[LukasDoubleU]

T4 moves its base from T3 Code v0.1.2 to v0.1.5, through v0.1.4 and skipping v0.1.3 as a separate step: 804 upstream commits (779 to v0.1.4, then 25 to v0.1.5). Nearly everything T4 carried from upstream has now shipped there, so T4 uses upstream's code for it and carries only the tray (#19176) and the last-message sort (#22032).

Closes #3

Changes users will notice

These come from following upstream's code; they belong in the release notes.

• Settled threads leave project folders. Folders hold active threads only; settled threads sit on the shared Settled shelf for every grouping. This is upstream's final #21039. A project with no active threads gets no folder unless you filter to it.
• Beta is now Labs. Upstream renamed the page, and its /settings/beta links redirect there. T4's own Beta page is gone: the boring sidebar and linked environments toggles are on Labs, Compact idle threads moved to Settings → Providers → Advanced.
• Ctrl+N on servers without clone tracking. The new-thread dialog no longer falls back to the blocking clone for servers that lack clone tracking; upstream removed that path.
• No update track switch. Upstream's Settings → About → Update track (#26288) moves every machine to the newest npm release of the other track. T4 publishes neither npm releases nor a Nightly feed, so T4 builds hide it, refuse a switch started from any T3 Code app, and ignore a track an earlier build saved. A desktop that someone moved to Nightly gets updates again.
• Startup recovery links to T4's releases. When the desktop app can't start, Reinstall and Open releases open this repository's releases instead of upstream's.
• Full conversations on switching back. Upstream's recovery (#25610) replaces T4's fix(server): switching back to a provider whose old conversation is full starts a fresh one #134: switching back to a provider whose old conversation has no room still starts a fresh one with the thread's history, and now also keeps background work running and covers ACP providers.

Also new for T4 users:

• Agents can offer to link a machine again. t3_environment_link is back, with its link card, as issue Hide the agent tool t3_environment_link #3 planned once an official release ships the peer-link stack. Asked to work on a machine that isn't linked, an agent offers the link in a card instead of sending you to Settings.
• Linked environments stay on. Upstream gates them behind a Labs toggle that starts off and also pauses existing links. T4 settings saved before the toggle existed have no value for it, so T4 defaults it to on; without that, every machine's links would stop after the update. Settings → Labs still turns them off.

From upstream

v0.1.3, v0.1.4 and v0.1.5 bring, among others:

• The new design is the only design (#24865, #25251, #25778); F6 and arrow keys move through the sidebar (#25877).
• Linked environments (#16653 and its stack) and project folders (#21039) upstream, with a Labs page, guest links (#24104) and custom snooze presets (#26208).
• MCP tool schemas cut by about a third, 18 tools merged into action tools (#25423, #25790).
• New drafts fall back to a configured model when the default provider is out of usage (#26164).
• Returning to a provider whose conversation is full starts a fresh one with the thread's history (#25610).
• Upstream deleted about 18k lines nothing reached (#26238), capped comments at four lines and requires a reason on every React effect.
• v0.1.5: turn a No project thread into a project (#26767), the undo notice moves to the sidebar footer (#26874), choose what the thread details card shows (#26904), a Labs toggle keeps usage limits in view (#26859), release notes in the update popover (#26893), and Update everything updates service hosts without waiting on npm (#26917). No migration changes.
• Hundreds of fixes on web, desktop, mobile and the server.

Carries dropped

Shipped in v0.1.4, so T4 now uses upstream's version:

• Peer-link stack: #16653, #16654, #16655, #16684, #16695, #16698, #16719, #17130.
• Project folders: #21039.
• Picked from main: #23886, #21299, #23798, #24589, #24571, #24622, #24617, #23751, #24032, #24343.

scripts/t4/upstream.json now has base v0.1.5 and only #19176 and #22032. The README's carried table and feature list follow, and versions read 0.1.6-t4.N.

Migrations

Upstream ships the peer-link migrations at the same ids and names as T4 (070–072), so T4 has no migrations of its own any more and the reconciler from #121 is gone.

• A database from any 0.1.3-t4.N build migrates as upstream's: nothing runs.
• A fresh database runs upstream's 001–072.
• 069 (message search) keeps T4's triggers, which also index messages agents and schedules write (Thread search finds the right thread first: ranked by match and recent use, indexed message search #127). Every T4 database already ran them.
• Upgrade note: a machine still on a 0.1.2-t4.N build has the peer-link migrations at 068–070. This version refuses to start on that database, with upstream's "would skip required schema migrations" error, and changes nothing. Install the current 0.1.3-t4.N release first, then this one.

scripts/t4/README.md describes this and keeps undo-peer-link-migrations.ps1 only for switching to an official release older than v0.1.4, which T4 doesn't support.

Conflicts

241 files conflicted. Most of the carried code resolved by merging against a base of v0.1.2 plus T4's carries, so only T4's own changes met upstream's. The rest, by area:

• MCP tools (#25423). T4's additions moved onto upstream's compact descriptions and action tools: pin on t3_thread_launch (Agents can pin the threads they start #129), nextAccount in orchestrator_capabilities, pinned threads across machines in t3_thread_list (feat: copy a thread's id, and let agents find pinned threads and bare thread ids across linked environments #50), bare thread ids found on linked machines, set_icon/clear_icon on t3_thread_update (feat: threads get their own icon, experts get Start new topic, and the thread menu gets shorter #113), wait-on-message (feat(server): a thread wait ends when a message reaches the waiting thread #83), webhookPath (feat: webhook paths for agents, memory-limit retries, Go ahead instructions and emoticons #112) and t3_request_attention (Experts: turns you didn't start stay quiet, and an agent can ask for you with Needs you #102). The thread metadata tool lost link_pull_request upstream, as the separate tools cover it.
• Orchestration instructions are upstream's shorter text, with T4's lines for topics, pinning at launch, pinned experts, t3_request_attention and the Go ahead section.
• fix(server): switching back to a provider whose old conversation is full starts a fresh one #134 and #25610 solve the same problem. T4 takes upstream's recovery, which also probes the exact payload, keeps background work and covers ACP. fix(server): switching back to a provider whose old conversation is full starts a fresh one #134's integration test stays and passes on upstream's code: switching back to Claude at 190k of 200k starts a fresh native thread with the whole history.
• Account failover and #26164. Upstream's fallback picks a new draft's starting model; T4's recommended-account hook may then move it to the best account of that provider, and the fallback notice matches any account of that provider. Failover of a running turn is unchanged.
• Claude adapter. The memory-limit start retry (feat: webhook paths for agents, memory-limit retries, Go ahead instructions and emoticons #112) moved into upstream's rewritten startup: a registration timeout while agents are at their memory limit still waits for room, otherwise upstream's own retry applies. Pinned-thread memory (feat: pinned threads keep a memory file #51) rides upstream's new prompt delivery.
• Sidebar. Upstream's derived list state, folders and keyboard navigation, with T4's sort and group menu, Background and Experts sections, topics, Needs you, thread icons and machine icons on top. Machine and status folders join the keyboard tree.
• Chat. MessagesTimeline is rebuilt on upstream's version, which dropped the paint-only path, with T4's divider, jump to my last message, minimap groups, reply action and message times re-applied.
• Notifications. Upstream's completion notice now waits 2 s and is dropped when the thread starts working again, expecting the next run to notify. With T4's quiet turns (feat: no completion notice for turns another agent started #82), a turn the user didn't start beginning in those 2 s swallowed the user's own notice. Such a turn now leaves it pending (own commit, with a test); a continuation of the user's own turn still replaces it, as upstream does.
• Copy thread ID keeps copying the bare id. Upstream's Copy → Thread copies a chip, so the two are different actions; the helper moved to upstream's @t3tools/client-runtime/thread-reference.
• Tests upstream deleted or changed. T4's cases moved onto upstream's helpers: the thread tail HTTP test, the in-memory projection store cases (upstream deleted that store) and others.
• v0.1.5 merge. Ten files conflicted, all small: T4's account failover and thread icon capabilities sit next to upstream's Turn into project, the thread menu keeps T4's Dismiss, icon and topic actions with upstream's new item under More, and sidebar shelves keep T4's header action while the undo notice moves to the footer (#26874). cliRelease.ts keeps the fork's release repository.
• Update paths. No path installs upstream on a T4 machine: the desktop feed and every server download use this repository's releases, and Update everything only offers T4 versions, which npm never has. The track switch could still strand a T4 desktop on a track with no builds, hence the patch above. Keyed on T4's release versions (X.Y.Z-t4.N, X.Y.Z-test.N), so upstream's tests keep testing upstream's switch.

Verification

Heavy steps ran one at a time. check:changed starts all its steps at once (format, lint, knip passes, a 4-way typecheck and unthrottled vitest), so its steps ran one by one instead, over the 432 files that differ from v0.1.5.

• Typecheck: every workspace package with a typecheck script passes, one at a time.
• Format, lint, knip, GraphQL: pass. Lint needed fork code to follow upstream's stricter rules: comments of four lines or fewer, a stated reason on each React effect, and the newer Effect diagnostics.
• Tests: 181 test files beside fork changes, --maxWorkers=2, one package at a time; all pass:
  • server 68 files (1,326 tests), web 45 (1,126), mobile 12 (247), desktop 10 (94).
  • contracts 10 (75), shared 11 (175), client-runtime 12 (146), provider-core 5 (21), provider-opencode 3 (52), three more packages 3 (24), scripts 2 (50, 4 skipped).
  • fix(server): switching back to a provider whose old conversation is full starts a fresh one #134's test passes on upstream's recovery: starts a fresh native thread when a returning handoff exceeds the old one.
  • New: the notification gate keeps the user's completion when a turn they didn't start begins within the grace (fails without its fix); a T4 build refuses track switches and ignores a saved track; T4's release page URL.
  • Two fork test expectations changed with upstream's behavior: project folders no longer include empty projects (#26387), and the thread menu's More → Copy now lists upstream's Thread copy.
• node --test .github/scripts/t4-upstream-watch.test.cjs: 11 pass with the new upstream.json.
• Not run here: the 19 browser test files (headless Chromium) and the full suites; CI runs them.
• Migrations:
  • migrate-dev-db copied a read-only snapshot of a real T4 database (history up to 072) and the v0.1.4 build ran no migrations on it; its slot check passed. v0.1.5 changes no migrations.
  • A fresh database ran all 72 migrations, then none on a second start.
• Tooling: upstream now pins vite-plus 1.4.0. A global vp 1.0.0 fails to load @effect/vitest files and skips lint rules, so everything above ran with the workspace's node_modules/.bin/vp.

Workflows

Upstream added agent-context-budget.yml, mobile-fingerprint-label.yml, relay-preview.yml, relay-preview-cleanup.yml and stale-needs-more-info.yml. They are left as they are, to be disabled on GitHub after the merge.

Done by Claude Opus 5.5 in Claude Code, in T3 Code.

🤖 Generated with Claude Code