diff --git a/skills/ingest/scripts/open-pr.sh b/skills/ingest/scripts/open-pr.sh
index 3e979ff..0e6ff63 100755
--- a/skills/ingest/scripts/open-pr.sh
+++ b/skills/ingest/scripts/open-pr.sh
@@ -16,10 +16,11 @@ set -euo pipefail
 : "${FORGEJO_USER:?missing FORGEJO_USER}"
 : "${FORGEJO_TOKEN:?missing FORGEJO_TOKEN}"
 
-slug="" title="" body_file="" base="main" label=""
+slug="" title="" body_file="" base="main" label="" branch=""
 while [[ $# -gt 0 ]]; do
   case "$1" in
     --slug)      slug="$2";      shift 2 ;;
+    --branch)    branch="$2";    shift 2 ;;
     --title)     title="$2";     shift 2 ;;
     --body-file) body_file="$2"; shift 2 ;;
     --base)      base="$2";      shift 2 ;;
@@ -28,16 +29,23 @@ while [[ $# -gt 0 ]]; do
   esac
 done
 
-: "${slug:?--slug required}"
 : "${title:?--title required}"
 : "${body_file:?--body-file required}"
 [[ -f "$body_file" ]] || { echo "open-pr: body file not found: $body_file" >&2; exit 1; }
 
-branch="feat/ai-ingest-${slug}"
+# --branch overrides the default; otherwise derive the ingest branch from --slug.
+# (run-prune passes its own chore/prune-orphans-* branch; run-ingest passes --slug.)
+if [[ -z "$branch" ]]; then
+  : "${slug:?--slug or --branch required}"
+  branch="feat/ai-ingest-${slug}"
+fi
 repo="$(basename -s .git "$(git config --get remote.origin.url)")"
 
 # 1. Branch + commit + push (AGENTS.md rule 5: never commit to main)
-git switch -c "$branch" 2>/dev/null || git switch "$branch"
+# Rolling PR: -C force-resets the branch label to the current base (we are on it after
+# clean_start) and CARRIES the freshly-written wiki/ changes, so a re-ingest of the same
+# source rebuilds the branch cleanly instead of hitting a dirty-switch refusal.
+git switch -C "$branch"
 git add wiki/
 # Scope BOTH the emptiness check and the commit to wiki/ — never commit anything that
 # happened to be staged outside wiki/ (a stray hook, an aborted prior run, etc.).
@@ -46,7 +54,10 @@ if git diff --cached --quiet -- wiki/; then
   exit 1
 fi
 git commit -m "$title" -- wiki/
-git push -u origin "$branch"
+# Try a normal push (new branch / fast-forward). If the branch was rebuilt from base and
+# diverged, force-with-lease updates the open PR in place — the lease refuses to clobber if
+# origin moved unexpectedly since our fetch, so concurrent work is never lost.
+git push -u origin "$branch" 2>/dev/null || git push -u --force-with-lease origin "$branch"
 
 # DRY_RUN: local git work done; skip the Forgejo API (offline tests).
 if [[ -n "${DRY_RUN:-}" ]]; then