diff --git a/CHANGELOG.md b/CHANGELOG.md
index af2dece18..613bd688e 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -81,6 +81,14 @@ plan sign-in. Retrying a failed summary refreshes its sidebar preview without re
 activity. The macOS app includes the microphone permission description and audio-input entitlement
 needed for dictation and voice calls.
 
+### The Pydantic AI Bot answers on a plain OpenAI key or an Anthropic key
+
+Picked with either key, the Pydantic AI Bot failed every run. Compose writes the endpoint the choice
+did not need as empty (`OPENAI_BASE_URL` for a plain OpenAI key, `ANTHROPIC_BASE_URL` for an
+Anthropic key), and Pydantic AI builds each provider's client from the environment, so the SDK was
+given "" as the address. The Bot now removes an empty value before building the model, as
+`agent-langgraph-agui` already does, so the SDK uses its own endpoint. A real endpoint is unchanged.
+
 ### Find older conversations and keep chat preferences across devices
 
 The sidebar loads older conversations as the person scrolls. Settings save the choice to emphasize
diff --git a/agent-pydantic-ai/src/main.py b/agent-pydantic-ai/src/main.py
index 6c6050649..e46fdc176 100644
--- a/agent-pydantic-ai/src/main.py
+++ b/agent-pydantic-ai/src/main.py
@@ -26,6 +26,26 @@ def _model_id() -> str:
     return model if model.startswith(f"{provider}:") else f"{provider}:{model}"
 
 
+def _drop_blank_base_urls() -> None:
+    """Compose exports missing overrides as ""; the SDKs only default an absent URL.
+
+    The model screen writes the endpoint it did not need as empty: `OPENAI_BASE_URL` for a plain
+    OpenAI key, `ANTHROPIC_BASE_URL` for an Anthropic key. Pydantic AI builds each provider's client
+    from the environment, so the empty value reached the SDK as the address and every run failed to
+    connect. Taking it out lets the SDK use its own endpoint; a real one is left as it is. The same
+    rule as `_normalize_openai_base_url` in `agent-langgraph-agui`.
+    """
+    for name in ("OPENAI_BASE_URL", "ANTHROPIC_BASE_URL"):
+        value = os.environ.get(name)
+        if value is None:
+            continue
+        if value.strip():
+            os.environ[name] = value.strip()
+        else:
+            os.environ.pop(name, None)
+
+
+_drop_blank_base_urls()
 agent = Agent(_model_id())
 app = FastAPI()
 
diff --git a/agent-pydantic-ai/tests/test_main.py b/agent-pydantic-ai/tests/test_main.py
index d9de661a5..822d32b77 100644
--- a/agent-pydantic-ai/tests/test_main.py
+++ b/agent-pydantic-ai/tests/test_main.py
@@ -6,6 +6,8 @@
 import time
 from pathlib import Path
 
+import httpx
+import httpx2
 import pytest
 import uvicorn
 from fastapi import FastAPI, Request
@@ -201,3 +203,61 @@ def test_a_run_reaches_the_model_the_setup_screen_chose(monkeypatch, provider, c
     assert '"RUN_ERROR"' not in response.text
     assert "hello" in response.text
     assert seen == [expected]
+
+
+# What Compose passes for the two plain keys: the key, and the endpoint it did not need as "".
+BLANK_URLS = {
+    "an OpenAI key": (
+        {"BOT_PROVIDER": "openai", "BOT_MODEL": "gpt-5.5", "OPENAI_API_KEY": "test-key", "ANTHROPIC_API_KEY": ""},
+        ("https", "api.openai.com", "/v1/responses"),
+        ("openai", "gpt-5.5"),
+    ),
+    "an Anthropic key": (
+        {"BOT_PROVIDER": "anthropic", "BOT_MODEL": "claude-sonnet-4-5", "ANTHROPIC_API_KEY": "test-key", "OPENAI_API_KEY": ""},
+        ("https", "api.anthropic.com", "/v1/messages"),
+        ("anthropic", "claude-sonnet-4-5"),
+    ),
+}
+
+
+@pytest.mark.parametrize("choice", list(BLANK_URLS))
+def test_a_key_reaches_the_official_endpoint_when_compose_leaves_the_url_blank(monkeypatch, choice):
+    environment, destination, expected = BLANK_URLS[choice]
+    seen = []
+    provider_seen = []
+    provider_app = _provider_app(provider_seen)
+
+    def respond_with(module):
+        async def respond(transport, request):
+            seen.append((request.url.scheme, request.url.host, request.url.path))
+            async with module.ASGITransport(app=provider_app) as local_provider:
+                return await local_provider.handle_async_request(request)
+
+        return respond
+
+    # Keep the real Pydantic AI and SDK clients; replace only the network transport, on both HTTP
+    # stacks, because the OpenAI SDK sends through httpx2 rather than httpx.
+    monkeypatch.setattr(httpx.AsyncHTTPTransport, "handle_async_request", respond_with(httpx))
+    monkeypatch.setattr(httpx2.AsyncHTTPTransport, "handle_async_request", respond_with(httpx2))
+    monkeypatch.delenv("OPENAI_API_BASE", raising=False)
+    monkeypatch.delenv("ANTHROPIC_AUTH_TOKEN", raising=False)
+    monkeypatch.setenv("MANAGED_AGENT_TOKEN", TOKEN)
+    monkeypatch.setenv("PYDANTIC_AI_NO_BANNER", "1")
+    monkeypatch.setenv("OPENAI_BASE_URL", "")
+    monkeypatch.setenv("ANTHROPIC_BASE_URL", "")
+    for key, value in environment.items():
+        monkeypatch.setenv(key, value)
+
+    from src import main
+
+    main = importlib.reload(main)
+    response = TestClient(main.app).post(
+        "/", json=RUN, headers={"x-openbot-agent-token": TOKEN}
+    )
+
+    assert seen == [destination]
+    assert provider_seen == [expected]
+    assert response.status_code == 200
+    assert '"RUN_FINISHED"' in response.text
+    assert '"RUN_ERROR"' not in response.text
+    assert "hello" in response.text