fix: yield to billion-context native mode via action-time env re-check (#405)

[ranxianglei]

Problem (#405)

billion-context's OpenCode 2.x native mode (PR ranxianglei/billion-context#824) owns compression from a package-installed plugin that rewrites model-API requests at http.request time. ACP's self-disable signals are all sampled statically:

1. index.ts setup check reads BILLION_CONTEXT_PROXY once — native mode writes it only after async proxy bootstrap → missed;
2. config hook / lib/bili-proxy.ts rely on /bili/ in provider baseURL — native mode never touches configured baseURLs → invisible.

Result: with both plugins installed, native mode double-compresses. The native entry ships a synchronous marker for exactly this handoff (markNativeHost() sets process.env.BILLION_CONTEXT_NATIVE = "opencode" at module evaluation, before any await, first-writer-wins) — but it can land after ACP setup sampled env.

Fix

Re-sample the owner markers at action time, reusing the existing yield path:

• lib/bili-proxy.ts: new pure detectBiliEnvYield(env?) ("launcher" | "native" | null, launcher precedence — native bootstrap refuses to run while BILLION_CONTEXT_PROXY is set) + describeBiliEnvYield(), injectable env for tests;
• index.ts: setup fast path covers both markers; guard() and the config hook re-sample env on every invocation/config run (one-time log per source per factory instance); deny-tools block extracted to a shared helper used by both the new env branch and the existing /bili/ branch (whose log message is preserved verbatim);
• lib/compress/types.ts: resolveToolContext() — first statement of every ACP tool's execute — throws a clear "disabled" error when a marker is set at action time. One chokepoint gates all five tools without touching the five tool files; covers the residual window where a tool call lands after the last config run.

Non-latching (unsetting the marker restores ACP), no state-format/API changes, hot path stays O(1) with no I/O.

Tests

New tests/bili-native-yield.test.ts (10 tests through the real factory): unit detector + precedence, setup fast path ×2 markers, runtime marker → config denies all 5 tools / all hooks no-op / tool execute throws, launcher-marker parity, re-enable after unsetting, exactly-one yield log across repeated invocations.

Mutation-checked: with index.ts + lib/compress/types.ts reverted to master, 7/10 fail; with the fix, 10/10 pass. Full suite: 1273 pass / 0 fail; typecheck + build clean.

Trade-off (fail-closed)

If the native marker is set but billion-context's own async bootstrap later fails, ACP stays yielded for that process lifetime — recovery is removing the native plugin and restarting. Deliberate: failing open risks double compression (the bug this PR fixes); a failed bootstrap at least leaves compression visibly unowned. The marker is only written when the native gate passes at module evaluation, so this window is narrow.

Review

Dual-agent review (independent source + test reviewers). Findings addressed in commit 32d94ac: prettier violations in two tracked files; stale-flag edge (env branch returned before assigning disabledByBiliProxy — flag now computed before either branch); launcher log wording restored byte-identical to master via new biliYieldLogMessage(); tool-gate test extended from 2 to all five tools; hooks-no-op test extended to cover command.execute.before; re-enable test wrapped in try/finally; sibling bili-proxy-integration.test.ts now also clears BILLION_CONTEXT_NATIVE. Accepted info-level item: the one-time-log dedup var never resets within a process lifetime (cosmetic — detection itself re-samples env on every call). Re-verified after fixes: typecheck clean, 1273/1273 tests pass, build OK.

Devlog: devlog/2026-09-16_billion-context-native-yield/ (REQ + DESIGN + WORKLOG).

Fixes #405

[github-actions]

📦 Built Plugin Artifact

Branch: 2026-09-16_billion-context-native-yield (32d94ac)

Option A — Install from npm PR tag (recommended)

opencode plugin opencode-acp@pr-406 --global

Each push to this PR publishes a new version under the pr-406 npm tag.

Option B — Install from GitHub

opencode plugin "github:ranxianglei/opencode-acp#2026-09-16_billion-context-native-yield" --global

Option C — Download artifact

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

tar xzf opencode-acp-pr406.tgz
cp -r package/dist ~/.cache/opencode/packages/opencode-acp@latest/node_modules/opencode-acp/dist

3. Restart opencode to pick up changes.

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This comment is automatically updated on each push.

[ranxianglei]

🤖 Powered by ework · qwen3.8-27b

Verified PR #406 (fixes #405). This is already-completed agent work (ework-agent-pr marker), so I pulled the branch, cross-checked the code, and re-ran verification locally rather than redoing it.

Code review

• Diff is focused and clean: 3 source files + 1 test + 3 devlog (REQ/DESIGN/WORKLOG all present; folder matches branch name). No version bump, no lockfile churn, no unrelated/whitespace changes.
• Design is correct — all three yield signals now re-sample env at action time instead of trusting a startup snapshot:
  • lib/bili-proxy.ts: new pure detectBiliEnvYield(env?) ("launcher" > "native" precedence — native bootstrap refuses to run while BILLION_CONTEXT_PROXY is set) + describeBiliEnvYield(), injectable env for tests.
  • index.ts: setup fast path covers both markers; guard() re-samples on every hook call; config hook re-samples each run; the deny-tools block is extracted to a shared denyAcpTools() used by both the new env branch and the existing /bili/ branch (whose log message is preserved verbatim). One-time log per source via announcedEnvYieldSource — no spam on the per-request hot path.
  • lib/compress/types.ts: resolveToolContext() throws a clear "disabled" error when a marker is set at action time. Confirmed it is the first statement of execute() in all five tools (lib/compress/range.ts:102, lib/compress/status.ts:662, lib/compress/decompress.ts:277, plus recap/search) — so the single chokepoint genuinely gates every ACP tool without touching the five tool files, covering the residual window where a tool call lands after the last config run.
• Non-latching holds end-to-end: unsetting the marker → detectBiliEnvYield() returns null → guard resumes + next config run stops denying. No state-format or API change; hot path stays O(1) with no I/O.

Local verification (independent re-run at head 278bea6)

• New tests/bili-native-yield.test.ts: 10/10 pass
• npm run typecheck: clean
• npm run build: clean
• Full suite: 1273 pass / 0 fail

CI status

• ✅ build, build-artifact, test (22), test (24), pr-validation — all success
• ⏳ e2e — still running; I'll follow up when it lands.

Remaining gates before merge

• e2e check green.
• Per AGENTS.md §5.3 / §5.6, source + test changes need ≥2 independent agent reviews — this is my first round; a second independent review is still outstanding.
• PR merge is human-only (§5.1.1.2) — I will not merge; please merge once the above are satisfied.

中文摘要:已核对 #406 代码与设计(action-time env 重采样 + resolveToolContext 单点拦截全部 5 个工具),本地复跑新测试 10/10、typecheck/build 干净、全量 1273 通过 0 失败;CI 除 e2e 外全绿,e2e 转绿并补齐第二个独立 agent review 后即可由人工合并。

[ranxianglei]

🤖 Powered by ework · qwen3.8-27b

Follow-up — CI is now fully green ✅

Check	Result
pr-validation	success
build	success
build-artifact	success
test (22)	success
test (24)	success
e2e	success

On the "behind master" state: the branch is 15 commits behind, but I verified zero file overlap between those master commits (paper docs, quality-gate rejection, lib/hooks.ts, READMEs) and this PR's files (index.ts, lib/bili-proxy.ts, lib/compress/types.ts, tests/bili-native-yield.test.ts, devlog). So it merges/rebases cleanly — no conflicts. A rebase onto current master is optional for tidiness, not required.

Status: ready for the second independent agent review + human merge. Per AGENTS.md §5.3/§5.6 the source + test changes still need a second independent reviewer (this was my first round), and per §5.1.1.2 the merge itself is human-only — I won't merge it.

中文摘要:e2e 已转绿,全部 6 项 CI 检查通过;分支虽落后 master 15 个提交但与其改动零文件重叠、可干净合并(可选 rebase)。代码与测试我已复核无误,待第二个独立 agent review + 人工合并即可。