carlos / todomvc-bakeoff Public

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1	# 🤖 AGENTS.md: todo-haskell
2
3	The one rule: **every visitor's list is theirs alone.** Every query that
4	reads or changes a todo is scoped to the list named by the caller's own
5	cookie, and a request naming anything outside that list changes nothing
6	and answers 404.
7
8	## Tenancy
9
10	- **One instance for the whole app.** `todo-haskell` runs as a single
11	Carloku instance on `todo-haskell.bfj.oncarlos.com`, with one SQLite
12	file.
13	- **Each visitor's list is kept separately by an anonymous cookie.** The
14	first visit mints a random 256-bit value, stores it as a row in
15	`lists`, and sets it as the `todo_list` cookie (`HttpOnly;
16	SameSite=Lax; Path=/`, plus `Secure` over https). A value the app
17	doesn't hold gets a fresh empty list, never an error.
18	- **No sign-in.** Losing the cookie loses the list; that's accepted.
19	- **Trust class C.** The todo text is stored in SQLite as plain text. The
20	operator can read it. That's a deliberate choice for a demo app, not an
21	oversight, and nobody should store anything secret in it.
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23	## Rules for changing this app
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25	- Work only in `apps/haskell/`. The bakeoff's `BRIEF.md` and
26	`CONTRACT.md` are binding.
27	- Migrations only ever add. Never drop or rewrite a table or a column.
28	- Servers bind `127.0.0.1` or a unix socket, nothing else.
29	- Cabal's store lives under `.cache/`, set by the `Makefile`. Don't
30	point it anywhere shared.
31	- Commits end with a `Co-Authored-By:` trailer naming the model.
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