Vercel AI SDK: Stateful Chat Apps with sovseal Memory

import { NextRequest } from "next/server";
import { streamText, tool } from "ai";
import { openai } from "@ai-sdk/openai";
import { AgentStateClient, EngineUnavailableError } from "@sovseal/sdk";
import { z } from "zod";

// Initialise the AgentStateClient once at module level.
// store/recall need no endpoint/apiKey — they talk to the local native host.
const client = new AgentStateClient();

export async function POST(req: NextRequest) {
  const { messages } = await req.json();
  const lastUserMessage = messages[messages.length - 1]?.content ?? "";

  // 1. Recall memories relevant to this message
  let recalledContext = "";
  try {
    const hits = await client.recall(lastUserMessage, { topK: 5 });
    recalledContext = hits.map((h) => h.text).join("\n");
  } catch (err) {
    if (!(err instanceof EngineUnavailableError)) throw err;
    console.warn(`Memory engine unavailable (${err.reason}) — proceeding without recall.`);
  }

  // 2. Stream the response with a storeMemory tool
  const response = streamText({
    model: openai("gpt-4o"),
    messages,
    system: `You are a helpful assistant. Here is context from previous conversations:
${recalledContext}`,
    tools: {
      storeMemory: tool({
        description:
          "Store a new fact or preference about the user for future conversations.",
        parameters: z.object({
          fact: z
            .string()
            .describe(
              "A declarative fact about the user, e.g. 'User prefers dark mode'"
            ),
        }),
        execute: async ({ fact }) => {
          try {
            const result = await client.store(fact);
            return { success: true, stored: fact, reinforced: result.reinforced };
          } catch (err) {
            if (err instanceof EngineUnavailableError) {
              return { success: false, reason: err.reason };
            }
            throw err;
          }
        },
      }),
    },
  });

  return response.toDataStreamResponse();
}

SOVSEAL_API_KEY=sov_live_your-api-key