---
title: env_var_update
url: "/docs/ai-agents/mcp-tools/variables/env_var_update/"
canonical_url: https://docs.blossom88.com/docs/ai-agents/mcp-tools/variables/env_var_update/
markdown_url: https://docs.blossom88.com/docs/ai-agents/mcp-tools/variables/env_var_update.md
summary: Change an Environment variable's value or build flag.
categories:
- mcp
- reference
---

# env_var_update

Change an Environment variable's value or build flag. It applies on the next deploy.

| | |
|---|---|
| Access | Changes Blossom |
| Same as | [`blossom env_var:update`](/docs/reference/cli/env_var/update/) |

## Arguments

| Argument | Type | Description |
|---|---|---|
| `id` | string | Environment variable id. Required. |
| `data` | object | Only the variable fields to change. Required. |
| `data.key` | string | Variable name, such as RAILS_ENV. |
| `data.value` | string | Value. |
| `data.build` | boolean | Also available while building. |

## Example

```json
{"id":"env_var-100","data":{"clone_url":"https://github.com/acme/shop","services":[{"name":"web","command":"web","port":3000,"publicly_exposed":true}]}}
```