diff --git a/ROADMAP.md b/ROADMAP.md
index cb9b136..62da980 100644
--- a/ROADMAP.md
+++ b/ROADMAP.md
@@ -71,3 +71,8 @@
 - [ ] **Testing & Quality**: Expand Playwright suites to cover internationalization/localization, workflow templates, and AJAX-driven navigation; continue running unit tests, static analysis, linters, and e2e jobs to close the testing triangle.
 - [ ] **Styling & Tooling**: Investigate SASS adoption for the Material UI theme, keep component files ≤100 LOC, and enforce plugin/service/controller patterns with DI so styles stay modular.
 - [ ] **Component Decomposition**: Audit remaining Jinja templates and Next.js components so each file owns a single macro/component, loops over declarative data, and delegates translation lookups to shared helpers.
+
+## Phase 11: Technical Debt
+- [x] **Structured workflow logging**: Add debug/trace warnings when parsing workflow definitions so graph builders surface malformed JSON and unbound bindings.
+- [ ] **Route modularization**: Split `backend/autometabuilder/web/server.py` into focused route modules or blueprints so each file stays under 100 LOC and supports DI of helpers.
+- [ ] **AJAX contract tests**: Expand the backend test suite to cover `/api/workflow/graph`, `/api/workflow/plugins`, and nav/translation payloads with mocked metadata so API drift is caught early.
diff --git a/backend/autometabuilder/web/workflow_graph.py b/backend/autometabuilder/web/workflow_graph.py
index 6decdf9..c0895bf 100644
--- a/backend/autometabuilder/web/workflow_graph.py
+++ b/backend/autometabuilder/web/workflow_graph.py
@@ -2,10 +2,13 @@
 from __future__ import annotations
 
 import json
+import logging
 from typing import Any, Dict, Iterable, List
 
 from .data import get_workflow_content, load_metadata
 
+logger = logging.getLogger(__name__)
+
 
 def _parse_workflow_definition() -> Dict[str, Any]:
     payload = get_workflow_content()
@@ -13,7 +16,8 @@ def _parse_workflow_definition() -> Dict[str, Any]:
         return {"nodes": []}
     try:
         parsed = json.loads(payload)
-    except json.JSONDecodeError:
+    except json.JSONDecodeError as exc:
+        logger.warning("Invalid workflow JSON: %s", exc)
         return {"nodes": []}
     return parsed if isinstance(parsed, dict) else {"nodes": []}
 
@@ -45,6 +49,8 @@ def _build_edges(nodes: Iterable[Dict[str, Any]]) -> List[Dict[str, str]]:
         outputs = node.get("outputs", {})
         for value in outputs.values():
             if isinstance(value, str):
+                if value in producers:
+                    logger.debug("Variable %s already produced by %s; overwriting with %s", value, producers[value], node["id"])
                 producers[value] = node["id"]
     edges: List[Dict[str, str]] = []
     for node in nodes:
@@ -55,6 +61,8 @@ def _build_edges(nodes: Iterable[Dict[str, Any]]) -> List[Dict[str, str]]:
                 source = producers.get(variable)
                 if source:
                     edges.append({"from": source, "to": node["id"], "var": variable, "port": port})
+                else:
+                    logger.debug("No producer found for %s referenced by %s.%s", variable, node["id"], port)
     return edges
 
 
@@ -63,6 +71,7 @@ def build_workflow_graph() -> Dict[str, Any]:
     plugin_map = load_metadata().get("workflow_plugins", {})
     nodes = _gather_nodes(definition.get("nodes", []), plugin_map)
     edges = _build_edges(nodes)
+    logger.debug("Built workflow graph with %d nodes and %d edges", len(nodes), len(edges))
     return {
         "nodes": nodes,
         "edges": edges,