Pin Pi defaultProvider/defaultModel in settings.json

src/ucode/agents/pi.py

@@ -52,6 +52,7 @@
 PI_UCODE_HOME = APP_DIR / "pi-home"
 PI_CONFIG_DIR = PI_UCODE_HOME / ".pi" / "agent"
 PI_CONFIG_PATH = PI_CONFIG_DIR / "models.json"
+PI_SETTINGS_PATH = PI_CONFIG_DIR / "settings.json"
 PI_BACKUP_PATH = APP_DIR / "pi-models.backup.json"
 
 SPEC: ToolSpec = {
@@ -182,11 +183,24 @@ def write_tool_config(
             providers.pop(stale, None)
     merged = deep_merge_dict(existing, overlay)
     write_json_file(PI_CONFIG_PATH, merged)
+    _write_settings(overlay["model"])
     state = mark_tool_managed(state, "pi", managed_keys)
     save_state(state)
     return state, token
 
 
+def _write_settings(model_selector: str) -> None:
+    # Pin defaultProvider/defaultModel in settings.json so Pi doesn't fall
+    # through to an env-key-backed provider (e.g. HF_TOKEN exposing
+    # huggingface) in `findInitialModel` when no --model is passed.
+    provider, _, model_id = model_selector.partition("/")
+    if not model_id:
+        return
+    existing = read_json_safe(PI_SETTINGS_PATH)
+    merged = deep_merge_dict(existing, {"defaultProvider": provider, "defaultModel": model_id})
+    write_json_file(PI_SETTINGS_PATH, merged)
+
+
 def default_model(state: dict) -> str | None:
     """Prefer Claude opus → sonnet → haiku; fall back to codex, gemini."""
     claude_models = state.get("claude_models") or {}

tests/test_agent_pi.py

@@ -267,9 +267,11 @@ def _setup(self, tmp_path, monkeypatch):
         monkeypatch.setattr(config_io_mod, "APP_DIR", tmp_path)
         config_file = tmp_path / "models.json"
         backup_file = tmp_path / "pi-backup.json"
+        settings_file = tmp_path / "settings.json"
         monkeypatch.setattr(pi_mod, "PI_CONFIG_PATH", config_file)
+        monkeypatch.setattr(pi_mod, "PI_SETTINGS_PATH", settings_file)
         monkeypatch.setattr(pi_mod, "PI_BACKUP_PATH", backup_file)
-        return pi_mod, config_file
+        return pi_mod, config_file, settings_file
 
     def _state(self, **overrides) -> dict:
         state = {
@@ -284,7 +286,7 @@ def _state(self, **overrides) -> dict:
         return state
 
     def test_stale_managed_providers_removed_before_merge(self, tmp_path, monkeypatch):
-        pi_mod, config_file = self._setup(tmp_path, monkeypatch)
+        pi_mod, config_file, _ = self._setup(tmp_path, monkeypatch)
 
         stale = {
             "providers": {
@@ -312,7 +314,7 @@ def test_legacy_providers_removed_on_upgrade(self, tmp_path, monkeypatch):
         """Earlier ucode versions wrote `databricks-anthropic`, `databricks-codex`,
         and `databricks-oss` providers. They must be stripped on the next write
         so users don't end up with stale entries pointing at routes that 400."""
-        pi_mod, config_file = self._setup(tmp_path, monkeypatch)
+        pi_mod, config_file, _ = self._setup(tmp_path, monkeypatch)
 
         config_file.write_text(
             json.dumps(
@@ -339,7 +341,7 @@ def test_legacy_providers_removed_on_upgrade(self, tmp_path, monkeypatch):
         assert "databricks-claude" in written_providers
 
     def test_config_written_with_correct_model_and_token(self, tmp_path, monkeypatch):
-        pi_mod, config_file = self._setup(tmp_path, monkeypatch)
+        pi_mod, config_file, _ = self._setup(tmp_path, monkeypatch)
 
         with (
             patch("ucode.agents.pi.get_databricks_token", return_value="tok"),
@@ -350,3 +352,19 @@ def test_config_written_with_correct_model_and_token(self, tmp_path, monkeypatch
         written = json.loads(config_file.read_text())
         assert written["model"] == "databricks-claude/claude-sonnet"
         assert written["providers"]["databricks-claude"]["apiKey"] == "tok"
+
+    def test_settings_pins_default_provider_and_model(self, tmp_path, monkeypatch):
+        # Without this, Pi's `findInitialModel` can fall through to a built-in
+        # provider when an unrelated env var (e.g. HF_TOKEN) makes one look
+        # auth-configured. Pinning the default keeps Pi on our provider.
+        pi_mod, _, settings_file = self._setup(tmp_path, monkeypatch)
+
+        with (
+            patch("ucode.agents.pi.get_databricks_token", return_value="tok"),
+            patch("ucode.agents.pi.save_state"),
+        ):
+            pi_mod.write_tool_config(self._state(), "claude-sonnet", token="tok")
+
+        settings = json.loads(settings_file.read_text())
+        assert settings["defaultProvider"] == "databricks-claude"
+        assert settings["defaultModel"] == "claude-sonnet"