diff --git a/app.py b/app.py
index 07312ec..15f0f0a 100644
--- a/app.py
+++ b/app.py
@@ -32,17 +32,17 @@ def _verify_signature(payload: bytes, signature_header: str | None) -> bool:
     return hmac.compare_digest(expected, signature_header.strip())
 
 
-def _handle_push(owner: str, repo: str, changed_files: list[str]) -> None:
+def _handle_push(owner: str, repo: str, branch: str, changed_files: list[str]) -> None:
     """Process all changed markdown files in a push event."""
     for file_path in changed_files:
         if not file_path.endswith(".md"):
             continue
-        logger.info("Checking %s/%s: %s", owner, repo, file_path)
+        logger.info("Checking %s/%s@%s: %s", owner, repo, branch, file_path)
         try:
-            content, sha = gitea_client.get_file(owner, repo, file_path)
+            content, sha = gitea_client.get_file(owner, repo, file_path, branch)
             updated, changed = processor.process_document(content)
             if changed:
-                gitea_client.update_file(owner, repo, file_path, updated, sha)
+                gitea_client.update_file(owner, repo, file_path, updated, sha, branch)
                 logger.info("Updated %s", file_path)
             else:
                 logger.info("No BLIGHT triggers found in %s", file_path)
@@ -65,6 +65,7 @@ def webhook():
     data = json.loads(payload)
     owner = data["repository"]["owner"]["login"]
     repo = data["repository"]["name"]
+    branch = data.get("ref", "").removeprefix("refs/heads/")
 
     # Collect unique file paths from all commits in the push
     seen: set[str] = set()
@@ -81,7 +82,7 @@ def webhook():
     # Process in background so we return 200 to Gitea immediately
     thread = threading.Thread(
         target=_handle_push,
-        args=(owner, repo, changed_files),
+        args=(owner, repo, branch, changed_files),
         daemon=True,
     )
     thread.start()
diff --git a/gitea_client.py b/gitea_client.py
index a9a1993..ad21eda 100644
--- a/gitea_client.py
+++ b/gitea_client.py
@@ -10,7 +10,7 @@ def _headers() -> dict:
     }
 
 
-def get_file(owner: str, repo: str, path: str) -> tuple[str, str]:
+def get_file(owner: str, repo: str, path: str, branch: str) -> tuple[str, str]:
     """Fetch a file's decoded content and its SHA from Gitea.
 
     Returns:
@@ -18,7 +18,7 @@ def get_file(owner: str, repo: str, path: str) -> tuple[str, str]:
         required for the subsequent update call.
     """
     url = f"{config.GITEA_URL}/api/v1/repos/{owner}/{repo}/contents/{path}"
-    response = requests.get(url, headers=_headers(), timeout=30)
+    response = requests.get(url, headers=_headers(), params={"ref": branch}, timeout=30)
     response.raise_for_status()
     data = response.json()
     content = base64.b64decode(data["content"]).decode("utf-8")
@@ -31,14 +31,16 @@ def update_file(
     path: str,
     content: str,
     sha: str,
-    commit_message: str = "BLIGHT: process triggers",
+    branch: str,
+    commit_message: str | None = None,
 ) -> None:
     """Write updated file content back to Gitea."""
     url = f"{config.GITEA_URL}/api/v1/repos/{owner}/{repo}/contents/{path}"
     payload = {
-        "message": commit_message,
+        "message": commit_message or f"BLIGHT: process triggers in {path}",
         "content": base64.b64encode(content.encode("utf-8")).decode("ascii"),
         "sha": sha,
+        "branch": branch,
     }
     response = requests.put(url, headers=_headers(), json=payload, timeout=30)
     response.raise_for_status()
diff --git a/processor.py b/processor.py
index c41ec8b..ee6eb42 100644
--- a/processor.py
+++ b/processor.py
@@ -12,6 +12,9 @@ DOCUMENT_PATTERN = re.compile(r"^BLIGHT::\s+(.+)$", re.MULTILINE | re.IGNORECASE
 
 FAILED_TEMPLATE = "<!-- BLIGHT_FAILED: {instruction} -->\n<!-- BLIGHT_ERROR: {error} -->"
 
+# Matches any BLIGHT: trigger in AI output that could cause a processing loop.
+_SANITIZE_PATTERN = re.compile(r"BLIGHT:", re.IGNORECASE)
+
 _MAX_RETRIES = 3
 _RETRY_DELAYS = [1, 2, 4]  # seconds between attempts
 
@@ -94,8 +97,8 @@ def _call_with_retry(document: str, instruction: str, *, document_scope: bool) -
     for attempt in range(_MAX_RETRIES):
         try:
             if document_scope:
-                return _provider.complete_document(document, instruction)
-            return _provider.complete(document, instruction)
+                return _sanitize(_provider.complete_document(document, instruction))
+            return _sanitize(_provider.complete(document, instruction))
         except Exception as exc:
             last_error = exc
             if attempt < _MAX_RETRIES - 1:
@@ -117,3 +120,8 @@ def _call_with_retry(document: str, instruction: str, *, document_scope: bool) -
         last_error,
     )
     return FAILED_TEMPLATE.format(instruction=instruction, error=last_error)
+
+
+def _sanitize(text: str) -> str:
+    """Defuse any BLIGHT: trigger patterns in AI output to prevent loop re-processing."""
+    return _SANITIZE_PATTERN.sub("BLIGHT&#58;", text)