> For clean Markdown of any page, append .md to the page URL.
> For a complete documentation index, see https://humanloop.com/docs/v5/api/tools/add-environment-variable/llms.txt.
> For AI client integration (Claude Code, Cursor, etc.), connect to the MCP server at https://humanloop.com/_mcp/server.

# Add Environment Variable

POST https://api.humanloop.com/v5/tools/{id}/environment-variables
Content-Type: application/json

Add an environment variable to a Tool.

Reference: https://humanloop.com/docs/api/tools/add-environment-variable

## Authentication

- `X-API-KEY` header (required) — API Key authentication via header

## Request

### Path parameters

- `id` (string, required) — Unique identifier for Tool.

### Body (application/json)

This endpoint expects a list of FileEnvironmentVariableRequest.

- `list of FileEnvironmentVariableRequest`

## Response

### 200

Successful Response

- `list of FileEnvironmentVariableRequest`

## Errors

### 422 Add Environment Variable Tools ID Environment Variables Post Request Unprocessable Entity Error

Validation Error

- `detail` (list of ValidationError, optional)

## Types

### FileEnvironmentVariableRequest

- `name` (string, required) — Name of the environment variable.
- `value` (string, required) — Value of the environment variable.

### ValidationError

- `loc` (list of ValidationErrorLocItem, required)
- `msg` (string, required)
- `type` (string, required)

### ValidationErrorLocItem

## Examples

**Request**

```json
[
  {
    "name": "name",
    "value": "value"
  }
]
```

**Response**

```json
[
  {
    "name": "name",
    "value": "value"
  }
]
```

**SDK Code**

```python
import requests

url = "https://api.humanloop.com/v5/tools/id/environment-variables"

payload = [
    {
        "name": "name",
        "value": "value"
    }
]
headers = {
    "X-API-KEY": "<apiKey>",
    "Content-Type": "application/json"
}

response = requests.post(url, json=payload, headers=headers)

print(response.json())
```

```typescript
import { HumanloopClient } from "humanloop";

const client = new HumanloopClient({ apiKey: "YOUR_API_KEY" });
await client.tools.addEnvironmentVariable("id", [{
        name: "name",
        value: "value"
    }]);

```

```go
package main

import (
	"fmt"
	"strings"
	"net/http"
	"io"
)

func main() {

	url := "https://api.humanloop.com/v5/tools/id/environment-variables"

	payload := strings.NewReader("[\n  {\n    \"name\": \"name\",\n    \"value\": \"value\"\n  }\n]")

	req, _ := http.NewRequest("POST", url, payload)

	req.Header.Add("X-API-KEY", "<apiKey>")
	req.Header.Add("Content-Type", "application/json")

	res, _ := http.DefaultClient.Do(req)

	defer res.Body.Close()
	body, _ := io.ReadAll(res.Body)

	fmt.Println(res)
	fmt.Println(string(body))

}
```

```ruby
require 'uri'
require 'net/http'

url = URI("https://api.humanloop.com/v5/tools/id/environment-variables")

http = Net::HTTP.new(url.host, url.port)
http.use_ssl = true

request = Net::HTTP::Post.new(url)
request["X-API-KEY"] = '<apiKey>'
request["Content-Type"] = 'application/json'
request.body = "[\n  {\n    \"name\": \"name\",\n    \"value\": \"value\"\n  }\n]"

response = http.request(request)
puts response.read_body
```

```java
import com.mashape.unirest.http.HttpResponse;
import com.mashape.unirest.http.Unirest;

HttpResponse<String> response = Unirest.post("https://api.humanloop.com/v5/tools/id/environment-variables")
  .header("X-API-KEY", "<apiKey>")
  .header("Content-Type", "application/json")
  .body("[\n  {\n    \"name\": \"name\",\n    \"value\": \"value\"\n  }\n]")
  .asString();
```

```php
<?php
require_once('vendor/autoload.php');

$client = new \GuzzleHttp\Client();

$response = $client->request('POST', 'https://api.humanloop.com/v5/tools/id/environment-variables', [
  'body' => '[
  {
    "name": "name",
    "value": "value"
  }
]',
  'headers' => [
    'Content-Type' => 'application/json',
    'X-API-KEY' => '<apiKey>',
  ],
]);

echo $response->getBody();
```

```csharp
using RestSharp;

var client = new RestClient("https://api.humanloop.com/v5/tools/id/environment-variables");
var request = new RestRequest(Method.POST);
request.AddHeader("X-API-KEY", "<apiKey>");
request.AddHeader("Content-Type", "application/json");
request.AddParameter("application/json", "[\n  {\n    \"name\": \"name\",\n    \"value\": \"value\"\n  }\n]", ParameterType.RequestBody);
IRestResponse response = client.Execute(request);
```

```swift
import Foundation

let headers = [
  "X-API-KEY": "<apiKey>",
  "Content-Type": "application/json"
]
let parameters = [
  [
    "name": "name",
    "value": "value"
  ]
] as [String : Any]

let postData = JSONSerialization.data(withJSONObject: parameters, options: [])

let request = NSMutableURLRequest(url: NSURL(string: "https://api.humanloop.com/v5/tools/id/environment-variables")! as URL,
                                        cachePolicy: .useProtocolCachePolicy,
                                    timeoutInterval: 10.0)
request.httpMethod = "POST"
request.allHTTPHeaderFields = headers
request.httpBody = postData as Data

let session = URLSession.shared
let dataTask = session.dataTask(with: request as URLRequest, completionHandler: { (data, response, error) -> Void in
  if (error != nil) {
    print(error as Any)
  } else {
    let httpResponse = response as? HTTPURLResponse
    print(httpResponse)
  }
})

dataTask.resume()
```