id: validation gap — no planted-bug / mutation check exists for tag observed-remove fold (P5.1)

Gap found by the #1075 validation audit (Phase 5, P5.1) — 2026-10-27

The plan of record (doc/2026-10-11T11-08-42Z_design_remaining_work/plan-phases.md) requires for P5.1 (observed-remove tags, the S8 model): "the S8 properties; planted-bug checks", and its §13 testing layers list layer 11 as "Mutation checks — planted bugs must fail — … membership, tags".

The property half exists and is strong (pkgs/id/tests/tag_claims.rs: the live-set oracle property under any delivery order, the compacted-fold agreement property, and the shrunk P5.1/P5.3 regression histories replayed at :481-505). But a fresh search of pkgs/id on main 37418e56 (2026-10-27) finds no planted-bug / mutation check for the tag fold: no planted or mutation references in pkgs/id/src/tag_claims.rs, pkgs/id/tests/tag_claims.rs, pkgs/id/tests/tag_index.rs, the justfile, or tests/README.md. Nothing demonstrates that a deliberately planted bug in the observed-remove fold (e.g. a clear removing a claim it never saw, or the causal-past walk dropping the transitive closure) is actually caught by the suite.

This is the tags counterpart of #1395 (membership voiding/frontier, P2.3/P2.8) — same class of gap, different subsystem, filed separately per the #1075 audit rules.

Acceptance criteria

A planted-bug/mutation check exists for the tag observed-remove fold: at least one deliberately introduced fault in the clear/causal-past logic is shown to make a named test fail, and the check is documented where the suite's other mutation checks live (justfile / tests/README.md).
The check runs on demand at phase end per plan §13 layer 11 (it does not need to run in the per-PR gate).

Found by: queue task 1256 (slice 4 of the #1075 audit), Lane D worker shift 2026-10-27.

CODE-510

🤖 Agent note · handed off

Agent: fleet monitor
Session / ID: repo-fleet-monitor run 2026-11-02 20:12 CST
Found via: monitor reconciliation
Task: Claim-evaporated repair: task 2585 is queued unclaimed (attempts 3/3, checkpoint stage handed_off) while this issue still carried claimed labels. Labels reset to queue/queued + status/needs-triage so GitHub matches the queue. The task is DEAD at its attempt cap and can never be claimed again — operator repair: raise the cap or enqueue a fresh packet resuming from stage handed_off.
Expectation: operator/lane pickup after repair; no holder is currently working this issue.

agent-note:v1 — task 2585 picked up by lane code-n, handed off to opencode claimant.

Task: task 2585 (triage, developing-today/code id: validation gap — no planted-bug / mutation check exists for tag observed-remove fold (P5.1) #1421)
State: claimed → handed_off (execution_lane: opencode)
Fresh check: id: validation gap — no planted-bug / mutation check exists for tag observed-remove fold (P5.1) #1421 OPEN, no hard-stop labels (held / user/owned / do-not-merge / do-not-auto-edit absent)
Next: opencode-claimant launches the bound session; it drives task 2585 to terminal state.
Attempts: 22/24 — near cap, claimant should complete before lease expiry.

🤖 Agent note · handed off

Agent: queue worker (repo-worker-code)
Session / ID: task 2585
Found via: queue claim
Task: Triage issue id: validation gap — no planted-bug / mutation check exists for tag observed-remove fold (P5.1) #1421 — validation gap: no planted-bug / mutation check for tag observed-remove fold (P5.1). Execution lane assigned opencode; handed off to the opencode claimant, which launches the bound session.
Expectation: effort s; done = claimant session triages issue id: validation gap — no planted-bug / mutation check exists for tag observed-remove fold (P5.1) #1421 against current main and routes or closes with evidence
Links: n/a yet

🤖 Agent note · handed off

Agent: queue worker (repo-worker-code), lane code-a
Session / ID: task 2585
Found via: queue claim
Task: task 2585 re-claimed; revalidated issue id: validation gap — no planted-bug / mutation check exists for tag observed-remove fold (P5.1) #1421 — still OPEN, no hard-stop labels; parked labels synced to the claimed set (queue/claimed + status/in-progress + work/assigned). Prior progress carries triage evidence (tag_claims.rs coverage at pkgs/id/tests/tag_claims.rs:137-215 and :433-470; no planted/mutation matches) and a preserved laptop worktree /home/user/git/fleet/2585 on branch queue/2585-1421-tag-mutation — resume from that, do not restart. Execution-lane assignment returned opencode, so handing off to the opencode claimant. CAUTION: attempts 24 of max 24 — AT CAP; if this claim expires unbound the task will need a cap raise.
Expectation: claimant launches the bound opencode session promptly and drives task 2585 (triage of issue id: validation gap — no planted-bug / mutation check exists for tag observed-remove fold (P5.1) #1421) to a terminal state.
Links: issue id: validation gap — no planted-bug / mutation check exists for tag observed-remove fold (P5.1) #1421

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id: validation gap — no planted-bug / mutation check exists for tag observed-remove fold (P5.1) #1421

Gap found by the #1075 validation audit (Phase 5, P5.1) — 2026-10-27

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id: validation gap — no planted-bug / mutation check exists for tag observed-remove fold (P5.1) #1421

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Gap found by the #1075 validation audit (Phase 5, P5.1) — 2026-10-27

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developing-today commented on Oct 27, 2026

dezren39 commented on Nov 3, 2026

35 remaining items

dezren39 commented on Nov 5, 2026

dezren39 commented on Nov 5, 2026

dezren39 commented on Nov 5, 2026

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