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

> ## Agent Instructions
> Automate.ax automations are TypeScript programs.
> Use Bun for installation and command examples.
> Use Automate.ax for the product name and automate.ax for the package, CLI, and domain.
> Treat documented public APIs as current; do not invent transitional or deprecated names.

# Update project environment variable

> Update selected fields on a Vercel project environment variable.

`updateVercelProjectEnvironmentVariable` edits one variable by its provider ID.

```ts automations/update-vercel-env.automation.ts theme={null}
import { automation } from "automate.ax"
import { updateVercelProjectEnvironmentVariable } from "automate.ax/vercel"

export default automation("Rotate Vercel environment variable", () => {
  updateVercelProjectEnvironmentVariable({
    environmentVariableId: "env_123",
    project: "docs-site",
    value: "rotated-secret",
  })
})
```

`project` and `environmentVariableId` are required. Supply any of `key`, `value`, `type`, `targets`, `gitBranch`, `customEnvironmentIds`, or `comment`; omitted fields remain unchanged. Pass `gitBranch: null` to clear branch scoping. The output is Vercel's complete typed updated-variable response.