diff --git a/src/evalopt_graph/checks.py b/src/evalopt_graph/checks.py
index 3083e43..73d1ada 100644
--- a/src/evalopt_graph/checks.py
+++ b/src/evalopt_graph/checks.py
@@ -13,6 +13,7 @@
 from collections.abc import Callable, Iterable
 from dataclasses import asdict, dataclass
 from typing import Any
+from urllib.parse import urlsplit
 
 # gate name -> key in profile["commands"]
 GATE_TO_CMD_KEY = {"tests": "test", "lint": "lint", "typecheck": "typecheck", "build": "build"}
@@ -144,11 +145,36 @@ def is_git_repo(repo_path: str) -> bool:
     return code == 0 and out.strip() == "true"
 
 
+_SCP_REMOTE_RE = re.compile(r"^(?:[^@/:\s]+@)?(?P<host>[^/:\s]+):\S+$")
+
+
+def _remote_hostname(remote_url: str) -> str | None:
+    """Return a normalized hostname for URL and Git scp-style remotes."""
+    candidate = remote_url.strip()
+    if not candidate:
+        return None
+    try:
+        if "://" in candidate:
+            parsed = urlsplit(candidate)
+            if parsed.scheme.lower() not in {"git", "http", "https", "ssh"}:
+                return None
+            hostname = parsed.hostname
+        else:
+            match = _SCP_REMOTE_RE.fullmatch(candidate)
+            hostname = match.group("host") if match else None
+    except ValueError:
+        return None
+    return hostname.removesuffix(".").lower() if hostname else None
+
+
 def is_github_repo(repo_path: str) -> bool:
     """True if the repo has a github.com remote or a .github directory (best-effort, read-only)."""
     code, out = _git(repo_path, "remote", "-v")
-    if code == 0 and "github.com" in out.lower():
-        return True
+    if code == 0:
+        for line in out.splitlines():
+            fields = line.split()
+            if len(fields) >= 2 and _remote_hostname(fields[1]) == "github.com":
+                return True
     return os.path.isdir(os.path.join(repo_path, ".github"))
 
 
diff --git a/tests/test_quality_gate.py b/tests/test_quality_gate.py
index 942009c..31c29dd 100644
--- a/tests/test_quality_gate.py
+++ b/tests/test_quality_gate.py
@@ -2,6 +2,7 @@
 
 from __future__ import annotations
 
+import subprocess
 import sys
 
 from evalopt_graph import MockProvider, evaluate, passes_quality_gate
@@ -10,6 +11,7 @@
     all_required_pass,
     detect_test_weakening,
     failing_gates,
+    is_github_repo,
     run_gates,
 )
 
@@ -90,6 +92,61 @@ def test_run_gates_real_subprocess_fail():
     assert results[0].exit_code == 3
 
 
+def _set_remote(tmp_path, remote_url: str):
+    repo = tmp_path / "repo"
+    if not repo.exists():
+        subprocess.run(["git", "init", "-q", str(repo)], check=True)
+        subprocess.run(["git", "-C", str(repo), "remote", "add", "origin", remote_url], check=True)
+    else:
+        subprocess.run(["git", "-C", str(repo), "remote", "set-url", "origin", remote_url], check=True)
+    return repo
+
+
+def test_is_github_repo_accepts_exact_github_remote_hosts(tmp_path):
+    repo = _set_remote(tmp_path, "https://github.com/owner/repo.git")
+    assert is_github_repo(str(repo)) is True
+
+    _set_remote(tmp_path, "git@github.com:owner/repo.git")
+    assert is_github_repo(str(repo)) is True
+
+    _set_remote(tmp_path, "ssh://git@github.com/owner/repo.git")
+    assert is_github_repo(str(repo)) is True
+
+    _set_remote(tmp_path, "https://GitHub.com./owner/repo.git")
+    assert is_github_repo(str(repo)) is True
+
+
+def test_is_github_repo_rejects_github_text_outside_exact_host(tmp_path):
+    repo = _set_remote(tmp_path, "https://evil.example/github.com/owner/repo.git")
+    assert is_github_repo(str(repo)) is False
+
+    _set_remote(tmp_path, "https://github.com.evil.example/owner/repo.git")
+    assert is_github_repo(str(repo)) is False
+
+    _set_remote(tmp_path, "https://github.com@evil.example/owner/repo.git")
+    assert is_github_repo(str(repo)) is False
+
+    _set_remote(tmp_path, "git@github.com.evil.example:owner/repo.git")
+    assert is_github_repo(str(repo)) is False
+
+    _set_remote(tmp_path, "https://github.com.../owner/repo.git")
+    assert is_github_repo(str(repo)) is False
+
+    _set_remote(tmp_path, "file:///tmp/github.com/owner/repo.git")
+    assert is_github_repo(str(repo)) is False
+
+    _set_remote(tmp_path, "file://github.com/owner/repo.git")
+    assert is_github_repo(str(repo)) is False
+
+
+def test_is_github_repo_preserves_dot_github_fallback(tmp_path):
+    repo = tmp_path / "not-a-git-repo"
+    repo.mkdir()
+    assert is_github_repo(str(repo)) is False
+    (repo / ".github").mkdir(parents=True)
+    assert is_github_repo(str(repo)) is True
+
+
 # ---------------- anti-gaming: test-weakening detector ----------------