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+---
+epic: 13
+story: 13.4
+title: "Crash Recovery"
+status: draft
+---
+
+## Epic 13 — Performance & Reliability
+**Goal:** Instant evaluation, never lose work.
+
+### Story 13.4: Crash Recovery
+
+As a CalcPad user,
+I want my work to be auto-saved continuously,
+So that I never lose more than 2 seconds of work after a crash or unexpected quit.
+
+**Acceptance Criteria:**
+
+**Given** the user is actively editing a sheet on macOS
+**When** the application is running
+**Then** NSDocument auto-save is leveraged to persist the document state at least every 2 seconds
+**And** the auto-saved state includes all sheet content, variable values, and cursor position
+
+**Given** the user is actively editing a sheet on Windows
+**When** the application is running
+**Then** a journal file is written to `%APPDATA%/CalcPad/recovery/` at least every 2 seconds
+**And** the journal file contains the full sheet content and metadata needed for restoration
+
+**Given** the user is actively editing a sheet on the web
+**When** the application is running
+**Then** sheet state is persisted to localStorage at least every 2 seconds
+**And** if the user is logged in with cloud sync enabled, the state is also queued for server sync
+
+**Given** CalcPad crashes or is force-quit
+**When** the user relaunches the application
+**Then** the recovery file is detected and the user is prompted to restore their session
+**And** the restored session contains all content from no more than 2 seconds before the crash
+**And** the user can choose to discard the recovered state and start fresh
+
+**Given** multiple sheets were open at the time of a crash
+**When** the user relaunches the application
+**Then** all sheets with recovery data are listed for restoration
+**And** the user can selectively restore individual sheets