From c075d07fa1c2e82ae3c3c0b8c55a2816a4d3ba62 Mon Sep 17 00:00:00 2001
From: Tiago Barbosa <tiago.filipe.barbosa@gmail.com>
Date: Tue, 2 Jun 2026 15:25:52 +0100
Subject: [PATCH] Add dotenv loader and wire CLI + MCP entry points to it

Introduces `yieldagent.env.load_dotenv`, a small `.env` reader so the
campaign-setup CLI and the Meta MCP server pick up local secrets without
`set -a; source .env`. No behavior change beyond env loading at startup.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
---
 src/yieldagent/agents/campaign_setup/cli.py |  6 ++-
 src/yieldagent/env.py                       | 57 +++++++++++++++++++++
 src/yieldagent/integrations/meta/server.py  |  4 +-
 3 files changed, 65 insertions(+), 2 deletions(-)
 create mode 100644 src/yieldagent/env.py

diff --git a/src/yieldagent/agents/campaign_setup/cli.py b/src/yieldagent/agents/campaign_setup/cli.py
index 25ed4d0..514e693 100644
--- a/src/yieldagent/agents/campaign_setup/cli.py
+++ b/src/yieldagent/agents/campaign_setup/cli.py
@@ -21,6 +21,8 @@
 
 from langgraph.types import Command
 
+from yieldagent.env import load_dotenv
+
 from .graph import build_graph
 from .nodes import DEFAULT_MODEL
 
@@ -100,6 +102,7 @@ async def _run(brief_path: Path, *, auto_approve: bool, dry_run: bool, model_nam
 
 
 def main() -> int:
+    load_dotenv()
     parser = argparse.ArgumentParser(prog="yieldagent-campaign-setup")
     parser.add_argument("brief", type=Path, help="Path to a markdown campaign brief")
     parser.add_argument(
@@ -111,7 +114,8 @@ def main() -> int:
         "--dry-run",
         action="store_true",
         help="Replace the Meta MCP server with a stub. No Meta credentials needed; "
-        "nothing is sent to Meta. Use this to try the agent end-to-end before wiring up real ad accounts.",
+        "nothing is sent to Meta. Use this to try the agent end-to-end before "
+        "wiring up real ad accounts.",
     )
     parser.add_argument("--model", default=DEFAULT_MODEL, help="Claude model name")
     args = parser.parse_args()
diff --git a/src/yieldagent/env.py b/src/yieldagent/env.py
new file mode 100644
index 0000000..e3ed5a4
--- /dev/null
+++ b/src/yieldagent/env.py
@@ -0,0 +1,57 @@
+"""Small `.env` loader for local CLI and MCP server entry points."""
+
+from __future__ import annotations
+
+import os
+from pathlib import Path
+
+
+def _find_dotenv(start: Path | None = None) -> Path | None:
+    current = (start or Path.cwd()).resolve()
+    if current.is_file():
+        current = current.parent
+    for directory in (current, *current.parents):
+        candidate = directory / ".env"
+        if candidate.is_file():
+            return candidate
+    return None
+
+
+def _parse_value(raw: str) -> str:
+    value = raw.strip()
+    if len(value) >= 2 and value[0] == value[-1] and value[0] in {"'", '"'}:
+        return value[1:-1]
+
+    for index, char in enumerate(value):
+        if char == "#" and (index == 0 or value[index - 1].isspace()):
+            return value[:index].strip()
+    return value
+
+
+def load_dotenv(path: Path | None = None, *, override: bool = False) -> Path | None:
+    """Load KEY=VALUE pairs from `.env` into `os.environ`.
+
+    This intentionally handles the simple format used by this repo without
+    adding a runtime dependency. Existing shell variables win unless
+    ``override=True`` is passed.
+    """
+    dotenv_path = path or _find_dotenv()
+    if dotenv_path is None:
+        return None
+
+    for line in dotenv_path.read_text().splitlines():
+        stripped = line.strip()
+        if not stripped or stripped.startswith("#"):
+            continue
+        if stripped.startswith("export "):
+            stripped = stripped.removeprefix("export ").lstrip()
+        if "=" not in stripped:
+            continue
+        key, raw_value = stripped.split("=", 1)
+        key = key.strip()
+        if not key or not key.replace("_", "").isalnum() or key[0].isdigit():
+            continue
+        if override or key not in os.environ:
+            os.environ[key] = _parse_value(raw_value)
+
+    return dotenv_path
diff --git a/src/yieldagent/integrations/meta/server.py b/src/yieldagent/integrations/meta/server.py
index b49e880..76cd946 100644
--- a/src/yieldagent/integrations/meta/server.py
+++ b/src/yieldagent/integrations/meta/server.py
@@ -14,14 +14,15 @@
 from mcp.server.fastmcp import FastMCP
 
 from yieldagent.domain import Campaign
+from yieldagent.env import load_dotenv
 
 from .client import MetaClient
 from .config import MetaConfig
 from .mapping import (
+    audience_to_targeting,
     campaign_objective,
     creative_payload,
     flight_to_meta_times,
-    audience_to_targeting,
     to_minor_units,
 )
 
@@ -138,6 +139,7 @@ async def publish_draft_campaign(campaign: dict[str, Any]) -> dict[str, Any]:
 
 
 def main() -> None:
+    load_dotenv()
     asyncio.run(mcp.run_stdio_async())