fix(git-guards): deny gh api/graphql top-level comment creation

git-guards/scripts/git-permission-guard.py

@@ -110,6 +110,19 @@
     (r"api\b(?=.*(?:-X|--method)\s+(?:PUT|PATCH|DELETE))(?=.*\b(?:rulesets|branches/[^/]+/protection)\b)",
      "modifies repository branch protection or rulesets directly",
      "Manage branch protections through the GitHub web interface instead."),
+    # REST equivalent of the DENY_GH "pr comment" block: POSTing to an issue's
+    # /comments collection creates the same unresolvable top-level comment.
+    # Requires the POST method (a GET listing comments stays allowed) and the
+    # issues/{n}/comments shape specifically, so pulls/{n}/comments and
+    # pulls/comments/{id} (the sanctioned review-thread endpoints) are unaffected.
+    (r"api\b(?=.*(?:-X\s+|--method[\s=])POST\b)(?=.*\brepos/[^\s/]+/[^\s/]+/issues/\d+/comments\b)",
+     "creates a top-level issue/PR comment that cannot be resolved or tracked",
+     (
+         "For code review feedback, you MUST use review threads (line-specific, resolvable comments) instead.\n"
+         "Use the documented thread workflows for creating review comments, replying, and resolving threads:\n"
+         "  - github-workflows/skills/resolve-pr-threads/graphql-queries.md\n"
+         "  - github-workflows/skills/resolve-pr-threads/rest-api-patterns.md"
+     )),
 ]
 
 # Maps incorrect GraphQL mutation names to (correct_name, example_command).
@@ -407,6 +420,19 @@ def check_graphql_guidance(command: str) -> None:
     Allows the command to proceed (it will fail naturally) while showing the
     correct pattern inline so Claude can self-correct immediately.
     """
+    # addComment is the GraphQL equivalent of the REST issues/{n}/comments POST
+    # and the DENY_GH "pr comment" entry: it creates the same unresolvable
+    # top-level comment, on any subject (issue, PR, commit, gist). Unlike the
+    # WRONG_MUTATIONS below, this mutation is real and would succeed, so it is
+    # a hard deny rather than corrective guidance.
+    if re.search(r"\baddComment\s*\(\s*input\s*:", command):
+        deny(
+            "This command creates a top-level issue/PR comment via the GraphQL API that cannot be "
+            "resolved or tracked. For code review feedback, you MUST use review threads instead:\n"
+            "  - github-workflows/skills/resolve-pr-threads/graphql-queries.md\n"
+            "  - github-workflows/skills/resolve-pr-threads/rest-api-patterns.md"
+        )
+
     warnings = []
 
     # Detection 1 - Shell $variable expansion (excluding --jq content)

git-guards/scripts/test_gh_guard.py

@@ -84,8 +84,25 @@ def check(label: str, cmd: str, expected_decision: str) -> bool:
 # Regression: Safe gh api graphql queries mentioning rulesets must not be blocked
 all_pass &= check("gh api graphql rulesets query safe", "gh api graphql --raw-field query='query { repository(name: \"repo\", owner: \"owner\") { rulesets(first: 10) { totalCount } } }'", "silent_allow")
 
-# Regression: API calls with -f body containing "rulesets" in text must NOT be blocked
-all_pass &= check("gh api comment with rulesets in body", "gh api repos/owner/repo/issues/42/comments -X POST -f body='See the rulesets docs for context'", "silent_allow")
+# Regression: a -f body value must not defeat the deny below (kept allow-only
+# text is incidental; the deny fires on the POST + issues/{n}/comments shape)
+all_pass &= check("gh api comment with rulesets in body", "gh api repos/owner/repo/issues/42/comments -X POST -f body='See the rulesets docs for context'", "deny")
+
+# DENY: REST equivalent of `gh pr comment` - POSTing to issues/{n}/comments
+# creates the same unresolvable top-level comment `gh pr comment` is denied for.
+all_pass &= check("gh api issue comment POST deny", "gh api repos/owner/repo/issues/42/comments -X POST -f body='hello'", "deny")
+all_pass &= check("gh api issue comment POST deny, flags before path", "gh api -X POST repos/owner/repo/issues/42/comments -f body='hello'", "deny")
+all_pass &= check("gh api issue comment POST deny, --method flag", "gh api repos/owner/repo/issues/42/comments --method POST -f body='hello'", "deny")
+all_pass &= check("gh api issue comment POST deny, --method= flag", "gh api repos/owner/repo/issues/42/comments --method=POST -f body='hello'", "deny")
+all_pass &= check("gh api issue comment POST deny, absolute URL", "gh api https://api.github.com/repos/owner/repo/issues/42/comments -X POST -f body='hello'", "deny")
+all_pass &= check("gh api issue comment POST deny, leading slash", "gh api /repos/owner/repo/issues/42/comments -X POST -f body='hello'", "deny")
+
+# Safe: a GET (no method flag, gh api's default) of the same path must still be allowed
+all_pass &= check("gh api issue comments GET safe", "gh api repos/owner/repo/issues/42/comments", "silent_allow")
+
+# Safe: the sanctioned review-thread endpoints must remain unaffected
+all_pass &= check("gh api pulls comments POST safe", "gh api repos/owner/repo/pulls/42/comments -X POST -f body='hello'", "silent_allow")
+all_pass &= check("gh api pulls comment reply POST safe", "gh api repos/owner/repo/pulls/comments/123/replies -X POST -f body='hello'", "silent_allow")
 
 print()
 print("ALL TESTS PASSED" if all_pass else "SOME TESTS FAILED")

git-guards/scripts/test_graphql_guidance.py

@@ -109,6 +109,30 @@ def check(label: str, cmd: str, expected_decision: str, expected_fragments: list
     ["MULTI-LINE QUERY"],
 )
 
+# 9: addComment mutation - GraphQL equivalent of `gh pr comment` / the REST
+# issues/{n}/comments POST, denied outright (not correctable - unlike
+# WRONG_MUTATIONS, this mutation name is real and would succeed)
+all_pass &= check(
+    "addComment mutation deny",
+    "gh api graphql --raw-field query='mutation { addComment(input: {subjectId: \"PR_kwABC\", body: \"hi\"}) { commentEdge { node { id } } } }'",
+    "deny",
+    ["top-level issue/PR comment", "resolve-pr-threads"],
+)
+
+# 10: addComment mutation with -f flag variant - still denied
+all_pass &= check(
+    "addComment mutation deny, -f flag",
+    "gh api graphql -f query='mutation { addComment(input: {subjectId: \"PR_kwABC\", body: \"hi\"}) { commentEdge { node { id } } } }'",
+    "deny",
+)
+
+# 11: addPullRequestReviewThreadReply (sanctioned) must stay unaffected
+all_pass &= check(
+    "addPullRequestReviewThreadReply unaffected",
+    "gh api graphql --raw-field query='mutation { addPullRequestReviewThreadReply(input: {pullRequestReviewThreadId: \"abc\", body: \"hi\"}) { comment { id } } }'",
+    "silent_allow",
+)
+
 print()
 print("ALL TESTS PASSED" if all_pass else "SOME TESTS FAILED")
 sys.exit(0 if all_pass else 1)