prep(dstamp): Adversary recon baseline — stamp mechanism + cold observables (HEAD 7ae7b0f is 9 commits past tag 0.7.0+3.3.1/eb96de9; chaos-version stamps base not head; abra nix-pinned 0.13.0-beta). No verdict yet, awaiting M1 claim.

REVIEW-dstamp.md

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+# REVIEW-dstamp.md — Adversary verdicts for phase `dstamp`
+
+Phase: investigate & solve the discourse abra-stamp drift (upgrade-HC1 stamps the
+prev-base tag commit instead of the PR-head version, harness-neutral, since ~06-10).
+SSOT: `/srv/cc-ci/cc-ci-plan/plan-phase-dstamp-discourse-drift.md`. Gates M1, M2.
+
+Verdict log is append-only. `review(...)`-prefixed commits carry verdicts (load-bearing
+watchdog signal). Findings filed under `## Adversary findings` in BACKLOG-dstamp.md.
+
+---
+
+## Prep notes (NOT a verdict — no gate claimed yet) @2026-06-11T15:5x
+
+Recon done cold before any Builder claim, to make M1/M2 verification fast and independent.
+Anti-anchoring: formed only from the plan (SSOT), the harness code, and direct host evidence
+— no dstamp JOURNAL exists yet; none read.
+
+**Stamp mechanism (from code):** HC1's "stamp" = the `coop-cloud.<stack>.chaos-version`
+docker service label abra writes on a `--chaos` deploy = the deployed recipe git commit
+(`runner/harness/lifecycle.py:468 deployed_identity`, `runner/harness/generic.py:146
+assert_upgraded`). Upgrade flow (`generic.py:226 perform_upgrade`): deploy prev-published
+base → `recipe_checkout_ref(recipe, head_ref)` (git checkout -f head) → `chaos_redeploy`
+(`abra app deploy --chaos`). HC1 asserts `chaos_commit == head_ref` (after stripping the
+`+U` untracked-overlay marker). PASS requires the chaos-version to equal the PR head.
+
+**Cold observable facts (from `/var/lib/cc-ci-runs/m2p-discourse/abra/recipes/discourse`
+snapshot + live `~/.abra/recipes/discourse` on cc-ci, 2026-06-11):**
+- Recipe HEAD `7ae7b0f` = "chore: upgrade to 0.9.0+3.5.0"; `git describe --tags` =
+  `0.7.0+3.3.1-9-g7ae7b0f` → HEAD is **9 commits past the newest annotated tag**
+  `0.7.0+3.3.1` (commit `eb96de9`). No `0.8.x`/`0.9.x` tag exists.
+- The drift symptom (per plan): chaos-version stamped `eb96de94+U` = the **prev-base tag
+  commit** (= the upgrade base `0.7.0+3.3.1`), NOT the PR-head `7ae7b0f`.
+- abra is **nix-pinned**: `abra version 0.13.0-beta-06a57de`, store path under
+  `/run/current-system` → binary drift requires a flake.lock/nixos-generation bump between
+  06-05 and 06-10 (verify against generations, don't assume).
+
+**Open question I'll independently re-derive when M1 is claimed:** why the `--chaos`
+redeploy after checkout-to-HEAD stamps the BASE commit (eb96de9), not HEAD (7ae7b0f).
+Candidates to test cold: (a) re-checkout to head silently reverted (abra fetch/reset during
+deploy); (b) abra chaos resolves the version from the app's recorded `.env` RECIPE/version
+(= the base) rather than the working-tree HEAD; (c) the "env drift" since 06-10 = recipe/
+mirror git state moved (unreleased commits pushed past last tag) or a tag re-pointed.
+
+**Guardrail teeth I will enforce at M2:** HC1 must still FAIL on a genuinely wrong stamp
+(synthesize a wrong-version deploy and show RED). Any "fix" that derives EXPECTED from
+"what makes the test pass" rather than abra's documented behavior = automatic FAIL.
+
+Status: idle, awaiting Builder to seed STATUS-dstamp.md and claim M1. Watchdog will ping
+on the `claim(...)` commit.