fix: correct action node schema and improve AI flow quality

- Fix action nodes to use next_node_id (not children) for continuation,
  matching how TreeNavigationPage.tsx navigates action nodes
- Validator now requires next_node_id on all action nodes and flags
  missing ones as broken dead ends
- Update _check_branch_termination: action nodes are not dead ends since
  they continue via next_node_id (validated separately)
- Improve scaffold prompt: branch names must describe observable symptoms
  users can self-identify, not internal category names
- Update branch_detail prompt with clearer action node schema, corrected
  few-shot example showing proper next_node_id on action nodes
- Improve assemble_tree root question to be more user-facing

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

backend/app/core/ai_tree_generator_service.py

@@ -34,8 +34,10 @@ Context: Your audience is technical MSP staff experienced with Windows Server, A
 Task: Given a flow type, category, name, description, and environment tags, suggest 4-7 top-level branches for the flow.
 
 For TROUBLESHOOTING flows:
-- Branches should be symptom-based categories (e.g., "Authentication Failures", "Connectivity Issues", "Performance Degradation")
-- Each branch represents a common way the problem manifests
+- Branches should describe the symptom the user observes — written as what the user sees or reports
+- The branch name becomes a selectable option on the first screen, so it must be self-identifying from a user's perspective
+- Good: "Drive letter missing after login", "Mapped drive shows as disconnected (red X)", "Access denied when opening files"
+- Bad: "Authentication Failures", "GPO Issues", "Connectivity Problems" — too vague for users to self-identify
 - Order from most common to least common
 
 For PROCEDURE flows:
@@ -45,9 +47,9 @@ For PROCEDURE flows:
 
 Rules:
 - Suggest 4-7 branches
-- Be specific to the technology/service described — avoid generic branches
-- Branch names should be concise (2-5 words)
-- Each branch needs a brief description (1 sentence)
+- Be specific to the technology/service described — avoid generic internal category names
+- Branch names should be concise (3-7 words) and describe the observable symptom or phase
+- Each branch needs a brief description (1 sentence) explaining what scenarios it covers
 - Return ONLY valid JSON, no markdown, no explanation
 
 Output format:
@@ -62,29 +64,32 @@ You must return ONLY valid JSON — no markdown, no code fences, no explanation.
 
 Required node schema:
 
-Decision nodes (branching diagnostic questions):
-{"id": "unique-slug", "type": "decision", "question": "The diagnostic question", "help_text": "Optional context or command hint", "options": [{"id": "opt-id", "label": "Answer choice", "next_node_id": "child-node-id"}], "children": []}
+Decision nodes (branching diagnostic questions — choose the right path):
+{"id": "unique-slug", "type": "decision", "question": "The diagnostic question", "help_text": "Optional context or command hint", "options": [{"id": "opt-id", "label": "Specific observable answer", "next_node_id": "child-node-id"}], "children": [<all child nodes listed here>]}
 
-Action nodes (investigation or remediation steps):
-{"id": "unique-slug", "type": "action", "title": "Short title", "description": "Detailed instructions", "commands": ["PowerShell or CMD commands"], "expected_outcome": "What success looks like", "children": []}
+Action nodes (a single investigation or remediation step — MUST have next_node_id pointing to the next node):
+{"id": "unique-slug", "type": "action", "title": "Short title", "description": "Detailed instructions", "commands": ["PowerShell or CMD commands"], "expected_outcome": "What success looks like", "next_node_id": "id-of-next-sibling-node"}
 
-Solution nodes (leaf nodes — the resolution):
+Solution nodes (leaf nodes — the final resolution, no children):
 {"id": "unique-slug", "type": "solution", "title": "Resolution title", "description": "Full resolution description", "resolution_steps": ["Step 1", "Step 2"]}
 
-Rules:
-1. Generate 3-10 nodes for this branch
-2. Start with a decision node if troubleshooting, action node if procedure
-3. Every branch path MUST end in a solution node — no dead ends
-4. Include realistic MSP commands (PowerShell preferred for Windows)
-5. Use unique node IDs prefixed with the branch context (e.g., "dns-check-service")
-6. CRITICAL — next_node_id must exactly match the "id" of a direct child in the "children" array of that same node. Never reference an ID that does not appear as a child of the current node.
-7. All option labels must be meaningful and specific
-8. Decision nodes must have at least 2 options
-9. Return a single root node with its children nested inside
-10. Build the tree bottom-up in your head: create leaf nodes first, then reference their IDs in parent options
+CRITICAL NAVIGATION RULES:
+- Decision node: each option's next_node_id MUST exactly match the "id" of a direct child in that decision node's "children" array
+- Action node: next_node_id MUST exactly match the "id" of a sibling node (another child of the same parent decision node)
+- Every action node MUST have a next_node_id — action nodes with no next step are broken dead ends
+- Solution nodes have no children and no next_node_id — they are the terminus
+- Every path through the tree MUST end at a solution node
 
-Few-shot example (abbreviated):
-{"id": "dns-root", "type": "decision", "question": "Can the client resolve any DNS names?", "help_text": "Run: nslookup google.com", "options": [{"id": "dns-opt-none", "label": "No DNS resolution at all", "next_node_id": "dns-check-service"}, {"id": "dns-opt-partial", "label": "Some names resolve, others don't", "next_node_id": "dns-check-specific"}], "children": [{"id": "dns-check-service", "type": "action", "title": "Check DNS Service", "description": "Verify the DNS Client service is running", "commands": ["Get-Service -Name Dnscache"], "expected_outcome": "Service should be Running", "children": [{"id": "dns-resolved", "type": "solution", "title": "DNS Service Restored", "description": "DNS client service was stopped", "resolution_steps": ["Restart DNS Client service", "Flush DNS cache: ipconfig /flushdns", "Test resolution"]}]}, {"id": "dns-check-specific", "type": "solution", "title": "Selective DNS Failure", "description": "Specific records missing or stale", "resolution_steps": ["Check DNS server configuration", "Verify zone records", "Clear DNS cache"]}]}"""
+Additional rules:
+1. Generate 4-10 nodes total for this branch
+2. Start with a decision node if troubleshooting, action node if procedure
+3. Decision nodes must have at least 2 options with specific, observable answer choices
+4. Include realistic MSP commands (PowerShell preferred for Windows)
+5. Use unique node IDs prefixed with the branch context (e.g., "gpo-check-link")
+6. Build the tree bottom-up in your head: create solution/leaf nodes first, then build parent nodes referencing their IDs
+
+Few-shot example showing correct action node next_node_id usage:
+{"id": "dns-root", "type": "decision", "question": "Can the client resolve any DNS names?", "help_text": "Run: nslookup google.com", "options": [{"id": "dns-opt-none", "label": "No — nslookup times out or returns 'server failed'", "next_node_id": "dns-check-service"}, {"id": "dns-opt-partial", "label": "Some names resolve but others fail", "next_node_id": "dns-check-specific"}], "children": [{"id": "dns-check-service", "type": "action", "title": "Check DNS Client Service", "description": "Verify the DNS Client service is running on the affected machine", "commands": ["Get-Service -Name Dnscache | Select-Object Status,StartType"], "expected_outcome": "Status should be Running", "next_node_id": "dns-service-solution"}, {"id": "dns-service-solution", "type": "solution", "title": "DNS Service Was Stopped", "description": "The DNS Client service was stopped, preventing all name resolution", "resolution_steps": ["Run: Start-Service Dnscache", "Set startup type: Set-Service Dnscache -StartupType Automatic", "Flush cache: ipconfig /flushdns", "Test: nslookup google.com"]}, {"id": "dns-check-specific", "type": "solution", "title": "Selective DNS Failure — Stale or Missing Records", "description": "Some records resolve correctly, indicating DNS is functional but specific records are stale or missing", "resolution_steps": ["Check DNS server for missing A/CNAME records", "Clear DNS cache on the DNS server: Clear-DnsServerCache", "Flush client cache: ipconfig /flushdns", "Verify with: nslookup <failing-hostname>"]}]}"""
 
 
 CORRECTIVE_PROMPT_TEMPLATE = """Your previous JSON was invalid for ResolutionFlow's tree schema.
@@ -297,14 +302,17 @@ def assemble_tree(
 
     # Determine root question based on flow type
     if flow_type == "troubleshooting":
-        root_question = f"What issue is the user experiencing with {name}?"
+        root_question = f"What is the user experiencing? Select the symptom that best matches their report."
+        root_help = "Choose the option that most closely describes the user's reported problem."
     else:
         root_question = f"Which phase of {name} are you working on?"
+        root_help = None
 
     tree_structure = {
         "id": "root",
         "type": "decision",
         "question": root_question,
+        **({"help_text": root_help} if root_help else {}),
         "options": options,
         "children": children,
     }

backend/app/core/ai_tree_validator.py

@@ -114,7 +114,12 @@ def validate_generated_tree(tree: dict[str, Any]) -> list[str]:
 
         elif node_type == "action":
             next_id = node.get("next_node_id")
-            if next_id:
+            if not next_id:
+                errors.append(
+                    f"Action node '{node_id}' is missing 'next_node_id'. "
+                    "Every action node must point to the next node (a sibling in the parent's children)."
+                )
+            else:
                 all_referenced_ids.add(next_id)
 
         elif node_type == "solution":
@@ -148,7 +153,11 @@ def validate_generated_tree(tree: dict[str, Any]) -> list[str]:
 
 
 def _check_branch_termination(node: dict[str, Any], errors: list[str]) -> None:
-    """Verify every branch eventually reaches a solution node."""
+    """Verify every branch eventually reaches a solution node.
+
+    Action nodes continue via next_node_id (validated separately).
+    Only decision nodes with no children are dead ends.
+    """
     if not isinstance(node, dict):
         return
 
@@ -159,10 +168,19 @@ def _check_branch_termination(node: dict[str, Any], errors: list[str]) -> None:
     if node_type == "solution":
         return  # Solution is a valid terminus
 
+    if node_type == "action":
+        # Action nodes continue via next_node_id (a sibling), not children.
+        # next_node_id presence is validated in _validate_node.
+        # Recurse into children if present (non-standard but tolerate it).
+        for child in children:
+            _check_branch_termination(child, errors)
+        return
+
+    # Decision node: must have children
     if not children:
         errors.append(
-            f"Node '{node_id}' (type={node_type}) is a dead end — "
-            "it has no children and is not a solution node"
+            f"Decision node '{node_id}' is a dead end — "
+            "it has no children"
         )
         return