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

# Module

> The base module interface

`Module` is the contract every adapter and environment module
extends.

```ts theme={null}
interface ModuleSetupContext {
  config: Record<string, unknown>;
  secrets: Record<string, unknown>;
}

interface Module {
  setup(context: ModuleSetupContext): Promise<void>;
  teardown(): Promise<void>;
}
```

## `setup(context)`

Called once when the module is activated.

* `config`: The module's resolved configuration (defaults applied).
* `secrets` The module's decrypted secrets (defaults applied).

For adapter modules, `context` carries the module-level config and
secrets from the `modules` database row. Service-level config and secrets
are delivered separately through
[`hydrateService`](/cyrnel/specs/adapter-module#hydrateservicestate).

For environment modules, `context` is an
[`EnvironmentSetupContext`](/cyrnel/specs/environment-module#setup) that adds
`bindings`, the host's callback surface.

The host awaits `setup` before declaring the module ready. Throw to abort
activation, the corresponding `modules` row keeps its `enabled` flag, but
the module is not registered as active until the next attempt succeeds.

`setup` may be called more than once over the life of a process if the
module is disabled and re-enabled. Implementations should be idempotent
on internal state.

## `teardown()`

Called when the module is deactivated or the host is shutting down.

Adapters: release pooled resources, flush any in-flight outbound calls,
forget secrets.

Environments: terminate isolates / workers / sub-processes. The host
considers the environment retired once `teardown` resolves; if `teardown`
hangs, the host's shutdown timeout (`SHUTDOWN_TIMEOUT_MS`) will eventually
force-exit.

Errors thrown from `teardown` are caught and logged at `warn` level. They
do not propagate to the caller.

## Lifecycle Notes

* The host **never calls `setup` twice in a row without an intervening
  `teardown`** for the same module instance. Module instances are not
  reused after teardown, the host calls `instantiate()` again if it
  needs the module back.
* For environment modules, `teardown` may be deferred while the module
  drains in-flight executions. See
  [`EnvironmentModule`](/cyrnel/specs/environment-module#draining).