[nwparker]

	Files	Added	Deleted	Net
Test	2	$\color{#1a7f37}{\Huge{\mathbf{+}}}$​110	0	$\color{#1a7f37}{\Huge{\mathbf{+}}}$​110
Prod	1	$\color{#1a7f37}{\Huge{\mathbf{+}}}$​12	$\color{#cf222e}{\Huge{\mathbf{−}}}$​4	$\color{#1a7f37}{\Huge{\mathbf{+}}}$​8

Stacked on #32343. Behind ORCA_INTERNAL_WSL_HOSTS for the mover; the shared path it touches is the headless start of a saved pane (paired clients, SSH-managed and WSL hosts). Not for merge until the stack is reviewed.

Summary

After a WSL move, a plain shell split beside an agent pane came back as a new agent with a new session, and lost its folder (D1b-10 real-host run on awin, report bug 6).

Before / after

• Before: an agent tab holding an agent pane plus two shell splits restored as three agents; the two splits ran fresh codex sessions.
• After: the agent pane resumes its recorded session; the splits start as plain shells.

Mechanism

When a host starts a saved pane with no live terminal (materializePendingMobileSessionTerminal), a pane with no recorded agent session fell back to the tab-wide launchAgent and launched that agent. launchAgent describes the tab, not a pane. The fallback (and the launchAgent label on the spawn) now applies only when the tab has a single pane, the same rule the renderer already uses for tab-wide launch evidence.

Why this approach

The per-pane sleeping record already says which pane ran an agent; only the tab-wide fallback was wrong. Keeping the fallback for single-pane tabs preserves the #7587 rescue (a pending agent tab whose startup command never arrived).

Testing

• New mobile-session-tabs-split-agent-tab.spec.ts: split sibling starts as a shell (fails on the old code), the recording pane still resumes, and no pane starts a fresh agent without a record (fails on the old code).
• orca-runtime.test.ts: 1455 pass; the 2 failing folder-import tests fail the same way on the base commit.
• pnpm tc and the changed-code quality gate pass.

[nwparker]

Standalone version for main: #32418, which is the same change. When the stack is next rebased onto a main that has #32418, drop this commit (ebee49bb367f), for example with git rebase --onto <new-main> ebee49bb367f. Otherwise it conflicts on the same lines. Its spec is identical, and the comment text is aligned.

[nwparker]

Restacked on #32343 7f62612. This commit is now 23adc7b99a97. Once #32418 lands, drop it when the stack is next rebased onto main: git rebase --onto <new-main> 23adc7b99a97.

[nwparker]

Contained in the dark landing PR #34059 (its head commit is an ancestor of the landing branch). Closing in favour of it; branch kept.