# Dry-run a custom pattern for a workspace

> Run a pattern over the default branch without saving it: of the repository, or (with workspace) of up to ten of its repositories, or those named in repos.

<div class="g1t-endpoint"><span class="g1t-method" data-method="post">POST</span><code>/workspaces/{workspace}/secret-scanning/custom-patterns/dry-run</code></div>

Returns the files read and up to fifty matches each, masked.

- **Authentication:** Required. Send an [access token](/reference/api/#authentication) as `Authorization: Bearer`.
- **MCP tool:** [`security`](/reference/mcp/#security) with `action` `dry_run_pattern`, and the same inputs
- **Scope:** An access token needs [`security:write`](/guides/authentication/#scopes).
- **Also at:** [`POST /repos/{owner}/{name}/secret-scanning/custom-patterns/dry-run`](/reference/api/secret-scanning/dry-run-custom-pattern/)

## Path parameters

| Name | Type | Required | Description |
| --- | --- | --- | --- |
| `workspace` | string | Yes | Instead of repo: the workspace's slug, for all of it (or its own, for patterns). |

## Body parameters

Send a JSON object. Names are `snake_case`, as in responses; the `camelCase` spelling is accepted too.

| Name | Type | Required | Description |
| --- | --- | --- | --- |
| `repos` | array of strings | No | With workspace: repository names to run it on; the first ten when empty. |
| `pattern_name` | string | No | What people call it: "Acme API key". |
| `pattern` | string | Yes | The secret's format, as a regular expression (the regex crate's syntax: no look-around or back-references). At most 1,000 characters; it may not match an empty string. |
| `before` | string | No | What must come right before the secret, as a regular expression. Default: the start of the line or a character that is not a letter or digit. |
| `after` | string | No | What must come right after it. Default: the end of the line or a character that is not a letter or digit. |

## Example request

```sh
curl -X POST https://api.g1t.sh/workspaces/flagon-io/secret-scanning/custom-patterns/dry-run \
  -H "Authorization: Bearer $G1T_TOKEN" \
  -H "Content-Type: application/json" \
  -d '{
    "pattern": "acme_[a-z0-9]{32}",
    "repos": [
      "hello"
    ]
  }'
```

## Example response

A successful request answers `200` with:

```json
{
  "repos": [
    {
      "name": "hello",
      "files_scanned": 214,
      "matches": [],
      "truncated": false,
      "commit": "4807077b296e6edbf410d55e72749d3e1170c291"
    }
  ]
}
```

## Errors

A failed request answers with one of these statuses and a body like `{"error": {"code": "not_found", "message": "Repository not found."}}`. See [errors](/reference/api/#errors).

| Status | Code | When |
| --- | --- | --- |
| 401 | `unauthenticated` | A token is required, or the one sent is not valid. |
| 403 | `forbidden` | The token is valid but not allowed to do this, such as a member-only change or an agent token outside its repository. |
| 404 | `not_found` | It does not exist, or you cannot see it. |
| 409 | `conflict` | The request conflicts with the current state. |
| 422 | `invalid` | The input is not valid. `message` says which field and why. |