> ## Documentation Index
> Fetch the complete documentation index at: https://docs.docs2work.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Error Handling

> How agents should handle Build API errors.

| Code                | HTTP | Meaning                             | Action                                              |
| ------------------- | ---- | ----------------------------------- | --------------------------------------------------- |
| `VALIDATION_FAILED` | 400  | Graph errors block activation       | POST /validate, read errors\[], fix each one, retry |
| `MISSING_FORM_ID`   | 400  | Node has no form\_id                | POST /forms then PATCH /nodes/:id                   |
| `MISSING_EDGE`      | 400  | conditional/split needs more edges  | Add edges for all outcome paths                     |
| `ORPHANED_NODE`     | 400  | Node has no incoming edges          | Add edge or DELETE /nodes/:id                       |
| `NO_END_REACHABLE`  | 400  | Branch has no end node              | Add end node and connecting edge                    |
| `MISSING_ASSIGNEE`  | 400  | Human node has no assignee          | PATCH /nodes/:id with assigneeEmail                 |
| `TRIGGER_NOT_SET`   | 400  | No trigger configured               | POST /trigger before activating                     |
| `CONFLICT`          | 409  | Node ID exists or session activated | New ID or new session                               |
| `EXPIRED`           | 410  | Session past 24 hours               | Create new session                                  |
| `INTERNAL_ERROR`    | 500  | Activation rolled back              | Nothing committed. Retry.                           |

## General principles

On a 400 error, read the field-level error details and reason about corrections before retrying. Never retry blindly. On a 500, nothing was committed to production — the org is unchanged. It is safe to retry.