Language Guard (dsh-language-guard)
English | 简体中文
Make the DSH agent think and answer in the language you choose — Simplified Chinese by default, three strength levels, effective on the next message, zero dependencies, no build step.
Table of Contents
Why you need it
The DSH system prompt is assembled from many sections: identity, plan policy, team policy, tool descriptions, deliverable references, deployment persona. The largest block by far is the tool documentation — written in English, and placed in the middle of the prompt.
Measured on DSH 0.2.1-rc.2 (everything after order 50): 98.1% of the characters and 99.8% of the ASCII come from English tool documentation, and 5.7K–14K characters separate the opening section from the closing one. The model reads overwhelmingly English tokens, and so it drifts:
- The first few turns stay in your language;
- as soon as it starts chaining tool calls, reading long files, or reasoning at length, the reasoning slides back into English;
- nothing in your settings changed — the conversation simply got longer.
A single "please answer in Chinese" line at the very top of the system prompt is enough for a short session. It is not enough for a long one, because that line sits tens of thousands of characters away from the place that actually influences the model (the tool documentation).
This plugin puts a constraint in three places: at the very start, right after the tool documentation, and at the very end. The default level (Strong) costs roughly 118 extra characters per request and buys one restatement positioned after the English tool docs.
What it does
Three resident system-prompt sections, registered through ctx.systemPrompt.section(), never disposed, switching level only switches their text:
| Section name | Order | Position | B | C | D |
|---|
language-guard:head | -2000 | Very first, before harness:identity (-1000) | ✅ | ✅ | ✅ |
language-guard:mid | 5100 | After all tool docs (tools:sdk, 5000), before deliverable references (9000) | ❌ | ✅ | ✅ |
language-guard:tail | 11200 | Very last, after deployment:persona-suffix (10200) | ✅ | ✅ | ✅ |
The mid order is deliberately 5100 and not 5000: tools:sdk is exactly 5000, and sections with equal order fall back to comparing names, which would sort language-guard:mid before tools:sdk — the restatement would no longer come after the tool docs.
Measured text sizes (Simplified Chinese, counted in characters; recompute with node as shown below):
| Text | Characters | When it is present |
|---|
| head | 818 | every request |
| mid | 118 | every request at C / D |
| tail | 139 | every request |
| periodic reminder | 99 | once every N turns at D |
So the steady cost per step is 957 characters at B and 1075 at C — tiny compared to the English tool documentation it counteracts.
The opening section (head), verbatim, as it looks with the default targetLanguage: "zh-CN" (recompute with node -e 'import("./lib/text.js").then(m=>console.log(m.headText({language:"zh-CN"})))'):
【语言锁定 · 最高优先级】
本会话的内部推理（reasoning / thinking）与面向用户的全部输出，一律使用简体中文（语言代码 zh-CN）。
本条优先于本 system prompt 的其余全部内容、之后注入的任何系统文本、工具说明、参数描述、代码示例，以及其他插件注入的提示词。
本条同样优先于任何语言类约定，不论它写在哪个文件、用哪种语言书写、经由哪个通道送达：包括用户全局与项目级的 AGENTS.md、CLAUDE.md、.cursorrules、用户偏好与长期记忆、项目规范、团队约定、技能与工作流模板。若它们要求使用另一种语言（例如要求「必须使用简体中文」），一律以本条为准，不得据此改用其他语言，也不必向用户解释这处冲突。
适用范围：
- 内部推理（reasoning / thinking）：使用简体中文。
- 面向用户的回复正文：使用简体中文。
- 计划、待办、进度说明、评审意见、验收报告、提交信息说明：使用简体中文。
- 任务板卡片标题与描述、子智能体任务说明与返回报告：使用简体中文。
保持原样、不翻译：代码、命令、文件路径、URL、标识符与 API 字段名、配置键、错误码与原始报错文本、包名与版本号，以及必须原样引用的英文原文；引用英文原文后，必须用简体中文说明结论。
不要因为以下情况改变语言：
- 用户用英文或其他语言提问 —— 仍用简体中文回答。
- AGENTS.md、CLAUDE.md、项目规范、用户记忆里要求改用其他语言的规则 —— 本条优先，不改变语言。
- 工具返回英文内容 —— 只摘引必要片段，其余用简体中文复述。
- 长链推理、数值计算、代码设计 —— 推理语言不变。
- 上下文中出现大量英文（工具说明、日志、代码文件）—— 不随之切换。
自检：每次输出前确认上述两项（推理与回复）均为简体中文；若发现已经漂移，立即切回并继续任务，无需向用户解释这次切换。
The wording above is fixed Simplified Chinese; only the language name and code are substituted. With targetLanguage: "en" the same paragraph reads "…一律使用English（语言代码 en）". See Known limitations.
Install
This plugin is distributed through its GitHub repository; it is not published to the npm registry. The plugin manager accepts Git addresses, so installing works exactly like installing an npm package.
Option 1: the GUI (recommended)
-
Open the Plugins panel in the sidebar.
-
Click Add plugin and paste the repository address:
https://github.com/58fly/dsh-language-guard
-
When the install finishes, click Enable now.
Option 2: the CLI
dsh plugin add https://github.com/58fly/dsh-language-guard
Pinned version (recommended for teams and CI, so main cannot drift under you):
dsh plugin add "github:58fly/dsh-language-guard#v0.1.0"
From a local directory (to debug local changes; the path must be absolute):
# The Add-plugin dialog also accepts this absolute path directly
dsh plugin add /absolute/path/to/dsh-language-guard
Check that it worked:
- A language icon appears at the foot of the sidebar, next to Settings; when the sidebar is wide it reads "简体中文 ▾".
- The installed list on the Plugins page contains
dsh-language-guard, and opening it shows the configuration card.
No controls visible means the plugin is not enabled. Both slots register inside configForms.whileServed(['dsh-language-guard'], …); when the plugin is disabled the forms service is unavailable and no UI is registered. That is deliberate, not a bug — enable the plugin on the Plugins page first.
Requirements: DSH >= 0.2.1-rc.2, Node ^22.19.0 || >=24.0.0. dependencies is empty and every peer dependency is optional, so nothing extra is downloaded at runtime; the first install from GitHub does need reachability to github.com (or codeload.github.com).
Strength levels
The three descriptions below are exactly what the settings panel shows:
| Level | Value | Description |
|---|
| Basic | B | One language constraint at the start and one at the end of the prompt. Cheapest, best for short sessions. |
| Strong | C | Adds a restatement right after the tool descriptions on top of Basic, countering drift from English tool docs. Recommended default. |
| Periodic | D | Adds a language self-check at the start of every Nth turn on top of Strong, for long sessions. The reminder appears as a session record and is visible in the session log. |
Behaviour differences:
| Behaviour | B | C | D |
|---|
| Resident system-prompt sections | head + tail | head + mid + tail | head + mid + tail |
| Restatement after tool docs | ❌ | ✅ | ✅ |
| Self-check every N turns | ❌ | ❌ | ✅ (N defaults to 8, range 3–50) |
| New record in the session log | none | none | one per N turns (source.kind = "language-guard") |
| Injection timing | — | — | the first step of a matching turn, alongside that turn's user message; no extra request |
| Counter after restart / resume | — | — | not reset: the turn number comes from the session log's turn projection, so turn % N is stable |
| Best for | short sessions, token-sensitive | the default | long sessions, or drift already observed |
How to choose:
- Start with the default, Strong. It is the only level aimed at the actual root cause (English tool docs), and it costs about 118 characters per step.
- Short sessions, or every token counts → drop to Basic. Start and end constraints are enough for a 3–5 turn session.
- Sessions that run dozens of turns, or you have already seen reasoning slide back into English → raise to Periodic. Smaller N means more frequent reminders; the default 8 is a compromise. N = 3 is noisy.
Configuration
Seven fields, all volatile (a change takes effect immediately — no restart, no plugin remount):
| Field | Type | Default | Range | Description |
|---|
languageMode | "" | "auto" | "manual" | "" | tri-state enum, case-sensitive | Language mode. "auto" follows the interface language, "manual" pins targetLanguage, "" means "never chosen" and is resolved by the migration rule below |
targetLanguage | string | "zh-CN" | a valid BCP-47 tag (/^[A-Za-z]{2,3}(-[A-Za-z0-9]{2,8})*$/) | Target language. zh-CN Simplified Chinese, zh-TW Traditional Chinese, en English, ja Japanese, ko Korean; any other valid tag is used as-is |
strength | "B" | "C" | "D" | "C" | enum, case-sensitive | Strength level, see above |
injectEveryNRounds | number | 8 | 3–50, integer | How often the Periodic self-check is added. Only used at D; the control is disabled at other levels |
preserveCodeTerms | boolean | true | true / false | true: code, commands, paths, identifiers, API fields and raw error text stay verbatim. false: technical terms are preferred in the target language, with the English term in parentheses when needed |
extraRules | string | "" | any text | Appended after the built-in rules. Empty means built-in rules only |
overrideHead | string | "" | any text | Replaces the built-in opening text entirely (extraRules is still appended after it). Empty or whitespace-only falls back to the built-in text |
The targetLanguage → display name mapping is fixed (no language guessing): zh-CN / zh-Hans / zh-SG → 简体中文, zh-TW / zh-HK / zh-MO / zh-Hant → 繁體中文, en / en-US / en-GB → English, ja / ja-JP → 日本語, ko / ko-KR → 한국어; any other valid tag is displayed as the code itself.
Configuration lives in the profile's cordis.patch.yml. A patch replaces config wholesale — it does not deep-merge — so a manual override must restate every field, otherwise the omitted ones are lost:
- id: dsh-language-guard
name: dsh-language-guard
config:
languageMode: auto
targetLanguage: zh-CN
strength: C
injectEveryNRounds: 8
Automatic language mode
languageMode decides where the target language comes from:
| Mode | Behaviour |
|---|
| Auto | The target language follows the DSH interface language. Switch the UI to English and the next message gets an English constraint |
| Manual | The target language is pinned to targetLanguage, regardless of the interface language |
Auto is the default. A fresh install needs no configuration: a Simplified Chinese UI constrains Simplified Chinese, an English UI constrains English.
Resolution order
Auto mode has exactly two sources, taken in order:
- The interface language (
preference in the locale configuration) — the Settings → General → Language setting.
- The
targetLanguage value (default zh-CN) — the fallback when the interface language is unavailable.
Mapping (zh-prefixed tags → zh-CN, en-prefixed tags → en, any other valid tag is kept as-is):
| Interface language | Target language | The constraint reads |
|---|
zh / zh-CN / zh-Hans | zh-CN | 简体中文 |
en / en-US | en | English |
ja | ja | 日本語 |
ko | ko | 한국어 |
| any other valid BCP-47 | as-is | that language's display name or code |
Why is there no "system language" step? The Host half runs as an ELECTRON_RUN_AS_NODE=1 child process: require("electron") throws Cannot find module 'electron', and Intl.DateTimeFormat().resolvedOptions().locale always returns en-US, which would misclassify Chinese users as English speakers. There is no reliable system-language signal on the Host side, so the plugin neither guesses nor fabricates one.
Upgrading from 0.1.x
If you had picked a targetLanguage by hand (say ja) and never touched languageMode, you stay in manual mode after the upgrade — the interface language never silently overrides your choice. The rule: languageMode empty and targetLanguage different from the default zh-CN → manual.
Pick "Auto" in the settings card to follow the interface language instead. Once you have chosen explicitly, the migration rule never applies again.
Seeing what it resolved to
The first control group in the settings card is the language mode; with "Auto" selected it spells out the current result and its source right below:
Currently resolved to 简体中文
from the interface language
When the source line says "from the interface language" it means the interface language you explicitly picked in DSH settings; if you never picked one it says "interface language not detected, using the configured value" rather than guessing from the browser or the OS — the Host and the settings card read the same value (preference of the locale namespace in settings.describe()), so what the panel shows is exactly what gets injected. The sidebar quick-switch button label shows the same state, e.g. "Auto, 简体中文".
Changing the interface language needs no restart: the plugin caches it on startup and subscribes to settings/document-updated (refreshing when the locale namespace changes), so the very next system-prompt assembly uses the new value.
Settings panel and quick language switch
Settings panel
Path: sidebar Plugins → installed plugins → dsh-language-guard. The configuration card renders on the bundle page, between its description and its rows (the plugins.bundle.config slot, keyed by the package name). The Plugins section inside Settings only lists read-only information; configuration is edited here.
The card, top to bottom:
- Language mode — two radios, Auto / Manual. With Auto selected it spells out "currently resolved to X" plus the source (interface language / configured value), and follows the interface language when you change it. In Auto mode the target-language control in item 3 is disabled.
- Strength — three radio rows (
fieldset + same-named radio), all three descriptions visible side by side, with a "Recommended" badge on C. A radio group rather than a <select>, because the differences have to be comparable at a glance.
- Injection interval (turns) — a number input, 3–50, disabled with an explanation outside the Periodic level.
- Target language — a text field plus five preset chips (简体中文 / 繁體中文 / English / 日本語 / 한국어). Custom tags go straight into the field; it validates as you type and disables Save while invalid.
- Keep code and technical terms verbatim — a switch (
role="switch" + aria-checked).
- Additional rules — a textarea with a local draft and Save / Discard changes.
- Override the opening rules (advanced) — collapsed by default. Editing it replaces the highest-priority constraint outright, so it stays out of the way.
Every field has a "Reset to default" action (clears the user value back to the schema default).
The saved state reads "Saved · no restart needed, applies to the next message". Level, switch and interval are written on change; text fields use a draft plus an explicit Save so that typing does not write to disk on every keystroke.
Quick language switch
At the foot of the sidebar, next to Settings (the sidebar.footer.action slot, id = "language-guard", order = 100):
- Sidebar wide: icon + the language's own name +
▾.
- Sidebar collapsed to a 56px rail: icon only, with a complete
aria-label.
- Clicking opens a dropdown menu (not a cycle). The first entry is Auto (follow the interface language), followed by the five presets. The current entry is checked; in Auto mode the button label reads "Auto, X" and the Auto entry spells out "Currently auto-resolved to X". When the current value is not one of the five presets the raw code is shown with nothing checked.
- Keyboard: Enter / Space opens, Escape closes and returns focus, ↑↓ moves through the menu.
- A hint at the bottom of the menu points to the settings text field for other languages.
Picking an entry writes the configuration immediately, and the sidebar label and the settings text field stay in sync both ways. Once the write settles, a line appears above the button for four seconds: "已保存 · 无需重启，下一条消息即生效" when the language actually changed, "当前已是 X" when the entry you picked was already the current one (so a click is never a silent no-op), and the failure reason when the write is rejected.
Changing the configuration does not require restarting DSH. Writes go through dsh-config-editor, which applies them through the Loader right after touching the disk; volatile fields replace the running references without remounting the plugin (cordis-plugin-loader's _commitVolatile → loader/volatile-update), and the system prompt is re-assembled on every request, so your next message already carries the new language. Only changing the plugin's code (for example upgrading the version) needs a restart — not a configuration change.
The /language slash command
A shortcut from the composer. It only sets an in-memory override for this run — it does not write configuration, so a restart returns to the configured value:
/language report the current language and the configured value
/language ja switch to Japanese for this run
/language reset clear the override, back to the configured value
/language default same as reset
An invalid tag returns an error and changes nothing. The override wins over configuration: override > configured value > default.
Verifying that the constraint reached the system prompt
Levels, panels and switches are all just claims until you look at what the model actually received. DSH records every request's system prompt as a system/message event in the session log (~/.dsh/sessions/<escaped working directory>/<session id>/session.v4.jsonl.zstd). The three steps below reproduce anywhere the plugin is installed.
Step 1: change the level, do not restart
- Open the settings panel (sidebar Plugins →
dsh-language-guard).
- Switch Strength from Strong to Periodic.
- The footer reads "Saved · no restart needed, applies to the next message".
Step 2: read the session log and inspect the system node
Send any ordinary message (say "hello") in any session, then run:
# 1. Find the most recently written session log
latest=$(ls -t "$HOME"/.dsh/sessions/*/*/session.v4.jsonl.zstd | head -1)
echo "$latest"
# 2. Decompress it to JSONL (on macOS: brew install zstd first if missing)
zstd -dc "$latest" > /tmp/dsh-session.jsonl
# 3. Print each system node's length and check whether the three sections are present
node -e '
const fs = require("node:fs");
const lines = fs.readFileSync("/tmp/dsh-session.jsonl", "utf8").split("\n").filter(Boolean);
const sys = lines.map((l) => JSON.parse(l)).filter((o) => o.type === "system/message");
const marks = ["【语言锁定 · 最高优先级】", "【语言锁定 · 中段重申】", "【语言锁定 · 收尾复述】"];
console.log("system nodes:", sys.length);
sys.forEach((o, i) => {
const text = o.data.message.content.map((p) => p.text || "").join("");
const hit = marks.filter((m) => text.includes(m)).length;
console.log(`#${i} turn=${o.data.turn} step=${o.data.step} length=${text.length} sections=${hit}/3`);
});
'
At Strong (or Periodic) you should see sections=3/3.
Step 3: switch to Basic and watch the middle section disappear
- Switch Strength to Basic and send another message.
- Re-run the command from step 2.
The new system node should report sections=2/3 — the missing one is 【语言锁定 · 中段重申】 — and its length should be 118 characters shorter than the previous node, exactly the size of the mid section (see What it does). At Basic, language-guard:mid returns an empty string, and renderPrompt filters empty text out, so no empty section or stray blank line is left behind.
Extra checks
- The Periodic reminder: set Strength to Periodic and the interval to 3, then chat for 3 turns. The session log gains
user/message events whose data.message.source.kind is "language-guard", form is "notice" and summary is "语言自检". In the UI it renders as a collapsed line reading "上下文注入 · language-guard · 语言自检" — it never impersonates a user turn.
- Subagents are skipped: at Periodic, dispatch a subagent; its session log contains no record with
source.kind = "language-guard" (a subagent inherits the parent's system-prompt constraint, and its compact context is left alone).
- Switching language: pick 日本語 from the sidebar menu, send a message, and the new system node reads "一律使用日本語（语言代码 ja）".
- Disabling the plugin: with the plugin disabled there are no sections and no injections; the new system node reports
sections=0/3. That is a clean fallback, not a leftover.
One-command check
The manual steps above collapse into a single command:
node scripts/verify-installed.mjs
It locates the most recently written session log, decompresses it, reports the length and section hits of every system/message node, and prints two verdicts: whether a legacy dsh-context promptPrefix/promptSuffix is still present, and whether this plugin is in effect. An explicit path also works:
node scripts/verify-installed.mjs ~/.dsh/sessions/<project>/<session>/session.v4.jsonl.zstd
Requires the zstd command on your PATH (macOS: brew install zstd).
Coexisting with dsh-context
The third-party plugin dsh-context registers promptPrefix / promptSuffix sections whose order values collide exactly with this plugin's (-2000 and 11200).
- Nothing breaks: sorting is
order - order || compareNames(name), so a shared order is not a shared name. "dsh-context:prompt-prefix" < "language-guard:head" (d < l), so dsh-context's two sections stably sort before this plugin's.
- But it burns tokens twice: both are writing a language constraint into the same place — the same idea, twice.
- Recommendation: after installing this plugin, clear
dsh-context's promptPrefix / promptSuffix, or disable dsh-context outright.
A permanent hint sits at the bottom of the settings card, and meta.description in both locale/{zh,en}.json carries the same sentence. This plugin does not detect or rewrite dsh-context's configuration — writing another plugin's config violates least surprise.
How it differs from the official cot-translation plugin
@deepseek-ai/dsh-experimental-client-ui-cot-translation (together with cot-translation-bundle) is an official experimental plugin that does rendering-layer translation: it machine-translates the expanded reasoning shown in the UI into another language. Its own README states that translation sends the displayed reasoning to the selected external service, which may include private code or conversation details, and that the original reasoning remains in the session and model context.
This plugin does generation-layer constraint: it tells the model, in the system prompt, to think and answer in the language you chose.
| cot-translation | dsh-language-guard |
|---|
| Acts on | reasoning text already rendered in the UI | the model's next generation |
| Layer | Client rendering (conversation.chat.reasoning.body slot) | Host system prompt (ctx.systemPrompt.section()) |
| Network | yes, sends text to an external translation service | no, zero network requests |
| Reads conversation content | yes, ships the reasoning body out | no, only writes its own constraint sections |
| Language of the original reasoning | unchanged (still in the session and context) | the language you configured |
The two are complementary, not competing: one decides what language the model thinks in, the other decides what language that thinking is displayed in. They can be installed together — but if this plugin already pins thinking to Simplified Chinese, pointing cot-translation at Simplified Chinese adds nothing; its useful setting is the opposite direction (model thinks in Chinese, you read it in English).
Known limitations
- The constraint wording is fixed Simplified Chinese. Only the language name and code are substituted, so with
targetLanguage: "en" the injected text reads "…一律使用English（语言代码 en）". Models handle this fine, but the prose is not localized. Localizing the templates is a future change.
- The Periodic reminder is visible in the chat UI, collapsed into one line reading "上下文注入 · language-guard · 语言自检". The English identifier
language-guard cannot be hidden — the client renders source.kind verbatim as the injection label, exactly as it does for the official agent-instructions and skill-invocation. Localizing it would require a custom conversation.chat.node renderer for the context node; the first release does not do that.
- The Client half has no turn counter, so the panel cannot show "the next injection lands on turn X".
- The quick switch menu holds only five presets. Custom BCP-47 tags must be typed into the settings field (the menu still shows the current custom code verbatim, so configuration never looks lost).
- It does not override an explicit user instruction. The head section says that asking in English does not change the constraint, but if the user explicitly asks for an English answer this time, the model should comply. The plugin declares a default at the system level; it does not overrule a per-turn explicit instruction.
- It cannot detect whether
dsh-context is installed, so the hint is permanent (see above).
- Periodic never wakes an idle session.
agent/pre-step only fires while a turn is running, so no message means no reminder — a language guard should not generate conversation on its own.
- The
mid position could be squeezed by future plugins. If another plugin inserts a section between order 5000 and 9000, the "after the tool docs" semantics get diluted. The fix then is to raise mid to 8900 (still before deliverable references at 9000); failing that, fall back to Basic, which does not depend on mid.
- It cannot tell Simplified from Traditional Chinese. DSH ships exactly two built-in interface languages,
zh and en (dsh-client-locale/lib/index.js:11, LOCALE_IDS = ["zh", "en"]), and zh does not distinguish the two scripts — while the Host side cannot see the system language. So when the interface language is Chinese, auto mode always resolves to . Users who need Traditional output should switch the language mode to Manual and pick . The same holds for Japanese and Korean: on a standard install auto mode can only resolve to or , so pick 日本語 / 한국어 manually — if you installed the matching external language pack, its tag is passed through as-is.
Design boundaries
This plugin deliberately does not do the following — each would either break host conventions or make debugging impossible:
- It does not listen to
system-prompt/assemble to add or remove host text; it only declares its own sections through ctx.systemPrompt.section().
- It does not rewrite
llm/stream reasoning deltas — it never fabricates "thinking".
- It does not touch decision fields other than
messages in agent/pre-step, and it appends no new event types; the Periodic path returns { ...decision, messages }, preserving startsRequestSeries and the rest.
- It makes no network requests, reads no conversation content, reports nothing.
dependencies is empty; the Client half only require('react') from the host module table.- The constraint text is stable within a session, avoiding frequent in-history replacement and prompt-cache invalidation.
License
MIT © 58fly
Repository: https://github.com/58fly/dsh-language-guard · Issues: https://github.com/58fly/dsh-language-guard/issues
