two-orchestrator-sessions-in-one-user-account-share-an

Summary

The design record for itd-2609221656373558: joining, the claim, the three modes, the bounds and the comparison.

Scope

1. The claim (internal/core/implement/claim.go): a claim file per record under the run's state in the machine store (~/.abcd/runs/<root-sha>/claims/<record>.json) carrying the session, the lane, the time and a lease; a claim is taken by an atomic create that fails if the file exists, which is the exclusion; a lapsed lease is claimable and the lapse is logged (criterion 3).
2. Joining: a session reads the run's state and writes session_open with its id; nothing signals the first session (criterion 1).
3. The modes: run.mode per window (claim | batch | split-roles), written into the window's log line; in batch the assignment comes from the run file, in split-roles the second session takes only review, audit and landing steps (criteria 2, 7).
4. The bounds: the second session's configuration carries role: second, which refuses the release path and any lane whose files touch the reading corpus, caps it at one lane, and gives it its own ceiling; contention (a failed claim, a busy queue, a locked store) backs it off with a logged reason (criteria 4, 5, 6).
5. The measurement: the run log's existing events plus claim, claim_denied, backoff and window_mode; the comparison is derived at the run's end (criteria 2, 6, 7).

Out of scope

• A third session; other accounts or machines; an automatic scheduler.

Approach

Everything lives in the machine-scoped run state the measurement ruling already put there, so two sessions share one directory and no repository file; the claim's exclusion is an atomic file create, which needs no lock manager and survives a killed session through its lease.

Footprint

• packages: internal/core/implement, internal/core/positioning, internal/surface/cli
• tests: the claim's exclusion under two writers; the lease lapse; each mode's window line; the second session's refusals; the backoff log; the derived comparison

How the criteria are satisfied