diff --git a/tests/test_litigation_providers.py b/tests/test_litigation_providers.py
new file mode 100644
index 0000000..29fa525
--- /dev/null
+++ b/tests/test_litigation_providers.py
@@ -0,0 +1,100 @@
+"""Regression tests for litigation LLM provider factory."""
+
+from __future__ import annotations
+
+import os
+
+import pytest
+
+from litigation.providers.factory import (
+    _openrouter_extra_body,
+    _openrouter_headers,
+    get_provider,
+)
+from litigation.providers.ollama_provider import OllamaProvider
+from litigation.providers.openai_compat_provider import OpenAICompatProvider
+
+
+def test_get_provider_ollama() -> None:
+    provider = get_provider("ollama", "llama3", ollama_base_url="http://127.0.0.1:11434")
+    assert isinstance(provider, OllamaProvider)
+    assert provider.model == "llama3"
+    assert provider.base_url == "http://127.0.0.1:11434"
+
+
+def test_get_provider_lm_studio() -> None:
+    provider = get_provider("lm_studio", "local-model", lm_studio_base_url="http://127.0.0.1:1234/v1")
+    assert isinstance(provider, OpenAICompatProvider)
+    assert provider.model == "local-model"
+    assert provider.base_url == "http://127.0.0.1:1234/v1"
+    assert provider.api_key == "lm-studio"
+
+
+def test_get_provider_openrouter_uses_env_key(monkeypatch: pytest.MonkeyPatch) -> None:
+    monkeypatch.setenv("OPENROUTER_API_KEY", "sk-test-key")
+    provider = get_provider("openrouter", "anthropic/claude-3.5-sonnet")
+    assert isinstance(provider, OpenAICompatProvider)
+    assert provider.api_key == "sk-test-key"
+    assert provider.base_url == "https://openrouter.ai/api/v1"
+
+
+def test_get_provider_openrouter_missing_api_key(monkeypatch: pytest.MonkeyPatch) -> None:
+    monkeypatch.delenv("OPENROUTER_API_KEY", raising=False)
+    with pytest.raises(ValueError, match="OPENROUTER_API_KEY"):
+        get_provider("openrouter", "anthropic/claude-3.5-sonnet")
+
+
+def test_get_provider_unknown_raises() -> None:
+    with pytest.raises(ValueError, match="Unknown provider"):
+        get_provider("azure", "gpt-4")
+
+
+def test_openrouter_headers_from_config() -> None:
+    cfg = {
+        "app_attribution": {
+            "http_referer": "https://example.com",
+            "x_title": "Morningstar Court",
+        }
+    }
+    headers = _openrouter_headers(cfg)
+    assert headers == {
+        "HTTP-Referer": "https://example.com",
+        "X-Title": "Morningstar Court",
+    }
+
+
+def test_openrouter_extra_body_from_config() -> None:
+    cfg = {
+        "provider": {"sort": "price", "allow_fallbacks": False},
+        "user": "court-session-42",
+    }
+    body = _openrouter_extra_body(cfg)
+    assert body == {
+        "provider": {"sort": "price", "allow_fallbacks": False},
+        "user": "court-session-42",
+    }
+
+
+def test_get_provider_openrouter_passes_headers_and_extra_body(
+    monkeypatch: pytest.MonkeyPatch,
+) -> None:
+    monkeypatch.setenv("OPENROUTER_API_KEY", "sk-test")
+    cfg = {
+        "app_attribution": {"http_referer": "https://court.test", "x_title": "Litigation"},
+        "provider": {"sort": "throughput"},
+        "user": "run-1",
+    }
+    provider = get_provider(
+        " OpenRouter ",
+        "openai/gpt-4o",
+        openrouter_api_key=os.environ["OPENROUTER_API_KEY"],
+        openrouter_config=cfg,
+    )
+    assert provider.default_headers == {
+        "HTTP-Referer": "https://court.test",
+        "X-Title": "Litigation",
+    }
+    assert provider.extra_body == {
+        "provider": {"sort": "throughput"},
+        "user": "run-1",
+    }