diff --git a/lib/crewai/tests/agents/test_parse_native_tool_call.py b/lib/crewai/tests/agents/test_parse_native_tool_call.py
new file mode 100644
index 0000000000..f815c2653a
--- /dev/null
+++ b/lib/crewai/tests/agents/test_parse_native_tool_call.py
@@ -0,0 +1,129 @@
+"""Contract tests for `_parse_native_tool_call`.
+
+Locks in the behavior of each native tool-call shape CrewAgentExecutor supports
+so provider-specific argument-passing bugs (e.g. #4972 — Bedrock Converse args
+silently dropped) can't silently regress.
+
+Each test asserts the parsed tuple `(call_id, func_name, func_args)` matches the
+expected wire-format contract for that provider, before any pydantic validation
+or tool dispatch runs.
+"""
+from __future__ import annotations
+
+from types import SimpleNamespace
+from unittest.mock import MagicMock
+
+import pytest
+
+from crewai.agents.crew_agent_executor import CrewAgentExecutor
+
+
+def _parse(tool_call):
+    """Invoke the bound method on a dummy self (the function does not touch self)."""
+    return CrewAgentExecutor._parse_native_tool_call(MagicMock(), tool_call)
+
+
+def test_openai_style_object():
+    """OpenAI: tool_call.function.arguments is a JSON string passed through verbatim."""
+    tc = SimpleNamespace(
+        id="call_abc",
+        function=SimpleNamespace(name="search", arguments='{"query": "hello"}'),
+    )
+    result = _parse(tc)
+    assert result == ("call_abc", "search", '{"query": "hello"}')
+
+
+def test_openai_style_object_without_id_synthesizes_one():
+    tc = SimpleNamespace(function=SimpleNamespace(name="x", arguments="{}"))
+    call_id, func_name, func_args = _parse(tc)
+    assert call_id.startswith("call_")
+    assert func_name == "x"
+    assert func_args == "{}"
+
+
+def test_gemini_style_function_call_object():
+    """Gemini: tool_call.function_call.args is a Struct-like mapping coerced to dict."""
+    tc = SimpleNamespace(
+        function_call=SimpleNamespace(name="lookup", args={"q": "hi"})
+    )
+    call_id, func_name, func_args = _parse(tc)
+    assert call_id.startswith("call_")
+    assert func_name == "lookup"
+    assert func_args == {"q": "hi"}
+
+
+def test_gemini_style_with_empty_args_yields_empty_dict():
+    tc = SimpleNamespace(function_call=SimpleNamespace(name="x", args=None))
+    _, _, func_args = _parse(tc)
+    assert func_args == {}
+
+
+def test_anthropic_style_object():
+    """Anthropic: tool_call.name + tool_call.input on the call object itself."""
+    tc = SimpleNamespace(id="toolu_01ABC", name="search", input={"query": "claude"})
+    result = _parse(tc)
+    assert result == ("toolu_01ABC", "search", {"query": "claude"})
+
+
+def test_dict_openai_format():
+    """Dict variant with the OpenAI-style nested function field."""
+    tc = {
+        "id": "call_42",
+        "function": {"name": "lookup", "arguments": '{"k": "v"}'},
+    }
+    result = _parse(tc)
+    assert result == ("call_42", "lookup", '{"k": "v"}')
+
+
+def test_dict_bedrock_converse_format():
+    """Regression for #4972: Bedrock Converse dict carries args under 'input', not 'function.arguments'.
+
+    Earlier versions used a truthy default that swallowed `input` and returned `{}`.
+    The dict branch must read `tool_call['input']` whenever the function-side is empty.
+    """
+    tc = {
+        "toolUseId": "tooluse_xyz",
+        "name": "search_in_user_knowledgebase",
+        "input": {"search_query": "test"},
+    }
+    call_id, func_name, func_args = _parse(tc)
+    assert call_id == "tooluse_xyz"
+    assert func_name == "search_in_user_knowledgebase"
+    assert func_args == {"search_query": "test"}, (
+        f"Bedrock args dropped: got {func_args!r}, expected {{'search_query': 'test'}}"
+    )
+
+
+def test_dict_bedrock_with_empty_input_dict_stays_empty():
+    """Edge case: explicit empty dict from Bedrock should not be replaced by anything."""
+    tc = {"toolUseId": "id1", "name": "noop", "input": {}}
+    _, _, func_args = _parse(tc)
+    assert func_args == {}
+
+
+def test_dict_missing_input_and_function_returns_empty_args():
+    """No arguments anywhere — should return empty dict, not raise."""
+    tc = {"id": "x", "name": "noop"}
+    _, _, func_args = _parse(tc)
+    assert func_args == {}
+
+
+def test_unrecognized_shape_returns_none():
+    """Plain object with no recognized fields signals 'not a native tool call'."""
+    assert _parse(SimpleNamespace(unrelated="data")) is None
+
+
+@pytest.mark.parametrize(
+    "tool_call,expected_args",
+    [
+        # OpenAI dict
+        ({"id": "1", "function": {"name": "f", "arguments": "{}"}}, "{}"),
+        # Bedrock dict
+        ({"toolUseId": "1", "name": "f", "input": {"a": 1}}, {"a": 1}),
+        # Mixed: function present but empty, input has the real args (Bedrock-via-OpenAI shim)
+        ({"name": "f", "function": {}, "input": {"a": 2}}, {"a": 2}),
+    ],
+)
+def test_dict_variants_preserve_args(tool_call, expected_args):
+    _, _, func_args = _parse(tool_call)
+    assert func_args == expected_args