---
title: "Error Code Reference"
description: "Complete list of Nexus OS error codes and their meanings. Code Name Description 100 AGENT NOT FOUND Agent does not exist 101 AGENT ALREADY EXISTS Agent name is taken 102 AGENT NOT RUNNING Agent is not in running state 10"
resource: https://www.aiagents.nexus/docs/manual/appendix/error-codes
generated: { by: "process:nexus-agent-assets", at: 2026-09-07T09:13:03Z }
status: stable
---

# Error Code Reference

Complete list of Nexus OS error codes and their meanings.

## Agent Errors (1xx)

| Code | Name | Description |
|------|------|-------------|
| 100 | AGENT_NOT_FOUND | Agent does not exist |
| 101 | AGENT_ALREADY_EXISTS | Agent name is taken |
| 102 | AGENT_NOT_RUNNING | Agent is not in running state |
| 103 | AGENT_CRASHED | Agent terminated unexpectedly |
| 104 | AGENT_TIMEOUT | Agent exceeded CPU timeout |
| 105 | AGENT_OOM | Agent exceeded memory limit |

## Saga Errors (2xx)

| Code | Name | Description |
|------|------|-------------|
| 200 | SAGA_NOT_FOUND | Saga does not exist |
| 201 | SAGA_STEP_FAILED | A saga step failed |
| 202 | SAGA_COMPENSATION_FAILED | Compensation step failed |
| 203 | SAGA_TIMEOUT | Saga exceeded total timeout |
| 204 | SAGA_ALREADY_RUNNING | Saga is already executing |

## Cost Errors (3xx)

| Code | Name | Description |
|------|------|-------------|
| 300 | BUDGET_EXCEEDED | Agent exceeded its budget |
| 301 | BUDGET_NOT_FOUND | No budget for this agent |
| 302 | INVALID_AMOUNT | Negative or zero amount |

## Trust Errors (4xx)

| Code | Name | Description |
|------|------|-------------|
| 400 | AXIS_UNREACHABLE | Cannot reach AXIS registry |
| 401 | VERIFICATION_FAILED | Agent failed trust check |
| 402 | CERTIFICATE_EXPIRED | Agent certificate expired |
| 403 | TRUST_SCORE_LOW | Trust score below threshold |

## Edge Errors (5xx)

| Code | Name | Description |
|------|------|-------------|
| 500 | DEPLOY_FAILED | Cloudflare deployment failed |
| 501 | CREDENTIALS_MISSING | No CF credentials stored |
| 502 | WORKER_NOT_FOUND | Worker does not exist |
| 503 | REGION_UNAVAILABLE | Target region not available |