adding an env example file

.env.example

@@ -0,0 +1,21 @@
+# Bespoke Labs Curator Environment Configuration
+
+#######################
+# Required Settings
+#######################
+
+# OpenAI API Key
+# Currently required as OpenAI is the only supported LLM provider
+# Support for other providers (Claude, etc.) may be added in the future
+# Get your key from: https://platform.openai.com/api-keys
+OPENAI_API_KEY=sk-your-key-here
+
+#######################
+# Optional Settings
+#######################
+
+# Cache Directory
+# Location where Curator stores its cache files
+# Default: ~/.curator
+# Note: This can also be set via the working_dir parameter in code
+CURATOR_CACHE_DIR=

README.md

@@ -133,4 +133,20 @@ nvm install 22
 node -v # should print `v22.11.0`
 # verifies the right npm version is in the environment
 npm -v # should print `10.9.0`
+
 ```
+
+<details>
+<summary><h2 style="display: inline-block">Development</h2></summary>
+
+### Environment Setup
+Copy `.env.example` to create your `.env` file:
+```bash
+cp .env.example .env
+```
+
+Available environment variables:
+- `OPENAI_API_KEY`: (Required) Your OpenAI API key for language model requests
+- `CURATOR_CACHE_DIR`: (Optional) Custom cache directory, defaults to `~/.cache/curator`. Used to store datasets, model responses, and metadata for caching and viewer functionality.
+
+</details>

src/bespokelabs/curator/prompter/prompter.py

@@ -140,12 +140,12 @@ def _completions(
 
         if self is None:
             raise ValueError("Prompter must be provided")
-
+        
         if working_dir is None:
-            curator_cache_dir = os.environ.get(
-                "CURATOR_CACHE_DIR",
-                os.path.expanduser(_CURATOR_DEFAULT_CACHE_DIR),
-            )
+            # First check if CURATOR_CACHE_DIR is set and non-empty
+            curator_cache_dir = os.environ.get("CURATOR_CACHE_DIR", "")
+            if not curator_cache_dir:  # If empty or not set
+                curator_cache_dir = os.path.expanduser(_CURATOR_DEFAULT_CACHE_DIR)
         else:
             curator_cache_dir = working_dir