diff --git a/.claude-plugin/marketplace.json b/.claude-plugin/marketplace.json
index a418e1d..2c07975 100644
--- a/.claude-plugin/marketplace.json
+++ b/.claude-plugin/marketplace.json
@@ -5,13 +5,13 @@
   },
   "metadata": {
     "description": "Local marketplace for the compact-plus plugin.",
-    "version": "1.0.0"
+    "version": "1.0.1"
   },
   "plugins": [
     {
       "name": "compact-plus",
       "description": "Preserve Claude Code session state before and after context compaction.",
-      "version": "1.0.0",
+      "version": "1.0.1",
       "author": {
         "name": "u1"
       },
diff --git a/.claude-plugin/plugin.json b/.claude-plugin/plugin.json
index a5048c4..0442495 100644
--- a/.claude-plugin/plugin.json
+++ b/.claude-plugin/plugin.json
@@ -1,7 +1,7 @@
 {
   "$schema": "https://json.schemastore.org/claude-code-plugin-manifest.json",
   "name": "compact-plus",
-  "version": "1.0.0",
+  "version": "1.0.1",
   "description": "Preserve Claude Code session state before and after context compaction.",
   "author": {
     "name": "u1"
diff --git a/AGENTS.md b/AGENTS.md
index cadf88b..d6308f4 100644
--- a/AGENTS.md
+++ b/AGENTS.md
@@ -40,3 +40,22 @@ Claude Code context compaction.
 - Hooks must fail open and must not block compaction.
 - Do not write machine-specific absolute paths into git-tracked files.
 - Use `${CLAUDE_PLUGIN_ROOT}`, `${HOME}`, `${TMPDIR:-/tmp}`, and repository-relative paths.
+
+## Version bump policy
+
+Every commit must bump the plugin version, following semver. Commits without a
+version bump are not allowed. Keep the following three slots in sync at the
+same value — the `Check version consistency` step in `.github/workflows/test.yml`
+enforces this and will fail CI on any mismatch:
+
+1. `.claude-plugin/plugin.json` (`version`)
+2. `.claude-plugin/marketplace.json` (`metadata.version`)
+3. `.claude-plugin/marketplace.json` (`plugins[0].version`)
+
+| Change type | Bump | Example |
+|-------------|------|---------|
+| Bug fix, display tweak, refactor, docs | patch (1.0.0 → 1.0.1) | Fix a silent hook failure, small README edit |
+| New feature, new skill, extension of existing behavior | minor (1.0.0 → 1.1.0) | Add a new hook, extend the `/compact-plus` skill |
+| Breaking change, incompatible skill / hook I/O change | major (1.0.0 → 2.0.0) | Incompatible shared-state file format change |
+
+When in doubt, prefer patch.
diff --git a/hooks/precompact-transcript-backup.sh b/hooks/precompact-transcript-backup.sh
index 5e0807c..86cc196 100755
--- a/hooks/precompact-transcript-backup.sh
+++ b/hooks/precompact-transcript-backup.sh
@@ -20,9 +20,13 @@ EPOCH=$(date +%s)
 DEST="$BACKUP_DIR/${EPOCH}-${SESSION_ID}.jsonl"
 cp "$TRANSCRIPT_PATH" "$DEST" 2>/dev/null || exit 0
 
-mapfile -t OLD_BACKUPS < <(find "$BACKUP_DIR" -maxdepth 1 -type f -name "*-${SESSION_ID}.jsonl" -print 2>/dev/null | sort -r | tail -n +21)
-if [[ ${#OLD_BACKUPS[@]} -gt 0 ]]; then
-  rm -f "${OLD_BACKUPS[@]}" 2>/dev/null || true
-fi
+# mapfile is a bash 4+ builtin and stock macOS /bin/bash is 3.2, so use a
+# POSIX while-read loop to prune old backups instead.
+find "$BACKUP_DIR" -maxdepth 1 -type f -name "*-${SESSION_ID}.jsonl" -print 2>/dev/null \
+  | sort -r \
+  | tail -n +21 \
+  | while IFS= read -r old; do
+      rm -f "$old" 2>/dev/null || true
+    done
 
 exit 0