test: live cross-process provider session reuse e2e (Myra codepath) (by Wren)

[conoremclaughlin]

Why

Stage 2 (#446) had strong unit coverage but its integration/live tiers were validated manually (shell runs against real Claude). This codifies the highest-value manual proof — the cross-process/Myra codepath — into a committed test, closing that gap.

What it asserts

Two SEPARATE ink chat --non-interactive processes (like two heartbeats) sharing one PCP session id, against a real server + real Claude:

• exactly ONE native jsonl created across both invocations — process 2 resumes, it does not fragment into a new file (this is the exact opacity the feature fixes);
• the ink transcript's backend_session marker matches that jsonl id;
• the resumed session recalls a codeword planted in process 1, though process 2 sent only the delta (cross-process continuity).

The first two are deterministic (independent of LLM phrasing); the recall is a substring check.

How it runs

• Opt-in: INK_LIVE_RUN_CLAUDE=1 yarn test:live (costs Claude API).
• Gated on server reachability; excluded from the default yarn test (via the existing **/*.live.test.ts exclude).
• realpath's the fixture cwd so it matches how Claude keys its project dir on macOS.
• Verified locally: 1 passed (~12s).

Coverage honesty

Covers 2B (cross-process). 2A (across-turn interactive) and the envelope-shape-drift reseed stay unit-covered — the interactive multi-turn path resists automation (readline doesn't consume piped stdin past the first line). Open to ideas if you know a clean way to drive interactive multi-turn.

🤖 Generated with Claude Code

[conoremclaughlin]

LGTM — no findings.

I checked the new live test against the Stage 2 cross-process path: it reattaches by PCP session id, recovers the backend_session marker from the transcript, asserts the native Claude jsonl doesn’t fragment on the second process, and verifies the codeword continuity as a higher-level smoke signal. The macOS realpath handling for Claude’s project-dir keying looks right.

Validation run locally:

• git diff --check origin/main...HEAD
• yarn test:live packages/cli/src/repl/session-reuse.live.test.ts (skipped as expected without INK_LIVE_RUN_CLAUDE/CLAUDE_LIVE_READY)
• yarn workspace @inklabs/cli vitest run src/commands/chat.session-reuse.test.ts src/commands/claude.test.ts src/backends/adapters.test.ts (122 passed)
• yarn workspace @inklabs/cli type-check
• yarn workspace @inklabs/cli build
• yarn workspace @inklabs/cli test (974 passed, 4 skipped)

I did not run the costly live Claude path in this review because the live opt-in env was not set.