I'm using openhands through the dgx spark. It is r...
# questions
t
I'm using openhands through the dgx spark. It is running but it is quite slow, however the main concern I have is the tasks I place never get completed and there's a runtime error I face after running for a while. Please is there anyone who has dealt with this error and can offer assistance.
l
Could you provide a bit more info? What are the exact commands you ran and what is the error you faced? What model are you using and how are you serving it?
t
Hey Graham, Apologies for the late reply. Here's the full context: The prompt that triggered the failure: "Design and implement the Next Generation switch that acts as the central hub for all types of payments and financial transactions. This switch can be used by central banking for an entire country, large financial institution, or any financial provider for routing financial transactions across various entities in robust and secure ways." The error: AgentStuckInLoopError. Sometimes the agent quietly fails to complete the task without throwing the error, just stalls. Stack: - OpenHands runtime container ghcr.io/all-hands-ai/runtime:0.44-nikolaik - LiteLLM router (ghcr.io/berriai/litellm:main-latest) sitting between OpenHands and the local model servers, so OpenHands calls LiteLLM which routes to Ollama or llama.cpp - Hardware: NVIDIA DGX Spark (GB10, sm_121, 119GB unified memory, aarch64)
What I tried: 1. First attempt: Nemotron-3-Super (123B MoE, A12B active) via Ollama. Slow and tasks would not complete. 2. Second attempt: switched the route to Nemotron-Nano-Omni Q8_0 via direct llama.cpp on :30000. Ran noticeably faster but still failed to complete the same task. What does "complete the task" mean here: I am not expecting a working production payments switch from one run. I would consider it complete if the agent produces architecture documentation, partial scaffolding, a security model, and a plan, the way Opus or GPT-5.5 would on the same prompt. What is actually happening is that the agent loops without producing any meaningful artifact before either throwing AgentStuckInLoopError or quietly stalling. What is already known to be brittle on this stack: - vLLM-FP8 crashed the host on 2026-04-30, suspected FlashInfer MoE FP4 backend on sm_121. NVIDIA's Spark guide prescribes VLLM_USE_FLASHINFER_MOE_FP4=0, VLLM_NVFP4_GEMM_BACKEND=marlin, FLASHINFER_FUSED_MOE_DISABLE_CUTLASS=1 to avoid that crash class. - Ollama-served Nemotron-3-Super was reportedly ~44x slower than llama.cpp-direct on the smaller Nano Omni, which is why nss-elite was cut over to direct llama.cpp on 2026-05-09. - Anthropic API credit on the personal key was exhausted 2026-04-30, so cloud fallbacks for elite-tier reasoning are unavailable. Everything stays local. Questions for you: (a) What is the right diagnostic to capture? I can grab the routed model name at failure from LiteLLM logs, the OpenHands runtime log around the failure, and journalctl -u ollama -n 200. Is there a specific OpenHands log line that confirms whether tool calls were parsed or not? (b) As an A/B test to isolate parser issues from runtime/container issues, would you recommend forcing the route to a known-good OpenAI-format tool-call model? Qwen3-Coder 30B via Ollama has been verified to emit native OpenAI tool_calls in this stack. If the loop error disappears under Qwen3-Coder, that confirms the root cause is parser/format, not OpenHands runtime. (c) For Nemotron-3-Super specifically: is there a recommended llama.cpp launch profile or tool-call parser plugin path for the Nemotron-3 family on OpenHands 0.44? Or is the safer near-term route to serve Super via vLLM with the three NVIDIA env vars above plus --tool-call-parser qwen3_coder? On the broader goal. The immediate aim is to get agent loops completing reliably on a local-only stack. Longer aim is to approach hosted-frontier quality (Opus 4.7, GPT 5.5 class), knowing that it is an ongoing pursuit and not a one-model swap, but a model for a specific use case. Appreciate any guidance.
l
This could potentially be a model issue, have you tried any other open models? We have a number mentioned here: https://index.openhands.dev
t
Alright, I tried it out, and it did not work well. I switched up to qwen3.5-flash, but it did not work completely, then I switched to qwen3-coder, and that worked better. I am curious, though, since this is for the SDK, I am running the OpenHands server. Does it matter how I am implementing the models, or will it be the same either way? I am using Claude code to help me debug on the NVIDIA DGX Spark because I do not have as much prior knowledge.