diff --git a/atlasbot/knowledge/loader.py b/atlasbot/knowledge/loader.py
index 9e0a09d..8310ed2 100644
--- a/atlasbot/knowledge/loader.py
+++ b/atlasbot/knowledge/loader.py
@@ -106,7 +106,7 @@ class KnowledgeBase:
         except Exception:
             return
         lines.append("KB: atlas.json")
-        lines.extend(atlas_json.splitlines())
+        self._extend_with_limit(lines, atlas_json.splitlines(), max_chars)
 
     def _append_runbooks(self, lines: list[str]) -> None:
         if not self._runbooks:
@@ -134,8 +134,19 @@ class KnowledgeBase:
             if not text:
                 continue
             lines.append(f"KB File: {path.relative_to(self._base)}")
-            lines.extend(text.splitlines())
+            if not self._extend_with_limit(lines, text.splitlines(), max_chars):
+                break
 
     @staticmethod
     def _within_limit(lines: list[str], max_chars: int) -> bool:
         return sum(len(line) for line in lines) < max_chars
+
+    @staticmethod
+    def _extend_with_limit(lines: list[str], new_lines: list[str], max_chars: int) -> bool:
+        total = sum(len(line) for line in lines)
+        for line in new_lines:
+            if total + len(line) >= max_chars:
+                return False
+            lines.append(line)
+            total += len(line)
+        return True