docs: point OpenCode 2.x users to billion-context

[ranxianglei]

Source: billion-context#985 — owner asked this repo's READMEs to recommend billion-context for OpenCode 2.x, both languages.

What changed

opencode-acp uses the OpenCode V1 plugin API and does not load on OpenCode 2.x, but the READMEs never said so up front — a 2.x user following the install command gets a silently-inert plugin. Docs-only change to README.md + README.zh-CN.md (zh/en in sync):

1. Prominent callout near the top: on OpenCode 2.x this extension will not load; the recommended context manager for 2.x is billion-context (bili opencode launcher or bili plugin install opencode native plugin); opencode-acp remains fully supported on OpenCode 1.x.
2. "Which do I need?" / 「该选哪个?」 table: split the single opencode row into opencode 1.x (this extension) and opencode 2.0+ (billion-context).
3. Matching note under Installation / 安装: the install command targets OpenCode 1.x only.

Companion PR in billion-context updating its own READMEs' OpenCode 2.0 section the same way: ranxianglei/billion-context#986.

Devlog entry added: devlog/2026-09-19_readme-opencode-v2-reco/.

Pre-flight

• scripts/ci/check-pr.sh 2026-09-19_readme-opencode-v2-reco origin/master — all checks passed (branch name, REQ/WORKLOG present, version unchanged → changelog check skipped)
• Docs-only diff: README.md, README.zh-CN.md, devlog/2 files; zero source/test/config changes

[github-actions]

📦 Built Plugin Artifact

Branch: 2026-09-19_readme-opencode-v2-reco (865934b)

Option A — Install from npm PR tag (recommended)

opencode plugin opencode-acp@pr-441 --global

Each push to this PR publishes a new version under the pr-441 npm tag.

Option B — Install from GitHub

opencode plugin "github:ranxianglei/opencode-acp#2026-09-19_readme-opencode-v2-reco" --global

Option C — Download artifact

1. Download the artifact from the Actions run
2. Extract the tarball and install:

tar xzf opencode-acp-pr441.tgz
cp -r package/dist ~/.cache/opencode/packages/opencode-acp@latest/node_modules/opencode-acp/dist

3. Restart opencode to pick up changes.

---

This comment is automatically updated on each push.

[ranxianglei]

🤖 Powered by ework · qwen3.8-27b

[bot] 🏷 PR #441 verified — clean docs-only diff, ready for human merge

Audited per the [PR] protocol (pulled the branch, did not redo work):

1. Diff audit vs current master 7ec1b76e (post v1.18.2 release merge): exactly 4 files, all docs:
   • README.md (+15/−1) and README.zh-CN.md (+8/−1) — the three promised changes each: prominent top callout (V1 plugin API, will not load on 2.x → recommend billion-context via bili opencode or bili plugin install opencode; fully supported on 1.x), "Which do I need?" table row split into opencode 1.x (opencode-acp) / opencode 2.0+ (billion-context), and the Installation note that the install command targets 1.x only.
   • devlog/2026-09-19_readme-opencode-v2-reco/REQ.md + WORKLOG.md.
   • Zero source/test/config changes; no version bump → changelog check correctly skipped by check-pr.sh.
2. zh/en sync: all three callouts checked line-by-line — English and Chinese are in sync (callout wording, both new table rows, install note); links target https://github.com/ranxianglei/billion-context in every place.
3. Terminology cross-check against billion-context's own README: the 2.0+ row's "bili opencode (built-in V2 plugin)" matches their own table wording for that lane, and the top callout mirrors the owner's exact phrasing from billion-context#985. No drift between the two repos' docs.
4. CI: PR Checks ✅ success (branch name + devlog REQ/WORKLOG), PR Build Artifact ✅ success, full CI test matrix still running at time of writing (that's why mergeable_state is currently blocked).
5. Companion PR docs: OpenCode 2.x usage — recommend bili paths, fix stale /acp note billion-context#986 exists on the other side of the doc pair, as described.

中文摘要：核对了 PR #441（README 把 OpenCode 2.x 用户引导到 billion-context，中英文同步）——diff 干净、仅 4 个文档文件、无源码/版本变更、中英三处改动逐条对齐、PR Checks 与构建检查已通过，等完整测试矩阵变绿即可由人工合并。

[ranxianglei]

🤖 Powered by ework · qwen3.8-27b

[bot] 🏷 CI 全部通过 ✅ — CI workflow now complete: test (22) ✅, test (24) ✅, build ✅, e2e ✅ (plus PR Checks and PR Build Artifact from before). PR mergeable_state is now clean.

中文摘要：完整测试矩阵（含 e2e）已全部变绿，PR #441 可以合并——合并操作请人工执行。