feat: add /acp-export command (session handoff export)

[ranxianglei]

Summary

Ports the upstream billion-context export command (session handoff export) into the Pi adapter, per #271.

What it does

/acp-export (named acp-export to avoid colliding with Pi's built-in /export):

• No selector — lists ACP-managed sessions with title / label / tokens / blocks.
• <id> — renders the folded view: block summaries in place of compressed ranges, in conversation order, via prune().
• <id> --full — renders the original messages from the session.
• --output <file> — writes the markdown file; without it the document is sent to the transcript (filtered from LLM context) or notified.

Design notes

• The Pi adapter keeps the full conversation in each session's .jsonl and ACP state in an adjacent <sessionFile>.acp.json (written every turn), so both the folded and full views are always available — no snapshot cache or v2 fallback needed (simpler than the proxy).
• Sessions are enumerated by scanning the session directory for *.acp.json files (any ACP-active session has one).
• Export documents are tagged acp-export and excluded from LLM-context projection (same as acp-status panels).
• Output contains no secrets or environment-specific paths (parity with upstream).

Delegation to acp-kernel (follow-up)

Per the owner's request, the handoff markdown rendering is now shared in the kernel instead of duplicated across the proxy and this adapter:

• src/export.ts now calls kernel renderHandoff({coreMessages, state, full, meta}) and kernel matchSession(all, selector, labelOf) (added in acp-kernel#183); the local renderHandoff / renderMessage / matchSession copies are removed (net −52 lines).
• Bumps acp-kernel 0.0.48 → 0.0.49 (the release that ships the handoff exports). package-lock.json is refreshed once 0.0.49 is on npm.
• Companion PRs: acp-kernel#183 (the shared renderer) and billion-context#434 (the proxy delegating to the same renderer).

Verification

• npm run typecheck — clean
• npm test — 472 pass, 0 fail, 3 skipped
• npm run build — success (acp-kernel inlined)

New tests: tests/export-cmd.test.ts (10 tests: arg parsing, list, folded, full, output, no-match, empty store, ambiguous selector, command wiring). Updated tests/integration.test.ts command count to 6.

Dependency / merge order

Blocked on acp-kernel#183 merging + acp-kernel 0.0.49 publishing. Until then CI is red at npm ci (cannot resolve 0.0.49). After 0.0.49 is live, run npm install to refresh the lockfile and the PR goes green.

[github-actions]

📦 Built Extension Artifact

Branch: 2026-09-01_acp-export-command (8a355a7)

Option A — Install from npm PR tag (recommended)

pi install npm:billion-context-pi@pr-272

Each push to this PR publishes a new version under the pr-272 npm tag.

Option B — Download artifact

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

tar xzf billion-context-pi-pr272.tgz
pi install ./package

---

This comment is automatically updated on each push.

[ranxianglei]

🤖 ework agent · qwen3.8-27b

[bot] 🏷 PR reviewed and verified on 2026-09-01_acp-export-command (head 4b57746).

Verification (local, on the PR branch)

• npm run typecheck — clean
• npm test — 472 pass, 0 fail, 3 skipped
• npm run build — success (acp-kernel inlined into dist/index.js, zero runtime deps preserved)
• GitHub CI: all 9 checks green (test ubuntu/windows × Node 22/24, e2e ubuntu/windows, docker, build-artifact, pr-validation)

Code review

• All host APIs used by src/export.ts verified against the installed @earendil-works/pi-coding-agent types: SessionManager.open(), getSessionDir(), getSessionFile(), getSessionId(), getSessionName(), buildContextEntries() all exist with the expected signatures.
• State-file resolution is consistent: SessionStateStore.load(sessionFile, id) reads <sessionFile>.acp.json (src/state.ts:18-21), which matches the *.acp.json directory scan used for session enumeration.
• prune(coreMessages, state) matches the kernel signature (prune(messages: CoreMessage[], state: CompressionState, options?)); message matching goes through entry ids + state.messageRefs, same as the live pipeline.
• The folded-view test is a real end-to-end check (context handler → compress → re-read from disk → prune): summary present, compressed original folded away, uncompressed tail retained. Good.
• Command wiring mirrors the acp-status panel pattern (issue Show /acp-status as persistent output instead of a notification #255) exactly, including the sendMessage → notify fallback.

One gap found — fixed

The src/messages.ts change adding ACP_EXPORT_CUSTOM_TYPE to CONTEXT_EXCLUDED_CUSTOM_TYPES (keeping export docs out of LLM-context projection) had no regression test — only acp-status was covered in tests/messages.test.ts. Without it, a future refactor could silently let full handoff documents leak into model context.

Extended the existing exclusion test to include an acp-export custom entry alongside the acp-status panel. Pushed as 803e731 ("test: cover acp-export exclusion from LLM-context projection"); full suite re-run: 472 pass, 0 fail, 3 skipped.

Minor notes (no action needed)

• Each /acp-export without --output persists the full handoff document into the session's .jsonl (custom message, same persistence semantics as acp-status panels). It's excluded from LLM context so there's no context cost, but long sessions grow the session file by the document size per export. Reasonable trade-off given Pi has no stdout surface for slash commands; just worth knowing.
• Unknown flags (e.g. /acp-export --foo) are treated as a session selector and fail with "no session matches" — acceptable, matches the simple parser style.

Ready for merge (merge stays human-only per repo policy).

[ranxianglei]

🤖 ework agent · qwen3.8-27b

[bot] 🏷 Follow-up: CI on the updated head 803e731 is fully green — all 9 checks passed (test ubuntu/windows × Node 22/24, e2e ubuntu/windows, docker, build-artifact, pr-validation).

[ranxianglei]

冲突了 解决下

[ranxianglei]

🤖 ework agent · qwen3.8-27b

[bot] 🏷 冲突已解决 ✅

冲突原因:master 已前进到 v0.1.56(bcd841e,含 delegate fix + release),release commit 把 acp-kernel pin 到了 0.0.50;而本分支的 398d6c8 把 pin 刷到了 0.0.49。package.json 和 package-lock.json 各一处 pin 冲突。

解决方式:取 master 侧的 0.0.50(更新版本,且 d4612c7 依赖的 handoff API renderHandoff/matchSession/defaultCountTokens 是 0.0.49 引入的,0.0.50 是其超集)。merge base 以来两条分支对这两个文件的改动只有 acp-kernel pin,无其他语义冲突;tests/integration.test.ts 自动合并干净。

验证(本地,合并后):

• npm ci — lockfile 与 package.json 一致,安装 acp-kernel@0.0.50
• npm run typecheck — clean(证明 0.0.50 类型导出包含全部 handoff API)
• npm test — 473 pass / 0 fail / 3 skipped(master 带入的新测试也全过)
• npm run build — success(dist/index.js 548.23 KB,acp-kernel inlined)

已推送 merge commit ec43f08 到 2026-09-01_acp-export-command。CI 跑完我再确认一遍结果。

[ranxianglei]

🤖 ework agent · qwen3.8-27b

[bot] 🏷 确认:merge commit ec43f08 上 CI 全绿 —— 9/9 checks passed(test ubuntu/windows × Node 22/24、e2e ubuntu/windows、docker、build-artifact、pr-validation)。PR 状态已变为 mergeable ✅(head ec43f08)。可以合并了(合并操作按仓库规范由人工执行)。