# Data and persistence Devii's durable state lives in the main DevPlace SQLite database, every table scoped by owner. See also [Architecture and sessions](/docs/devii-architecture.html) and [Tools and scopes](/docs/devii-tools.html). ## Tables | Table | Scope | Purpose | |---|---|---| | `devii_conversations` | `(owner_kind, owner_id)` | The full message list (JSON) per owner. Upserted after each turn for **users only**; loaded back on reconnect so a conversation survives reloads and restarts. | | `devii_usage_ledger` | `(owner_kind, owner_id, created_at)` | One row per turn: token counts, `cost_usd`, model. The **authoritative source** for the rolling 24h spend cap. | | `devii_turns` | `(owner_kind, owner_id, started_at)` | Per-turn audit: truncated prompt and reply, iterations, tool-call count, cost, error. | | `devii_tasks` | `(owner_kind, owner_id)` | Autonomous tasks and reminders (schedule, status, next run, plus a `notify` flag and captured `tz`). Owner-scoped. A signed-in user's rows are run by the lock-owner service, so reminders survive restarts. | | `devii_lessons` | `(owner_kind, owner_id)` | The self-learning memory: observation, conclusion, next action, tags. BM25-searched, owner-isolated. | | `devii_behavior` | `(owner_kind, owner_id)` | One row per owner: the persistent `# TRUTH RULES AND BEHAVIOR` system-prompt section Devii self-configures via `update_behavior`. | | `devii_virtual_tools` | `(owner_kind, owner_id)` | The user-defined tools (name, description, stored prompt, input hint, enabled) added to Devii's tool list per owner. | | `email_accounts` | `(owner_kind, owner_id, label)` | IMAP/SMTP connection settings the `email_*` tools use, one row per named account. Soft-deletable; the password is stored as written and never returned by a tool. Signed-in users only. | Indexes for these are created idempotently in `database.init_db()`. ## Persistent vs ephemeral - **Signed-in users:** conversations, tasks, lessons, self-configured behavior, and user-defined tools persist in the main DB, survive restarts, and rehydrate on reconnect. A pending task or reminder is re-armed at boot by the lock-owner service and fires even if the user never reopens Devii; a `notify` reminder then raises a `reminder` notification and toast. The user's browser timezone is persisted to `users.timezone` for correct wall-clock-to-UTC scheduling. - **Guests:** tasks, lessons, behavior, and user-defined tools use a fresh **in-memory** database per session, never written to disk; conversations are not persisted at all. State is gone when the guest session ends, so a guest reminder runs only while that session stays connected and never sends a notification. ## Owner isolation Every store filters reads and writes by the owner tuple. The lesson store is built per session over the owner's scope, so one account's lessons are never visible to another - a hard isolation boundary, see [Security and limits](/docs/devii-security.html). ## Display vs source of truth The in-memory `CostTracker` shows a live per-session figure but resets on reboot; it is **not** used for the cap. The 24h limit and all spend reporting read `devii_usage_ledger`, so the financial ceiling is correct across restarts and matches the admin analytics endpoint. The cap and pricing themselves are set in [Configuration and CLI](/docs/devii-config.html).