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

# Error Reference

> A handy guide to HTTP status codes and error responses across all each::labs APIs.

## Error Response Format

All each::labs APIs return errors in a clean, consistent JSON format:

```json theme={"dark"}
{
  "error": "Human-readable error message"
}
```

## HTTP Status Codes

| Status | Meaning               | Description                                   |
| ------ | --------------------- | --------------------------------------------- |
| `400`  | Bad Request           | Invalid request parameters or body            |
| `401`  | Unauthorized          | Missing or invalid API key                    |
| `403`  | Forbidden             | Operation not allowed (e.g., locked resource) |
| `404`  | Not Found             | Resource does not exist                       |
| `429`  | Too Many Requests     | Rate limit exceeded                           |
| `500`  | Internal Server Error | Unexpected server error                       |

## Common Errors

### 400: Bad Request

```json theme={"dark"}
{
  "error": "slug parameter is required"
}
```

**Causes:**

* Missing required parameters
* Invalid parameter types or values
* Malformed JSON body
* Input validation failure

### 401: Unauthorized

```json theme={"dark"}
{
  "error": "Invalid or missing API key"
}
```

**Causes:**

* `X-API-Key` header not included
* API key is invalid or expired

### 403: Forbidden

```json theme={"dark"}
{
  "error": "Workflow is locked and cannot be modified"
}
```

**Causes:**

* Attempting to modify a locked workflow or version
* Insufficient permissions for the requested operation

### 404: Not Found

```json theme={"dark"}
{
  "error": "Failed to fetch model: model not found"
}
```

**Causes:**

* Invalid model slug
* Non-existent prediction ID, workflow ID, or execution ID
* Resource was deleted

### 429: Rate Limited

```json theme={"dark"}
{
  "error": "Rate limit exceeded. Please retry after 60 seconds."
}
```

**Handling:**

* Implement exponential backoff
* Check the `Retry-After` header when available
* Consider reducing request frequency

### 500: Internal Server Error

```json theme={"dark"}
{
  "error": "Failed to fetch models: internal error"
}
```

**Handling:**

* Retry with exponential backoff
* If persistent, contact support

## Product-Specific Errors

### each::api: Prediction Errors

| Error                    | Description                                |
| ------------------------ | ------------------------------------------ |
| `"Prediction not found"` | Invalid prediction ID                      |
| `"Model not found"`      | Invalid model slug                         |
| `"Invalid input"`        | Input doesn't match model's request schema |

### each::workflows: Execution Errors

| Error                                     | Description                                       |
| ----------------------------------------- | ------------------------------------------------- |
| `"Workflow not found"`                    | Invalid workflow ID or slug                       |
| `"Version not found"`                     | Invalid version ID                                |
| `"Workflow is locked"`                    | Attempting to modify a locked workflow            |
| `"ExecutionFailed"`                       | A workflow step failed during execution           |
| `"invalid input: missing required field"` | Trigger input doesn't match workflow input schema |

### each::sense: Agent Errors

| Error                          | Description                        |
| ------------------------------ | ---------------------------------- |
| `"Session not found"`          | Invalid session ID                 |
| `"Model execution failed"`     | Underlying model execution error   |
| `"Workflow execution timeout"` | Execution exceeded 15-minute limit |

## Retry Strategy

We recommend exponential backoff for transient errors (429, 500). Here's how to set that up:

<CodeGroup>
  ```python Python theme={"dark"}
  import time
  import requests

  def request_with_retry(url, headers, json=None, max_retries=3):
      for attempt in range(max_retries):
          response = requests.post(url, headers=headers, json=json)
          if response.status_code in (429, 500):
              wait = 2 ** attempt
              time.sleep(wait)
              continue
          return response
      return response
  ```

  ```javascript JavaScript theme={"dark"}
  async function requestWithRetry(url, options, maxRetries = 3) {
    for (let attempt = 0; attempt < maxRetries; attempt++) {
      const response = await fetch(url, options);
      if ([429, 500].includes(response.status)) {
        await new Promise((r) => setTimeout(r, 2 ** attempt * 1000));
        continue;
      }
      return response;
    }
    return response;
  }
  ```
</CodeGroup>