agent stops working when provider Nvidia NIM returns a specific error

Bug Description

When using nvidia nim, and the provider returns either of these:

• "LLM returned error: Error calling LLM: timed out after 300s"
• "LLM returned error: Error calling LLM: timed out after 600s"

the agent stops working because nanobot thinks its the model output

Steps to Reproduce

1. detect the output as error
2. try the next model that is configured as fallback

Expected Behavior

that it would try the fallback model

Relevant Logs

5/Sep/2026:20:16:44 +0200] [348302] STDERR: 2026-09-05 20:16:44 | DEBUG | - | [turn cron:heartbeat:MY_ID] State BUILD took 498.2ms -> event ok
[05/Sep/2026:20:16:44 +0200] [348302] STDERR: 2026-09-05 20:16:44 | DEBUG | - | Starting agent loop iteration 0 for session cron:heartbeat
[05/Sep/2026:20:21:44 +0200] [348302] STDERR: 2026-09-05 20:21:44 | DEBUG | - | LLM usage: prompt=0 completion=0 cached=0
[05/Sep/2026:20:21:44 +0200] [348302] STDERR: 2026-09-05 20:21:44 | ERROR | - | LLM returned error: Error calling LLM: timed out after 300s
[05/Sep/2026:20:21:44 +0200] [348302] STDERR: 2026-09-05 20:21:44 | DEBUG | - | [turn cron:heartbeat:MY_ID] State RUN took 300056.4ms -> event ok
[05/Sep/2026:20:21:44 +0200] [348302] STDERR: 2026-09-05 20:21:44 | DEBUG | - | [turn cron:heartbeat:MY_ID] State SAVE took 15.7ms -> event ok
[05/Sep/2026:20:21:44 +0200] [348302] STDERR: 2026-09-05 20:21:44 | INFO  | - | Response to cli:user: Error calling LLM: timed out after 300s
[05/Sep/2026:20:21:44 +0200] [348302] STDERR: 2026-09-05 20:21:44 | DEBUG | - | [turn cron:heartbeat:MY_ID] State RESPOND took 0.1ms -> event ok
[05/Sep/2026:20:21:44 +0200] [348302] STDERR: 2026-09-05 20:21:44 | DEBUG | - | [turn cron:heartbeat:MY_ID] Turn completed after 7 states
[05/Sep/2026:20:21:44 +0200] [348302] STDERR: 2026-09-05 20:21:44 | INFO  | - | Cron: job 'heartbeat' completed
[05/Sep/2026:20:21:44 +0200] [348302] STDERR: 2026-09-05 20:21:44 | INFO  | - | Replay-window consolidation for cron:heartbeat: chunk=2 msgs, replay_max=120

nanobot Version

v0.3.0

Python Version

Other (specify below)

Operating System

Linux

Channel / Platform

Telegram

LLM Provider

Other (specify below)

Additional Context

Python version: 3.14 LLM provider: Nvidia NIM