fix: handle empty environment variables for list fields

- Use Optional[list[str]] with None default for allowed_paths
- Add env_parse_none_str="" to treat empty strings as None
- Add effective_allowed_paths property for safe access

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

CHANGELOG.md

@@ -7,6 +7,12 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+## [0.2.2] - 2026-01-09
+
+### Fixed
+- Config parsing for empty environment variables (allowed_paths, cors_*)
+- Use `env_parse_none_str=""` to treat empty strings as None
+
 ## [0.2.1] - 2026-01-09
 
 ### Fixed

pyproject.toml

@@ -1,6 +1,6 @@
 [project]
 name = "webber"
-version = "0.2.1"
+version = "0.2.2"
 description = "Mrs. Webber - Multi-Agent AI Development System"
 authors = [
     {name = "jpmschweitzer"}

src/shared/config.py

@@ -8,6 +8,7 @@ from pathlib import Path
 from functools import lru_cache
 from typing import Optional
 
+from pydantic import field_validator
 from pydantic_settings import BaseSettings, SettingsConfigDict
 
 
@@ -57,7 +58,7 @@ class Settings(BaseSettings):
     # Tool execution
     tool_timeout_seconds: int = 120
     sandbox_enabled: bool = True
-    allowed_paths: list[str] = []
+    allowed_paths: Optional[list[str]] = None
 
     # Sessions
     session_ttl_hours: int = 24
@@ -67,8 +68,14 @@ class Settings(BaseSettings):
         env_file=".env",
         case_sensitive=False,
         extra="ignore",
+        env_parse_none_str="",  # Treat empty string as None
     )
 
+    @property
+    def effective_allowed_paths(self) -> list[str]:
+        """Return allowed_paths or empty list if None."""
+        return self.allowed_paths or []
+
 
 @lru_cache()
 def get_settings() -> Settings: