> ## Documentation Index > Fetch the complete documentation index at: https://docs.recoupable.dev/llms.txt > Use this file to discover all available pages before exploring further. # Reconnect to session sandbox > Live runtime probe for the sandbox bound to a session. Unlike `GET /api/sandbox/status` (DB-only read), this endpoint actually runs a quick command inside the sandbox to verify it is reachable. Used by the chat UI on session re-entry / tab refocus to decide whether to flip out of "loading sandbox…" or surface a "resume" affordance. Returns one of three operational outcomes via the `status` field: `"connected"` (sandbox is alive, included `expiresAt` reflects current expiry), `"expired"` (the runtime state is gone — the UI should offer to resume from snapshot if `hasSnapshot` is true, otherwise create a fresh sandbox), or `"no_sandbox"` (no sandbox has been provisioned for this session yet). ## OpenAPI ````yaml GET /api/sandbox/reconnect openapi: 3.1.0 info: title: Recoup API - Session Sandboxes description: >- Per-session sandbox lifecycle for agent runs. These endpoints provision, restore, and report status on the Sandbox bound to a single agent session. Distinct from the legacy `/api/sandboxes` (plural) account-scoped endpoints — these are session-scoped and used by the open-agents-style chat UI to drive the "loading sandbox…" state on session entry. license: name: MIT version: 1.0.0 servers: - url: https://api.recoupable.dev security: - ApiKeyAuth: [] - BearerAuth: [] paths: /api/sandbox/reconnect: get: summary: Reconnect to session sandbox description: >- Live runtime probe for the sandbox bound to a session. Unlike `GET /api/sandbox/status` (DB-only read), this endpoint actually runs a quick command inside the sandbox to verify it is reachable. Used by the chat UI on session re-entry / tab refocus to decide whether to flip out of "loading sandbox…" or surface a "resume" affordance. Returns one of three operational outcomes via the `status` field: `"connected"` (sandbox is alive, included `expiresAt` reflects current expiry), `"expired"` (the runtime state is gone — the UI should offer to resume from snapshot if `hasSnapshot` is true, otherwise create a fresh sandbox), or `"no_sandbox"` (no sandbox has been provisioned for this session yet). parameters: - name: sessionId in: query required: true description: The id of the session whose sandbox to reconnect to. schema: type: string responses: '200': description: Reconnect probe completed. Inspect `status` for the outcome. content: application/json: schema: $ref: '#/components/schemas/ReconnectResponse' '400': description: Missing `sessionId` query parameter. content: application/json: schema: $ref: '#/components/schemas/Error' '401': description: Unauthorized — invalid or missing API key / Bearer token. content: application/json: schema: $ref: '#/components/schemas/Error' '403': description: Forbidden — the authenticated account does not own this session. content: application/json: schema: $ref: '#/components/schemas/Error' '404': description: Not found — no session exists with the given `sessionId`. content: application/json: schema: $ref: '#/components/schemas/Error' components: schemas: ReconnectResponse: type: object required: - status - hasSnapshot - lifecycle properties: status: type: string enum: - connected - expired - no_sandbox description: >- `connected` when the live runtime probe succeeded; `expired` when the recorded runtime state is no longer reachable (the UI should offer resume-from-snapshot or fresh-create); `no_sandbox` when the session has never had a sandbox provisioned. hasSnapshot: type: boolean description: >- True when a paused/snapshotted sandbox exists and can be resumed. Used by the UI to decide whether to show "resume" vs "create" affordances on `expired` / `no_sandbox`. expiresAt: type: integer format: int64 description: >- Epoch milliseconds when the sandbox runtime will expire. Present only when `status` is `"connected"`; reflects the freshly-probed expiry, which may differ from `lifecycle.sandboxExpiresAt` if the sandbox extended itself between writes. lifecycle: $ref: '#/components/schemas/SandboxLifecycle' Error: type: object required: - status - error properties: status: type: string enum: - error description: Always `"error"` for error responses. error: type: string description: Human-readable error message. SandboxLifecycle: type: object required: - serverTime - state - lastActivityAt - hibernateAfter - sandboxExpiresAt description: >- Lifecycle envelope shared between `GET /api/sandbox/status` and `GET /api/sandbox/reconnect`. Server-clock-stamped snapshot of the sandbox's lifecycle FSM state and the timestamps the UI uses to render countdown timers. properties: serverTime: type: integer format: int64 description: >- Server's current epoch milliseconds. Use this — not the client clock — when computing how much time is left before `hibernateAfter` or `sandboxExpiresAt`. state: type: string nullable: true enum: - provisioning - active - hibernating - hibernated - restoring - archived - failed description: >- Lifecycle FSM state. `null` for sessions that have never had a sandbox. lastActivityAt: type: integer format: int64 nullable: true description: >- Epoch milliseconds of the last recorded sandbox activity, or null if there has been none. hibernateAfter: type: integer format: int64 nullable: true description: >- Epoch milliseconds after which the sandbox is eligible for hibernation, or null when not applicable. sandboxExpiresAt: type: integer format: int64 nullable: true description: >- Epoch milliseconds when the sandbox runtime expires, or null when not applicable. securitySchemes: ApiKeyAuth: type: apiKey in: header name: x-api-key BearerAuth: type: http scheme: bearer ````