# Additive-v2 Dual-Write Implementation Plan

> **For agentic workers:** REQUIRED SUB-SKILL: Use superpowers:subagent-driven-development (recommended) or superpowers:executing-plans to implement this plan task-by-task. Steps use checkbox (`- [ ]`) syntax for tracking.

**Goal:** Make store-format v2 *additive* — upgraded `secrets` clients read either blob suffix and dual-write existing `properties` externals — so the destructive `migrate --finalize` becomes optional GC and the cross-machine coordination gate disappears.

**Architecture:** Replace the marker-driven single-suffix helper `_external_blob_suffix(type)` with two helpers: a read-resolver that tries `.properties.age` then falls back to `.gradle-properties.age`, and a write-targets helper that writes the v2 suffix always plus the v1 suffix *only when a v1 twin already exists* (dual-write existing externals; brand-new externals are v2-only — the intended forcing function). Reads and writes no longer depend on the `.secrets-format` marker, which keeps its meaning (born-v2 / finalized). Because fresh pushes now write the v2 suffix on any store, the migrate/finalize test fixtures (which relied on push producing a v1 blob) are updated to fabricate an old-client v1 blob.

**Tech Stack:** Single bash 3.2 script (`secrets`); `age`, `git`, `jq`. Tests: `bats-core` (`test/migrate.bats`, `test/manifest.bats`). Every standalone `[[ ]]` test assertion ends with `|| false` (bash 3.2 ERR-trap gotcha).

**Spec:** `docs/superpowers/specs/2026-06-08-additive-v2-dual-write-design.md`. **Ticket:** EGB-712.

---

## Background facts (verified against branch `brian/egb-712-...`, post-EGB-710)

- `_external_blob_suffix()` — `secrets:548-555`. Returns `properties` for `gradle-properties` on a v2 store (`_store_format == 2`), else the type verbatim; `file` always returns `file`. Blob path = `external/<slug>.<suffix>.age`.
- Callers of `_external_blob_suffix`: push file write `secrets:655`, push properties write `secrets:684`, pull read `secrets:713`, verify read `secrets:2056`. All four are replaced; then the helper is deleted.
- `_secrets_files_slug(path)` (`secrets:512`) derives the machine-independent slug. dotenv and `file` blobs are byte-identical in v1/v2 (only the `properties` suffix diverges).
- `_store_format()` (`secrets:529`) and the marker stay as-is — set only by `init` (born-v2) and `migrate --finalize`. Push must NOT stamp it (see spec §3).
- Existing test that codifies OLD write behavior: `test/migrate.bats:52` "push on a v1 store still writes .gradle-properties.age (back-compat)" — rewritten in Task 2.
- Tests that fabricate-or-rely-on a v1 properties blob from `make_v1_store; push` and break once push writes v2-only (repaired in Task 3): the migrate copy-forward/idempotent tests, the `--dry-run` rename test, the dotenv+file untouched test, all four finalize tests, the EGB-710 manifest-free / undeclared-twin tests, and the two `--status` tests that need an actual v1 blob. (dotenv-only and already-v2 tests are unaffected.)
- Baseline before this plan: `bats test/` = 242 passing.

## File structure

- Modify: `secrets` — delete `_external_blob_suffix` (548-555); add `_resolve_external_blob_read` + `_external_blob_write_targets` in its place; rewire push (651-688), pull (712-713), verify (2052-2068); extend `_migrate_status`; docs in `cmd_help`.
- Modify: `test/migrate.bats` — add `m_fake_v1_blob` helper; add read-fallback + write-rule + status-coverage tests; repair the v1-blob-dependent fixtures.
- Modify: `CLAUDE.md`, `README.md`, `VERSION` (→ `0.7.0.0`), `CHANGELOG.md`.

---

## Task 1: Read-resolver — reads try both suffixes

**Files:** `secrets` (replace `_external_blob_suffix` with the read-resolver; rewire pull + verify reads), `test/migrate.bats`.

- [ ] **Step 1: Write the failing test** — a v2 store whose properties blob exists ONLY in the v1 suffix must still pull.

Add to `test/migrate.bats` (after the format-marker tests, ~line 60):

```bash
@test "pull reads a v1-suffix properties blob on a v2 store (read-fallback)" {
  init_with_remote                                   # born-v2 store (marker=2)
  m_gradle_src $'beaconClerkPkTest=pk_test_v1\n'
  create_project_dir rffallback
  printf 'gradle-properties ~/.gradle/gradle.properties beaconClerkPkTest\n' > .secrets-files
  "$SECRETS_BIN" push rffallback >/dev/null 2>&1     # writes .properties.age on a v2 store
  # Simulate an external that exists only in the v1 suffix (an old client wrote it):
  local v2blob; v2blob=$(ls "$SECRETS_DIR/rffallback/external/"*.properties.age)
  mv "$v2blob" "${v2blob%.properties.age}.gradle-properties.age"
  rm -f "$HOME/.gradle/gradle.properties"
  "$SECRETS_BIN" pull rffallback >/dev/null 2>&1
  run grep -q 'beaconClerkPkTest=pk_test_v1' "$HOME/.gradle/gradle.properties"
  [ "$status" -eq 0 ]
}
```

- [ ] **Step 2: Run it, confirm it fails**

Run: `bats test/migrate.bats -f "read-fallback"`
Expected: FAIL — old pull (`secrets:713`) uses `_external_blob_suffix gradle-properties` = `properties` on a v2 store, looks only for `.properties.age` (which we renamed away), warns "no encrypted data", restores nothing → the grep fails.

- [ ] **Step 3: Replace `_external_blob_suffix` with the read-resolver.** Replace `secrets:542-555` (the comment block + `_external_blob_suffix()` through its closing `}`) with:

```bash
# Resolve the on-disk path of an external blob for READING. Tries the v2 suffix
# (.properties.age) first, then falls back to the v1 (.gradle-properties.age) for
# `properties` externals, so an upgraded client finds the blob whichever format
# wrote it (additive v2 — EGB-712). `file` externals share one suffix in both
# formats. Echoes the path of the blob that exists; if neither exists, echoes the
# canonical v2 path so the caller's "no blob" message reads sensibly. Read-only.
_resolve_external_blob_read() {
  local project="$1" slug="$2" mtype="$3"
  local base="$SECRETS_DIR/$project/external/$slug"
  case "$mtype" in
    file)
      echo "$base.file.age" ;;
    properties|gradle-properties)
      if [ -f "$base.properties.age" ]; then
        echo "$base.properties.age"
      elif [ -f "$base.gradle-properties.age" ]; then
        echo "$base.gradle-properties.age"
      else
        echo "$base.properties.age"
      fi ;;
    *)
      echo "$base.$mtype.age" ;;
  esac
}
```

(The write-targets helper is added in Task 2 — leave a gap; do not reintroduce `_external_blob_suffix`.)

- [ ] **Step 4: Rewire the pull read.** At `secrets:712-713`, replace:

```bash
    local slug; slug=$(_secrets_files_slug "$mpath")
    local blob="$SECRETS_DIR/$project/external/$slug.$(_external_blob_suffix "$mtype").age"
```

with:

```bash
    local slug; slug=$(_secrets_files_slug "$mpath")
    local blob; blob=$(_resolve_external_blob_read "$project" "$slug" "$mtype")
```

- [ ] **Step 5: Rewire the verify read.** At `secrets:2055-2065`, replace:

```bash
    slug=$(_secrets_files_slug "$epath")
    erel="external/$slug.$(_external_blob_suffix "$etype").age"
    # Account for BOTH the v1 and v2 suffix forms in the orphan set. During the
    # migration window (after copy-forward, before --finalize) the v2 twin
    # coexists with the v1 blob; neither should read as an orphan whichever
    # format the store currently reports. (file's two forms are identical.)
    expected="${expected}external/$slug.$etype.age"$'\n'
    [ "$etype" = "gradle-properties" ] && expected="${expected}external/$slug.properties.age"$'\n'
    eblob="$pdir/$erel"
    if [ ! -f "$eblob" ]; then
      echo "FINDING: external '$epath' ($etype) is declared but has no blob in the store ($project/$erel missing). Run 'secrets push'." >&2
```

with:

```bash
    slug=$(_secrets_files_slug "$epath")
    # Account for BOTH suffix forms in the orphan set — a dual-written `properties`
    # external (additive v2 — EGB-712) legitimately has both blobs on disk; neither
    # is an orphan. (file's two forms are identical.)
    expected="${expected}external/$slug.$etype.age"$'\n'
    [ "$etype" = "gradle-properties" ] && expected="${expected}external/$slug.properties.age"$'\n'
    eblob=$(_resolve_external_blob_read "$project" "$slug" "$etype")
    erel="${eblob#"$pdir"/}"
    if [ ! -f "$eblob" ]; then
      echo "FINDING: external '$epath' ($etype) is declared but has no blob in the store ($project/$erel missing). Run 'secrets push'." >&2
```

(Note: `_external_blob_suffix` still has two remaining callers in push — push isn't rewired until Task 2, so the script still parses and runs. Those calls keep working because the function is only deleted in Task 2 Step 6, after push is rewired.)

**IMPORTANT:** do NOT delete `_external_blob_suffix` yet — push (`secrets:655`, `secrets:684`) still calls it until Task 2. Deleting it now breaks push.

- [ ] **Step 6: Run the read-fallback test + full migrate suite**

Run: `bats test/migrate.bats`
Expected: the new "read-fallback" test PASSES; all other migrate tests still PASS (push unchanged; pull/verify now use the resolver, which is equivalent to the old behavior whenever the suffix matches the store format).

- [ ] **Step 7: Commit**

```bash
git add secrets test/migrate.bats
git commit -m "feat: read-resolver tries both external suffixes (additive v2, EGB-712)"
```

---

## Task 2: Write-targets — twin rule (dual-write existing, v2-only for new)

**Files:** `secrets` (add `_external_blob_write_targets`; rewire push file + properties writes; delete `_external_blob_suffix`), `test/migrate.bats`.

- [ ] **Step 1: Write the failing tests.** Add to `test/migrate.bats`:

```bash
@test "push writes the v2 suffix for a fresh external even on a v1 store" {
  make_v1_store
  m_gradle_src $'beaconClerkPkTest=pk_test_abc\n'
  create_project_dir freshv1
  printf 'gradle-properties ~/.gradle/gradle.properties beaconClerkPkTest\n' > .secrets-files
  "$SECRETS_BIN" push freshv1 >/dev/null 2>&1
  run bash -c "ls $SECRETS_DIR/freshv1/external/*.properties.age"
  [ "$status" -eq 0 ]                                              # v2 suffix regardless of marker
  run bash -c "ls $SECRETS_DIR/freshv1/external/*.gradle-properties.age 2>/dev/null"
  [ "$status" -ne 0 ]                                              # no v1 twin for a brand-new external
}

@test "push dual-writes the v1 twin so old clients stay fresh" {
  make_v1_store
  m_gradle_src $'beaconClerkPkTest=pk_test_old\n'
  create_project_dir dualwrite
  printf 'gradle-properties ~/.gradle/gradle.properties beaconClerkPkTest\n' > .secrets-files
  "$SECRETS_BIN" push dualwrite >/dev/null 2>&1                    # v2-only (fresh)
  m_fake_v1_twin dualwrite                                         # simulate a pre-existing v1 twin
  m_gradle_src $'beaconClerkPkTest=pk_test_new\n'
  "$SECRETS_BIN" push dualwrite >/dev/null 2>&1                    # twin exists -> dual-write both
  # Prove the v1 twin was refreshed: drop the v2 blob, pull, expect the NEW value.
  rm -f "$SECRETS_DIR/dualwrite/external/"*.properties.age
  rm -f "$HOME/.gradle/gradle.properties"
  "$SECRETS_BIN" pull dualwrite >/dev/null 2>&1
  run grep -q 'beaconClerkPkTest=pk_test_new' "$HOME/.gradle/gradle.properties"
  [ "$status" -eq 0 ]
}
```

- [ ] **Step 2: Add the `m_fake_v1_twin` test helper.** In `test/migrate.bats`, next to `make_v1_store` (~line 12), add:

```bash
# Simulate an old (v1) client's properties blob: copy the pushed v2
# .properties.age to its v1 .gradle-properties.age twin. (Current clients never
# write the v1 suffix for a fresh external, so tests fabricate it.) Use `cp` to
# KEEP the v2 blob (dual present); see m_make_v1_only to leave only the v1 blob.
m_fake_v1_twin() {
  local proj="$1" v2
  v2=$(ls "$SECRETS_DIR/$proj/external/"*.properties.age)
  cp "$v2" "${v2%.properties.age}.gradle-properties.age"
}
# Like m_fake_v1_twin but renames (leaves ONLY the v1 blob) — for old-client-only
# / copy-forward fixtures.
m_make_v1_only() {
  local proj="$1" v2
  v2=$(ls "$SECRETS_DIR/$proj/external/"*.properties.age)
  mv "$v2" "${v2%.properties.age}.gradle-properties.age"
}
```

- [ ] **Step 3: Run the new tests, confirm they fail**

Run: `bats test/migrate.bats -f "fresh external even on a v1 store"`
Expected: FAIL — on a v1 store, the old push (`_external_blob_suffix gradle-properties` = `gradle-properties`) writes `.gradle-properties.age`, so the `*.properties.age` assertion fails.
Run: `bats test/migrate.bats -f "dual-writes the v1 twin"`
Expected: FAIL — old push writes a single suffix; the second push won't refresh the v1 twin.

- [ ] **Step 4: Add the write-targets helper.** Immediately after `_resolve_external_blob_read` (added in Task 1), insert:

```bash
# The on-disk path(s) to WRITE for an external blob, one per line. For a
# `properties` external this is the v2 suffix (.properties.age) ALWAYS, plus the
# v1 suffix (.gradle-properties.age) WHEN a v1 twin already exists in the store
# (dual-write keeps old clients fresh; a brand-new external is v2-only — the
# intended forcing function, additive v2 / EGB-712). `file` externals have a
# single suffix in both formats. Independent of the store marker.
_external_blob_write_targets() {
  local project="$1" slug="$2" mtype="$3"
  local base="$SECRETS_DIR/$project/external/$slug"
  case "$mtype" in
    file)
      echo "$base.file.age" ;;
    properties|gradle-properties)
      echo "$base.properties.age"
      [ -f "$base.gradle-properties.age" ] && echo "$base.gradle-properties.age" ;;
    *)
      echo "$base.$mtype.age" ;;
  esac
}
```

- [ ] **Step 5: Rewire the push writes.** At `secrets:651-658` (the `file` branch), replace:

```bash
    if [ "$mtype" = "file" ]; then
      # EGB-652: whole-file sync — encrypt the file verbatim (binary-safe).
      mkdir -p "$SECRETS_DIR/$project/external"
      local fslug; fslug=$(_secrets_files_slug "$mpath")
      age -r "$pubkey" -o "$SECRETS_DIR/$project/external/$fslug.$(_external_blob_suffix file).age" "$expanded"
      info "Encrypted file $mpath"
      pushed=$((pushed + 1))
      continue
    fi
```

with:

```bash
    if [ "$mtype" = "file" ]; then
      # EGB-652: whole-file sync — encrypt the file verbatim (binary-safe).
      mkdir -p "$SECRETS_DIR/$project/external"
      local fslug; fslug=$(_secrets_files_slug "$mpath")
      local wt
      while IFS= read -r wt; do
        [ -n "$wt" ] || continue
        age -r "$pubkey" -o "$wt" "$expanded"
      done < <(_external_blob_write_targets "$project" "$fslug" file)
      info "Encrypted file $mpath"
      pushed=$((pushed + 1))
      continue
    fi
```

Then at `secrets:682-684` (the properties branch), replace:

```bash
    mkdir -p "$SECRETS_DIR/$project/external"
    local slug; slug=$(_secrets_files_slug "$mpath")
    age -r "$pubkey" -o "$SECRETS_DIR/$project/external/$slug.$(_external_blob_suffix "$mtype").age" "$tmp"
```

with:

```bash
    mkdir -p "$SECRETS_DIR/$project/external"
    local slug; slug=$(_secrets_files_slug "$mpath")
    local wt
    while IFS= read -r wt; do
      [ -n "$wt" ] || continue
      age -r "$pubkey" -o "$wt" "$tmp"
    done < <(_external_blob_write_targets "$project" "$slug" "$mtype")
```

- [ ] **Step 6: Delete the now-unused `_external_blob_suffix`.** Confirm zero remaining callers first:

Run: `grep -n "_external_blob_suffix" secrets`
Expected: no matches (all four call sites rewired). If any remain, rewire them before deleting. Then delete the `_resolve_external_blob_read`-replaced... — it's already gone (replaced in Task 1). Verify the function is absent: `grep -c "_external_blob_suffix()" secrets` → `0`.

- [ ] **Step 7: Run the two new write tests**

Run: `bats test/migrate.bats -f "fresh external even on a v1 store"` then `-f "dual-writes the v1 twin"`
Expected: both PASS.

- [ ] **Step 8: Rewrite the obsolete back-compat test.** Replace the `@test "push on a v1 store still writes .gradle-properties.age (back-compat)"` block (`test/migrate.bats:52-60`) with:

```bash
@test "push on a v1 store writes the v2 suffix for a fresh external (additive v2)" {
  make_v1_store
  m_gradle_src $'beaconClerkPkTest=pk_test_abc\n'
  create_project_dir v1push
  printf 'gradle-properties ~/.gradle/gradle.properties beaconClerkPkTest\n' > .secrets-files
  "$SECRETS_BIN" push v1push >/dev/null 2>&1
  run bash -c "ls $SECRETS_DIR/v1push/external/*.properties.age"
  [ "$status" -eq 0 ]
}
```

- [ ] **Step 9: Run the full migrate suite — expect the v1-blob-dependent fixtures to FAIL.** This is expected; Task 3 repairs them.

Run: `bats test/migrate.bats`
Expected: the read-fallback + two write tests + rewritten back-compat test PASS; several copy-forward/finalize/status tests now FAIL (push no longer writes a `.gradle-properties.age` for them to migrate). Note which fail — Task 3 fixes exactly those.

- [ ] **Step 10: Commit** (suite intentionally not yet fully green — Task 3 follows immediately)

```bash
git add secrets test/migrate.bats
git commit -m "feat: twin-rule write targets — dual-write existing, v2-only for new (additive v2, EGB-712)"
```

---

## Task 3: Repair migrate/finalize/status fixtures

**Files:** `test/migrate.bats`. No production code changes — this re-greens the suite by fabricating the old-client v1 blobs that push no longer writes.

The rule for each repair: after the `"$SECRETS_BIN" push <proj>` line, insert a fabrication call:
- Use **`m_make_v1_only <proj>`** (rename → only the v1 blob exists) for tests asserting a `*.gradle-properties.age` blob exists / is copy-forwarded (mirrors the pre-EGB-712 state where push produced a v1 blob).
- Use **`m_fake_v1_twin <proj>`** (keep both) only where a test needs both suffixes present.

- [ ] **Step 1: Repair the copy-forward / dry-run / idempotent tests.** In each of these tests, insert `m_make_v1_only <proj>` immediately after the `push <proj>` line:
  - `"migrate --dry-run reports the rename and writes nothing"` (proj `dryproj`)
  - `"migrate copy-forward creates the v2 twin and keeps the v1 blob (byte-identical)"` (proj `cfproj`)
  - `"migrate copy-forward is idempotent"` (proj `idemproj`)
  - `"migrate leaves dotenv and file blobs untouched"` (proj `mixproj`) — note this one ALSO pushes a `file` external; `m_make_v1_only` only touches `*.properties.age`, leaving the `.file.age` blob alone (correct).

Worked example — the copy-forward test becomes:

```bash
@test "migrate copy-forward creates the v2 twin and keeps the v1 blob (byte-identical)" {
  make_v1_store
  m_gradle_src $'beaconClerkPkTest=pk_test_abc\n'
  create_project_dir cfproj
  printf 'gradle-properties ~/.gradle/gradle.properties beaconClerkPkTest\n' > .secrets-files
  "$SECRETS_BIN" push cfproj >/dev/null 2>&1
  m_make_v1_only cfproj
  local old; old=$(ls "$SECRETS_DIR/cfproj/external/"*.gradle-properties.age)
  run "$SECRETS_BIN" migrate
  [ "$status" -eq 0 ]
  local new; new=$(ls "$SECRETS_DIR/cfproj/external/"*.properties.age)
  [ -f "$old" ]
  [ -f "$new" ]
  cmp -s "$old" "$new"
}
```

- [ ] **Step 2: Repair the finalize tests.** Insert `m_make_v1_only <proj>` after the `push <proj>` line in:
  - `"finalize refuses when verify --all is not green"` (proj `failverify`) — then the existing `migrate` step creates the twin; corrupting `*.properties.age` still trips verify.
  - `"finalize refuses an un-twinned v1 blob (project not migrated)"` (proj `untwinned`) — leaves a lone v1 blob, no twin: exactly the un-twinned state the test wants.
  - `"finalize green path drops v1, keeps v2, stamps the marker"` (proj `finproj`).
  - `"finalize cuts a recovery tag before deleting v1 blobs"` (proj — read it from the test).

- [ ] **Step 3: Repair the EGB-710 manifest-free / undeclared-twin tests.** Insert `m_make_v1_only <proj>` after the `push <proj>` line in:
  - `"migrate copy-forwards a v1 properties blob with no .secrets.json (manifest-free)"` (proj `nomanifestblob`) — insert BEFORE the `rm -f .secrets.json` line.
  - `"migrate twins a store blob even when the manifest no longer declares it"` (proj `staleblob`) — insert before the `.secrets.json` rewrite.

- [ ] **Step 4: Repair the `--status` tests that need a real v1 blob.**
  - `"migrate --status flags a project that needs migrating"` (proj `needsmig`) — insert `m_make_v1_only needsmig` after push, so a lone un-twinned v1 blob exists → NEEDS MIGRATE.
  - `"migrate --status reports finalize-ready once every blob is twinned"` (proj `readymig`) — insert `m_make_v1_only readymig` after push and BEFORE the `migrate` step (migrate then creates the twin → finalize-ready).

- [ ] **Step 5: Run the full migrate suite**

Run: `bats test/migrate.bats`
Expected: ALL pass. If any copy-forward test still reports "nothing to migrate", its `m_make_v1_only` call is missing or misplaced (must come after push, before migrate).

- [ ] **Step 6: Run the WHOLE suite** (manifest.bats exercises externals end-to-end and must still be green)

Run: `bats test/`
Expected: all pass. If a `manifest.bats` external test fails, check it isn't asserting a specific suffix that additive-v2 changed (a fresh push now writes `.properties.age`); update such an assertion the same way (assert `.properties.age`, or use the resolver-agnostic round-trip via pull).

- [ ] **Step 7: Commit**

```bash
git add test/migrate.bats
git commit -m "test: fabricate old-client v1 blobs in migrate/finalize/status fixtures (additive v2, EGB-712)"
```

---

## Task 4: `migrate --status` — dual-write coverage line

**Files:** `secrets` (`_migrate_status`, `secrets:2190-2227`), `test/migrate.bats`.

Adds visibility into which `properties` externals are v2-only (old clients can't read them — the forcing function) vs dual-written (old clients still served).

- [ ] **Step 1: Write the failing test.** Add to `test/migrate.bats`:

```bash
@test "migrate --status counts v2-only externals (old clients not served)" {
  make_v1_store
  m_gradle_src $'beaconClerkPkTest=pk_test_abc\n'
  create_project_dir v2onlyext
  printf 'gradle-properties ~/.gradle/gradle.properties beaconClerkPkTest\n' > .secrets-files
  "$SECRETS_BIN" push v2onlyext >/dev/null 2>&1          # v2-only (fresh, no v1 twin)
  run "$SECRETS_BIN" migrate --status
  [ "$status" -eq 0 ]                                     # no v1 blobs -> finalize-ready
  [[ "$output" == *"v2-only"* ]] || false                # surfaced as v2-only coverage
}
```

- [ ] **Step 2: Run it, confirm it fails**

Run: `bats test/migrate.bats -f "counts v2-only externals"`
Expected: FAIL — `_migrate_status` currently only counts `*.gradle-properties.age`; it never mentions `v2-only`.

- [ ] **Step 3: Extend `_migrate_status`.** In `_migrate_status` (`secrets:2190`), inside the `for dir` loop, after the existing `while ... done < <(find "$dir" -type f -name '*.gradle-properties.age' ...)` block and before the per-project classification, add a v2-only count, then surface it in the per-project line. Concretely, replace the classification block:

```bash
    if [ "$v1" -eq 0 ]; then
      echo "  $project: v2-ready (no v1 properties blobs)"
    elif [ "$untwinned" -eq 0 ]; then
      echo "  $project: migrated ($v1 v1 blob(s), all twinned)"
    else
      echo "  $project: NEEDS MIGRATE ($untwinned of $v1 v1 blob(s) un-twinned) — cd into the project and run 'secrets migrate'"
      any_untwinned=1
    fi
```

with:

```bash
    # v2-only externals: a .properties.age with no .gradle-properties.age twin —
    # old (v1) clients cannot read these (the additive-v2 forcing function).
    local v2only=0 pf
    while IFS= read -r pf; do
      [ -f "$pf" ] || continue
      [ -f "${pf%.properties.age}.gradle-properties.age" ] || v2only=$((v2only + 1))
    done < <(find "$dir" -type f -name '*.properties.age' 2>/dev/null)
    local v2note=""
    [ "$v2only" -gt 0 ] && v2note=" [$v2only v2-only — old clients not served]"
    if [ "$v1" -eq 0 ]; then
      echo "  $project: v2-ready (no v1 properties blobs)$v2note"
    elif [ "$untwinned" -eq 0 ]; then
      echo "  $project: migrated ($v1 v1 blob(s), all twinned)$v2note"
    else
      echo "  $project: NEEDS MIGRATE ($untwinned of $v1 v1 blob(s) un-twinned) — cd into the project and run 'secrets migrate'$v2note"
      any_untwinned=1
    fi
```

(`local` inside the loop is bash-3.2-fine — it re-declares per iteration.)

- [ ] **Step 4: Run the new test + status suite**

Run: `bats test/migrate.bats -f "status"`
Expected: all status tests PASS, including the new v2-only one.

- [ ] **Step 5: Run the full suite**

Run: `bats test/`
Expected: all pass.

- [ ] **Step 6: Commit**

```bash
git add secrets test/migrate.bats
git commit -m "feat: migrate --status surfaces v2-only externals (coverage, EGB-712)"
```

---

## Task 5: Docs, help, version, changelog

**Files:** `secrets` (`cmd_help`), `CLAUDE.md`, `README.md`, `VERSION`, `CHANGELOG.md`.

- [ ] **Step 1: `cmd_help` — reframe finalize as optional.** In `cmd_help()`, replace the finalize line:

```
  secrets migrate --finalize    Drop v1 blobs and mark the store v2 (after verify)
```

with:

```
  secrets migrate --finalize    Optional GC: drop v1 blobs and mark the store pure v2
```

- [ ] **Step 2: `CLAUDE.md` — additive-v2 paragraph.** In the "Store format" bullet (line ~65), after the migration-chain sentence, add (new sentence, same bullet):

```
 Additive v2 (EGB-712): upgraded clients read either blob suffix (`_resolve_external_blob_read` tries `.properties.age` then `.gradle-properties.age`) and dual-write a `properties` external only when a v1 twin already exists (`_external_blob_write_targets`) — so existing externals keep old clients fresh, brand-new externals are v2-only (a gentle forcing function), and `migrate --finalize` is now OPTIONAL GC rather than a required, coordination-gated flag-day. dotenv and `file` blobs are identical across formats, so they always propagate to old clients.
```

- [ ] **Step 3: `README.md` — propagation table.** Add, near the migrate rows in the command table or in a short "Upgrading / store format" subsection, the propagation-by-secret-type summary (verbatim from spec §6):

```markdown
**Do teammates on an older `secrets` get new secrets?**

| Secret type | Old client gets it? |
|---|---|
| `.env` / `.env.*` / `.dev.vars` | **Yes, always** (blob name identical across formats) |
| whole-file external | **Yes, always** |
| `properties` external that already existed | **Yes** (dual-written) |
| brand-new `properties` external | **No — must upgrade `secrets`** (the forcing function) |

"Upgrade your secrets" = `git pull` the tool clone (binary ≥ 0.6.0.0) and/or `secrets migrate` the store. A read-only teammate only needs the tool `git pull`.
```

- [ ] **Step 4: `VERSION`** — set to `0.7.0.0`.

- [ ] **Step 5: `CHANGELOG.md`** — insert above the top entry:

```markdown
## [0.7.0.0] - 2026-06-08

### Changed

- **Additive store-format v2 (EGB-712)** — upgraded `secrets` clients now read
  either external blob suffix (`.properties.age` or the legacy
  `.gradle-properties.age`) and **dual-write** a `properties` external whenever a
  v1 twin already exists in the store. Existing externals keep working for
  teammates on an older `secrets`; only a brand-new `properties` external is
  written v2-only (a gentle "upgrade to see it" forcing function). dotenv and
  whole-`file` externals are unchanged across formats and always propagate.
- **`secrets migrate --finalize` is now optional GC**, not a required milestone.
  Because clients dual-write and read-fall-back, no teammate is ever cut off by
  *not* finalizing; finalize only reclaims the duplicate v1 blobs, and stays
  deferrable indefinitely. Its safety gates are unchanged.

### Added

- **`secrets migrate --status`** now reports `v2-only` externals per project
  (the ones an un-upgraded client cannot read), so you can see the forcing
  function's footprint at a glance.
```

- [ ] **Step 6: Run the full suite**

Run: `bats test/`
Expected: all pass (docs don't affect tests). Confirm the count is baseline 242 + net new tests from Tasks 1/2/4 (read-fallback, two write tests, v2-only status) minus the rewritten back-compat test (replaced, not added) = **246**.

- [ ] **Step 7: Sanity — help renders**

Run: `./secrets help 2>&1 | grep -- "--finalize"`
Expected: shows the reframed "Optional GC" line. (Help only prints; touches no store.)

- [ ] **Step 8: Commit**

```bash
git add secrets CLAUDE.md README.md VERSION CHANGELOG.md
git commit -m "docs: additive-v2 propagation + optional-GC finalize; bump 0.7.0.0 (EGB-712)"
```

---

## Self-review against the spec

- **§1 read resolution** → Task 1 (`_resolve_external_blob_read`, wired into pull + verify). Test: read-fallback.
- **§2 write rule / twin rule** → Task 2 (`_external_blob_write_targets`, push wiring). Tests: fresh-→v2-only, existing-twin-→dual-write.
- **§3 marker NOT stamped** → no production change (push never touches the marker); guarded implicitly by Task 3 keeping the `make_v1_store; push; migrate` flow working (store stays markerless after push). The plan deliberately does not add marker-stamping.
- **§4 finalize = optional GC** → unchanged logic; reframed in Task 5 docs/help. Existing finalize tests stay green (Task 3 keeps them green).
- **§5 migrate / --status coverage** → Task 4 (v2-only line); `migrate` copy-forward unchanged (EGB-710).
- **§6 propagation table** → Task 5 README/CLAUDE.md.
- **§7 caveat** → documented in CHANGELOG/CLAUDE.md framing; the read-fallback test exercises the v1-only read path.
- **§8 back-compat matrix** → covered across Task 1 (reads), Task 2 (writes), Task 3 (old-client v1 blobs simulated).
- **Safety invariants** → no path-rail changes; bash 3.2 (no associative arrays; `while read` + `find`); recursive walks unchanged; finalize gating untouched.

**Type/name consistency:** `_resolve_external_blob_read(project, slug, mtype)` and `_external_blob_write_targets(project, slug, mtype)` use the same arg order everywhere; test helpers `m_fake_v1_twin` (keep both) and `m_make_v1_only` (rename to v1-only) are used consistently per their documented semantics.

**Placeholder scan:** none — every step carries verbatim code or an exact enumerated edit with the precise insertion point.

## Operator-local follow-up (not part of this plan)

Per `.ship-policy.json`, before any PR ask the operator to run `./test/run-security.sh` and complete the SIGNOFF. EGB-712 also needs its one stale AC bullet ("Marker auto-stamps…") corrected to match the §3 decision (no auto-stamp) — a one-line Linear edit.