dsh-reasoning-cn

The Think dropdown in DeepSeek Harness Web UI typically streams reasoning text in English, yet no major model exposes an API parameter to pin the thinking language, and system-prompt instructions are often ignored in agent mode. dsh-reasoning-cn addresses this with two complementary layers: a zero-cost steering layer that appends a Simplified Chinese instruction to the system prompt and re-asserts it at the first step of every turn, and an optional translation layer that hooks the response stream, buffers a reasoning block when English, Japanese, or Traditional Chinese characters are detected, and calls a cheap non-thinking model to convert the block into Simplified Chinese. Translation is off by default, and every failure, timeout, or oversized block fails open with the original text passed through unchanged so no thinking content is ever lost.

Because translation happens before the agent loop persists session logs, a successful conversion propagates consistently into the session log, the Web replay, and the reasoning_content field returned by tool calls; a degraded path keeps all three in the original language. The plugin validates translated output for non-emptiness, length expansion, code fences, and Chinese-character ratio, rolling back to the original text if any check fails. A WeakSet marker prevents the translation request from being recursively processed by its own converter.

This plugin is built for Simplified Chinese speakers who use DeepSeek Harness Web UI daily and want to follow the reasoning process in their own language. If you only need a language nudge, the zero-cost steering layer alone suffices and sends no extra LLM requests. Enable the translation layer only when you want a hard display guarantee, and make sure your chosen provider's data-retention policy, access scope, and per-call cost are acceptable. The current version targets Simplified Chinese exclusively, does not translate final answers, and does not retain the English source text, keeping the data boundary simple and easy to audit.