diff --git a/.claude/skills/git-workflow/SKILL.md b/.claude/skills/git-workflow/SKILL.md
index 387faf5..97aa80e 100644
--- a/.claude/skills/git-workflow/SKILL.md
+++ b/.claude/skills/git-workflow/SKILL.md
@@ -46,6 +46,7 @@ mise run git:sync              # Sync current branch after base PR merge
 4. Push     -> git push -u origin feature/your-feature
 5. PR       -> gh pr create -a "@me" -t "feat: ..."
 6. Open     -> mise run git:open-pr <pr#>  (CI wait -> browser -> merge watch -> cleanup)
+               ⚠ Run ONCE after final push. If CI fails, stop watcher -> fix -> push -> relaunch.
 7. Cleanup  -> (auto: merge detected -> git:cleanup runs)
 ```
 
@@ -59,11 +60,17 @@ Claude: [Bash(run_in_background=true)] mise run git:open-pr -- <pr#>
 
 3 phases run automatically:
 1. **CI wait** — `gh pr checks --watch` waits for CI to pass
-2. **Open in browser** — Opens PR page in default browser
+2. **Open in browser** — Uses `scripts/open-url.local.sh` if present (gitignored), else default browser
 3. **Merge watch** — Polls PR state every 30s
    - MERGED -> macOS notification + `mise run git:cleanup` -> exit
    - CLOSED -> message -> exit
 
+**Singleton rule — only ONE watcher per PR:**
+- `git:open-pr` must run **only once** per PR — after the final push, when no more changes are expected.
+- If CI fails and you need to push a fix: **stop the existing watcher** with `TaskStop` first, fix and push, then launch a new `git:open-pr`.
+- Never have multiple `git:open-pr` background tasks running for the same PR.
+- Use `--no-wait` to skip CI wait phase when you just want the merge watcher.
+
 **Claude behavior**: When background task output arrives via `<system-reminder>`, Claude MUST:
 1. Read the output file with `TaskOutput` or `Read`
 2. Report the result to the user immediately
diff --git a/.gitignore b/.gitignore
index da20dc3..ee7aeb7 100644
--- a/.gitignore
+++ b/.gitignore
@@ -18,6 +18,9 @@ Cargo.lock
 .gemini/
 .codex/
 
+# Local hooks (user-specific, not committed)
+scripts/*.local.sh
+
 /tmp/
 OUTPUT.md
 crates/agtrace-sdk/examples/debug/
diff --git a/tasks.toml b/tasks.toml
index a961d76..fdc13f5 100644
--- a/tasks.toml
+++ b/tasks.toml
@@ -155,8 +155,14 @@ if [[ "$WAIT_CI" == true && -n "$PR_NUMBER" ]]; then
 fi
 
 # Phase 2: Open in browser
+# Use local hook if available (gitignored), otherwise default browser
 echo "[git:open-pr] Phase 2/3: Opening PR in browser..."
-gh pr view "$PR_NUMBER" --web
+OPEN_HOOK="./scripts/open-url.local.sh"
+if [[ -x "$OPEN_HOOK" ]]; then
+  "$OPEN_HOOK" "$URL"
+else
+  gh pr view "$PR_NUMBER" --web
+fi
 
 # Phase 3: Watch for merge
 if [[ -n "$PR_NUMBER" ]]; then