diff --git a/tests/tool_parsers/test_utils.py b/tests/tool_parsers/test_utils.py
new file mode 100644
index 00000000000..d72696554d4
--- /dev/null
+++ b/tests/tool_parsers/test_utils.py
@@ -0,0 +1,148 @@
+# SPDX-License-Identifier: Apache-2.0
+# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
+
+import pytest
+
+from vllm.tool_parsers.utils import coerce_to_schema_type
+
+
+class TestCoerceToSchemaType:
+    class TestNullHandling:
+        def test_null_converted_when_type_is_null(self):
+            assert coerce_to_schema_type("null", "null") is None
+
+        def test_null_converted_when_null_in_type_list(self):
+            assert coerce_to_schema_type("null", ["string", "null"]) is None
+
+        def test_null_preserved_as_string_when_type_is_string(self):
+            assert coerce_to_schema_type("null", "string") == "null"
+
+        def test_null_case_insensitive(self):
+            assert coerce_to_schema_type("NULL", "null") is None
+            assert coerce_to_schema_type("Null", "null") is None
+
+        def test_none_string_never_converted(self):
+            assert coerce_to_schema_type("none", "null") == "none"
+            assert coerce_to_schema_type("none", "string") == "none"
+            assert coerce_to_schema_type("none", ["string", "null"]) == "none"
+
+        def test_nil_string_never_converted(self):
+            assert coerce_to_schema_type("nil", "string") == "nil"
+            assert coerce_to_schema_type("nil", ["string", "null"]) == "nil"
+
+        def test_non_null_value_with_null_type(self):
+            assert coerce_to_schema_type("hello", ["null", "string"]) == "hello"
+
+    class TestStringType:
+        def test_string_type(self):
+            assert coerce_to_schema_type("hello", "string") == "hello"
+
+        def test_str_alias(self):
+            assert coerce_to_schema_type("hello", "str") == "hello"
+
+        def test_text_alias(self):
+            assert coerce_to_schema_type("hello", "text") == "hello"
+
+        def test_varchar_alias(self):
+            assert coerce_to_schema_type("hello", "varchar") == "hello"
+
+        def test_char_alias(self):
+            assert coerce_to_schema_type("x", "char") == "x"
+
+        def test_enum_alias(self):
+            assert coerce_to_schema_type("option_a", "enum") == "option_a"
+
+    class TestIntegerType:
+        def test_integer_type(self):
+            assert coerce_to_schema_type("42", "integer") == 42
+
+        def test_int_alias(self):
+            assert coerce_to_schema_type("42", "int") == 42
+
+        def test_negative_integer(self):
+            assert coerce_to_schema_type("-7", "integer") == -7
+
+        def test_invalid_integer_fallback(self):
+            assert coerce_to_schema_type("not_a_number", "integer") == "not_a_number"
+
+        def test_uint32_alias(self):
+            assert coerce_to_schema_type("5", "uint32") == 5
+
+        def test_long_alias(self):
+            assert coerce_to_schema_type("100", "long") == 100
+
+    class TestNumberType:
+        def test_number_type(self):
+            assert coerce_to_schema_type("3.14", "number") == 3.14
+
+        def test_float_alias(self):
+            assert coerce_to_schema_type("2.5", "float") == 2.5
+
+        def test_double_alias(self):
+            assert coerce_to_schema_type("2.5", "double") == 2.5
+
+        def test_whole_float_returns_int(self):
+            assert coerce_to_schema_type("5.0", "number") == 5
+            assert isinstance(coerce_to_schema_type("5.0", "number"), int)
+
+        def test_invalid_number_fallback(self):
+            assert coerce_to_schema_type("abc", "number") == "abc"
+
+    class TestBooleanType:
+        def test_true(self):
+            assert coerce_to_schema_type("true", "boolean") is True
+
+        def test_false(self):
+            assert coerce_to_schema_type("false", "boolean") is False
+
+        def test_bool_alias(self):
+            assert coerce_to_schema_type("true", "bool") is True
+
+        def test_one_is_true(self):
+            assert coerce_to_schema_type("1", "boolean") is True
+
+        def test_zero_is_false(self):
+            assert coerce_to_schema_type("0", "boolean") is False
+
+        def test_invalid_boolean_fallback(self):
+            assert coerce_to_schema_type("maybe", "boolean") == "maybe"
+
+    class TestObjectArrayType:
+        def test_object_type(self):
+            assert coerce_to_schema_type('{"a": 1}', "object") == {"a": 1}
+
+        def test_array_type(self):
+            assert coerce_to_schema_type("[1, 2, 3]", "array") == [1, 2, 3]
+
+        def test_invalid_json_fallback(self):
+            assert coerce_to_schema_type("not json", "object") == "not json"
+
+        def test_dict_alias(self):
+            assert coerce_to_schema_type('{"k": "v"}', "dict") == {"k": "v"}
+
+        def test_list_alias(self):
+            assert coerce_to_schema_type("[1]", "list") == [1]
+
+    class TestMultiType:
+        def test_null_takes_priority_over_string(self):
+            assert coerce_to_schema_type("null", ["string", "null"]) is None
+
+        def test_integer_tried_before_string(self):
+            assert coerce_to_schema_type("42", ["integer", "string"]) == 42
+
+        def test_falls_through_to_string(self):
+            assert coerce_to_schema_type("hello", ["integer", "string"]) == "hello"
+
+    class TestFallback:
+        def test_unknown_type_returns_string(self):
+            assert coerce_to_schema_type("hello", "unknown_type") == "hello"
+
+        def test_json_fallback_for_unknown_type(self):
+            assert coerce_to_schema_type('{"a": 1}', "unknown_type") == {"a": 1}
+
+        @pytest.mark.parametrize("schema_type", ["string", "str", "text"])
+        def test_string_types_preserve_value(self, schema_type):
+            assert coerce_to_schema_type("anything", schema_type) == "anything"
+
+        def test_unrecognized_type_falls_back_to_json(self):
+            assert coerce_to_schema_type("42", "interval") == 42
diff --git a/vllm/tool_parsers/minimax_m2_tool_parser.py b/vllm/tool_parsers/minimax_m2_tool_parser.py
index 85fb266b958..b831d147375 100644
--- a/vllm/tool_parsers/minimax_m2_tool_parser.py
+++ b/vllm/tool_parsers/minimax_m2_tool_parser.py
@@ -25,6 +25,7 @@ from vllm.tool_parsers.abstract_tool_parser import (
     Tool,
     ToolParser,
 )
+from vllm.tool_parsers.utils import coerce_to_schema_type
 
 logger = init_logger(__name__)
 
@@ -146,80 +147,6 @@ class MinimaxM2ToolParser(ToolParser):
 
         return list(types)
 
-    def _convert_param_value_with_types(
-        self, value: str, param_types: list[str]
-    ) -> Any:
-        """
-        Convert parameter value to the correct type based on a list of possible types.
-        Tries each type in order until one succeeds.
-
-        Args:
-            value: The string value to convert
-            param_types: List of possible type strings
-
-        Returns:
-            The converted value
-        """
-        # Normalize types
-        normalized_types = [t.lower() for t in param_types]
-
-        # Try each type in order of preference (most specific first, string as fallback)
-        # Priority: null > integer > number > boolean > object > array > string
-        type_priority = [
-            "null",
-            "integer",
-            "int",
-            "number",
-            "float",
-            "boolean",
-            "bool",
-            "object",
-            "array",
-            "string",
-            "str",
-            "text",
-        ]
-
-        for param_type in type_priority:
-            if param_type not in normalized_types:
-                continue
-
-            if param_type == "null":
-                if value.lower() == "null":
-                    return None
-                continue
-            elif param_type in ["string", "str", "text"]:
-                return value
-            elif param_type in ["integer", "int"]:
-                try:
-                    return int(value)
-                except (ValueError, TypeError):
-                    continue
-            elif param_type in ["number", "float"]:
-                try:
-                    val = float(value)
-                    return val if val != int(val) else int(val)
-                except (ValueError, TypeError):
-                    continue
-            elif param_type in ["boolean", "bool"]:
-                lower_val = value.lower().strip()
-                if lower_val in ["true", "1", "yes", "on"]:
-                    return True
-                elif lower_val in ["false", "0", "no", "off"]:
-                    return False
-                continue
-            elif param_type in ["object", "array"]:
-                try:
-                    return json.loads(value)
-                except json.JSONDecodeError:
-                    continue
-
-        # Fallback: try JSON parse, then return as string
-        try:
-            return json.loads(value)
-        except json.JSONDecodeError:
-            return value
-
     def _get_param_types_from_config(
         self, param_name: str, param_config: dict
     ) -> list[str]:
@@ -280,9 +207,7 @@ class MinimaxM2ToolParser(ToolParser):
                 param_type = self._get_param_types_from_config(param_name, param_config)
 
                 # Convert value
-                param_dict[param_name] = self._convert_param_value_with_types(
-                    param_value, param_type
-                )
+                param_dict[param_name] = coerce_to_schema_type(param_value, param_type)
 
         return ToolCall(
             type="function",
diff --git a/vllm/tool_parsers/utils.py b/vllm/tool_parsers/utils.py
index 464ed40f948..68af1e3dc84 100644
--- a/vllm/tool_parsers/utils.py
+++ b/vllm/tool_parsers/utils.py
@@ -450,6 +450,103 @@ def make_valid_python(text: str) -> tuple[str, str] | None:
     return candidate, added_text
 
 
+_TYPE_ALIASES: dict[str, str] = {
+    "str": "string",
+    "text": "string",
+    "varchar": "string",
+    "char": "string",
+    "enum": "string",
+    "int": "integer",
+    "int32": "integer",
+    "int64": "integer",
+    "uint": "integer",
+    "uint32": "integer",
+    "uint64": "integer",
+    "long": "integer",
+    "short": "integer",
+    "unsigned": "integer",
+    "float": "number",
+    "float32": "number",
+    "float64": "number",
+    "double": "number",
+    "bool": "boolean",
+    "dict": "object",
+    "arr": "array",
+    "list": "array",
+    "sequence": "array",
+}
+
+
+def coerce_to_schema_type(value: str, schema_type: str | list[str]) -> Any:
+    """Best-effort coercion of a raw string value to a JSON Schema type.
+
+    Tries each type in priority order (null > integer > number > boolean >
+    object > array > string) and returns the first successful coercion.
+    Falls back to the original string when no coercion succeeds.
+
+    Args:
+        value: The raw string value from the model output.
+        schema_type: One or more JSON Schema type strings
+            (e.g. ``"string"`` or ``["string", "null"]``).
+    """
+    if isinstance(schema_type, str):
+        schema_type = [schema_type]
+
+    normalized_types = {
+        _TYPE_ALIASES.get(key, key) for t in schema_type for key in [t.strip().lower()]
+    }
+
+    # Priority: null > integer > number > boolean > object > array > string
+    type_priority = [
+        "null",
+        "integer",
+        "number",
+        "boolean",
+        "object",
+        "array",
+        "string",
+    ]
+
+    for candidate_type in type_priority:
+        if candidate_type not in normalized_types:
+            continue
+
+        if candidate_type == "null":
+            if value.lower() == "null":
+                return None
+            continue
+        if candidate_type == "string":
+            return value
+        if candidate_type == "integer":
+            try:
+                return int(value)
+            except (ValueError, TypeError):
+                continue
+        if candidate_type == "number":
+            try:
+                val = float(value)
+                return val if val != int(val) else int(val)
+            except (ValueError, TypeError):
+                continue
+        if candidate_type == "boolean":
+            lower_val = value.lower().strip()
+            if lower_val in ("true", "1"):
+                return True
+            if lower_val in ("false", "0"):
+                return False
+            continue
+        if candidate_type in ("object", "array"):
+            try:
+                return json.loads(value)
+            except (json.JSONDecodeError, ValueError, TypeError):
+                continue
+
+    try:
+        return json.loads(value)
+    except (json.JSONDecodeError, ValueError):
+        return value
+
+
 def compute_tool_delta(
     previously_sent_args: str,
     new_call: ToolCall,