> ## Documentation Index
> Fetch the complete documentation index at: https://modal-devin.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

# Resumability

> How suspended sessions preserve work and what happens after a redeploy.

When a Devin session suspends, `modal-devin` preserves its Sandbox filesystem with a
[Modal filesystem snapshot](https://modal.com/docs/guide/sandbox-snapshots). A later
attempt can continue with project files, installed tools, and other filesystem changes
from the captured workspace.

## Which workspace a session uses

| Situation                                | Starting filesystem                      |
| ---------------------------------------- | ---------------------------------------- |
| New session                              | Latest deployed worker image             |
| Suspended session with a usable snapshot | Preserved session filesystem             |
| Suspended session whose snapshot expired | Latest deployed worker image             |
| Terminal session                         | Later attempts receive a fresh workspace |

## Redeploying an image

A preserved filesystem is a complete session workspace. New packages or repository
changes in a later base image stay separate from it.

This means:

* New sessions receive the latest deployment.
* Resumed sessions favor continuity over image updates.
* An expired or unavailable snapshot causes the session to start from the latest
  image.

If a critical image change must apply to every session, complete or replace affected
suspended sessions rather than assuming a redeploy will update them.

## Retention

Snapshots are retained for 30 days by default. Configure another positive duration,
or choose indefinite retention when your operational process includes cleanup of
retired deployments.

Keep the Modal application deployed while relying on long-lived resumability. If the
deployment or its persistent resources are removed, the mapping to a preserved
workspace may no longer be available.

## Recovery after uncertainty

If the worker exits but the final Devin state remains unconfirmed, `modal-devin`
attempts to preserve the workspace before reporting the invocation as failed. This
favors recoverability over an uncertain success result.

## Duplicate safety

Outposts and Modal can both retry delivery. `modal-devin` coordinates attempts so a
duplicate avoids starting a second worker for an already served session.