diff --git a/.claude-plugin/marketplace.json b/.claude-plugin/marketplace.json
index f84fe7b0..bd35aa93 100644
--- a/.claude-plugin/marketplace.json
+++ b/.claude-plugin/marketplace.json
@@ -227,8 +227,8 @@
     {
       "name": "pr-cycle",
       "source": "./commands/pr-cycle",
-      "description": "/pr-cycle — one-shot PR cycle command. Pushes the current branch (`git push -u origin HEAD`), `gh pr create --fill`, then SELF-MERGES with ` && gh pr merge --squash --admin --delete-branch` in the SAME command block — one command does create → merge. Refuses on main/master. Pass extra gh flags as args. 0.4.1 — command appends the merge ITSELF instead of relying on the `pr-cycle-hook` PreToolUse hook: slash-command `!`-exec does NOT route through the Bash-tool PreToolUse hook, so the hook never fired for /pr-cycle (PRs left created-but-unmerged); self-merge fixes it, idempotent with the hook (skips any command already containing `gh pr merge`). Command half of the pr-cycle split (routing hook = `pr-cycle-hook`, still serves agent Bash-tool `gh pr create`).",
-      "version": "0.4.1"
+      "description": "/pr-cycle — one-shot PR cycle command. Pushes the current branch (`git push -u origin HEAD`), `gh pr create --fill`, SELF-MERGES with `gh pr merge --squash --admin --delete-branch`, then SWEEPS merged agent worktrees in the SAME command block — one command does create → merge → clean. Refuses on main/master. Pass extra gh flags as args. 0.5.0 — POST-MERGE WORKTREE SWEEP closes the leak where `--delete-branch` removed the remote branch but left the `.claude/worktrees/agent-*` DIRECTORY piling up across /cycle-bg runs. After a successful merge the command cd's to the MAIN worktree and removes every linked agent worktree whose upstream is `[gone]` (the squash-safe 'merged + branch deleted' signal — `--is-ancestor` cannot detect a squash merge, but `git push -u` then `--delete-branch` reliably leaves the upstream gone), plus `git branch -D` + `git worktree prune`. cd-to-main first means even the just-merged CURRENT worktree (when /pr-cycle ran inside one) is swept. SAFETY: never touches a worktree with a live OR absent (`track=none`) upstream — those may hold un-pushed work — nor `locked` worktrees (another checkout); only paths under `/.claude/worktrees/` are eligible. 0.4.1 — command appends the merge ITSELF instead of relying on the `pr-cycle-hook` PreToolUse hook: slash-command `!`-exec does NOT route through the Bash-tool PreToolUse hook, so the hook never fired for /pr-cycle (PRs left created-but-unmerged); self-merge fixes it, idempotent with the hook (skips any command already containing `gh pr merge`). Command half of the pr-cycle split (routing hook = `pr-cycle-hook`, still serves agent Bash-tool `gh pr create`).",
+      "version": "0.5.0"
     },
     {
       "name": "pr-cycle-hook",
diff --git a/CHANGELOG.md b/CHANGELOG.md
index bb00518f..9008f48d 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -6,6 +6,24 @@ For the full audit trail, see `git log`.
 
 ---
 
+## 2026-06-07 — 🧹 pr-cycle 0.5.0 — 머지 후 worktree sweep (누적 누수 차단)
+
+`/cycle-bg` 를 돌릴수록 `.claude/worktrees/agent-*` worktree 디렉터리가 계속 쌓이던
+누수를 차단. `gh pr merge --delete-branch` 는 **원격 브랜치만** 지우고 worktree
+디렉터리는 남겼는데, pr-cycle 에 정리 단계가 없어 누적됐음 (pr→merge→clean 의 clean 부재).
+
+- 🧹 **머지 후 sweep** — 머지 성공 후 MAIN worktree 로 cd → upstream 이 `[gone]` 인
+  `.claude/worktrees/agent-*` worktree 만 `git worktree remove --force` + `git branch -D`
+  + `git worktree prune`. MAIN 으로 먼저 cd 하므로 /pr-cycle 가 worktree **안에서**
+  돌았어도 방금 머지된 자기 worktree 까지 정리됨.
+- 🔑 **squash-safe 신호** — squash 머지는 worktree 커밋이 origin/main 의 조상이 안 돼
+  `--is-ancestor` 로 "머지됨" 판정 불가. 대신 `git push -u` → `--delete-branch` 후
+  upstream 이 `[gone]` 으로 변하는 걸 신호로 사용.
+- 🔒 **안전** — upstream 이 살아있거나(`track=none` 미푸시 작업 가능성) `locked`(다른
+  체크아웃) worktree 는 절대 건드리지 않음. `/.claude/worktrees/` 경로만 대상.
+- 검증: sh 문법 · 4-상태 worktree 분류(merged/`[gone]`·미푸시·locked·main) 보존 로직 ·
+  g22 lockstep(plugin 0.5.0 ↔ marketplace 0.5.0).
+
 ## 2026-06-07 — 🎓 domain 0.12.0 — 자동사용(USE) 절반 복원 · skillopt-hook 의 SessionStart 주입을 domain 안으로
 
 0.11.0 통합에서 빠졌던 **자동사용 훅**을 domain 플러그인 내부에 포팅 — `activate` 가
diff --git a/commands/pr-cycle/.claude-plugin/plugin.json b/commands/pr-cycle/.claude-plugin/plugin.json
index 31136dc0..beec89a1 100644
--- a/commands/pr-cycle/.claude-plugin/plugin.json
+++ b/commands/pr-cycle/.claude-plugin/plugin.json
@@ -1,7 +1,7 @@
 {
   "name": "pr-cycle",
-  "description": "/pr-cycle — one-shot PR cycle command. Pushes the current branch (`git push -u origin HEAD`), `gh pr create --fill`, then SELF-MERGES with ` && gh pr merge --squash --admin --delete-branch` in the SAME command block — one command does create → merge. Refuses on main/master. Pass extra gh flags as args (e.g. --title \"...\" --body \"...\"). 0.4.1 — the command now appends the merge ITSELF instead of relying on the `pr-cycle-hook` PreToolUse hook: the command body executes via slash-command `!`-exec, which does NOT route through the Bash-tool PreToolUse hook, so the hook never fired for /pr-cycle and PRs were left created-but-unmerged. Self-merging fixes it and is idempotent with the hook (the hook skips any command already containing `gh pr merge`); the hook still serves agent-issued `gh pr create` Bash-tool calls + cross-repo/worktree cleanup. Command half of the pr-cycle split.",
-  "version": "0.4.1",
+  "description": "/pr-cycle — one-shot PR cycle command. Pushes the current branch (`git push -u origin HEAD`), `gh pr create --fill`, SELF-MERGES with `gh pr merge --squash --admin --delete-branch`, then SWEEPS merged agent worktrees in the SAME command block — one command does create → merge → clean. Refuses on main/master. Pass extra gh flags as args (e.g. --title \"...\" --body \"...\"). 0.5.0 — POST-MERGE WORKTREE SWEEP closes the leak where `--delete-branch` removed the remote branch but left the `.claude/worktrees/agent-*` DIRECTORY piling up across /cycle-bg runs. After a successful merge the command cd's to the MAIN worktree and removes every linked agent worktree whose upstream is `[gone]` (the squash-safe 'merged + branch deleted' signal — `--is-ancestor` cannot detect a squash merge, but `git push -u` then `--delete-branch` reliably leaves the upstream gone), plus `git branch -D` + `git worktree prune`. cd-to-main first means even the just-merged CURRENT worktree (when /pr-cycle ran inside one) is swept. SAFETY: never touches a worktree with a live OR absent (`track=none`) upstream — those may hold un-pushed work — nor `locked` worktrees (another checkout); only paths under `/.claude/worktrees/` are eligible. 0.4.1 — the command now appends the merge ITSELF instead of relying on the `pr-cycle-hook` PreToolUse hook: the command body executes via slash-command `!`-exec, which does NOT route through the Bash-tool PreToolUse hook, so the hook never fired for /pr-cycle and PRs were left created-but-unmerged. Self-merging fixes it and is idempotent with the hook (the hook skips any command already containing `gh pr merge`); the hook still serves agent-issued `gh pr create` Bash-tool calls + cross-repo/worktree cleanup. Command half of the pr-cycle split.",
+  "version": "0.5.0",
   "author": { "name": "dancinlab" },
   "repository": "https://github.com/dancinlab/sidecar",
   "license": "MIT",
diff --git a/commands/pr-cycle/commands/pr-cycle.md b/commands/pr-cycle/commands/pr-cycle.md
index 092f2733..759efb4a 100644
--- a/commands/pr-cycle/commands/pr-cycle.md
+++ b/commands/pr-cycle/commands/pr-cycle.md
@@ -1,5 +1,5 @@
 ---
-description: /pr-cycle — one-shot PR cycle. Pushes the current branch (git push -u origin HEAD), runs gh pr create --fill, then SELF-MERGES with ` && gh pr merge --squash --admin --delete-branch` IN THE SAME command block. 0.4.1 — the merge is appended by the command itself (not left to the pr-cycle PreToolUse hook): the command body runs via slash-command `!`-exec, which does NOT route through the Bash-tool PreToolUse hook, so relying on the hook left PRs created-but-unmerged; self-merging fixes that and stays idempotent (the hook skips any command already containing `gh pr merge`). Refuses on main/master. Pass extra gh flags as args (e.g. --title "..." --body "...").
+description: /pr-cycle — one-shot PR cycle. Pushes the current branch (git push -u origin HEAD), runs gh pr create --fill, SELF-MERGES with `gh pr merge --squash --admin --delete-branch`, then SWEEPS merged agent worktrees IN THE SAME command block. 0.5.0 — post-merge worktree sweep: after a successful merge it cd's to the MAIN worktree and removes every `.claude/worktrees/agent-*` linked worktree whose upstream is `[gone]` (the squash-safe "merged + branch deleted" signal — `--is-ancestor` can't detect squash merges, but `git push -u` then `--delete-branch` reliably leaves the upstream gone), plus `git branch -D` + `git worktree prune`. Fixes the leak where `--delete-branch` removed the remote branch but left the worktree DIRECTORY piling up across /cycle-bg runs. NEVER touches a worktree with a live or absent (`track=none`) upstream — those may hold un-pushed work — nor `locked` worktrees (another checkout). 0.4.1 — the merge is appended by the command itself (not the PreToolUse hook): the body runs via slash-command `!`-exec, which does NOT route through the Bash-tool PreToolUse hook, so relying on the hook left PRs created-but-unmerged; self-merging fixes that and stays idempotent. Refuses on main/master. Pass extra gh flags as args (e.g. --title "..." --body "...").
 argument-hint: "[gh pr create flags, e.g. --title \"...\" --body \"...\"]"
 allowed-tools: Bash
 ---
@@ -12,6 +12,34 @@ if [ "$BR" = "main" ] || [ "$BR" = "master" ]; then
   echo "  (git switch -c feat/<slug>)"
   exit 0
 fi
-echo "▸ /pr-cycle on '$BR' — push + create + self-merge"
+echo "▸ /pr-cycle on '$BR' — push + create + self-merge + worktree sweep"
 git push -u origin HEAD 2>&1 | tail -2
-gh pr create --fill $ARGUMENTS && gh pr merge --squash --admin --delete-branch`
+if gh pr create --fill $ARGUMENTS && gh pr merge --squash --admin --delete-branch; then
+  # ── post-merge worktree sweep ──────────────────────────────────────────────
+  # Remove harness agent worktrees whose upstream is [gone] (= merged + branch
+  # deleted). Squash-safe: a squashed branch is NOT an ancestor of main, so we
+  # key off the deleted upstream, not --is-ancestor. cd to MAIN first so even the
+  # just-merged CURRENT worktree (if /pr-cycle ran inside one) becomes sweepable.
+  MAIN=$(git worktree list --porcelain | awk 'NR==1 && /^worktree /{print $2; exit}')
+  [ -n "$MAIN" ] && cd "$MAIN" 2>/dev/null || true
+  git fetch -p origin >/dev/null 2>&1 || true
+  git worktree list --porcelain | awk '
+    /^worktree /{wt=$2; br=""; lk=""}
+    /^branch /{br=$2; sub("refs/heads/","",br)}
+    /^locked/{lk="L"}
+    /^$/{if(wt!=""){print wt"|"br"|"lk; wt=""}}
+    END{if(wt!=""){print wt"|"br"|"lk}}' | while IFS="|" read -r wt br lk; do
+    case "$wt" in *"/.claude/worktrees/"*) ;; *) continue ;; esac   # only harness agent worktrees
+    [ "$wt" = "$MAIN" ] && continue                                  # never the main checkout
+    [ -n "$lk" ] && continue                                         # never locked (another checkout)
+    [ -n "$br" ] || continue
+    track=$(git for-each-ref --format='%(upstream:track)' "refs/heads/$br" 2>/dev/null)
+    [ "$track" = "[gone]" ] || continue                             # only merged+deleted (squash-safe)
+    if git worktree remove --force "$wt" 2>/dev/null; then
+      git branch -D "$br" 2>/dev/null || true
+      echo "  🧹 swept merged worktree: $wt"
+    fi
+  done
+  git worktree prune 2>/dev/null || true
+  echo "✓ /pr-cycle done — PR merged + merged worktrees swept"
+fi`