# Create a custom pattern for a workspace

> Create a custom secret pattern: a name, a regular expression for the secret, optional regular expressions for what comes right before and after it, and test strings.

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

Patterns run in linear time (no look-around or back-references) and within size limits. With publish true, push protection and scans use it at once and the history is scanned again for it; otherwise it is a draft. A repository's takes Admin; a workspace's, an owner. On a private repository it needs the g1t plan.

- **Authentication:** Required. Send an [access token](/reference/api/#authentication) as `Authorization: Bearer`.
- **MCP tool:** [`security`](/reference/mcp/#security) with `action` `create_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`](/reference/api/secret-scanning/create-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 |
| --- | --- | --- | --- |
| `test_strings` | array of strings | No | Up to 20 strings to show the pattern working on. |
| `publish` | boolean | No | Use it in push protection and scans now (true), or keep a draft (false, the default). |
| `pattern_name` | string | Yes | 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 \
  -H "Authorization: Bearer $G1T_TOKEN" \
  -H "Content-Type: application/json" \
  -d '{
    "pattern_name": "Acme API key",
    "pattern": "acme_[a-z0-9]{32}",
    "publish": false
  }'
```

## Example response

A successful request answers `200` with:

```json
{
  "pattern": {
    "id": "pat_01kq2p9f6g7h8j9k0m1n2p3q4r",
    "scope": "workspace",
    "workspace": "flagon-io",
    "repo": null,
    "name": "Acme API key",
    "pattern": "acme_[a-z0-9]{32}",
    "before": null,
    "after": null,
    "test_strings": [],
    "state": "draft",
    "created_by": "syntaqx",
    "created_at": "2026-10-06T09:14:02.118Z",
    "updated_by": "syntaqx",
    "updated_at": "2026-10-06T09:14:02.118Z",
    "open_alerts": 0
  },
  "tests": []
}
```

## 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. |