---
title: microvm gc
description: Discover prefix-matched images and their VMs; --yes performs cleanup
---

## 1. Synopsis

Discover prefix-matched images and their VMs; `--yes` performs cleanup

```sh
microvm gc --prefix <string> [options]
```

## 2. Parameters

| Parameter | Kind | Type | Required | Default | Choices | Help |
| --- | --- | --- | --- | --- | --- | --- |
| `--region` | flag | `string` | no | none | any | AWS region. Defaults to $AWS\_REGION, then $AWS\_DEFAULT\_REGION, then us-east-1 |
| `--unlisted-region` | flag | `string` | no | none | any | Deprecated since 1.3.0: `--region` takes any region name |
| `--prefix` | flag | `string` | yes | none | any | Match image names starting with this nonempty prefix |
| `--keep` | flag | `string` | no | none | any | Preserve this exact image name or ARN, together with all its VMs. Repeatable |
| `--yes` | flag | `boolean` | no | none | any | Terminate VMs and delete images. Without this flag, only report candidates |

The 3 global flags (`--json`, `--dense`, `--quiet`) are accepted here as on every command, and are left out of the table above for that reason; see [Global flags](/microvms-agentd/reference/#3-global-flags).

## 3. Response

On success stdout carries one envelope whose `type` is `microvm.gc`. Its `data` object carries these keys: `dryRun`, `imagesMatched`, `imagesKept`, `microvmsMatched`, `microvmsTerminated`, `imagesDeleted`, `imagesInUse`, `failures`.

[The envelope](/microvms-agentd/reference/envelope/) describes the fields around `data`. [Response types](/microvms-agentd/reference/response-types/) lists every `type` the CLI emits and which commands share each one.

## 4. Failures

A failure exits with one of the statuses on [Exit codes](/microvms-agentd/reference/exit-codes/) and writes the error shape on [The envelope](/microvms-agentd/reference/envelope/): a stable `code` to branch on, an `exitCode` that matches the process status, a human-readable `error`, and `suggestions`.

Where a failure is one this project has measured on the platform, the envelope's `finding` names the section of the platform notes that documents it. The exit-code table links each one.

## 5. Provenance

This page is generated from `docs/manifest.json`, the output of `microvm manifest`, which the CLI derives from its own argument tree. This page reads the `gc` entry of `data.commands`. `site/scripts/gen-reference.mjs` writes it into the site's content directory on every `pnpm run sync`, so an edit made here is overwritten by the next run.

To change the page, change the source. Regenerate the source with `mise run manifest` from the repository root; `mise run manifest:check` fails when the committed file no longer matches what the binary emits.