# Harness Language > Set, switch (English <-> Chinese), or refresh a harness project's Use when this capability is needed. - Skill: `tomevault-io/harness-language` (Agent Skill, multi-file: 2 files) - Install (CLI): `npx skillmds@latest add tomevault-io/harness-language` - Raw SKILL.md: https://api.skillmd.com/api/skills/tomevault-io/harness-language/raw - Safety review: pending (external: skill-scanner PASS, skillspector PASS) - Works with: Claude Code, Claude.ai, OpenAI Codex - Category: Coding & Dev Tools - Author: tomevault-io (https://skillmd.com/u/tomevault-io) - Updated: 2026-09-17 - Page: https://skillmd.com/skills/tomevault-io/harness-language --- # /harness-language Set / switch / refresh a harness project's **output-language policy** — the project-wide rule that decides which language the project's AI produces. Two target states are supported: - **`en`** — the single-language English policy (everything the project's AI produces is English). - **`zh`** — the consumer-split Chinese policy (human-facing output in Chinese, agent/LLM-facing artifacts in English; the current canonical split). The command rewrites **only** the three policy-bearing surfaces of the *target project*: 1. `.harness/rules/00-core.md` — the policy SECTION (heading-anchored). 2. `CLAUDE.md` — the single top policy LINE. 3. `.github/copilot-instructions.md` — the single top policy LINE. Nothing else in the project changes. It is non-destructive (a `.bak` precedes every edit; a clean git tree is required so `git reset` is a full rollback), idempotent (a second run on an already-current project is a clean no-op), and reversible (`en` -> `zh` -> `en` restores the exact original bytes, because all text is pulled from the plugin templates). > This skill is the **judgment layer**. All mechanical work — locating the policy section > by its canonical heading, slicing it, substituting the canonical block, swapping the > one-line policy, writing the `.bak`, the byte-identity NOOP — is done by one > deterministic helper, `language-policy.{ps1,sh}`, which the skill bootstraps from the > plugin template cache and drives with explicit flags. The skill does NO markdown > string-replacement and embeds NO policy text itself. ## When to invoke - `/harness-language en` — make the project English-only. - `/harness-language zh` — make the project use the consumer-split Chinese policy. - `/harness-language` (no arg) — **refresh** the project's CURRENT language to the latest canonical text (useful for an old project initialized before the policy was refined). - For a layout/version upgrade (scripts, hooks, verify_all) → use `/harness-upgrade`. - For a brand-new project → use `/harness-init` (it asks the language at init). ## Procedure Use `TodoWrite` to track. Stages are gated: never apply without an explicit user "yes". ### 1. Target & precondition gate The current working directory is the target project. - Confirm `.git/` exists. If not → **halt**, no changes ("not a git repository"). - Refuse on a **dirty working tree** (`git status --porcelain` non-empty) with "commit or stash your changes first" — this preserves the `git reset` rollback path. (The helper's `.bak` covers any untracked policy surface.) - Confirm at least one of `.harness/rules/00-core.md` OR `CLAUDE.md` exists. If **neither** → **halt**, point the user at `/harness-init` (empty project) or `/harness-adopt` (no-harness project): "this project has no language-policy surface to operate on". ### 2. Validate the argument - If an argument is present and is not `en` or `zh` → **halt** ("only en|zh are supported"), change nothing. ### 3. Locate the plugin template cache + read the target version Resolve the plugin template root, in this order (first hit wins) — identical to `/harness-upgrade`: 1. **`$CLAUDE_PLUGIN_ROOT`** if set → `$CLAUDE_PLUGIN_ROOT/skills/harness-init/templates`. Best-effort only; if unset, fall through — do NOT depend on it. 2. **Versioned plugin cache glob (load-bearing):** `~/.claude/plugins/cache/harness-kit-marketplace/harness-kit/*/skills/harness-init/templates`. On multiple matches pick the **highest semver** directory. 3. **Dev / marketplace-less fallbacks:** `~/.claude/plugins/cache/*/harness-kit/*/skills/harness-init/templates`, then `~/.claude/skills/harness-init/templates`. 4. **None resolve → halt** ("could not locate the harness-kit plugin template cache; reinstall the plugin"). The helper is never invoked. The helper's `--template-root` is the directory **above** `skills/harness-init/templates` — the resolved cache root `/harness-kit//` (the directory that contains `skills/`). Read `/.claude-plugin/plugin.json` `version` and surface it in the plan as human prose ("Target policy version: x.y.z"). > The helper does ZERO cache discovery — discovery is judgment, so it stays in this AI > layer. The helper is a pure deterministic transform driven by `--template-root`. The > canonical policy text is read ONLY from the resolved templates, never fabricated and > never sourced from the target project — so a stale project that does not already contain > the canonical text still gets the correct target text. ### 4. Determine the target language (detect-then-ASK; never silently guess) - **Explicit `en`/`zh`** → that is the target. Detection still runs (to report "switching from to " or "already "), but the choice is fixed by the argument. - **No-arg refresh** → you have no language yet, but the helper REQUIRES `--lang`. To read the current language WITHOUT changing anything, invoke the helper with a placeholder `--lang --dry-run` purely to capture the `DETECT||` record from stdout — the helper emits `DETECT|...` unconditionally after arg-validation and before any mutation, and `--dry-run` writes nothing, so the placeholder language is inert. Then **confirm the detected language with `AskUserQuestion`**, pre-filled: "Detected ``. Refresh to the current canonical `` policy? [yes / switch to the other language / cancel]". The confirmed value becomes the real `--lang` from step 5. - **Ambiguous** (`DETECT|ambiguous|...`: conflicting sources or no recognizable policy surface) → `AskUserQuestion` with **no pre-filled default** ("Could not determine the current language. Set it to: [en / zh / cancel]"). Never guess. Detection order (the helper computes it): `.harness/rules/00-core.md` policy heading → `CLAUDE.md` top policy line → `.github/copilot-instructions.md` top policy line; first confident hit wins. ### 5. Plan (dry-run) → present → confirm → apply 1. Invoke the helper with `--dry-run`: ``` pwsh -File /.harness/scripts/language-policy.ps1 -TemplateRoot -Lang -DryRun # or bash /.harness/scripts/language-policy.sh --template-root --lang --dry-run ``` (Drive whichever copy is present in the target project's `.harness/scripts/`; if the project has no `language-policy.*` yet, copy it from `/skills/harness-init/templates/common/.harness/scripts/` first — the same self-bootstrap `/harness-upgrade` does for its helper.) 2. **Parse the machine-readable stdout** (one record per line, pipe-delimited): | Prefix | Meaning | |---|---| | `LANG\|` | resolved target language | | `DETECT\|\|` | current-language inference (`00-core`/`CLAUDE`/`copilot`/`none`) | | `PLAN\|\|\|` | planned action (dry-run) | | `RESULT\|\|\|` | applied action | | `BAK\|` | backup written | | `SKIP\|\|` | absent policy surface tolerated (e.g. no copilot file) | | `CONFLICT\|section\|\|` | no recognizable policy heading in 00-core.md | | `SUMMARY\|rewritten=.. noop=.. skipped=.. baks=.. conflicts=..` | totals | `` ∈ `REWRITE-SECTION REWRITE-LINE INSERT-SECTION NOOP SKIP`. 3. Present the plan to the user: which files will change, whether this is a switch (`` -> ``) or a same-language refresh, the target policy version, and the `.bak` locations. Then `AskUserQuestion`: `Apply this plan? [yes / no]`. 4. On **"yes"**, re-invoke the helper for real (drop `--dry-run`). ### 6. Branch on the helper's exit code | Exit | Meaning | Skill action | |---|---|---| | `0` | success / nothing-to-do / dry-run printed | continue to step 7 | | `1` | precondition / arg error (bad `--lang`, missing `--template-root`, no surface) | surface the helper's stderr, halt | | `2` | **section-conflict** — `00-core.md` exists but carries neither canonical policy heading (hand-mangled or absent) | relay the `CONFLICT\|section\|...` line; run `AskUserQuestion` "00-core.md has no recognizable Output-language policy section. Insert the canonical `` section? [insert / abort]". On **insert** → re-invoke with `--force` (the helper inserts the section before the first `## ` heading, or at EOF). On **abort** → halt, change nothing. NEVER auto-insert without the explicit answer. | ### 7. Final report Print the summary: ``` Set output-language policy to (policy version ) Switched: -> (or: refreshed / already current — nothing to do) 00-core.md: CLAUDE.md: copilot: Backups: <.bak paths> ``` If the project has its own `verify_all`, you MAY suggest the user re-run it — but the command edits policy prose, not scripts, so no verify_all run is required by this command. ## Hard rules - **Non-destructive.** Clean git tree is a precondition (rollback = `git reset`); every edited file gets a timestamped `.bak`. - **Surgical scope.** Only the `00-core.md` policy section and the single `CLAUDE.md` / copilot policy line change; every other byte of every file is preserved. - **Single section invariant.** After a switch, `00-core.md` has exactly one policy heading and one policy section — the old-language section (heading + body) is the unit replaced. - **Idempotent.** A second run with the same target is a clean no-op (no write, no `.bak`). - **Self-bootstrapping, single source of text.** The canonical en/zh text comes ONLY from the resolved plugin templates — never fabricated, never copied from the target project. - **Detect-then-confirm.** Never write without an explicit user answer when the language is inferred (no-arg refresh) or ambiguous, and never auto-insert into an unrecognized `00-core.md` structure. ## Anti-patterns - Don't hand-edit the three policy files yourself — drive the helper. - Don't proceed past the plan without an explicit "yes". - Don't guess the current language when detection is ambiguous — ask. - Don't auto-insert a policy section into a hand-mangled `00-core.md` — surface the conflict and ask. - Don't depend on `$CLAUDE_PLUGIN_ROOT` being set — the glob fallback chain is the load-bearing discovery path. - Don't run this against this kit's own dogfood repo — it targets *generated* projects. ## Out of scope (v1) - Whole-project content translation (only the three policy surfaces; translating docs / READMEs / agent files is a separate follow-up). - Languages other than `en` and `zh`. - A persisted `PROJECT_LANG` marker / a new `{{...}}` placeholder (detection from the existing policy prose is reliable; no new placeholder is introduced). - The other i18n overlay files beyond the three policy surfaces. --- > Source: [Alan-IFT/harness-kit](https://github.com/Alan-IFT/harness-kit) — distributed by [TomeVault](https://tomevault.io).