openclaw - 💡(How to fix) Fix Bug: DeepSeek V4 Flash incomplete turn (payloads=0, tools=2, replaySafe=no, stopReason=stop) in 2026.5.27/28

Summary

DeepSeek V4 Flash via OpenRouter produces incomplete turns (payloads=0, tools=2, replaySafe=no, stopReason=stop) in OpenClaw 2026.5.27 and 2026.5.28. The model worked without issues in 2026.5.26.

Steps to reproduce

1. Configure openrouter/deepseek/deepseek-v4-flash as primary model
2. Send any message that triggers tool calls (e.g. "search for X" or "read file Y")
3. After a few turns, especially when the conversation context grows, the model starts generating partial tool calls — it begins {"tool_calls": [{"function": {"name": "... but stops mid-JSON with stopReason=stop
4. Since replaySafe=no, OpenClaw does not retry the turn — surfaces "Agent couldn't generate a response"

Expected behavior

Incomplete turns from the model should be retried (at least once) even when replaySafe=no, or the underlying cause of partial tool call generation from DeepSeek Flash on OpenRouter should be fixed.

Actual behavior

incomplete turn detected: provider=openrouter/deepseek/deepseek-v4-flash stopReason=stop payloads=0 tools=2 replaySafe=no planningRetries=0/1 reasoningRetries=0/2 emptyRetries=0/1 missingAssistantRetries=0/1 — surfacing error to user

The model receives stopReason=stop (not length, not content_filter), meaning the model itself decided to stop — but it stopped before completing the tool call JSON. OpenClaw then checks replaySafe=no and refuses to retry.

Context

• OpenClaw: 2026.5.28 (also broken on 5.27; worked on 5.26)
• Model: openrouter/deepseek/deepseek-v4-flash
• Provider: OpenRouter (https://openrouter.ai/api/v1)
• OS: Ubuntu 24.04, npm global install
• Install method: npm global

What was tried (did not help)

• queue.mode=interrupt + debounceMs=1000
• session-memory.enabled=false
• thinkingDefault=off
• timeoutSeconds=120
• Compaction adjustments (reserveTokens=20000, keepRecentTokens=40000)

Workaround

Switching to openrouter/deepseek/deepseek-v4-pro eliminates the issue — Pro completes tool calls reliably. This is expensive compared to Flash.

Notes

• deepseek-v4-flash via native DeepSeek API (api.deepseek.com) reportedly works fine — the issue appears to be specific to the OpenRouter bridge for Flash
• The replaySafe=no + emptyRetries=0/1 logic means no retry occurs at all, which makes the agent fully unusable when this happens