fix: add .env file support and update docs

- Adds stdlib-only .env loader (no python-dotenv dependency)
- Env vars always take precedence over .env values
- Updates SKILL.md with .env usage example
- Updates configuration reference

Signed-off-by: Magnus Hedemark <magnus919@pm.me>

agent-council/SKILL.md

@@ -148,6 +148,16 @@ python3 -m pip install -e /path/to/agent-council/
 | `AGENT_COUNCIL_MODEL` | No | `openai/gpt-4o-mini` | Model string (`provider/model`) |
 | `AGENT_COUNCIL_BASE_URL` | No | Provider default | Custom API endpoint (OpenRouter, LiteLLM, etc.) |
 
+You can set these as environment variables or create a `.env` file in the directory you run `agent-council` from:
+
+```bash
+# .env file
+AGENT_COUNCIL_API_KEY=sk-...
+AGENT_COUNCIL_MODEL=openai/gpt-4o-mini
+```
+
+Environment variables take precedence over `.env` file values.
+
 Model strings follow PydanticAI convention: `openai/gpt-4o-mini`, `anthropic/claude-sonnet-4-20250514`, `deepseek/deepseek-v4-flash`, `google/gemini-2.0-flash`.
 
 ## Output

agent-council/agent_council/config.py

@@ -1,14 +1,49 @@
-"""Configuration — env var loading with sensible defaults."""
+"""Configuration — env var loading with sensible defaults and .env support."""
 
 import os
+from pathlib import Path
+
+
+def _load_dotenv(path: Path | None = None) -> None:
+    """Load .env file using stdlib only. Looks for .env in cwd by default.
+
+    Minimal implementation — no python-dotenv dependency. Handles:
+      KEY=value
+      KEY="quoted value"
+      # comments
+      export KEY=value  (strips export prefix)
+    """
+    dotenv_path = path or Path.cwd() / ".env"
+    if not dotenv_path.exists():
+        return
+
+    for line in dotenv_path.read_text().splitlines():
+        line = line.strip()
+        if not line or line.startswith("#"):
+            continue
+        if line.startswith("export "):
+            line = line[7:].strip()
+        if "=" not in line:
+            continue
+        key, _, value = line.partition("=")
+        key = key.strip()
+        value = value.strip().strip("\"'")
+        if key and key not in os.environ:
+            os.environ[key] = value
 
 
 def load_config() -> dict:
-    """Load configuration from environment variables.
+    """Load configuration from environment variables and .env files.
+
+    Checks for a .env file in the current working directory first,
+    then falls back to environment variables. Env vars always take
+    precedence over .env values.
 
     Returns dict with keys: api_key, model, base_url.
     Raises ValueError if AGENT_COUNCIL_API_KEY is not set.
     """
+    _load_dotenv()
+
     api_key = os.environ.get("AGENT_COUNCIL_API_KEY")
     model = os.environ.get("AGENT_COUNCIL_MODEL", "openai/gpt-4o-mini")
     base_url = os.environ.get("AGENT_COUNCIL_BASE_URL")
@@ -16,9 +51,12 @@ def load_config() -> dict:
     if not api_key:
         raise ValueError(
             "AGENT_COUNCIL_API_KEY is not set. "
-            "Set it to your LLM provider's API key:\n"
+            "Set it via environment variable or create a .env file:\n"
             "  export AGENT_COUNCIL_API_KEY='sk-...'\n"
-            "  export AGENT_COUNCIL_MODEL='openai/gpt-4o-mini'  # or your model"
+            "  export AGENT_COUNCIL_MODEL='openai/gpt-4o-mini'  # or your model\n\n"
+            "Or create a .env file in the current directory:\n"
+            "  AGENT_COUNCIL_API_KEY=sk-...\n"
+            "  AGENT_COUNCIL_MODEL=openai/gpt-4o-mini"
         )
 
     config = {