fix(embedded): preserve shell environment variables when constructor defaults are empty

The HindsightEmbedded constructor included every parameter in the config dict
even when the caller left them at their default of "".  Those empty-string
values travelled through the daemon-startup env pipeline and overwrote the
caller's actual shell environment variables (os.environ) set via export or
.env files, so HINDSIGHT_API_LLM_API_KEY (and every other key) was silently
ignored unless passed explicitly to the constructor.

Root cause: the HINDSIGHT_* propagation loop in _start_daemon used
'value is not None' as its guard, so an empty string was always propagated
and overwrote any prior os.environ value.

Changes (defence in depth):
- embedded.py: _set_if_truthy helper — only add keys with truthy values to
  the config dict.  An empty default no longer poisons the merged env.
- daemon_embed_manager.py: guard propagation on 'value' (truthy) instead of
  'value is not None', so even if an empty string reaches this loop it is
  harmlessly skipped.

Closes #3253.

Author: handnewb

hindsight-all/hindsight/embedded.py

@@ -45,6 +45,21 @@
 logger = logging.getLogger(__name__)
 
 
+def _set_if_truthy(target: dict[str, str]):
+    """Return a setter that only writes non-empty values to *target*.
+
+    Callers that rely on shell environment variables
+    (``os.environ``) should not have those silently overridden by a
+    constructor default of ``\"\"``.  See issue #3253.
+    """
+
+    def _set(key: str, value: str) -> None:
+        if value:
+            target[key] = value
+
+    return _set
+
+
 class HindsightEmbedded:
     """
     Hindsight client with automatic daemon lifecycle management.
@@ -110,20 +125,20 @@ def __init__(
         """
         self.profile = profile
 
-        # Build config dict for daemon (matches CLI format)
-        self.config = {
-            "HINDSIGHT_API_LLM_PROVIDER": llm_provider,
-            "HINDSIGHT_API_LLM_API_KEY": llm_api_key,
-            "HINDSIGHT_API_LLM_MODEL": llm_model,
-            "HINDSIGHT_API_LOG_LEVEL": log_level,
-            "HINDSIGHT_EMBED_DAEMON_IDLE_TIMEOUT": str(idle_timeout),
-        }
-
-        if llm_base_url:
-            self.config["HINDSIGHT_API_LLM_BASE_URL"] = llm_base_url
-
-        if database_url:
-            self.config["HINDSIGHT_EMBED_API_DATABASE_URL"] = database_url
+        # Build config dict for daemon (matches CLI format).
+        # Only include keys with actual values so that callers relying on shell
+        # environment variables (os.environ) aren't silently overridden by empty
+        # defaults.  See issue #3253.
+        self.config: dict[str, str] = {}
+        _set_if = _set_if_truthy(self.config)
+
+        _set_if("HINDSIGHT_API_LLM_PROVIDER", llm_provider)
+        _set_if("HINDSIGHT_API_LLM_API_KEY", llm_api_key)
+        _set_if("HINDSIGHT_API_LLM_MODEL", llm_model)
+        _set_if("HINDSIGHT_API_LOG_LEVEL", log_level)
+        _set_if("HINDSIGHT_EMBED_DAEMON_IDLE_TIMEOUT", str(idle_timeout) if idle_timeout else "")
+        _set_if("HINDSIGHT_API_LLM_BASE_URL", llm_base_url or "")
+        _set_if("HINDSIGHT_EMBED_API_DATABASE_URL", database_url or "")
 
         self._ui = ui
         self._ui_port = ui_port
@@ -175,17 +190,13 @@ def _ensure_started(self):
                 self._started = False
 
             if self._closed:
-                raise RuntimeError(
-                    "Cannot use HindsightEmbedded after it has been closed"
-                )
+                raise RuntimeError("Cannot use HindsightEmbedded after it has been closed")
 
             # Use embed manager interface for daemon management
             logger.info(f"Ensuring daemon is running for profile '{self.profile}'...")
             success = self._manager.ensure_running(self.config, self.profile)
             if not success:
-                raise RuntimeError(
-                    f"Failed to start daemon for profile '{self.profile}'"
-                )
+                raise RuntimeError(f"Failed to start daemon for profile '{self.profile}'")
 
             # Get daemon URL and create client
             daemon_url = self._manager.get_url(self.profile)
@@ -196,9 +207,7 @@ def _ensure_started(self):
             # Start UI if requested
             if self._ui:
                 logger.info(f"Starting UI for profile '{self.profile}'...")
-                ui_started = self._manager.start_ui(
-                    self.profile, self._ui_port, self._ui_hostname
-                )
+                ui_started = self._manager.start_ui(self.profile, self._ui_port, self._ui_hostname)
                 if not ui_started:
                     logger.warning(f"Failed to start UI for profile '{self.profile}'")
 
@@ -219,8 +228,7 @@ def _cleanup(self, stop_daemon_on_close: bool = False):
             # Mark closed to prevent new operations but skip shared-state
             # teardown — the daemon's idle timeout handles the rest.
             logger.warning(
-                "Cleanup lock acquisition timed out for profile '%s'; "
-                "marking closed, daemon will idle-stop on its own",
+                "Cleanup lock acquisition timed out for profile '%s'; marking closed, daemon will idle-stop on its own",
                 self.profile,
             )
             self._closed = True
@@ -433,10 +441,7 @@ def url(self) -> str:
     def is_running(self) -> bool:
         """Check if the client is initialized and the daemon is responsive."""
         return (
-            self._started
-            and not self._closed
-            and self._client is not None
-            and self._manager.is_running(self.profile)
+            self._started and not self._closed and self._client is not None and self._manager.is_running(self.profile)
         )
 
     @property

hindsight-embed/hindsight_embed/daemon_embed_manager.py

@@ -540,7 +540,7 @@ def _start_daemon_locked(
         # HINDSIGHT_API_EMBEDDINGS_PROVIDER) are silently dropped because the
         # whitelist above only covers LLM/log/idle_timeout keys.
         for key, value in config.items():
-            if key.startswith("HINDSIGHT_") and value is not None:
+            if key.startswith("HINDSIGHT_") and value:
                 env[key] = str(value)
 
         # Use profile-specific database (check config for override)