Three planning records still treat the worktree-store intent itd-2609091014076309's planning interview as owed, though it was held on 2026-09-30 (its record lists the rulings, and its Open Questions read 'None open'): spc-42's '## Blocked on' lists that interview as the blocker; iss-213's deferral_reason says 'Owed: the store draft's planning interview'; itd-148's Acceptance Criteria note and Open Questions defer to after it; and spc-42's Scope item 2 calls the check verb's name one of the store intent's open questions, though that intent's Decision 5 settled it as a sub-verb of ahoy. Found by the lane for iss-2610111926302792.

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mentions6

• iss-213Several agents sharing ONE git worktree silently invalidated a verification result and came close to losing committed work. Observed repeatedly during the 2026-08-11 install-test round, in a repo that is about to run more agents, not fewer.
• iss-2608230847432285Per-agent worktrees do not isolate a session whose shell cwd reverts to the shared checkout, so the mitigation iss-213 recommended has a hole. This refines iss-213, which recorded several agents sharing one git worktree silently invalidating a verification result, and whose recommended direction was to give each agent its own worktree so the whole class disappears. That direction is now in force via the AGENTS.md Concurrent sessions section, and on 2026-08-23 three concurrent sessions demonstrated it does not hold. A session's shell cwd can be silently reset from its worktree back to the primary working directory, and the notice arrives on the tool result AFTER the command that caused it, so the contamination lands on the NEXT command. It fails toward the shared tree, which is the wrong direction: two sessions wrote into the main checkout while believing they were in their own worktree. One appended to two Go test files, the other filed a capture and edited three record files, and both discovered it only when a third session read git status in the main checkout and asked who owned the diffs. Nobody lost work, because the convention that a diff you did not make is a peer's work held and the owners were asked rather than the files committed. The isolation property did not hold; the coordination convention compensated for it. Two details generalise beyond this instance. First, the failure is silent in BOTH directions: nothing warns the writer, and nothing would have warned a committer using git add -A, because the misplaced files are indistinguishable from that session's own in git status. What stood between this and a bad commit was one session committing with explicit paths and another happening to run git status for an unrelated reason. Detection was not mechanical in any of the three cases. Second, this is the write-side twin of iss-213 rather than a restatement of it: iss-213's dangerous member was a verification result that described no tree in particular, on the read side, while this is work landing in a tree whose HEAD another session is preparing to move. Same root cause, that the checkout is the unit of isolation and nothing enforces which checkout a session is in, on opposite sides of the read/write boundary. The mechanical mitigation is to address the tree explicitly on every git invocation, git -C <abs-path>, and to use absolute paths for file writes, rather than relying on a persisted cd: a cd is a session-global mutation with no scope and no expiry, which is the wrong shape for the mechanism that is supposed to provide isolation. AGENTS.md states that the checkout is the unit of isolation without saying what makes a session stay in its checkout, and that gap is what let three sessions make the same mistake in one day. Decide the routing: an AGENTS.md line under Concurrent sessions is the cheapest rung and matches how the sequential-id caveat was handled, while the durable form is whatever makes a session's tree unambiguous rather than remembered.
• iss-2610111926302792Present-state planning prose still calls itd-2609091014076309 'the store draft' although the intent is in planned/: itd-148 (lines 64 and 188), spc-42 (lines 27 and 112) and iss-213 (line 11). The drift fix for iss-2610090744073409 corrected the CONCURRENCY rule, the build brief page and lane.go, and left these planning records as out of its remedy's scope; its ruthless review recorded them.
• itd-148Every change starts in its own worktree in abcd's store: the primary checkout is a read-only surface, and abcd blocks mutations there for every session but a declared coordinator
• itd-2609091014076309Session and agent worktrees live in a machine-scoped store that abcd lists and reclaims, never beside the user's own projects
• spc-42every-change-starts-in-its-own-worktree-the-primary-checkout