diff --git a/agent-workspace/domain-skills/github/pr-issue-triage.md b/agent-workspace/domain-skills/github/pr-issue-triage.md
new file mode 100644
index 00000000..87dd493e
--- /dev/null
+++ b/agent-workspace/domain-skills/github/pr-issue-triage.md
@@ -0,0 +1,299 @@
+# GitHub - PR and Issue Triage
+
+`https://github.com/{owner}/{repo}/pulls` and `/issues` - read-only triage for
+public repositories. Use this when choosing a small contribution, checking
+whether a PR is duplicate, or estimating a pull request's scope before review.
+
+## Do this first
+
+**Use the REST API as the source of truth.** The GitHub PR and issue list pages
+contain duplicate/auxiliary DOM rows, while the API returns parsed JSON and
+works without logging in for public repos.
+
+```python
+import json, os
+
+owner = "browser-use"
+repo = "browser-harness"
+base = f"https://api.github.com/repos/{owner}/{repo}"
+token = os.environ.get("GITHUB_TOKEN", "")
+headers = {
+    "Accept": "application/vnd.github+json",
+    "X-GitHub-Api-Version": "2022-11-28",
+}
+if token:
+    headers["Authorization"] = f"Bearer {token}"
+
+rate = json.loads(http_get("https://api.github.com/rate_limit", headers=headers))
+print(rate["resources"]["core"]["remaining"], rate["resources"]["search"]["remaining"])
+```
+
+Use the browser after the API pass only when you need a visual screenshot,
+hydrated labels, or manual confirmation of the GitHub page state.
+
+## Common workflows
+
+### PR shortlist (API)
+
+Use `/pulls` for pull requests. Do **not** use `/issues` for a PR shortlist:
+GitHub's issues endpoint includes both issues and pull requests.
+
+```python
+import json
+
+pulls = json.loads(http_get(
+    base + "/pulls?state=open&sort=updated&direction=desc&per_page=20",
+    headers=headers,
+))
+
+shortlist = []
+for pr in pulls:
+    shortlist.append({
+        "number": pr["number"],
+        "title": pr["title"],
+        "user": pr["user"]["login"],
+        "draft": pr["draft"],
+        "updated_at": pr["updated_at"],
+        "head_sha": pr["head"]["sha"],
+        "base_ref": pr["base"]["ref"],
+        "html_url": pr["html_url"],
+    })
+print(shortlist)
+```
+
+Triage signal:
+- `draft=True` means do not treat the PR as ready for review.
+- `base_ref` should usually be the repository default branch.
+- `updated_at` helps find active duplicates before starting a similar PR.
+
+### Pull request detail and files (API)
+
+Fetch PR detail and file changes together. This gives the fastest answer to
+"is this PR small and focused?".
+
+```python
+import json
+
+pull_number = 481
+detail = json.loads(http_get(base + f"/pulls/{pull_number}", headers=headers))
+files = json.loads(http_get(
+    base + f"/pulls/{pull_number}/files?per_page=100",
+    headers=headers,
+))
+
+summary = {
+    "number": detail["number"],
+    "title": detail["title"],
+    "state": detail["state"],
+    "draft": detail["draft"],
+    "mergeable": detail["mergeable"],
+    "mergeable_state": detail["mergeable_state"],
+    "commits": detail["commits"],
+    "additions": detail["additions"],
+    "deletions": detail["deletions"],
+    "changed_files": detail["changed_files"],
+    "issue_comments": detail["comments"],
+    "review_comments": detail["review_comments"],
+}
+changed = [{
+    "filename": f["filename"],
+    "status": f["status"],
+    "changes": f["changes"],
+    "additions": f["additions"],
+    "deletions": f["deletions"],
+} for f in files]
+print(summary)
+print(changed)
+```
+
+For review conversation:
+
+```python
+issue_comments = json.loads(http_get(
+    base + f"/issues/{pull_number}/comments?per_page=50",
+    headers=headers,
+))
+review_comments = json.loads(http_get(
+    base + f"/pulls/{pull_number}/comments?per_page=50",
+    headers=headers,
+))
+reviews = json.loads(http_get(
+    base + f"/pulls/{pull_number}/reviews?per_page=50",
+    headers=headers,
+))
+```
+
+For CI/check state, use the PR head SHA:
+
+```python
+head_sha = detail["head"]["sha"]
+checks = json.loads(http_get(
+    base + f"/commits/{head_sha}/check-runs?per_page=50",
+    headers=headers,
+))
+runs = checks.get("check_runs", [])
+print([{
+    "name": r["name"],
+    "status": r["status"],
+    "conclusion": r["conclusion"],
+    "html_url": r["html_url"],
+} for r in runs])
+```
+
+Reference path: `/commits/{head_sha}/check-runs`.
+
+### Issue duplicate check (API)
+
+Use `/issues` to list open issues, and GitHub search to check whether your PR
+idea already exists in issues or PRs.
+
+```python
+import json
+
+items = json.loads(http_get(
+    base + "/issues?state=open&sort=updated&direction=desc&per_page=50",
+    headers=headers,
+))
+
+issues = []
+prs_in_issue_feed = []
+for item in items:
+    target = prs_in_issue_feed if "pull_request" in item else issues
+    target.append({
+        "number": item["number"],
+        "title": item["title"],
+        "user": item["user"]["login"],
+        "labels": [label["name"] for label in item.get("labels", [])],
+        "comments": item["comments"],
+        "updated_at": item["updated_at"],
+        "html_url": item["html_url"],
+    })
+print("issues", issues)
+print("prs mixed into /issues", prs_in_issue_feed)
+```
+
+Search for duplicates before starting a PR:
+
+```python
+import json, urllib.parse
+
+query = f"repo:{owner}/{repo} github triage in:title,body is:open"
+url = "https://api.github.com/search/issues?q=" + urllib.parse.quote(query) + "&per_page=10"
+results = json.loads(http_get(url, headers=headers))
+for item in results["items"]:
+    kind = "PR" if "pull_request" in item else "ISSUE"
+    print(kind, item["number"], item["title"], item["html_url"])
+```
+
+For a specific issue's discussion:
+
+```python
+issue_number = 479
+comments = json.loads(http_get(
+    base + f"/issues/{issue_number}/comments?per_page=50",
+    headers=headers,
+))
+print([{"user": c["user"]["login"], "created_at": c["created_at"], "body": c["body"][:200]} for c in comments])
+```
+
+Reference path: `/issues/{issue_number}/comments`.
+
+### Browser verification
+
+Use browser navigation only after API triage, usually to capture a screenshot or
+confirm the visible list. Keep navigation, wait, extraction, and screenshot in
+the same `browser-harness` invocation.
+
+```python
+import json
+
+new_tab("https://github.com/browser-use/browser-harness/pulls")
+wait_for_load()
+wait(2)
+rows = json.loads(js(r"""
+JSON.stringify(Array.from(document.querySelectorAll('[id^="issue_"]')).map(row => {
+  const link = row.querySelector('a[href*="/pull/"]');
+  const meta = row.querySelector('.opened-by');
+  const labels = Array.from(row.querySelectorAll('a.IssueLabel, span.IssueLabel'))
+    .map(x => x.textContent.trim())
+    .filter(Boolean);
+  return {
+    title: link ? link.textContent.trim().replace(/\s+/g, ' ') : null,
+    href: link ? link.href : null,
+    meta: meta ? meta.textContent.trim().replace(/\s+/g, ' ') : null,
+    labels: labels
+  };
+}).filter(row => row.title && row.href))
+"""))
+print(rows[:10])
+print(capture_screenshot())
+```
+
+If browser rows disagree with the API, trust the API and use the browser output
+only as visual evidence.
+
+### Quick triage rubric
+
+```python
+def classify_pr(detail, files, checks):
+    paths = [f["filename"] for f in files]
+    runs = checks.get("check_runs", [])
+    completed_runs = [r for r in runs if r.get("status") == "completed"]
+    return {
+        "small": detail["changed_files"] <= 3 and detail["additions"] + detail["deletions"] <= 300,
+        "docs_or_skill_only": bool(paths) and all(p.endswith(".md") or "/domain-skills/" in p for p in paths),
+        "has_tests_or_docs": any(p.startswith("tests/") or p.endswith(".md") for p in paths),
+        "checks_green": bool(runs) and len(completed_runs) == len(runs) and all(
+            r.get("conclusion") in {"success", "skipped"} for r in completed_runs
+        ),
+        "paths": paths,
+    }
+```
+
+Use this as a rough screen, not a merge decision. For contribution planning,
+prefer small PRs with a narrow path set, concrete evidence, and no open duplicate
+PR touching the same files.
+
+## Gotchas
+
+- **`/issues` includes PRs.** Any item with a `pull_request` key is a PR, not a
+  standalone issue. Use `/pulls?state=open` for a PR list.
+
+- **Search is rate-limited separately.** Unauthenticated search is only
+  10 requests/minute. Core REST is 60 requests/hour. Check `/rate_limit` before
+  looping.
+
+- **`mergeable` can be `null`.** GitHub computes it asynchronously. If it is
+  `null`, wait briefly and refetch `/pulls/{pull_number}`.
+
+- **Changed files are paginated.** `/pulls/{pull_number}/files?per_page=100`
+  returns at most 100 files per page. Follow pagination headers for large PRs.
+
+- **Check runs hang off the head commit.** First fetch PR detail, then call
+  `/commits/{head_sha}/check-runs`. Branch names are not enough.
+
+- **Issue comments and review comments are different.** `/issues/{n}/comments`
+  contains timeline discussion. `/pulls/{n}/comments` contains inline code review
+  comments. Fetch both when reviewing PR state.
+
+- **Browser DOM rows are noisy.** The PR list can include duplicate or auxiliary
+  rows under `[id^="issue_"]`; filter out rows without a title and href. API data
+  is cleaner.
+
+- **Logged-in UI may differ.** The visible page can include reviewer controls,
+  subscribed state, or private affordances that do not appear for logged-out
+  users. Do not bake those into a public-data triage skill.
+
+## Provenance
+
+Validated on 2026-07-03 against `browser-use/browser-harness` using
+`browser-harness` attached to local Chrome:
+
+- `/pulls?state=open&sort=updated&direction=desc&per_page=5` returned open PRs.
+- `/pulls/{pull_number}` exposed `draft`, `mergeable_state`, `changed_files`,
+  `additions`, `deletions`, `comments`, and `review_comments`.
+- `/pulls/{pull_number}/files` returned filenames, statuses, and change counts.
+- `/issues/{pull_number}/comments`, `/pulls/{pull_number}/comments`, and
+  `/commits/{head_sha}/check-runs` returned PR discussion/check data.
+- Browser verification on `/pulls` produced visible PR rows, but also confirmed
+  noisy DOM rows, so the API remains the primary path.
diff --git a/tests/unit/test_github_domain_skills.py b/tests/unit/test_github_domain_skills.py
new file mode 100644
index 00000000..617b99f0
--- /dev/null
+++ b/tests/unit/test_github_domain_skills.py
@@ -0,0 +1,45 @@
+from pathlib import Path
+
+
+ROOT = Path(__file__).resolve().parents[2]
+
+
+def test_github_pr_issue_triage_skill_has_required_sections():
+    path = ROOT / "agent-workspace" / "domain-skills" / "github" / "pr-issue-triage.md"
+    assert path.exists(), "GitHub PR/Issue triage skill should be documented"
+
+    text = path.read_text(encoding="utf-8")
+    required = [
+        "# GitHub - PR and Issue Triage",
+        "## Do this first",
+        "## Common workflows",
+        "### PR shortlist (API)",
+        "### Pull request detail and files (API)",
+        "### Issue duplicate check (API)",
+        "### Browser verification",
+        "## Gotchas",
+        "pulls?state=open",
+        "issues?state=open",
+        "/pulls/{pull_number}/files",
+        "/issues/{issue_number}/comments",
+        "/commits/{head_sha}/check-runs",
+    ]
+
+    for needle in required:
+        assert needle in text
+
+
+def test_github_pr_issue_triage_skill_addresses_reviewed_edge_cases():
+    path = ROOT / "agent-workspace" / "domain-skills" / "github" / "pr-issue-triage.md"
+    text = path.read_text(encoding="utf-8")
+
+    required = [
+        'query = f"repo:{owner}/{repo} github triage in:title,body is:open"',
+        '"docs_or_skill_only": bool(paths) and all(',
+        'runs = checks.get("check_runs", [])',
+        'completed_runs = [r for r in runs if r.get("status") == "completed"]',
+        '"checks_green": bool(runs) and len(completed_runs) == len(runs) and all(',
+    ]
+
+    for needle in required:
+        assert needle in text