diff --git a/routstr/upstream/openrouter.py b/routstr/upstream/openrouter.py
index 63995295..1caeaa5c 100644
--- a/routstr/upstream/openrouter.py
+++ b/routstr/upstream/openrouter.py
@@ -1,4 +1,3 @@
-import json
 from typing import TYPE_CHECKING
 
 import httpx
@@ -19,38 +18,6 @@ class OpenRouterUpstreamProvider(BaseUpstreamProvider):
     supports_anthropic_messages = True
     litellm_provider_prefix = "openrouter/"
 
-    def prepare_request_body(
-        self, body: bytes | None, model_obj: Model
-    ) -> bytes | None:
-        """Set provider.require_parameters on tool-use requests.
-
-        Without it OpenRouter can route a tool call to an endpoint that doesn't
-        support function calling and 404 with "No endpoints found that support
-        tool use". We leave a client-supplied value untouched.
-        """
-        body = super().prepare_request_body(body, model_obj)
-        if not body:
-            return body
-
-        try:
-            data = json.loads(body)
-        except json.JSONDecodeError:
-            return body
-
-        if not isinstance(data, dict) or not data.get("tools"):
-            return body
-
-        provider = data.get("provider")
-        if not isinstance(provider, dict):
-            provider = {}
-
-        if "require_parameters" in provider:
-            return body
-
-        provider["require_parameters"] = True
-        data["provider"] = provider
-        return json.dumps(data).encode()
-
     def _apply_provider_field(self, response_json: object) -> None:
         """Stamp the ``provider`` field for OpenRouter responses.
 
diff --git a/tests/unit/test_require_parameters.py b/tests/unit/test_require_parameters.py
deleted file mode 100644
index 83c90652..00000000
--- a/tests/unit/test_require_parameters.py
+++ /dev/null
@@ -1,95 +0,0 @@
-import json
-import os
-
-os.environ.setdefault("UPSTREAM_BASE_URL", "http://test")
-os.environ.setdefault("UPSTREAM_API_KEY", "test")
-os.environ.setdefault("LIGHTNING_ADDRESS", "test@stm.to")
-
-from routstr.upstream import GenericUpstreamProvider
-from routstr.upstream.openrouter import OpenRouterUpstreamProvider
-
-
-def _model(model_id: str = "openai/gpt-4o"):  # type: ignore[no-untyped-def]
-    from routstr.payment.models import Architecture, Model, Pricing
-
-    return Model(
-        id=model_id,
-        name=model_id,
-        created=0,
-        description="",
-        context_length=128000,
-        architecture=Architecture(
-            modality="text->text",
-            input_modalities=["text"],
-            output_modalities=["text"],
-            tokenizer="GPT",
-            instruct_type=None,
-        ),
-        pricing=Pricing(prompt=0.0, completion=0.0),
-    )
-
-
-def _tool_body() -> dict:
-    return {
-        "model": "openai/gpt-4o",
-        "messages": [{"role": "user", "content": "What's the weather?"}],
-        "tools": [
-            {
-                "type": "function",
-                "function": {"name": "get_weather", "parameters": {}},
-            }
-        ],
-    }
-
-
-def _prepare(provider, body: dict) -> dict:  # type: ignore[no-untyped-def]
-    out = provider.prepare_request_body(json.dumps(body).encode(), _model())
-    assert out is not None
-    return json.loads(out)
-
-
-def test_injects_require_parameters_for_tool_request() -> None:
-    data = _prepare(OpenRouterUpstreamProvider(api_key="test"), _tool_body())
-    assert data["provider"]["require_parameters"] is True
-
-
-def test_generic_provider_on_openrouter_url_is_left_alone() -> None:
-    # Only OpenRouterUpstreamProvider injects; a generic provider pointed at the
-    # same base URL doesn't.
-    provider = GenericUpstreamProvider(base_url="https://openrouter.ai/api/v1")
-    data = _prepare(provider, _tool_body())
-    assert "provider" not in data
-
-
-def test_no_injection_without_tools() -> None:
-    body = {"model": "openai/gpt-4o", "messages": [{"role": "user", "content": "hi"}]}
-    data = _prepare(OpenRouterUpstreamProvider(api_key="test"), body)
-    assert "provider" not in data
-
-
-def test_empty_tools_list_does_not_inject() -> None:
-    body = _tool_body()
-    body["tools"] = []
-    data = _prepare(OpenRouterUpstreamProvider(api_key="test"), body)
-    assert "provider" not in data
-
-
-def test_direct_provider_does_not_inject() -> None:
-    provider = GenericUpstreamProvider(base_url="https://api.openai.com/v1")
-    data = _prepare(provider, _tool_body())
-    assert "provider" not in data
-
-
-def test_keeps_client_set_require_parameters() -> None:
-    body = _tool_body()
-    body["provider"] = {"require_parameters": False}
-    data = _prepare(OpenRouterUpstreamProvider(api_key="test"), body)
-    assert data["provider"]["require_parameters"] is False
-
-
-def test_preserves_other_provider_fields() -> None:
-    body = _tool_body()
-    body["provider"] = {"order": ["openai", "azure"]}
-    data = _prepare(OpenRouterUpstreamProvider(api_key="test"), body)
-    assert data["provider"]["order"] == ["openai", "azure"]
-    assert data["provider"]["require_parameters"] is True