diff --git a/paperforge/cli.py b/paperforge/cli.py
index 1cf7b816..25bef9cc 100644
--- a/paperforge/cli.py
+++ b/paperforge/cli.py
@@ -464,7 +464,6 @@ def build_parser() -> argparse.ArgumentParser:
     p_paper_navigation = sub.add_parser("paper-navigation", help="Navigate paper structure through the Layer 4 gateway")
     p_paper_navigation.add_argument("query", help="Paper identifier or DOI for structural navigation")
     p_paper_navigation.add_argument("--json", action="store_true", help="Output JSON")
-    p_paper_navigation.add_argument("--limit", type=int, default=5, help="Max results (default 5)")
 
     p_scoped_fetch = sub.add_parser("scoped-fetch", help="Fetch paper content scoped by query through the Layer 4 gateway")
     p_scoped_fetch.add_argument("query", help="Paper identifier, title, or scoped query for targeted fetch")
diff --git a/paperforge/commands/content_discovery.py b/paperforge/commands/content_discovery.py
index 8147c472..555dec13 100644
--- a/paperforge/commands/content_discovery.py
+++ b/paperforge/commands/content_discovery.py
@@ -5,7 +5,7 @@ from __future__ import annotations
 from paperforge.retrieval import gateway
 
 
-def run(args):
+def run(args) -> int:
     """Execute ``content-discovery`` via the Layer 4 gateway."""
     result = gateway.route_gateway(
         args.vault_path,
diff --git a/paperforge/commands/paper_lookup.py b/paperforge/commands/paper_lookup.py
index f732e556..35e022da 100644
--- a/paperforge/commands/paper_lookup.py
+++ b/paperforge/commands/paper_lookup.py
@@ -5,7 +5,7 @@ from __future__ import annotations
 from paperforge.retrieval import gateway
 
 
-def run(args):
+def run(args) -> int:
     """Execute ``paper-lookup`` via the Layer 4 gateway."""
     result = gateway.route_gateway(
         args.vault_path,
diff --git a/paperforge/retrieval/gateway.py b/paperforge/retrieval/gateway.py
index cf0c494c..0bf85766 100644
--- a/paperforge/retrieval/gateway.py
+++ b/paperforge/retrieval/gateway.py
@@ -18,13 +18,6 @@ from paperforge.memory.db import get_connection, get_memory_db_path
 
 logger = logging.getLogger(__name__)
 
-# Map gateway intent names to build_query_plan intent strings
-INTENTS: dict[str, str] = {
-    "paper-lookup": "known-paper",
-    "content-discovery": "content",
-    "paper-navigation": "known-paper",
-    "scoped-fetch": "known-paper",
-}
 
 
 def route_gateway(
diff --git a/paperforge/retrieval/structure_tree.py b/paperforge/retrieval/structure_tree.py
index 8bf184da..c0e00d17 100644
--- a/paperforge/retrieval/structure_tree.py
+++ b/paperforge/retrieval/structure_tree.py
@@ -13,12 +13,13 @@ def build_structure_tree(structured_blocks: list[dict[str, Any]]) -> dict[str, A
         role = block.get("role")
         text = str(block.get("text", "")).strip()
         if role in {"section_heading", "subsection_heading", "introduction_heading", "abstract_heading"} and text:
+            parent_title = nodes[-1]["title"] if nodes else ""
             current_section = {
                 "node_id": f"sec:{block.get('block_id')}",
                 "kind": "section",
                 "title": text,
                 "level": 1 if role != "subsection_heading" else 2,
-                "section_path": [text] if role != "subsection_heading" else [nodes[-1]["title"], text] if nodes else [text],
+                "section_path": [text] if role != "subsection_heading" else [parent_title, text],
                 "page_span": [block.get("page", 0), block.get("page", 0)],
                 "block_span": [[block.get("page", 0), block.get("block_id", "")]],
                 "children": [],