Cline rules

1# Dad Reminder App project rule
2 
3## Project goal
4Build a small Python FastAPI server that receives a Twilio SMS, triggers a Vapi outbound reminder call to dad, and sends a confirmation SMS back to me.
5 
6## Source of truth
7Before making implementation decisions, read `spec.md` and follow it exactly unless I explicitly override it.
8 
9## Stack
10- Python 3.11+
11- FastAPI
12- uvicorn
13- Twilio
14- Vapi
15- httpx
16- pydantic-settings
17- python-dotenv
18 
19## Required implementation behavior
20- Match the project structure defined in `spec.md`
21- Keep route handlers thin
22- Put business logic in helper modules
23- Use async `httpx`, not `requests`
24- Use `pydantic-settings` in `config.py`
25- Do not read env vars directly with `os.environ.get()`
26- Twilio webhook input is form data, not JSON
27- Always return valid TwiML XML from the SMS webhook
28- Prefer small, focused modules and typed functions
29 
30## Working style
31- Before editing, inspect the current repo state and compare it against `spec.md`
32- When implementing, finish one file cleanly before moving to the next
33- After changes, run the smallest useful validation step
34- If a requirement in `spec.md` is ambiguous, flag it briefly and choose the safest implementation
35- Do not invent extra features unless they directly help reliability or testing
36 
37## Testing expectations
38- Verify `/health`
39- Verify unknown-number rejection
40- Verify empty-body handling
41- Verify Vapi failure path
42- Verify Twilio response format
43