[teamleaderleo]

cmux cloud start-session --agent claude started Claude on a Cloud machine that had none of the person's Claude login, so every turn answered "The provider rejected Claude Code's credentials on this Cloud machine." This happened even in a run whose app held the login: the cmuxterm-hq cloud-start-session capture (run 41415284694, with claudeLogin set by cmuxterm-hq#6219).

The composer's Cloud start already passes the login (CloudStartChat+Login, #29771, #29962, #31183, #31264): DEV and dogfood builds only, on a machine the person owns, and recorded on the machine's harness_login row. start-session never took that step. It now runs the same step after the machine connects and before the session starts. passHarnessLogin now takes a harness name, so both entry points share one path.

CmuxNextApp line count is unchanged. The ratchet was paid by removing a redundant local and merging two declarations in CloudStartSession.run.

Changelog

Fixed: In DEV builds, cmux cloud start-session gives the Cloud machine your Claude login, the way a composer Cloud start does.

Test

cmux-ci run --class light --script scripts/ci/package-test-lane.sh --arg=suite --arg=Packages/macOS/CmuxNext --arg=CloudStartSessionTests ...

• Red at 7f96a7a (test only): fails on base, since CloudStartSession has no login step.
• Green at the head: results below once the fleet run ends.

Observed / Not run

• Observed: the pre-push gate (no new violations).
• Observed: the cloud-start-session capture at cloud.startChat: a composer Cloud start works on the app server's link #31969's head 02834b1 failed, showing the credentials card (that run's screenshot).
• Not run yet: the capture rerun at this PR's head.

Agent session: agent session

🤖 Generated with Claude Code

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

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Summary by cubic

Fixes cmux cloud start-session so the Cloud machine gets the person's Claude login before the session starts, matching a composer Cloud start. Previously a Claude session on a machine without the login answered every turn with the provider's credentials rejection.

• passHarnessLogin now takes a harness name, so CloudStartChat and CloudStartSession share one login path.
• The step runs after the machine connects, before the session starts, and only in DEV and dogfood builds. The run re-checks the asking account after it, since the login can wait on a confirm.

^{Written for commit 6a078b3. Summary will update on new commits.}

[teamleaderleo]

Owned by an agent session · session

[github-actions]

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

Review 6a078b3: 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=pr32052 -f ref=lane/cloud-start-session-login -f platform=macos -f backend_mode=local

Shipped in:

• cmux NEXT nightly 1.0.0-nightly.4142409326201 (4f5bcd158c)
• cmux NEXT nightly 1.0.0-nightly.4142547762901 (19a2a238c7)
• cmux NEXT nightly 1.0.0-nightly.4142671611101 (36d2e27166)
• cmux NEXT nightly 1.0.0-nightly.4142821761901 (937b52c218)
• cmux NEXT nightly 1.0.0-nightly.4143019763401 (17e607bf23)
• cmux NEXT nightly 1.0.0-nightly.4143038272801 (912566a91a)

[teamleaderleo]

Review (codex gpt-6-astra high, router-review): BLOCK at 101d2cc

BLOCK at 101d2cc

Visual verdict: no images; Leo tries the build

1. [P1] [blocking] Packages/macOS/CmuxNext/Sources/CmuxNextApp/Cloud/CloudStartSession.swift:187 — After the new awaited login step, run no longer checks the captured account before opening the remote tab. passHarnessLogin catches cancellation and returns false, so a sign-out or team switch during login can leave this run continuing and starting a session under the wrong account. Add try still(name) immediately after the await and cover account change during login with a regression test.

[teamleaderleo]

Capture cloud-start-session at 6a078b3313f7. Every step passed: cmux cloud start-session --agent claude on a Cloud machine, then Claude answered cloud chat ok. At #31969's head (before this fix), the same capture showed the credentials refusal card.

Light	Dark

[teamleaderleo]

Review (codex, router-review): SHIP at 6a078b3

Reviewer: codex gpt-6-astra high, fast tier.

Follow-ups: 1. Each lands as an issue in this repo that links this receipt; the lane that opened the PR fixes it forward.

SHIP at 6a078b3

Visual verdict: no images; Leo tries the build

No correctness findings in the changed flow. The focused suite could not run because this box has no Swift toolchain.

Follow-ups: [P2] [follow-up] No after screenshots were provided for this Cloud flow.

[cmux-bot]

cmux-bot approves 6a078b3: an independent review passed this exact head (router-review receipt by teamleaderleo). A push needs a new review; a later BLOCK at this head dismisses this approval.

[teamleaderleo]

Red/green on the fleet (scripts/ci/package-test-lane.sh, CloudStartSessionTests + CloudStartChatLoginTests + CloudStartChatMachineTests):

• Red at 7f96a7a (test only): the test target fails, because start-session has no login step (step 2b395c216ff0e08f4ce32378).
• Green at 6a078b3: all 3 suites pass (step 601a9c42ad94cdbf56d8a673).
• The capture above, at the same head, shows Claude's reply on the machine.