Claude Translate

Serve your Cyrillic markdown docs to Claude Code as cached English translations — and cut the context tokens agents burn re-reading them.

Russian prose tokenizes ~1.8–2× worse than English, and agent workflows read the same docs over and over: project wikis, registries, architecture notes, CLAUDE.md on every session start. claude-translate translates a doc once per version on a cheap Haiku tier (claude -p --safe-mode --model claude-haiku-4-5, billed to your existing Claude subscription — no API key) and serves the cached English on every subsequent Read.

Built on the same engine as cursor-translate (@cursor-translate/core).

The core value — and its honest economics

Two mechanisms do the actual saving. Both are automatic once installed:

Mechanism	When it saves
Lazy EN doc cache — the PreToolUse hook redirects every Read of a Cyrillic .md/.mdx to a cached English translation	On every read of every cached doc, in every session and subagent
English CLAUDE.md generated from a Russian source (claudemd)	Loaded into every session and re-sent with the context on every turn — the highest-leverage doc in a repo

Translation is an investment (one Haiku spend per doc version), serving is the return (every read). Which means:

• Pays off: stable docs that agents read often — knowledge bases, project registries, CLAUDE.md.
• First-time translation is the investment: a fresh doc repays itself in ~1–3 reads (check the break-even reads line in your own report).
• Edits are cheap: re-translation is section-incremental — only the changed sections are re-billed. And since agents Read a doc around every Edit, reads ≥ edits in practice, and a single read of a mid-size doc typically covers a one-section update. A doc only stays net-negative when it's bulk-rewritten often and rarely read afterwards (one-off scratch notes).
• Saves ~nothing: code-heavy sessions that rarely Read Cyrillic markdown — the savings scale directly with how much Cyrillic documentation your agents actually read.

Don't take the pitch's word for it — every cache hit, every translate spend (with real claude -p cost receipts) and every missed opportunity is logged. Pull your own numbers any time:

claude-translate report --days 7

ROI operational (docs + CLI/MCP prompts — excludes display & warmup):
  doc cache served (lazy read / MCP resolve_doc): ~518011 tokens saved (86 reads)
  incremental doc translate: ~526353 tokens
  net operational ROI: …
ROI investment (one-time doc cache warmup):
  break-even reads (warmup ÷ avg savings/read): ~4 more doc_cache_served events
session opportunity (interactive — not auto-translated):
  user_prompt (RU sent as-is to main model): ~22014 tokens (114 events)

How to read it: doc cache served is your realized saving; the doc translate lines are what the Haiku tier spent to earn it; session opportunity is what the extras below could additionally capture (and what they'd cost you in trade-offs). Inside Claude Code the same summary is available as the /translate-report slash command.

Installation

npm install -g claude-translate
claude-translate init --path
source ~/.zshrc   # or open a new terminal

Then enable the plugin (hooks + MCP + slash commands) inside Claude Code:

/plugin marketplace add davlet42/claude-translate
/plugin install claude-translate@claude-translate

For local development instead: claude --plugin-dir /path/to/claude-translate/plugin.

Requires the claude CLI logged in (Pro/Max subscription) and Node ≥ 20.

Quick start

cd ~/Projects/your-repo
claude-translate docs --dry-run   # see what would be cached
claude-translate docs             # warm the EN cache (one-time Haiku spend)
claude-translate claudemd         # English CLAUDE.md from Russian source
claude-translate report --days 7  # savings vs costs

How the core works

Lazy translate on Read

The plugin's PreToolUse hook (matcher Read): if the file is .md/.mdx with Cyrillic and the cache is missing or stale (sha mismatch), it translates via Haiku, caches under ~/.claude/translate-proxy/cache/<project>/…en.md, and rewrites the tool call's file_path to the cache. It also injects a context note telling Claude to edit the original file, never the cache. Everything fails open: no CLI, quota exhausted, timeout → the original Russian file is read.

CLAUDE.md workflow (biggest per-session win)

CLAUDE.md is loaded into every Claude Code session. Keep the Russian source in CLAUDE.ru.md and generate the English CLAUDE.md:

claude-translate claudemd            # first run: seeds CLAUDE.ru.md from a Russian CLAUDE.md
# edit CLAUDE.ru.md later…
claude-translate claudemd            # re-translate (sha marker tracks staleness)
claude-translate claudemd --check    # CI check: exit 1 when stale

Shared cache with cursor-translate

Before spending on a translation, the doc cache checks the sibling install — cursor-translate keeps the same cache format under ~/.cursor/translate-proxy. A fresh entry (sha match against the current source) is copied over as action: sibling_copy with zero translate cost; only if the sibling is also missing or stale does a real translation run. Works in both directions: docs you translated in Cursor are reused by Claude Code and vice versa.

Config: cache.share_siblings: true (default). Override or disable: CLAUDE_TRANSLATE_SIBLING_HOMES="/path/one:/path/two" (empty string disables).

Content mode: replace the Read result instead of the path

hooks:
  lazy_read_mode: content   # default: path

In content mode the PostToolUse hook swaps the Read result's file.content for the English translation while the model keeps seeing the original file path — no cache-path confusion in references. Trade-off: Edit old_string matching against the Russian file will not line up with what the model read, so prefer path mode for docs you expect the agent to edit.

CLI commands

Command	Purpose
init [--path]	Config, glossary, hook assets, bin wrappers, optional shell PATH
doc <file>	Translate one file → global cache
docs [path]	Scan project *.md with Cyrillic → cache all
claudemd [--check] [--force]	Keep an English CLAUDE.md generated from CLAUDE.ru.md (sha-tracked)
resolve <file>	Lazy: ensure EN cache, print readPath
hook-resolve	stdin JSON for the PreToolUse Read hook
prompt "<text>"	RU→EN translate to stdout
agent [claude flags] -- "<prompt>"	Full RU→EN → claude -p → EN→RU
report [--days 7]	Metrics by source

Metrics sources (~/.claude/translate-proxy/metrics.jsonl)

source	Trigger
doc_cache_served	Lazy read / MCP served EN cache (realized savings)
doc_translate_cost	Doc translation spend (reason: claudemd for CLAUDE.md syncs)
prompt_translated / response_back_translated	CLI agent & prompt, MCP translate
display_hook	Display-translation outcome per reply (see extras)
user_prompt / agent_response	Opportunity audit from hooks (what auto-translate would save)

Extras (opt-in, off by default, experimental)

Everything below is flipped in your local ~/.claude/translate-proxy/config.yaml — the file is created on your machine by claude-translate init from the packaged template and is yours to edit; nothing here requires forking the repo.

The platform reality that shapes these features: Claude Code's UserPromptSubmit hook cannot rewrite your prompt (block + add context only), and no hook can transform the assistant's transcript text. So prompt- and reply-side savings can only be attacked from angles — each with a real trade-off. The doc cache above has no such trade-off; these do.

Russian on screen, English in the transcript (display translation)

Read this first — it is not real-time. MessageDisplay is a post-render hook: every reply appears in English first and is replaced with Russian only when the translation lands. The translate tier runs on your own Claude subscription (claude -p, Haiku), so it queues behind everything else your account is doing: roughly 10–60 s per reply on an idle account, and minutes while parallel agent sessions hammer the same subscription. Treat this mode as eventual Russian in exchange for output-token savings. If you want replies in Russian immediately, leave both flags off (the default): the model simply answers in Russian — at the cost of ~1.5–2× output tokens on replies and a slightly heavier transcript, while skipping the Haiku translate spend entirely.

response:
  display_back_translate: true   # MessageDisplay hook: RU on screen (eventually), EN in transcript
  english_replies: true          # ask the model to reply in English (~2× fewer output tokens)

With both on, the model is instructed (via SessionStart) to answer in English, and the MessageDisplay hook translates each displayed reply to Russian through Haiku. The transcript keeps the English text, so later turns and compactions stay cheap.

Mechanics (v0.3.5): Claude Code dispatches the chunk events of one message concurrently, so on the final chunk the hook resolves the full message text from the session transcript (transcript_path) instead of reassembling buffered deltas; mixed-language replies are segmented per paragraph (Russian paragraphs pass through verbatim, only English runs are translated); the hook timeout is 600 s to survive subscription throttling. Every outcome is logged to metrics.jsonl as source: "display_hook" (displayed, unchanged, already_russian, below_min_chars, above_max_chars, quota_latched, unrecognized_payload, hook_error) — grep display_hook answers "why was this reply shown in English". Replies shorter than display_min_chars (80) or longer than display_max_chars (12000) are shown as-is. Requires Claude Code ≥ 2.1.152.

Full agent wrapper (headless) — the only place prompts get auto-translated

claude-translate agent --model sonnet -- "сделай ревью PR и опиши риски"

User RU → Haiku (translate in)
       → claude -p (your model; hooks/doc-cache still active)
       → Haiku (translate out, optional — response.back_translate)

Interactive sessions can't get this (the platform limit above); the wrapper is for scripts, cron jobs and CI where the RU→EN→agent→RU loop runs outside the model.

MCP tools: translate / resolve_doc — for hosts without hooks

Cloud Agents, CI runners and other MCP clients have no PreToolUse hook — there, resolve_doc is the explicit way to get the EN cache for a Cyrillic doc (include_body: true to inline the content). translate is an on-demand RU↔EN capability on the cheap tier, glossary-aware and metered. In interactive Claude Code with the plugin installed these mostly stay idle — the hooks already did the job — and that's by design.

Opportunity audits

UserPromptSubmit / Stop / SubagentStop hooks log what auto-translation would have saved (user_prompt, agent_response, subagent_summary sources) — that's the session opportunity block in report. Audit only, no behavior change.

Two-tier model strategy

Tier	Model	Used for	~API rate (in/out per 1M)
Main agent	Fable / Opus / Sonnet (your setting)	Code, reasoning, tools	$5–25+ / $25–75+
Translate tier	claude-haiku-4-5 (default)	RU↔EN prose only	~$1 / $5

Translate hops run as:

claude -p --safe-mode --no-session-persistence --tools "" \
  --model claude-haiku-4-5 --system-prompt "<translator prompt>"

--safe-mode keeps subscription (OAuth) auth working while disabling hooks, plugins, MCP, CLAUDE.md discovery — a minimal, recursion-safe, cheap call. (--bare is not used: it drops OAuth.)

Override: CLAUDE_TRANSLATE_MODEL=claude-haiku-4-5 or translator.model in ~/.claude/translate-proxy/config.yaml. CI/headless without a subscription: CLAUDE_TRANSLATE_PROVIDER=openai + OPENAI_API_KEY.

Plugin contents

• Hooks: PreToolUse lazy read (600s timeout), PostToolUse content mode, MessageDisplay display translation (600s timeout, off by default), UserPromptSubmit/Stop opportunity audits, SessionStart context note (adds the english-replies instruction when enabled). All guarded by CLAUDE_TRANSLATE_HOP=1 against recursion; disabled features exit before booting node.
• MCP: translate + resolve_doc (reuses @cursor-translate/mcp; wrapper installed by init exports the Claude home).
• Slash commands: /translate-docs (warm cache), /translate-report (metrics summary).

Config

~/.claude/translate-proxy/config.yaml — your local file, created by init from templates/config.yaml:

translator:
  provider: claude-cli
  model: claude-haiku-4-5

Custom translation rules: .claude/claude-translate.md, a ## claude-translate section in CLAUDE.md/AGENTS.md, or ~/.claude/translate-proxy/claude-translate-rules.md. Project glossary: .claude/claude-translate-glossary.yaml.

Related docs

• Runtime guide — hook contracts (exact stdin/stdout JSON), config and env reference, metrics, troubleshooting, fail-open guarantees
• Cloud and remote sessions — what works on the web/CI, committed EN caches, claudemd --check gate
• Publishing — npm release flow, CI, lockfile notes
• Changelog

License

MIT