{"slug": "deepseek-v4-flash-0731-tool-call-repetition-collapse-portable-reproducer-3-incl", "title": "DeepSeek-V4-Flash-0731 tool-call repetition collapse: portable reproducer (3 stacks incl. Ollama cloud 6/6)", "summary": "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.", "body_md": "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:\n\n| Serving stack | Trials | Strict loops | Notes | \n|---|---|---|---|\n| Ollama cloud, deepseek-v4-flash:0731-cloud | 6 | 6/6 | 61-97x \"Run.\", all rolls hit the 2,048-token cap | \n| Alibaba DashScope intl, deepseek-v4-flash | 6 | 2/6 | remaining 4 rolls emitted 6-19x \"Run.\" before the tool call | \n| Community SM80 vLLM (haosdent fork), 8x A100 | 6 | 4/6 | where we first hit it in production | \n\nStrict 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.\n\n```\npython3 cross_check.py <openai_compatible_base_url> <api_key> <model> <tag> 6\n```\n\nRun from the directory containing dsv4-repro-payload-sanitized.json.\n\nDistilled from a production incident (Petabit Scale, 2026-08-12/13). The\nconversation is real (394 messages, 210 tool results, 51 declared tools) with\nevery identifier neutralized; sanitization did not remove the trigger.\nNotably, synthetic conversations matching its shape (depth, tool count,\nstructure, mid-chain ending, repeated-history priming) produced 0/22 loops -\nthe attractor appears to require realistic content statistics. Related:\n[ggml-org/llama.cpp#26694](https://github.com/ggml-org/llama.cpp/issues/26694) (Flash-0731 GGUF/Metal), [QwenLM/qwen-code#4695](https://github.com/QwenLM/qwen-code/issues/4695)\n(V4-Pro on DashScope, incl. a dose-response showing in-context\nself-reinforcement). Reported to DeepSeek ([service@deepseek.com](mailto:service@deepseek.com)) with full\nreceipts on 2026-08-14. Contact: [ras@petabitscale.com](mailto:ras@petabitscale.com)", "url": "https://wpnews.pro/news/deepseek-v4-flash-0731-tool-call-repetition-collapse-portable-reproducer-3-incl", "canonical_source": "https://gist.github.com/rasatpetabit/64ea43e9795bdb8844ba590155ae9f87", "published_at": "2026-08-14 03:11:29+00:00", "updated_at": "2026-09-11 02:55:43.448204+00:00", "lang": "en", "topics": ["large-language-models", "ai-agents", "ai-infrastructure", "ai-research", "mlops"], "entities": ["DeepSeek", "DeepSeek-V4-Flash-0731", "Ollama", "Alibaba DashScope", "vLLM", "Petabit Scale", "llama.cpp", "QwenLM"], "alternates": {"html": "https://wpnews.pro/news/deepseek-v4-flash-0731-tool-call-repetition-collapse-portable-reproducer-3-incl", "markdown": "https://wpnews.pro/news/deepseek-v4-flash-0731-tool-call-repetition-collapse-portable-reproducer-3-incl.md", "text": "https://wpnews.pro/news/deepseek-v4-flash-0731-tool-call-repetition-collapse-portable-reproducer-3-incl.txt", "jsonld": "https://wpnews.pro/news/deepseek-v4-flash-0731-tool-call-repetition-collapse-portable-reproducer-3-incl.jsonld"}}