_config_test.py b/cosmos_framework/configs/toml_config/sft_config_test.py
index 8ff8f3f0..cd274fe9 100644
--- a/cosmos_framework/configs/toml_config/sft_config_test.py
+++ b/cosmos_framework/configs/toml_config/sft_config_test.py
@@ -101,6 +101,50 @@ def test_other_keys_still_emitted(self) -> None:
         assert "experiment=vision_sft_nano" in overrides
         assert any(o.startswith("optimizer.lr=") for o in overrides), overrides
 
+    @pytest.mark.parametrize(
+        "value",
+        ["20260913", "1e-4", "true", "null", "lr=1e-5", "run(v2)", "run[1]", "exp#3", "bob's run", "a\\'b", "ends\\"],
+    )
+    def test_string_value_reaches_hydra_as_the_same_string(self, value: str) -> None:
+        """A TOML string must not be re-typed (int/float/bool/None) or rejected by the override grammar."""
+        from hydra.core.override_parser.overrides_parser import OverridesParser
+
+        raw = {"job": {"task": "vfm", "experiment": "vision_sft_nano", "name": value}}
+        (override,) = [o for o in build_hydra_overrides(raw) if o.startswith("job.name=")]
+        parsed = OverridesParser.create().parse_override(override).value()
+        assert isinstance(parsed, str) and parsed == value, override
+
+    def test_string_list_items_reach_hydra_as_the_same_strings(self) -> None:
+        from hydra.core.override_parser.overrides_parser import OverridesParser
+
+        warmup = ["480", "bob's"]
+        raw = {
+            "job": {"task": "vfm", "experiment": "vision_sft_nano"},
+            "trainer": {"callbacks": {"compile_tokenizer": {"warmup_resolutions": warmup}}},
+        }
+        (override,) = [o for o in build_hydra_overrides(raw) if "warmup_resolutions=" in o]
+        assert OverridesParser.create().parse_override(override).value() == warmup, override
+
+    def test_non_string_values_keep_their_types(self) -> None:
+        """Numbers, bools, lists, ``${...}`` interpolation and the ``???`` skip are unchanged."""
+        from hydra.core.override_parser.overrides_parser import OverridesParser
+
+        raw = {
+            "job": {"task": "vfm", "experiment": "vision_sft_nano"},
+            "optimizer": {"lr": 1.0e-5, "betas": [0.9, 0.99]},
+            "trainer": {"max_iter": 200},
+            "model": {"ema": {"enabled": False}, "tokenizer": {"vae_path": "${oc.env:WAN_VAE_PATH}"}},
+            "checkpoint": {"load_path": "???"},
+        }
+        overrides = OverridesParser.create().parse_overrides(build_hydra_overrides(raw)[1:])
+        parsed = {o.key_or_group: o.value() for o in overrides}
+        assert parsed["optimizer.lr"] == 1.0e-5
+        assert parsed["optimizer.betas"] == [0.9, 0.99]
+        assert parsed["trainer.max_iter"] == 200 and isinstance(parsed["trainer.max_iter"], int)
+        assert parsed["model.config.ema.enabled"] is False
+        assert parsed["model.config.tokenizer.vae_path"] == "${oc.env:WAN_VAE_PATH}"
+        assert "checkpoint.load_path" not in parsed
+
 
 # --------------------------------------------------------------------------- #
 # 3. end-to-end load_experiment_from_toml on the shipped vision_sft_nano recipe #
diff --git a/cosmos_framework/configs/toml_config/toml_config_helper.py b/cosmos_framework/configs/toml_config/toml_config_helper.py
index 4d1535c5..719c3508 100644
--- a/cosmos_framework/configs/toml_config/toml_config_helper.py
+++ b/cosmos_framework/configs/toml_config/toml_config_helper.py
@@ -16,6 +16,7 @@
 
 from __future__ import annotations
 
+import re
 from typing import Any
 
 
@@ -181,14 +182,19 @@ def _emit_with_remap(
     out.append(f"{'.'.join(new_path)}={_hydra_format(value)}")
 
 
-def _hydra_format(v: Any, in_list: bool = False) -> str:
-    """Convert a Python value to a Hydra CLI override RHS.
+def _hydra_quote(s: str) -> str:
+    """Single-quote a string for a Hydra override RHS.
 
-    ``in_list=True`` indicates the value is being emitted inside a list
-    literal (``[a,b,c]``); strings then get single-quoted unconditionally
-    so numeric-looking entries like ``"480"`` stay strings rather than
-    being coerced to int by Hydra's list parser.
+    Inside quotes Hydra keeps backslashes literally except where they precede a
+    quote or end the string, so only those runs are doubled; quotes are escaped.
     """
+    s = re.sub(r"(\\*)'", lambda m: m.group(1) * 2 + "\\'", s)
+    s = re.sub(r"(\\+)$", lambda m: m.group(1) * 2, s)
+    return f"'{s}'"
+
+
+def _hydra_format(v: Any) -> str:
+    """Convert a Python value to a Hydra CLI override RHS."""
     if v is None:
         return "null"
     if isinstance(v, bool):
@@ -196,17 +202,13 @@ def _hydra_format(v: Any, in_list: bool = False) -> str:
     if isinstance(v, (int, float)):
         return str(v)
     if isinstance(v, list):
-        return "[" + ",".join(_hydra_format(x, in_list=True) for x in v) + "]"
+        return "[" + ",".join(_hydra_format(x) for x in v) + "]"
     if isinstance(v, str):
-        # Inside a list literal, always quote so numeric-looking strings
-        # ("480") aren't parsed as int. At top level, quote only when the
-        # string contains characters Hydra would otherwise interpret —
-        # commas (sweep / list marker) or whitespace. Env-interpolation
-        # strings like ``${oc.env:NAME}`` are safe unquoted because Hydra
-        # recognizes the ``${...}`` form even with a colon inside.
-        if in_list or "," in v or " " in v:
-            return f"'{v}'"
-        return v
+        # Always quote. Hydra re-types an unquoted RHS, so a string field set to
+        # "20260913", "true" or "null" would arrive as int/bool/None, and one
+        # containing "=", "(", "[" or "#" is rejected by the override grammar.
+        # Quoted values still resolve ``${oc.env:NAME}`` interpolation.
+        return _hydra_quote(v)
     return str(v)