diff --git a/tangled_pr_close.py b/tangled_pr_close.py
new file mode 100755
index 0000000..e30585a
--- /dev/null
+++ b/tangled_pr_close.py
@@ -0,0 +1,106 @@
+#!/usr/bin/env python3
+"""Close an existing Tangled pull as the bot, via the session cookie.
+
+WHY: engine/ could create, edit, merge, resubmit and comment on a pull, but not CLOSE one. The
+appview exposes close as an htmx POST (the "Close" button on the pull page):
+
+  POST /{owner}/{repo}/pulls/{n}/close      -> closes (hx-swap; success is a 2xx)
+
+Same session-cookie auth as tangled_pr_edit.py. Closing does not create a round and does not
+touch the patch. This tool trusts nothing: after the POST it re-fetches the pull page and
+confirms the state badge reads Closed. Use --comment-file to post one comment FIRST naming the
+successor (the phase-8 rule: every closed pull says which readable PR carries its work).
+
+USAGE:
+  tangled_pr_close.py --owner notplants-bot.bsky.social --repo lichen.page.review --pull 397 \
+      [--comment-file note.md] [--dry-run]
+"""
+import argparse, os, re, subprocess, sys, urllib.error, urllib.parse, urllib.request
+
+BASE = "https://tangled.org"
+HERE = os.path.dirname(os.path.abspath(__file__))
+sys.path.insert(0, HERE)
+
+
+def load_cookie():
+    import secrets as _store
+    c = _store.get("tangled.cookie")
+    if not c:
+        sys.exit("no tangled.cookie in the secret store — refresh with scripts/get-tangled-cookie.py")
+    return c
+
+
+def state_of(owner, repo, pull, cookie):
+    import tangled_comments as tc
+    doc = tc.fetch(f"{BASE}/{owner}/{repo}/pulls/{pull}", cookie)
+    badges = set(re.findall(r'>\s*(Merged|Closed|Open)\s*<', doc))
+    return badges
+
+
+def main():
+    ap = argparse.ArgumentParser(description="close a Tangled pull via a reused session cookie")
+    ap.add_argument("--owner", required=True)
+    ap.add_argument("--repo", required=True)
+    ap.add_argument("--pull", required=True, type=int)
+    ap.add_argument("--comment-file", default=None, help="post this comment before closing")
+    ap.add_argument("--dry-run", action="store_true", help="show state and the request; do not POST")
+    a = ap.parse_args()
+
+    cookie = load_cookie()
+    before = state_of(a.owner, a.repo, a.pull, cookie)
+    print(f"#{a.pull} state before: {sorted(before) or 'unknown'}")
+    if "Merged" in before:
+        sys.exit(f"#{a.pull} is MERGED — refusing to close a merged pull")
+    if "Closed" in before and "Open" not in before:
+        print(f"#{a.pull} is already Closed; nothing to do")
+        return
+    if a.dry_run:
+        print(f"DRY RUN: would POST {BASE}/{a.owner}/{a.repo}/pulls/{a.pull}/close")
+        return
+
+    if a.comment_file:
+        r = subprocess.run([sys.executable, os.path.join(HERE, "tangled_comment_post.py"),
+                            "--owner", a.owner, "--repo", a.repo, "--pull", str(a.pull),
+                            "--body-file", a.comment_file], capture_output=True, text=True)
+        print(r.stdout.strip())
+        if r.returncode != 0:
+            sys.exit(f"comment failed, NOT closing: {r.stderr.strip()[:300]}")
+
+    close_url = f"{BASE}/{a.owner}/{a.repo}/pulls/{a.pull}/close"
+    page_url = f"{BASE}/{a.owner}/{a.repo}/pulls/{a.pull}"
+    req = urllib.request.Request(close_url, data=b"", method="POST", headers={
+        "Cookie": cookie,
+        "Content-Type": "application/x-www-form-urlencoded",
+        "User-Agent": "tangled-pr-bot",
+        "HX-Request": "true",
+        "HX-Current-URL": page_url,
+        "Referer": page_url,
+    })
+
+    class NoRedirect(urllib.request.HTTPRedirectHandler):
+        def redirect_request(self, *args, **kw):
+            return None
+    opener = urllib.request.build_opener(NoRedirect)
+    try:
+        r = opener.open(req, timeout=90)
+        hdrs, code, resp = r.headers, r.getcode(), r.read(3000).decode("utf-8", "replace")
+    except urllib.error.HTTPError as e:
+        hdrs, code, resp = e.headers, e.code, e.read(3000).decode("utf-8", "replace")
+    target = hdrs.get("HX-Redirect", "") or hdrs.get("HX-Location", "") or hdrs.get("Location", "")
+    print(f"HTTP {code}" + (f" -> {target}" if target else ""))
+    if "/login" in target or "oauth" in target.lower():
+        sys.exit("AUTH FAILED: session cookie expired — refresh with scripts/get-tangled-cookie.py")
+    if code // 100 != 2:
+        print("  close did not return 2xx — response snippet:")
+        print("  " + " ".join(resp.split())[:600])
+        sys.exit(2)
+
+    after = state_of(a.owner, a.repo, a.pull, cookie)
+    print(f"#{a.pull} state after:  {sorted(after) or 'unknown'}")
+    if "Closed" not in after:
+        sys.exit("POST returned 2xx but the pull page does not read Closed — check by hand")
+    print(f"#{a.pull} CLOSED")
+
+
+if __name__ == "__main__":
+    main()