diff --git a/.github/actions/contributor-check/action.yml b/.github/actions/contributor-check/action.yml
index faef0d9..0e6241a 100644
--- a/.github/actions/contributor-check/action.yml
+++ b/.github/actions/contributor-check/action.yml
@@ -1,7 +1,8 @@
 name: "Contributor Reputation Check"
 description: >
   Screens GitHub contributors for account-shape anomalies, cross-repo
-  credential laundering, and coordination patterns. Delegates to
+  credential laundering, and coordination patterns. Public comments are
+  AgentTrust-branded; risk checks delegate to pinned
   microsoft/agent-governance-toolkit scripts (MIT License).
 
 inputs:
@@ -112,6 +113,21 @@ runs:
           --number "$STEP_NUMBER" \
           --item-type "$STEP_TYPE"
 
+    - name: Apply AgentTrust comment branding
+      if: ${{ steps.inputs.outputs.type != 'manual' && steps.inputs.outputs.number != '0' }}
+      shell: bash
+      env:
+        GITHUB_TOKEN: ${{ inputs.github-token }}
+        STEP_NUMBER: ${{ steps.inputs.outputs.number }}
+        STEP_TYPE: ${{ steps.inputs.outputs.type }}
+        STEP_TARGET_REPO: ${{ steps.inputs.outputs.target_repo }}
+      run: |
+        python "${{ github.action_path }}/brand_comment.py" \
+          --github-token "$GITHUB_TOKEN" \
+          --target-repo "$STEP_TARGET_REPO" \
+          --number "$STEP_NUMBER" \
+          --item-type "$STEP_TYPE"
+
     - name: Cleanup
       if: always()
       shell: bash
diff --git a/.github/actions/contributor-check/brand_comment.py b/.github/actions/contributor-check/brand_comment.py
new file mode 100644
index 0000000..75b07d4
--- /dev/null
+++ b/.github/actions/contributor-check/brand_comment.py
@@ -0,0 +1,110 @@
+#!/usr/bin/env python3
+"""Apply AgentTrust branding to the public contributor-check comment.
+
+The check implementation delegates to microsoft/agent-governance-toolkit at a
+pinned commit. That upstream script owns the risk calculation and writes an
+idempotent PR/issue comment. Keep its hidden marker so future runs update the
+same comment, but make the visible footer point at the AgentTrust action.
+"""
+
+from __future__ import annotations
+
+import argparse
+import json
+from urllib.error import HTTPError
+from urllib.request import Request, urlopen
+
+
+MARKER = "<!-- agt-contributor-check -->"
+AGENTTRUST_FOOTER = (
+    "*Automated check by "
+    "[AgentTrust Contributor Check]"
+    "(https://github.com/agentrust-io/.github/tree/main/.github/actions/contributor-check).*"
+)
+
+
+def _api(token: str, method: str, path: str, data: dict | None = None) -> dict | list | None:
+    url = f"https://api.github.com{path}"
+    headers = {
+        "Authorization": f"Bearer {token}",
+        "Accept": "application/vnd.github+json",
+        "X-GitHub-Api-Version": "2022-11-28",
+    }
+    req = Request(url, method=method, headers=headers)
+    if data is not None:
+        req.add_header("Content-Type", "application/json")
+        req.data = json.dumps(data).encode()
+
+    try:
+        with urlopen(req, timeout=15) as resp:
+            return json.loads(resp.read())
+    except HTTPError as exc:
+        if exc.code == 404:
+            return None
+        raise
+
+
+def _branded_body(body: str) -> str:
+    if AGENTTRUST_FOOTER in body:
+        return body
+
+    lines = body.splitlines()
+    for index, line in enumerate(lines):
+        if line.startswith("*Automated check by ") and "Contributor Check" in line:
+            lines[index] = AGENTTRUST_FOOTER
+            return "\n".join(lines)
+
+    return f"{body.rstrip()}\n\n{AGENTTRUST_FOOTER}"
+
+
+def main() -> None:
+    parser = argparse.ArgumentParser(description="Brand contributor-check comment")
+    parser.add_argument("--github-token", required=True)
+    parser.add_argument("--target-repo", required=True)
+    parser.add_argument("--number", type=int, required=True)
+    parser.add_argument("--item-type", choices=["pr", "issue", "manual"], required=True)
+    args = parser.parse_args()
+
+    if args.item_type == "manual" or args.number <= 0:
+        print("No PR/issue comment to brand.")
+        return
+
+    owner, repo = args.target_repo.split("/", 1)
+    page = 1
+    while True:
+        comments = _api(
+            args.github_token,
+            "GET",
+            f"/repos/{owner}/{repo}/issues/{args.number}/comments?per_page=100&page={page}",
+        )
+        if not comments:
+            print("No contributor-check comment found.")
+            return
+
+        for comment in comments:
+            body = comment.get("body") or ""
+            if MARKER not in body:
+                continue
+
+            branded = _branded_body(body)
+            if branded == body:
+                print("Contributor-check comment already has AgentTrust branding.")
+                return
+
+            _api(
+                args.github_token,
+                "PATCH",
+                f"/repos/{owner}/{repo}/issues/comments/{comment['id']}",
+                {"body": branded},
+            )
+            print("Applied AgentTrust branding to contributor-check comment.")
+            return
+
+        if len(comments) < 100:
+            print("No contributor-check comment found.")
+            return
+        page += 1
+
+
+if __name__ == "__main__":
+    main()