fix: stop recursive AGENTS.md walk, load top-level only (#3110)

The recursive os.walk for AGENTS.md in subdirectories was undesired.
Only load AGENTS.md from the working directory root, matching the
behavior of CLAUDE.md and .cursorrules.

agent/prompt_builder.py

@@ -490,39 +490,19 @@ def _load_hermes_md(cwd_path: Path) -> str:
 
 
 def _load_agents_md(cwd_path: Path) -> str:
-    """AGENTS.md — hierarchical, recursive directory walk."""
-    top_level_agents = None
+    """AGENTS.md — top-level only (no recursive walk)."""
     for name in ["AGENTS.md", "agents.md"]:
         candidate = cwd_path / name
         if candidate.exists():
-            top_level_agents = candidate
-            break
-
-    if not top_level_agents:
-        return ""
-
-    agents_files = []
-    for root, dirs, files in os.walk(cwd_path):
-        dirs[:] = [d for d in dirs if not d.startswith('.') and d not in ('node_modules', '__pycache__', 'venv', '.venv')]
-        for f in files:
-            if f.lower() == "agents.md":
-                agents_files.append(Path(root) / f)
-    agents_files.sort(key=lambda p: len(p.parts))
-
-    total_content = ""
-    for agents_path in agents_files:
-        try:
-            content = agents_path.read_text(encoding="utf-8").strip()
-            if content:
-                rel_path = agents_path.relative_to(cwd_path)
-                content = _scan_context_content(content, str(rel_path))
-                total_content += f"## {rel_path}\n\n{content}\n\n"
-        except Exception as e:
-            logger.debug("Could not read %s: %s", agents_path, e)
-
-    if not total_content:
-        return ""
-    return _truncate_content(total_content, "AGENTS.md")
+            try:
+                content = candidate.read_text(encoding="utf-8").strip()
+                if content:
+                    content = _scan_context_content(content, name)
+                    result = f"## {name}\n\n{content}"
+                    return _truncate_content(result, "AGENTS.md")
+            except Exception as e:
+                logger.debug("Could not read %s: %s", candidate, e)
+    return ""
 
 
 def _load_claude_md(cwd_path: Path) -> str:
@@ -576,7 +556,7 @@ def build_context_files_prompt(cwd: Optional[str] = None, skip_soul: bool = Fals
 
     Priority (first found wins — only ONE project context type is loaded):
       1. .hermes.md / HERMES.md  (walk to git root)
-      2. AGENTS.md / agents.md   (recursive directory walk)
+      2. AGENTS.md / agents.md   (cwd only)
       3. CLAUDE.md / claude.md   (cwd only)
       4. .cursorrules / .cursor/rules/*.mdc  (cwd only)