[firstintent]

Local Claude sessions can select an authorized account from a preinstalled cswap in the new-session model menu's advanced options. Default login and other vendors work without cswap. Selecting the current default account allows cswap's native fallback; isolated accounts retain their identity and profile across resumes, role switches and delegated children. Explicit grants are checked independently of project access.

The launcher wraps the existing stream-json argv with cswap run, using pipes and a child-local exec relay. The relay preserves binary overrides, keeps auth probes off SDK stdin, verifies the effective profile, and selects fresh/resume in that profile. cswap and Claude retain credential/refresh ownership. Public DTOs expose no profile paths or raw email. Account discovery rejects cswap's optional model-based quota probe. Remote, terminal and non-Claude selection are unsupported.

Maps to local issue docs-local/issues/#229. Based on dev and targets dev. No version bump or deployment.

Validation:

• make check, make test, real-PTY make test-web, fmt and diff checks passed.
• SPA production build and make web-check: 871 tests passed; DSH plugin npm test: 287 passed.
• Playwright: 3 passed for installed/absent cswap and the existing lazy-create flow.
• make perf-gate passed without changing thresholds: session-list p95 41.51ms, status p95 31.32ms, gateway lock hold p99 0.196ms.
• Strict auth-probe stdin regression failed before the fix and passed after; offline adapter/relay tests also cover multiple turns, profile-bound resume, slot drift, metadata loss, default fallback, uninstall and account grants.
• Installed cswap 0.29.0 + Claude Code 2.1.318 completed initialize through the real relay in temporary homes using a fake token; native PID registration was verified. No real subscription inference, OAuth rotation or spend was tested.
• Independent checker found no remaining blockers after fixes.
• Final commit CI: https://github.com/firstintent/ccteam/actions/runs/41819942198 (fmt/clippy/deterministic baseline all passed).