From af0796689f0829b726ffa2633dccd25ab41125a8 Mon Sep 17 00:00:00 2001
From: 9qeklajc <tthefux@gmail.com>
Date: Sat, 20 Jun 2026 23:55:03 +0200
Subject: [PATCH] make openrouter default to provider supporting tool use

---
 routstr/upstream/openrouter.py        | 33 ++++++++++
 tests/unit/test_require_parameters.py | 95 +++++++++++++++++++++++++++
 2 files changed, 128 insertions(+)
 create mode 100644 tests/unit/test_require_parameters.py

diff --git a/routstr/upstream/openrouter.py b/routstr/upstream/openrouter.py
index 36932d22..0c69d2cc 100644
--- a/routstr/upstream/openrouter.py
+++ b/routstr/upstream/openrouter.py
@@ -1,3 +1,4 @@
+import json
 from typing import TYPE_CHECKING
 
 import httpx
@@ -18,6 +19,38 @@ 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
new file mode 100644
index 00000000..83c90652
--- /dev/null
+++ b/tests/unit/test_require_parameters.py
@@ -0,0 +1,95 @@
+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