DeepSeek-V4-Flash-0731 tool-call repetition collapse: portable reproducer (3 stacks incl. Ollama cloud 6/6) A developer at Petabit Scale published a portable reproducer showing that DeepSeek-V4-Flash-0731 collapses into repeating the short action-announcement "Run." instead of emitting tool calls during long agentic conversations. The failure was reproduced on three independent serving stacks — Ollama cloud (6/6 trials), Alibaba DashScope international (2/6), and a community SM80 vLLM fork on 8x A100 (4/6) — using a sanitized ~240k-token, 394-message conversation distilled from a production incident on 2026-08-12/13. Synthetic conversations matching the same shape produced 0/22 loops, suggesting the attractor depends on realistic content statistics; the issue was reported to DeepSeek on 2026-08-14. One fixed, fully sanitized ~240k-token agentic conversation that makes DeepSeek-V4-Flash-0731 collapse into repeating a short action-announcement "Run." instead of emitting a tool call. Reproduced 2026-08-14 on three serving stacks that share no code or hardware: | Serving stack | Trials | Strict loops | Notes | |---|---|---|---| | Ollama cloud, deepseek-v4-flash:0731-cloud | 6 | 6/6 | 61-97x "Run.", all rolls hit the 2,048-token cap | | Alibaba DashScope intl, deepseek-v4-flash | 6 | 2/6 | remaining 4 rolls emitted 6-19x "Run." before the tool call | | Community SM80 vLLM haosdent fork , 8x A100 | 6 | 4/6 | where we first hit it in production | Strict loop metric implemented in the script : a normalized sentence-segment occurring =20 times in one completion, or =24 consecutive segments of <=5 words. Sampling: temperature 1.0, top p 0.95, no penalties, tool choice=auto. python3 cross check.py