[azooz2003-bit]

Summary

Two gaps in the cmux-next iPhone app, plus the shared preview they need.

1. Newlines in the composers

Composer	On-screen Return	Hardware Return	Shift- or Option-Return	Grows to
Agent chat (GUI)	new line	sends	new line	8 lines, then scrolls
Chief (CmuxConversation)	new line (unchanged)	sends (new)	new line (new)	unchanged (header)
Terminal "Send to …"	sends (unchanged, SPEC 10.2)	sends	new line (new)	6 lines, then scrolls

• The agent chat field was a SwiftUI TextField, which decides Return by itself. It is now ChatComposerField, a UITextView over the shared ComposerReturnTextView and ComposerReturnPolicy in CmuxMobileDesign.
• Hardware Return only does what the send button would: send, or queue/steer while the agent runs. It never sends an empty draft and never presses Stop.
• While text is being composed (marked text, for example Japanese), Return belongs to the input method.
• The terminal keeps Return = send, because a shell expects it. A multi-line draft still gets a new line: Shift-Return, Option-Return, or New Line in the field's edit menu. The draft goes to the program as one paste (ComposerSubmit, unchanged).

2. Preview any file everywhere

• One preview: FilePreviewGallery, built from ArtifactPreview pages.
  • Images: pinch, double-tap, swipe down to close.
  • Video: plays.
  • PDF, syntax-colored code and text, rendered Markdown and HTML (with a Source toggle).
  • Audio, Office/iWork, RTF and anything else Quick Look renders: an embedded QLPreviewController (new .audio/.document kinds and ArtifactContent.quickLook).
  • Types nothing on the phone can show: a share sheet ("Share or Open In…").
  • Every page has Share or Save (Save to Files, Save Image, AirDrop) and a position line ("3 of 5"). Swipe between a message's attachments.
• Wired into:
  • agent-chat composer attachments before sending;
  • sent agent-chat attachments (files were inert; images used an image-only viewer, now removed);
  • terminal composer attachments (UIKit presentation, like Files and Links);
  • Files and Artifacts / Files and Links;
  • diffs: Open File in the diff screen and the diff card menus;
  • tool calls: long press opens the files the call touched;
  • files agents mention: links and path:line inline code in answers open the preview, web links open as before;
  • Chief: file links (onOpenLink), queued composer attachments (Quick Look), and a message's documents (Quick Look, swipeable).
• Feed: a link in an event's markdown no longer navigates the pooled web view (which went blank). Web links open in Safari; others open the event.
• Trust: Mac files are read only through the link's file service (LinkFileArtifactSource), so the Mac's workspace-root and Chat Folders rules (cnx-ios: fix full-verify defects D1–D14 (Chief, teams, previews, Codex default, polish) #22354, D9) still decide. Chief resolves only absolute paths. Phone-held attachments use an attachment: reference that never goes to the Mac. Nothing widens access.

CmuxConversation changes land upstream, byte-identical, in #24573 (feat-imsg-parity-gui).

Changelog

• Added: the iPhone agent chat composer takes several lines (Return starts a new line, the send button sends; on a hardware keyboard Return sends and Shift-Return starts a new line).
• Added: tap any file in the iPhone app (attachments before and after sending, Files and Artifacts, diffs, files agents mention) to preview it, swipe between a message's files, and share or save it.

Tests

Failing tests first: c4c894d397dc. On mini-cmux11s with verify/termqa/cmux_mobile_kit-test-ios.sh:

• Red on the tests-only commit: the CmuxMobileAgentChatTests build fails (ArtifactContent has no member quickLook, no ComposerReturnPolicy, and so on).
• Green on head 32251815e7b3: CmuxMobileAgentChatTests 132/132, CmuxMobileLiveTests 262/262, CmuxMobileChiefTests 79/79. ComposerSubmitTests 5/5 and CmuxMobileShellTests passed on earlier heads.
• Sent attachments: red on 3475760ebbbc (no recordedImage/recordedImageID), green on the fix.
• New suites in ComposerFilesTests.swift:
  • Return policy, chat and terminal;
  • the text view's Return and New Line;
  • kinds for every common type;
  • local attachments decoded like Mac files (image, text, docx through Quick Look, video, binary, PDF);
  • missing bytes;
  • a Mac file through the fallback source;
  • local copies named and stable;
  • FileLink (web, app and anchor links refused; path:line, file://#L);
  • MarkdownFilePath (console.log is not a file).

Live check (real usage, real link, no shortcuts)

• Setup:
  • Phone: headless iPhone 17 Pro simulator cmux-composer-files (iOS 26.5) on mini-cmux8s, Demo build of this branch, signed in with the dev credential.
  • Mac: the hidden rig Mac app on mini-cmux11s (fleet build cmux-mobile-e2e-e196c421, open -g -j -n), workspace live-files in a real project folder.
  • Link: WireGuard (path=Direct, then path=Turn).
  • Agent: a real Claude Code chat (Opus 5.5), started from the phone's New Agent Chat With….
  • Driving: axe HID input. Recording: simctl io recordVideo. Simulator.app was never opened, and nothing on the laptop took focus.
• Newlines (agent chat): the on-screen Return typed "Reply with the line count of this prompt.\nline two\nline three". Claude answered "Your prompt has 3 lines of text" and described the attached photo.
• Newlines (Chief): hardware Shift-Return and Option-Return, then Return, sent one three-line message to the Mac's Chief.
• Composer attachments (photo, notes.txt, report.pdf, clip.mp4): each tap opened the full-screen preview (image, syntax-colored text, PDF, playing video), paging "1 of 5" to "5 of 5", with Share or Save. Claude received all of them; it ran a command on …/.cmux/attachments/phone-…/clip.mp4.
• Sent message:
  • The live check found a bug: the sent bubble showed no attachments, because acpmux's user_message names images only. Fixed in 05f0ad0b0987/32251815e7b3 (tests first in 3475760ebbbc).
  • After the fix, the new turn's bubble shows the photo plus notes.txt, report.pdf and clip.mp4. Tapping each opens it, paging "1 of 4" to "4 of 4".
  • After an app relaunch, the earlier turn's photo, which now comes from the Mac's record through _acpmux/attachment, shows in the bubble and opens full screen.
• Files agents mention: tapping report.pdf in Claude's answer opened the PDF read from the Mac over the link (Copy Path shown).
• Mac files (terminal Files and Links):
  • At first the Mac refused with "isn't sharing any folders with this phone yet" (forbidden, "no workspace roots are shared"), which is the trust rule holding.
  • With the project folder set as a Chat Folder, these opened from the Mac: report.pdf, photo.png, page.html (rendered, with Source), notes.md (rendered), brief.docx (Quick Look) and main.swift (syntax colored).
• Evidence: git-ignored, on the laptop under ~/cmux-mobile-builds/20261023-composer-files/evidence/ (videos 01–10, shots/).

Observed / Not run

• Not observed: Chief's queued-attachment Quick Look (the agent-chat equivalent was observed); the Feed link change (no Feed event with a link on the rig); the diff "Open File" menu (unit-wired only).
• Not finished: Claude's tool permission in the second turn asks for device authentication, which a simulator without a passcode can't answer, so that turn was declined.
• No real iPhone (user direction: simulators only).

Review

A fresh correctness review subagent reviewed both rounds. Round 1 found no blockers and 6 should-fix items, fixed in 0909d699c39b. Round 2, on the sent-attachment fix, found no blockers and 2 should-fix items, fixed in 32251815e7b3. Both are in PR comments.

🤖 Generated with Claude Code

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[github-actions]

cmux status _{(one comment, edited in place; each line is updated by the job that owns it)}

Review 3225181: HQ feed card · gallery before/after runs · checks

App of this head (app.zip, kept 1 day)

gh workflow run reload-build.yml -R manaflow-ai/cmux --ref feat-cmux-next -f tag=pr24572 -f ref=feat-cmux-next-ios-composer-files -f platform=macos -f backend_mode=local

red: cmux-next checks (god files, concurrency, crash safety, l10n); NEW: red check: Daemon capabilities export is fresh (+7 more) is not red on the base 36289e3; do not merge until green; see lane-rules

[azooz2003-bit]

Correctness review (fresh subagent), findings and resolution

This was a read-only review of origin/feat-cmux-next...HEAD at 2861a08391af. It found no blockers. It checked access: no Mac file can be read except through the link's file service. Chief's source has baseDirectory: nil, so only absolute paths reach the Mac, and attachment: references never do.

#	Finding	Resolution (0909d699c39b)
1	CmuxConversation edits were not on feat-imsg-parity-gui	Upstream PR with the same files byte-identical (linked from the description)
2	FileLink treated app links (maps:, shortcuts:, x-apple-…:) as file paths	Only scheme-less links, file://, name.ext:12 and Makefile:3 count as files; tests added
3	Composer focus: a stale captured value, a yield loop that could run out, no teardown	The Task reads the binding again when it runs; focus asked before the field has a window lands in didMoveToWindow; dismantleUIView clears focus
4	Share copy written on the main actor for every page	Written in a detached task
5	A message's documents waited for every download in sequence, and a failed tapped item opened another	The tapped item loads first (opening stops if it fails); the others load concurrently
6	A Chief file-link tap was swallowed while something was presented	Ignored while a controller is presented
nit	console.log, res.json and similar read as files	Ambiguous extensions need a /
nit	file://…#L12 lost its line	Line read from the fragment
nit	A queued attachment named ..	Sanitized to Attachment
nit	Empty attachment showed its internal reference	Shows the file name
nit	One Preview/Source toggle shared across gallery pages	Each page keeps its own
nit	Feed: sms/facetime opened the event; #anchor links did too	Both open with the system; anchors stay put
left	VoiceOver label "Attachment" without the file name (CmuxConversation shelf)	Not changed (the shelf item has no name)
left	Diff Open File resolves a repo-relative path against the session folder	Not changed; it matches Files and Artifacts
left	Local copies keyed by reference only (two Macs, same path)	Not changed (a temp cache; the next open rewrites it)

After the fixes, the iOS kit tests on mini-cmux11s passed: AgentChat 126/126, Live 247/247, Chief 74/74, ComposerSubmit 5/5.

[blacksmith-sh]

Found 10 test failures on Blacksmith runners:

Failures

Test	View Logs
/tmp/tmpbh4ssck_/summary-fail.json (live):/summary-fail.json (live):	View Logs
/tmp/tmpq3j14pzj/summary-missing.json (live):/summary-missing.json (live):	View Logs
[tabs] debug.tab_switch timed 0 of 40 switches/ [tabs] debug.tab_switch timed 0 of 40 switches	View Logs
[tabs] debug.tab_switch timed 0 of 40 switches/ [tabs] debug.tab_switch timed 0 of 40 switches	View Logs
[tabs] the window draws no frames/[tabs] the window draws no frames	View Logs
[tabs] the window draws no frames/[tabs] the window draws no frames	View Logs
convention violations found (ERROR lines above)./ convention violations found (ERROR lines above).	View Logs
test_base_passes (main.NoticesPairTests.test_base_passes)/ test_base_passes (main.NoticesPairTests.test_base_passes)	View Logs
test_targets_outside_the_app_go_to_the_mac_canary (main.SwiftCanaryFleetCoverage.te st_targets_outside_the_app_go_to_the_mac_canary)/ test_targets_outside_the_app_go_to_the_mac_canary (main.SwiftCanaryFleetCoverage.te st_targets_outside_the_app_go_to_the_mac_canary)	View Logs
the committed export failed: check-daemon-capabilities-fresh: plans/cmux-next/ daemon-capabilities.json is stale:	View Logs

^{Need help on this PR? Tag @codesmith-bot with what you need.}

[teamleaderleo]

Bead cx-o2yrq created for this PR by the cmux coordinator.

[azooz2003-bit]

Non-green checks on head 3229117fb061, classified. This PR changes only cmux-next-ios/ and Packages/iOS/CmuxConversation/:

• fast gates (prepush gate, Sidebar-Look): names the base-update merge commit 3229117fb06 with CmuxNextSidebar/Views files that come from the base. The checkout is shallow, so the gate reads the merge as adding the whole tree. That bug is fixed in fast gates: deepen a pull request's checkout so a head that brings the base in is not read as adding the whole tree #24539. A local prepush-gate.py run on the same head reports no new violations.
• cmux-next checks: ThinScroller.swift:206 sleep, ThinScrollerFadeTests.swift:37 notification center, the perf-gate unlit test and stale daemon-capabilities.json are all base files (CmuxNextDesign, plans/), not in this diff.
• nightly-guards / workflow-guard-tests: FileNotFoundError: xcodebuild on the runner, which is infrastructure.
  iOS kit tests on this head (mini-cmux11s): AgentChat 126/126, Live 261/261, Chief 79/79 (one MacHome flake on the first run passed on rerun; MacHome isn't touched here).

[azooz2003-bit]

Review round 2 (fresh subagent): sent attachments, 3229117fb061..05f0ad0b0987

No blockers. Isolation is fine: the source is @mainactor, so the loader's weak capture is safe. Scope is fine: only acpmux-image: ids are fetched, and acpmux serves only images the session's own log names.

#	Finding	Resolution (32251815e7b3)
1	Thumbnails downloaded again on every cell rebuild	AcpmuxSessionSource caches the 24 newest images it read, shares a read in flight, and never caches a failed read
2	sentAttachments was never pruned	An entry is dropped when its record arrives or when a returned draft goes again under a new id; at most 8 are kept (test added)
nit	The same image twice in one prompt shared one id	The id carries #n, and recordedImageID strips it (test added)
nit	A failed Mac fetch said "isn't on this iPhone anymore"	It says "Connect to your Mac to see …" (test added)
left	A peer Mac's relay refuses _acpmux/attachment	Not changed: a peer-Mac session shows a placeholder for history images. A relay pass-through is a trust-policy change, so it is left to its owner

[azooz2003-bit]

Merge note for head 32251815e7b3:

• Reds that are not this PR's:
  • nightly-guards: no xcodebuild on that runner.
  • cmux-next checks: the ThinScroller findings are base files in CmuxNextDesign.
  • ios-simulator-build and its ios-tests wrapper: stale explicit PCMs in the runner's persistent DerivedData (ghostty.h has been modified since the module file). Fixed in test-ios: rerun CmuxiOS unit tests once when the runner's precompiled modules are stale #24600.
• Still pending: CmuxMobileKit tests, queued about an hour for capacity. The same suites passed on this head on mini-cmux11s with an iOS simulator: AgentChat 132/132, Live 262/262, Chief 79/79.
• Real-usage live check: passed (see the description). Both review rounds are resolved.