> For the complete documentation index, see [llms.txt](https://vampauth.gitbook.io/vampauth-docs/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://vampauth.gitbook.io/vampauth-docs/development/sessions.md).

# Sessions and concurrency

Turn on **Loader session leases** when a running script should keep renewing its authorization.

The loader renews roughly once a minute. The lease window is 150 seconds. A denied or unrenewed lease ends the authorized run. The runtime can cancel the script's root task; use `VAMPAUTH.is_active()` or `VAMPAUTH.assert_active()` in tasks you start yourself.

## Concurrent runs

The project setting `loader_max_concurrent` allows 1–10 active keyed leases per key, default 1. Reaching that limit returns `instance_limit`. It doesn't allow a key to bind to more devices.

An old run can keep a slot until it releases or its lease expires. Close it and let that window pass before retrying. Repeatedly opening new instances won't free the old slot.

## Presence without leases

With leases disabled, heartbeats provide advisory presence rather than the same ongoing access enforcement. Advisory session state lives in the serving process and resets on restart. Keyless runs don't use keyed leases.

Changes to keys, bindings, loaders, or routing can invalidate a lease or require another execution. `configuration_changed` means fetch the current snippet and start a fresh run; don't try to repair a session token by hand.


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