diff --git a/ship/SKILL.md.tmpl b/ship/SKILL.md.tmpl
index e262d74e..377d87be 100644
--- a/ship/SKILL.md.tmpl
+++ b/ship/SKILL.md.tmpl
@@ -403,16 +403,55 @@ For each comment in `comments`:
## Step 12: Version bump (auto-decide)
-**Idempotency check:** Before bumping, compare VERSION against the base branch.
+**Idempotency check:** Before bumping, classify the state by comparing `VERSION` against the base branch AND against `package.json`'s `version` field. Four states: FRESH (do bump), ALREADY_BUMPED (skip bump), DRIFT_STALE_PKG (sync pkg only, no re-bump), DRIFT_UNEXPECTED (stop and ask).
```bash
BASE_VERSION=$(git show origin/:VERSION 2>/dev/null || echo "0.0.0.0")
CURRENT_VERSION=$(cat VERSION 2>/dev/null || echo "0.0.0.0")
-echo "BASE: $BASE_VERSION HEAD: $CURRENT_VERSION"
-if [ "$CURRENT_VERSION" != "$BASE_VERSION" ]; then echo "ALREADY_BUMPED"; fi
+PKG_VERSION=""
+PKG_EXISTS=0
+if [ -f package.json ]; then
+ PKG_EXISTS=1
+ if command -v node >/dev/null 2>&1; then
+ PKG_VERSION=$(node -e 'const p=require("./package.json");process.stdout.write(p.version||"")' 2>/dev/null)
+ PARSE_EXIT=$?
+ elif command -v bun >/dev/null 2>&1; then
+ PKG_VERSION=$(bun -e 'const p=require("./package.json");process.stdout.write(p.version||"")' 2>/dev/null)
+ PARSE_EXIT=$?
+ else
+ echo "ERROR: package.json exists but neither node nor bun is available. Install one and re-run."
+ exit 1
+ fi
+ if [ "$PARSE_EXIT" != "0" ]; then
+ echo "ERROR: package.json is not valid JSON. Fix the file before re-running /ship."
+ exit 1
+ fi
+fi
+echo "BASE: $BASE_VERSION VERSION: $CURRENT_VERSION package.json: ${PKG_VERSION:-}"
+
+if [ "$CURRENT_VERSION" = "$BASE_VERSION" ]; then
+ if [ "$PKG_EXISTS" = "1" ] && [ -n "$PKG_VERSION" ] && [ "$PKG_VERSION" != "$CURRENT_VERSION" ]; then
+ echo "STATE: DRIFT_UNEXPECTED"
+ echo "package.json version ($PKG_VERSION) disagrees with VERSION ($CURRENT_VERSION) while VERSION matches base."
+ echo "This looks like a manual edit to package.json bypassing /ship. Reconcile manually, then re-run."
+ exit 1
+ fi
+ echo "STATE: FRESH"
+else
+ if [ "$PKG_EXISTS" = "1" ] && [ -n "$PKG_VERSION" ] && [ "$PKG_VERSION" != "$CURRENT_VERSION" ]; then
+ echo "STATE: DRIFT_STALE_PKG"
+ else
+ echo "STATE: ALREADY_BUMPED"
+ fi
+fi
```
-If output shows `ALREADY_BUMPED`, VERSION was already bumped on this branch (prior `/ship` run). Skip the bump action (do not modify VERSION), but read the current VERSION value — it is needed for CHANGELOG and PR body. Continue to the next step. Otherwise proceed with the bump.
+Read the `STATE:` line and dispatch:
+
+- **FRESH** → proceed with the bump action below (steps 1–4).
+- **ALREADY_BUMPED** → skip the bump. Reuse `CURRENT_VERSION` for CHANGELOG and PR body. Continue to the next step.
+- **DRIFT_STALE_PKG** → a prior `/ship` bumped `VERSION` but failed to update `package.json`. Run the sync-only repair block below (after step 4). Do NOT re-bump. Reuse `CURRENT_VERSION` for CHANGELOG and PR body.
+- **DRIFT_UNEXPECTED** → `/ship` has halted (exit 1). Resolve manually; /ship cannot tell which file is authoritative.
1. Read the current `VERSION` file (4-digit format: `MAJOR.MINOR.PATCH.MICRO`)
@@ -428,7 +467,49 @@ If output shows `ALREADY_BUMPED`, VERSION was already bumped on this branch (pri
- Bumping a digit resets all digits to its right to 0
- Example: `0.19.1.0` + PATCH → `0.19.2.0`
-4. Write the new version to the `VERSION` file.
+4. **Validate** `NEW_VERSION` and write it to **both** `VERSION` and `package.json`. This block runs only when `STATE: FRESH`.
+
+```bash
+if ! printf '%s' "$NEW_VERSION" | grep -qE '^[0-9]+\.[0-9]+\.[0-9]+\.[0-9]+$'; then
+ echo "ERROR: NEW_VERSION ($NEW_VERSION) does not match MAJOR.MINOR.PATCH.MICRO pattern. Aborting."
+ exit 1
+fi
+echo "$NEW_VERSION" > VERSION
+if [ -f package.json ]; then
+ if command -v node >/dev/null 2>&1; then
+ node -e 'const fs=require("fs"),p=require("./package.json");p.version=process.argv[1];fs.writeFileSync("package.json",JSON.stringify(p,null,2)+"\n")' "$NEW_VERSION" || {
+ echo "ERROR: failed to update package.json. VERSION was written but package.json is now stale. Fix and re-run — the new idempotency check will detect the drift."
+ exit 1
+ }
+ elif command -v bun >/dev/null 2>&1; then
+ bun -e 'const fs=require("fs"),p=require("./package.json");p.version=process.argv[1];fs.writeFileSync("package.json",JSON.stringify(p,null,2)+"\n")' "$NEW_VERSION" || {
+ echo "ERROR: failed to update package.json. VERSION was written but package.json is now stale."
+ exit 1
+ }
+ else
+ echo "ERROR: package.json exists but neither node nor bun is available."
+ exit 1
+ fi
+fi
+```
+
+**DRIFT_STALE_PKG repair path** — runs when idempotency reports `STATE: DRIFT_STALE_PKG`. No re-bump; sync `package.json.version` to the current `VERSION` and continue. Reuse `CURRENT_VERSION` for CHANGELOG and PR body.
+
+```bash
+REPAIR_VERSION=$(cat VERSION)
+if command -v node >/dev/null 2>&1; then
+ node -e 'const fs=require("fs"),p=require("./package.json");p.version=process.argv[1];fs.writeFileSync("package.json",JSON.stringify(p,null,2)+"\n")' "$REPAIR_VERSION" || {
+ echo "ERROR: drift repair failed — could not update package.json."
+ exit 1
+ }
+else
+ bun -e 'const fs=require("fs"),p=require("./package.json");p.version=process.argv[1];fs.writeFileSync("package.json",JSON.stringify(p,null,2)+"\n")' "$REPAIR_VERSION" || {
+ echo "ERROR: drift repair failed."
+ exit 1
+ }
+fi
+echo "Drift repaired: package.json synced to $REPAIR_VERSION. No version bump performed."
+```
---
diff --git a/test/ship-version-sync.test.ts b/test/ship-version-sync.test.ts
new file mode 100644
index 00000000..80908ec1
--- /dev/null
+++ b/test/ship-version-sync.test.ts
@@ -0,0 +1,198 @@
+// /ship Step 12: VERSION ↔ package.json drift detection + repair.
+// Mirrors the bash blocks in ship/SKILL.md.tmpl Step 12. When the template
+// changes, update both sides together.
+//
+// Coverage gap: node-absent + bun-present path. Simulating "no node" in-process
+// is flaky across dev machines; covered by manual spot-check + CI running on
+// bun-only images if/when we add them.
+
+import { test, expect, beforeEach, afterEach } from "bun:test";
+import { execSync } from "node:child_process";
+import { mkdtempSync, writeFileSync, readFileSync, rmSync, existsSync } from "node:fs";
+import { tmpdir } from "node:os";
+import { join } from "node:path";
+
+let dir: string;
+beforeEach(() => {
+ dir = mkdtempSync(join(tmpdir(), "ship-drift-"));
+});
+afterEach(() => {
+ rmSync(dir, { recursive: true, force: true });
+});
+
+const writeFiles = (files: Record) => {
+ for (const [name, content] of Object.entries(files)) {
+ writeFileSync(join(dir, name), content);
+ }
+};
+
+const pkgJson = (version: string | null, extra: Record = {}) =>
+ JSON.stringify(
+ version === null ? { name: "x", ...extra } : { name: "x", version, ...extra },
+ null,
+ 2,
+ ) + "\n";
+
+const idempotency = (base: string): { stdout: string; code: number } => {
+ const script = `
+cd "${dir}" || exit 2
+BASE_VERSION="${base}"
+CURRENT_VERSION=$(cat VERSION 2>/dev/null || echo "0.0.0.0")
+PKG_VERSION=""
+PKG_EXISTS=0
+if [ -f package.json ]; then
+ PKG_EXISTS=1
+ if command -v node >/dev/null 2>&1; then
+ PKG_VERSION=$(node -e 'const p=require("./package.json");process.stdout.write(p.version||"")' 2>/dev/null)
+ PARSE_EXIT=$?
+ elif command -v bun >/dev/null 2>&1; then
+ PKG_VERSION=$(bun -e 'const p=require("./package.json");process.stdout.write(p.version||"")' 2>/dev/null)
+ PARSE_EXIT=$?
+ else
+ echo "ERROR: no parser"; exit 1
+ fi
+ if [ "$PARSE_EXIT" != "0" ]; then
+ echo "ERROR: invalid JSON"; exit 1
+ fi
+fi
+if [ "$CURRENT_VERSION" = "$BASE_VERSION" ]; then
+ if [ "$PKG_EXISTS" = "1" ] && [ -n "$PKG_VERSION" ] && [ "$PKG_VERSION" != "$CURRENT_VERSION" ]; then
+ echo "STATE: DRIFT_UNEXPECTED"; exit 1
+ fi
+ echo "STATE: FRESH"
+else
+ if [ "$PKG_EXISTS" = "1" ] && [ -n "$PKG_VERSION" ] && [ "$PKG_VERSION" != "$CURRENT_VERSION" ]; then
+ echo "STATE: DRIFT_STALE_PKG"
+ else
+ echo "STATE: ALREADY_BUMPED"
+ fi
+fi`;
+ try {
+ const stdout = execSync(script, { shell: "/bin/bash", encoding: "utf8" });
+ return { stdout: stdout.trim(), code: 0 };
+ } catch (e: any) {
+ return { stdout: (e.stdout || "").toString().trim(), code: e.status ?? 1 };
+ }
+};
+
+const bump = (newVer: string): { code: number } => {
+ const script = `
+cd "${dir}" || exit 2
+NEW_VERSION="${newVer}"
+if ! printf '%s' "$NEW_VERSION" | grep -qE '^[0-9]+\\.[0-9]+\\.[0-9]+\\.[0-9]+$'; then
+ echo "invalid semver" >&2; exit 1
+fi
+echo "$NEW_VERSION" > VERSION
+if [ -f package.json ]; then
+ node -e 'const fs=require("fs"),p=require("./package.json");p.version=process.argv[1];fs.writeFileSync("package.json",JSON.stringify(p,null,2)+"\\n")' "$NEW_VERSION"
+fi`;
+ try {
+ execSync(script, { shell: "/bin/bash", stdio: "pipe" });
+ return { code: 0 };
+ } catch (e: any) {
+ return { code: e.status ?? 1 };
+ }
+};
+
+const syncRepair = (): { code: number } => {
+ const script = `
+cd "${dir}" || exit 2
+REPAIR_VERSION=$(cat VERSION)
+node -e 'const fs=require("fs"),p=require("./package.json");p.version=process.argv[1];fs.writeFileSync("package.json",JSON.stringify(p,null,2)+"\\n")' "$REPAIR_VERSION"`;
+ try {
+ execSync(script, { shell: "/bin/bash", stdio: "pipe" });
+ return { code: 0 };
+ } catch (e: any) {
+ return { code: e.status ?? 1 };
+ }
+};
+
+const pkgVersion = () =>
+ JSON.parse(readFileSync(join(dir, "package.json"), "utf8")).version;
+
+// --- Idempotency classification: 6 cases ---
+
+test("FRESH: VERSION == base, pkg synced", () => {
+ writeFiles({ VERSION: "0.0.0.0\n", "package.json": pkgJson("0.0.0.0") });
+ expect(idempotency("0.0.0.0")).toEqual({ stdout: "STATE: FRESH", code: 0 });
+});
+
+test("FRESH: VERSION == base, no package.json", () => {
+ writeFiles({ VERSION: "0.0.0.0\n" });
+ expect(idempotency("0.0.0.0")).toEqual({ stdout: "STATE: FRESH", code: 0 });
+});
+
+test("ALREADY_BUMPED: VERSION ahead, pkg synced", () => {
+ writeFiles({ VERSION: "0.1.0.0\n", "package.json": pkgJson("0.1.0.0") });
+ expect(idempotency("0.0.0.0")).toEqual({ stdout: "STATE: ALREADY_BUMPED", code: 0 });
+});
+
+test("ALREADY_BUMPED: VERSION ahead, no package.json", () => {
+ writeFiles({ VERSION: "0.1.0.0\n" });
+ expect(idempotency("0.0.0.0")).toEqual({ stdout: "STATE: ALREADY_BUMPED", code: 0 });
+});
+
+test("DRIFT_STALE_PKG: VERSION ahead, pkg stale", () => {
+ writeFiles({ VERSION: "0.1.0.0\n", "package.json": pkgJson("0.0.0.0") });
+ expect(idempotency("0.0.0.0")).toEqual({ stdout: "STATE: DRIFT_STALE_PKG", code: 0 });
+});
+
+test("DRIFT_UNEXPECTED: VERSION == base, pkg edited (exits non-zero)", () => {
+ writeFiles({ VERSION: "0.0.0.0\n", "package.json": pkgJson("0.5.0.0") });
+ const r = idempotency("0.0.0.0");
+ expect(r.stdout.startsWith("STATE: DRIFT_UNEXPECTED")).toBe(true);
+ expect(r.code).toBe(1);
+});
+
+// --- Parse failures: 2 cases ---
+
+test("idempotency: invalid JSON exits non-zero with clear error", () => {
+ writeFiles({ VERSION: "0.1.0.0\n", "package.json": "{ not valid" });
+ const r = idempotency("0.0.0.0");
+ expect(r.code).toBe(1);
+ expect(r.stdout).toContain("invalid JSON");
+});
+
+test("idempotency: package.json with no version field treated as ", () => {
+ writeFiles({ VERSION: "0.1.0.0\n", "package.json": pkgJson(null) });
+ // PKG_VERSION is empty → drift check skipped → ALREADY_BUMPED
+ expect(idempotency("0.0.0.0")).toEqual({ stdout: "STATE: ALREADY_BUMPED", code: 0 });
+});
+
+// --- Bump: 3 cases ---
+
+test("bump: writes VERSION and package.json in sync", () => {
+ writeFiles({ VERSION: "0.0.0.0\n", "package.json": pkgJson("0.0.0.0") });
+ expect(bump("0.1.0.0").code).toBe(0);
+ expect(readFileSync(join(dir, "VERSION"), "utf8").trim()).toBe("0.1.0.0");
+ expect(pkgVersion()).toBe("0.1.0.0");
+});
+
+test("bump: rejects invalid NEW_VERSION", () => {
+ writeFiles({ VERSION: "0.0.0.0\n", "package.json": pkgJson("0.0.0.0") });
+ const r = bump("not-a-version");
+ expect(r.code).toBe(1);
+ // VERSION is unchanged — validation runs before any write.
+ expect(readFileSync(join(dir, "VERSION"), "utf8").trim()).toBe("0.0.0.0");
+});
+
+test("bump: no package.json is silent", () => {
+ writeFiles({ VERSION: "0.0.0.0\n" });
+ expect(bump("0.1.0.0").code).toBe(0);
+ expect(readFileSync(join(dir, "VERSION"), "utf8").trim()).toBe("0.1.0.0");
+ expect(existsSync(join(dir, "package.json"))).toBe(false);
+});
+
+// --- THE critical regression test: drift-repair does NOT double-bump ---
+
+test("DRIFT REPAIR: sync path syncs pkg to VERSION without re-bumping", () => {
+ // Simulate a prior /ship that bumped VERSION but failed to touch package.json.
+ writeFiles({ VERSION: "0.1.0.0\n", "package.json": pkgJson("0.0.0.0") });
+ // Idempotency classifies as DRIFT_STALE_PKG.
+ expect(idempotency("0.0.0.0").stdout).toBe("STATE: DRIFT_STALE_PKG");
+ // Sync-only repair runs — no re-bump.
+ expect(syncRepair().code).toBe(0);
+ // VERSION is unchanged. package.json now matches VERSION. No 0.2.0.0.
+ expect(readFileSync(join(dir, "VERSION"), "utf8").trim()).toBe("0.1.0.0");
+ expect(pkgVersion()).toBe("0.1.0.0");
+});