diff --git a/nanobot/config/loader.py b/nanobot/config/loader.py
index fd7d1e8..e6899d3 100644
--- a/nanobot/config/loader.py
+++ b/nanobot/config/loader.py
@@ -12,35 +12,53 @@ def get_config_path() -> Path:
     return Path.home() / ".nanobot" / "config.json"
 
 
+def _get_oauth_store_dir() -> Path:
+    """Get the OAuth store directory."""
+    return Path.home() / ".nanobot"
+
+
 def get_data_dir() -> Path:
     """Get the nanobot data directory."""
     from nanobot.utils.helpers import get_data_path
     return get_data_path()
 
 
+def _inject_oauth_credentials(config: Config) -> Config:
+    """Inject OAuth credentials from store into config if available."""
+    from nanobot.config.oauth_store import OAuthStore
+
+    store = OAuthStore(_get_oauth_store_dir())
+    creds = store.load("anthropic")
+    if creds and creds.access_token and not creds.is_expired:
+        config.providers.anthropic.api_key = creds.access_token
+
+    return config
+
+
 def load_config(config_path: Path | None = None) -> Config:
     """
     Load configuration from file or create default.
-    
+
     Args:
         config_path: Optional path to config file. Uses default if not provided.
-    
+
     Returns:
         Loaded configuration object.
     """
     path = config_path or get_config_path()
-    
+
     if path.exists():
         try:
             with open(path) as f:
                 data = json.load(f)
             data = _migrate_config(data)
-            return Config.model_validate(convert_keys(data))
+            config = Config.model_validate(convert_keys(data))
+            return _inject_oauth_credentials(config)
         except (json.JSONDecodeError, ValueError) as e:
             print(f"Warning: Failed to load config from {path}: {e}")
             print("Using default configuration.")
-    
-    return Config()
+
+    return _inject_oauth_credentials(Config())
 
 
 def save_config(config: Config, config_path: Path | None = None) -> None:
diff --git a/tests/test_config_oauth_integration.py b/tests/test_config_oauth_integration.py
new file mode 100644
index 0000000..8ef6f1a
--- /dev/null
+++ b/tests/test_config_oauth_integration.py
@@ -0,0 +1,65 @@
+"""Test OAuth store integration with config loading."""
+import json
+import pytest
+import tempfile
+from pathlib import Path
+from nanobot.config.loader import load_config
+from nanobot.config.oauth_store import OAuthStore
+from nanobot.config.schema import OAuthCredentials
+
+
+def test_oauth_token_injected_into_config(tmp_path, monkeypatch):
+    """OAuth token from store should be injected into provider api_key."""
+    # Create a minimal config file (no api key set)
+    config_path = tmp_path / "config.json"
+    config_path.write_text(json.dumps({
+        "agents": {"defaults": {"model": "anthropic/claude-opus-4-5"}},
+        "providers": {"anthropic": {"apiKey": ""}}
+    }))
+
+    # Save OAuth credentials
+    store = OAuthStore(tmp_path)
+    creds = OAuthCredentials(access_token="sk-ant-oat01-test-inject")
+    store.save("anthropic", creds)
+
+    # Monkeypatch get_config_path to use our tmp dir
+    monkeypatch.setattr("nanobot.config.loader.get_config_path", lambda: config_path)
+    # Monkeypatch the OAuth store path
+    monkeypatch.setattr("nanobot.config.loader._get_oauth_store_dir", lambda: tmp_path)
+
+    config = load_config(config_path)
+
+    assert config.providers.anthropic.api_key == "sk-ant-oat01-test-inject"
+
+
+def test_config_without_oauth_unchanged(tmp_path, monkeypatch):
+    """Config without OAuth store should load normally."""
+    config_path = tmp_path / "config.json"
+    config_path.write_text(json.dumps({
+        "providers": {"anthropic": {"apiKey": "sk-ant-api03-regular"}}
+    }))
+
+    monkeypatch.setattr("nanobot.config.loader._get_oauth_store_dir", lambda: tmp_path / "nonexistent")
+
+    config = load_config(config_path)
+
+    assert config.providers.anthropic.api_key == "sk-ant-api03-regular"
+
+
+def test_oauth_does_not_overwrite_existing_key(tmp_path, monkeypatch):
+    """If user already has an API key, OAuth should still override (OAuth takes priority)."""
+    config_path = tmp_path / "config.json"
+    config_path.write_text(json.dumps({
+        "providers": {"anthropic": {"apiKey": "sk-ant-api03-existing"}}
+    }))
+
+    store = OAuthStore(tmp_path)
+    creds = OAuthCredentials(access_token="sk-ant-oat01-oauth-wins")
+    store.save("anthropic", creds)
+
+    monkeypatch.setattr("nanobot.config.loader._get_oauth_store_dir", lambda: tmp_path)
+
+    config = load_config(config_path)
+
+    # OAuth token takes priority over existing API key
+    assert config.providers.anthropic.api_key == "sk-ant-oat01-oauth-wins"