feat(chat + c-a2ui): LLM-generated labels — thread titles + drop KNOWN_LABELS

apps/website/content/docs/chat/api/api-docs.json

@@ -6586,7 +6586,7 @@
   {
     "name": "buildA2uiActionMessage",
     "kind": "function",
-    "description": "Builds an A2uiActionMessage from handler params and the current surface.\n The action.context is serialized as v1 DynamicValue-wrapped entries.",
+    "description": "Builds an A2uiActionMessage from handler params and the current surface.\n The action.context is serialized as v1 DynamicValue-wrapped entries.\n Sets action.label when the source component is a Button with a Text\n child whose literalString is non-empty.",
     "signature": "buildA2uiActionMessage(params: Record<string, unknown>, surface: A2uiSurface): A2uiActionMessage",
     "params": [
       {

cockpit/chat/a2ui/python/src/graph.py

@@ -18,13 +18,15 @@
 
 import json
 import logging
+import os
 import re
 from typing import Any, Literal
 
 from langchain_core.messages import AIMessage, HumanMessage, SystemMessage
 from langchain_openai import ChatOpenAI
 from langgraph.graph import StateGraph, MessagesState, END
 from langgraph.types import Command
+from langgraph_sdk import get_client
 from pydantic import BaseModel, Field, ValidationError, field_validator
 
 
@@ -757,14 +759,67 @@ def route(state: MessagesState) -> Command[Literal["build_form", "search_flights
     return Command(goto="build_form")
 
 
+# ── generate_title node (inline; matches Pattern D from spec
+#     2026-05-19-llm-generated-labels-design.md) ──────────────────────────────
+
+_TITLE_PROMPT = (
+    "In 3-5 words, summarize what the user is asking about. "
+    "Output ONLY the title — no quotes, no period, no prefix."
+)
+_TITLE_MODEL = "gpt-5-mini"
+
+
+async def generate_title(state: MessagesState, config) -> dict:
+    """Background title generation: on the first turn, summarize the user's
+    intent into 3-5 words and persist to LangGraph thread metadata so the
+    sidenav shows something meaningful instead of a UUID slice.
+
+    Idempotent — skips when metadata.thread_title already exists. Errors
+    are swallowed (title is a UX nicety, never a blocker). Runs after the
+    user-visible terminal node so it never blocks the response. See spec
+    2026-05-19-llm-generated-labels-design.md.
+    """
+    thread_id = (config.get("configurable") or {}).get("thread_id")
+    if not thread_id:
+        return {}
+    sdk_url = os.environ.get("LANGGRAPH_API_URL", "http://localhost:2024")
+    try:
+        client = get_client(url=sdk_url)
+        thread = await client.threads.get(thread_id)
+        if (thread.get("metadata") or {}).get("thread_title"):
+            return {}
+        first_user = next(
+            (m for m in state["messages"] if getattr(m, "type", None) == "human"),
+            None,
+        )
+        if not first_user or not isinstance(first_user.content, str):
+            return {}
+        # Skip action-message JSON (those flow as human-role too)
+        if first_user.content.lstrip().startswith("{"):
+            return {}
+        llm = ChatOpenAI(model=_TITLE_MODEL, temperature=0)
+        response = await llm.ainvoke([
+            SystemMessage(content=_TITLE_PROMPT),
+            HumanMessage(content=first_user.content),
+        ])
+        title = (response.content or "").strip().strip('"').strip("'")[:80]
+        if title:
+            await client.threads.update(thread_id, metadata={"thread_title": title})
+    except Exception as err:  # noqa: BLE001 — title is a UX nicety; never block
+        _logger.warning("Thread title generation failed: %s", err)
+    return {}
+
+
 _builder = StateGraph(MessagesState)
 _builder.add_node("route", route)
 _builder.add_node("build_form", build_form)
 _builder.add_node("search_flights", search_flights)
 _builder.add_node("confirm_booking", confirm_booking)
+_builder.add_node("generate_title", generate_title)
 _builder.set_entry_point("route")
-_builder.add_edge("build_form", END)
-_builder.add_edge("search_flights", END)
-_builder.add_edge("confirm_booking", END)
+_builder.add_edge("build_form", "generate_title")
+_builder.add_edge("search_flights", "generate_title")
+_builder.add_edge("confirm_booking", "generate_title")
+_builder.add_edge("generate_title", END)
 
 graph = _builder.compile()