[ThomasK33]

Summary

5b PR 3 of phase 5 (Loop host I/O) of the agent-loop refactor. Four modules that an agent turn reaches read and write their files through injected file services instead of fs/promises, os and writeFileAtomic:

• additionalSystemContext.ts: the scratchpad (additional-system-context.md) and its disabled marker.
• memoryContextPersistence.ts: the memory-context file of the context window.
• runtimeScratchDir.ts: the host scratch dir, and the Docker client config read of the devcontainer mount check.
• subagentTranscriptArtifacts.ts: the sub-agent transcript index.

The session-dir files go through SessionFiles (phase 2). The turn passes the SessionFiles of its HistoryService, so a memory layer keeps these files off the disk too. The Docker client config (~/.docker) is no session file, so that read goes through HostFiles and HostPaths (5a PR 5).

Behavior does not change: every default is the Node layer (nodeSessionFiles, nodeHostFiles, nodeHostPaths), which calls the same fs/promises functions, os.homedir(), ensurePrivateDir and writeFileAtomic.

Order

Plan order: stack 5b is PR 1 to PR 9. This PR waits for phase 2 PR 7 and phase 4 PR 14 (#7425, merged), which changed updateSubagentTranscriptArtifactsFile. It uses no code of 5b PRs 4 and 5, so it opens on its own, with base main.

Implementation

• additionalSystemContext.ts: readAdditionalSystemContext and writeAdditionalSystemContext take an optional last files argument (default nodeSessionFiles). ensurePrivateDir is files.ensurePrivateDir.
• memoryContextPersistence.ts: the MemoryContextStore constructor takes files (same default). AgentSession passes historyService.files.
• runtimeScratchDir.ts: ensureScratchDirForSpec takes files after abortSignal, and RemoteScratchDirCache.ensure forwards an optional files. Both create the host and devcontainer-mount dirs, which are in the session dir. canBindMountHostPathsIntoContainers takes the home dir from nodeHostPaths.userHome() and gets a HostFiles argument.
• subagentTranscriptArtifacts.ts: readSubagentTranscriptArtifactsFile takes files, and updateSubagentTranscriptArtifactsFile and upsertSubagentTranscriptArtifactIndexEntry take files? beside locks. HistoryService passes this.files to its 2 index reads.
• turnRequestBuilder.ts: the scratchpad read and both scratch-dir calls pass historyService.files.
• Callers outside the turn keep the Node default: InstructionsService (the scratchpad panel), the child-artifact roll-up of WorkspaceService (its copies still call fs/promises), artifactsOperations.ts and terminalService.ts.

The plan estimated about 360 lines. This PR adds 266 and removes 47.

Validation

• Done check of the plan: pairs.mjs --phase5 lists no host import in the 4 files (it listed 2 in each on main).
• 5 new cases, each on memory file layers. With main's production files, all 5 fail:
  • additionalSystemContext.test.ts: the scratchpad and its marker are in the memory volume, the Node default reads none, and the temp dir on disk stays empty.
  • memoryContextPersistence.test.ts: save, load and discard work in memory, and the session dir on disk does not exist.
  • runtimeScratchDir.test.ts: ensureScratchDirForSpec creates the host dir in memory only. canBindMountHostPathsIntoContainers reads a client config that exists only in memory HostFiles and names a remote context (false), while the disk without a config gives true.
  • historyService.test.ts: a transcript index written through memory SessionFiles is in memory and not on disk, and getSubagentTranscript finds it by owner and by session scan.
• The plan's tests (additionalSystemContext.test.ts, agentSession*.test.ts, runtimeScratchDir.test.ts, historyService*.test.ts) plus the golden and contract tests of sessionFiles/, memoryContextPersistence, subagentTranscript*, instructionsService, turnRequestBuilder*, terminalService*, artifactsOperations*, DevcontainerRuntime* and sessionLocks/: 2476 pass, 0 fail in 94 files.
• make static-check, make lint-eslint, make crap-check and make dry-check pass. crap-check warns only that the AgentSession constructor and prepareOrThrow are touched hotspots, with unchanged complexity.
• make test (host suite lock) on head 0c9c084: bun test src had 27908 pass, 7 skip, 1 fail. The failure was BackgroundProcessManager > terminate > should deliver SIGTERM to the bash process (a 3 s timeout under a host load of 13). Its file passed twice on a rerun (166 pass, 0 fail). The shared scripts/storybook/vscode run had 729 pass, 1 skip, 0 fail, and the 18 isolated files had 0 fail. Loop-test tripwire, 3 runs against main: 0 trips.
• After a merge of main e89cf28 (🤖 refactor: the durable journal and the removal tombstones read and write through SessionFiles and HostFiles #7426, 🤖 refactor: the session usage service reads and writes its files through the HistoryService's SessionFiles #7428): a test-only commit drops a duplicate import, typecheck and the 4 static gates pass, and the related tests (the list above plus workspaceRemoval, sessionUsageService* and utils/journal/) have 2582 pass, 0 fail in 101 files.

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[chatgpt-codex-connector]

Codex Review Summary

This comment shows the latest Codex review activity on this pull request.

Review	Status	Commit	Review trigger
📝 Code Review	✅ Completed 2026-10-24T19:58:03.514666Z	348be23	PR opened
🔒 Security Review	✅ Completed 2026-10-24T19:57:39.626362Z	348be23	PR opened

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[github-actions]

🟢 e2e stories (Haiku): 14 passed

27 agent steps · 7 replayed from cache · 31 model calls · 219.0k tokens (70% cached)
Spend: $0.10 of the $1.00 cap (proxy ledger)

All 14 tests in 9 files

	Test	Agent	Time
🟢	chatRestart.e2e.ts · 1 passed	2 steps · 4 calls	24.1s
🟢	a chat survives a restart of the server	2 steps · 4 calls	24.1s
🟢	compaction.e2e.ts · 1 passed	3 steps · 7 calls	43.1s
🟢	/compact replaces the old chat with a summary	3 steps · 7 calls	43.1s
🟢	pluginTrustRestart.e2e.ts · 1 passed	4 steps · 2 calls	9.2s
🟢	a trusted plugin hook stays trusted after the server restarts	4 steps · 2 calls	9.2s
🟢	settingsRoundTrip.e2e.ts · 1 passed	3 steps · 5 calls	29.6s
🟢	a chat survives trips through Settings	3 steps · 5 calls	29.6s
🟢	sidebarPerWorkspace.e2e.ts · 1 passed	4 steps · 1 call	7.3s
🟢	a new workspace starts with its right sidebar collapsed while another keeps it open	4 steps · 1 call	7.3s
🟢	smoke.e2e.ts · 1 passed	2 steps · 1 call	3.7s
🟢	the agent opens the playground workspace	2 steps · 1 call	3.7s
🟢	streamErrors.e2e.ts · 1 passed	1 step · 1 call	10.2s
🟢	stream errors show in the chat, and the chat recovers	1 step · 1 call	10.2s
🟢	todoNudge.e2e.ts · 1 passed	2 steps · 4 calls	24.1s
🟢	the agent finishes open TODO items after the turn-end nudge	2 steps · 4 calls	24.1s
🟢	touchAlignment.e2e.ts · 6 passed	6 steps · 6 calls	27.2s
🟢	the Settings close button is level with the title on a touch screen 390px wide	1 step · 1 call	3.7s
🟢	the Settings close button is level with the title on a touch screen 768px wide	1 step · 1 call	7.6s
🟢	Backup settings checkboxes are small and level with their labels on a touch phone	1 step · 1 call	7.0s
🟢	the heartbeat checkbox is small and level with its label on a touch phone	1 step · 1 call	3.3s
🟢	a reply's model and time stay on one line on a touch phone	1 step · 1 call	3.0s
🟢	the workspace actions menu stays on the title row on a touch phone	1 step · 1 call	2.6s

_{e2e 0.20.0 · 3m 2s · web · run artifacts}

🟢 e2e Electron stories (Haiku): 3 passed

3 agent steps · 3 model calls · 8.0k tokens (21% cached)
Spend: $0.02 of the $1.00 cap (proxy ledger)

All 3 tests in 3 files

	Test	Agent	Time
🟢	electron/deepLink.e2e.ts · 1 passed	1 step · 1 call	5.2s
🟢	a deep link of a second launch starts a chat in the running app	1 step · 1 call	5.2s
🟢	electron/menuBar.e2e.ts · 1 passed	1 step · 1 call	8.9s
🟢	the workspace menu bar is the desktop title bar	1 step · 1 call	8.9s
🟢	electron/smoke.e2e.ts · 1 passed	1 step · 1 call	5.4s
🟢	Xum Electron opens the playground workspace	1 step · 1 call	5.4s

_{e2e 0.20.0 · 21.5s · electron · run artifacts}

🟢 e2e agent repros (Haiku): no tests selected

Spend: $0.00 of the $1.00 cap (proxy ledger)

_{e2e 0.20.0 · 5.3s · 2 targets (web, phone) · run artifacts}