feat: merge document_agent into sample_agent for unified canvas exper…

…ience

- Add document state field to AgentState in src/todos.py
- Create new src/document.py with write_document tool and HITL confirmation
- Update main.py to include document tools and enable predictive state streaming
- Set config metadata for copilotkit:emit-intermediate-state for live document editing
- Remove separate document_agent from langgraph.json and route.ts
- Update canvas page to use agentId='default' instead of 'document_agent'
- Delete document_agent.py (functionality now in main agent)

The canvas editor now uses the flagship gpt-5.4-2026-03-05 model with all skill files
loaded from the skills/ directory, providing better diagram generation with labeled
elements and professional visualizations.

apps/agent/langgraph.json

@@ -4,8 +4,7 @@
   "dependencies": ["."],
   "package_manager": "uv",
   "graphs": {
-    "sample_agent": "./main.py:graph",
-    "document_agent": "./document_agent.py:graph"
+    "sample_agent": "./main.py:graph"
   },
   "env": "../../.env"
 }

apps/agent/main.py

@@ -9,6 +9,7 @@
 
 from src.query import query_data
 from src.todos import AgentState, todo_tools
+from src.document import document_tools
 from src.form import generate_form
 from skills import load_all_skills, load_skill
 
@@ -18,7 +19,7 @@
 
 agent = create_agent(
     model=ChatOpenAI(model="gpt-5.4-2026-03-05"),
-    tools=[query_data, *todo_tools, generate_form],
+    tools=[query_data, *todo_tools, *document_tools, generate_form],
     middleware=[CopilotKitMiddleware()],
     state_schema=AgentState,
     system_prompt=f"""
@@ -59,7 +60,22 @@
         tools instead of `widgetRenderer`. Follow the skill below exactly:
 
         {_excalidraw_skill_text}
+
+        ## Document Editing
+
+        When the user asks to write, edit, create, or modify a document, use the `write_document` tool.
+        Always write the complete document, even when making small changes. After writing, the user will
+        see a confirmation dialog to review and accept or reject your changes. Be concise and follow
+        their specific instructions for content and format.
     """,
 )
 
-graph = agent
+graph = agent.with_config({
+    "metadata": {
+        "copilotkit:emit-intermediate-state": [{
+            "state_key": "document",
+            "tool": "write_document",
+            "tool_argument": "document",
+        }]
+    }
+})

apps/agent/src/document.py

@@ -0,0 +1,34 @@
+import uuid
+from langchain.tools import tool, ToolRuntime
+from langchain.messages import ToolMessage, AIMessage
+from langgraph.types import Command
+
+
+@tool
+def write_document(document: str, runtime: ToolRuntime) -> Command:
+    """
+    Write or update a document. Use markdown formatting.
+    Do not use italic or strike-through - reserved for diffs.
+    Write the complete document, even when making small edits.
+    Keep document changes minimal - don't rewrite everything.
+    """
+    return Command(update={
+        "document": document,
+        "messages": [
+            ToolMessage(
+                content="Document written.",
+                tool_call_id=runtime.tool_call_id
+            ),
+            AIMessage(
+                content="",
+                tool_calls=[{
+                    "id": str(uuid.uuid4()),
+                    "name": "confirm_changes",
+                    "args": {},
+                }]
+            ),
+        ],
+    })
+
+
+document_tools = [write_document]

apps/agent/src/todos.py

@@ -2,7 +2,7 @@
 from langchain.tools import ToolRuntime, tool
 from langchain.messages import ToolMessage
 from langgraph.types import Command
-from typing import TypedDict, Literal
+from typing import TypedDict, Literal, Optional
 import uuid
 
 class Todo(TypedDict):
@@ -14,6 +14,7 @@ class Todo(TypedDict):
 
 class AgentState(BaseAgentState):
     todos: list[Todo]
+    document: Optional[str] = None
 
 @tool
 def manage_todos(todos: list[Todo], runtime: ToolRuntime) -> Command:

apps/app/src/app/api/copilotkit/route.ts

@@ -25,36 +25,17 @@ defaultAgent.use(
   })
 );
 
-// 3. Define the document agent for the canvas editor
-const documentAgent = new LangGraphAgent({
-  deploymentUrl: process.env.LANGGRAPH_DEPLOYMENT_URL || "http://localhost:8123",
-  graphId: "document_agent",
-  langsmithApiKey: process.env.LANGSMITH_API_KEY || "",
-});
-
-// Wire up MCP apps middleware for document agent
-documentAgent.use(
-  new MCPAppsMiddleware({
-    mcpServers: [{
-      type: "http",
-      url: process.env.MCP_SERVER_URL || "https://mcp.excalidraw.com",
-      serverId: "example_mcp_app",
-    }],
-  })
-);
-
 // Allow long-running agent + MCP tool calls
 export const maxDuration = 300;
 
-// 4. Define the route and CopilotRuntime for the agents
+// Define the route and CopilotRuntime for the agent
 export const POST = async (req: NextRequest) => {
   const { handleRequest } = copilotRuntimeNextJSAppRouterEndpoint({
     endpoint: "/api/copilotkit",
     serviceAdapter: new ExperimentalEmptyAdapter(),
     runtime: new CopilotRuntime({
       agents: {
         default: defaultAgent,
-        document_agent: documentAgent,
       },
       a2ui: { injectA2UITool: true },
     }),

apps/app/src/app/canvas/page.tsx

@@ -46,7 +46,7 @@ export default function CanvasPage() {
 
             {/* Right: Chat Panel */}
             <div className="w-[400px] overflow-hidden rounded-lg" style={{ background: "var(--surface-primary)", boxShadow: "0 1px 3px rgba(0, 0, 0, 0.08)" }}>
-              {mounted && <CopilotChat agentId="document_agent" className="h-full flex flex-col" />}
+              {mounted && <CopilotChat agentId="default" className="h-full flex flex-col" />}
             </div>
           </div>
         </CopilotKit>
@@ -95,7 +95,7 @@ const DocumentEditor = () => {
   });
 
   const { agent } = useAgent({
-    agentId: "document_agent",
+    agentId: "default",
     updates: [UseAgentUpdate.OnStateChanged, UseAgentUpdate.OnRunStatusChanged],
   });
 
@@ -156,7 +156,7 @@ const DocumentEditor = () => {
   // Human-in-the-loop: confirm_changes (legacy)
   useHumanInTheLoop(
     {
-      agentId: "document_agent",
+      agentId: "default",
       name: "confirm_changes",
       render: ({ args, respond, status }) => (
         <ConfirmChanges
@@ -181,8 +181,8 @@ const DocumentEditor = () => {
   // Human-in-the-loop: write_document (primary)
   useHumanInTheLoop(
     {
-      agentId: "document_agent",
-      name: "write_document",
+      agentId: "default",
+      name: "confirm_changes",
       description: "Present the proposed changes to the user for review",
       parameters: z.object({
         document: z.string().describe("The full updated document in markdown format"),