Nexus AI News MCP server

Nexus

A Jev-powered AI news feed.

Nexus ingests AI news from multiple sources, dedupes it, classifies each item with a single Jev (TypeSafe System One) call, and serves the result as a reverse-chronological feed with filters and a guarded, extractive chat search. No graph database, no generative LLM in the request path.

Sources (arxiv, hackernews, github, twitter, rss)
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dedup.ts (URL → title → arXiv-id → Jaccard + entity fingerprints)
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PostgreSQL raw_items
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Jev enrichment (TypeSafe System One, model jev-latest, 1 call/item)
   relevant? (Noul) · vertical (Choice) · event_type (Choice) · significance (Score)
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PostgreSQL feed_items (reverse-chron, indexed)
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Fastify API — GET /api/feed · GET /api/feed/meta · POST /api/chat
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React feed client — ActivityFeed, FilterBar, HotCards, guarded ChatBox

Quick Start

# 1. Start infrastructure (PostgreSQL)
docker compose up -d

# 2. Install dependencies
pnpm install

# 3. Build all packages
pnpm build

# 4. Start API and client dev servers (separate terminals)
pnpm dev:api
pnpm dev:client

# 5. Run the agent (source polling + Jev enrichment) separately
pnpm --filter @nexus/agent start

The client opens at http://localhost:5173 and the API serves at http://localhost:3001.

Monorepo Layout

Adding a Source Adapter

The primary contribution path is adding new data sources. Every adapter feeds raw items into the dedup + Jev enrichment pipeline, which classifies and inserts them into the feed automatically.

The RawItem Interface

// packages/agent/src/sources/types.ts
interface RawItem {
  source: string;        // adapter name, e.g. "arxiv"
  source_url: string;    // canonical URL for deduplication
  title: string;         // headline / paper title
  content: string;       // body text (Jev classifies, excerpt is sliced from here)
  published_at: string;  // ISO 8601 timestamp
  raw_metadata: Record<string, unknown>; // source-specific fields
}

Write Your Adapter

Extend BaseAdapter and implement fetchItems(). You get rate limiting, exponential retry with backoff, and URL-based deduplication for free.

// packages/agent/src/sources/my-source.ts
import type { RawItem } from "./types.js";
import { BaseAdapter } from "./base-adapter.js";

export class MySourceAdapter extends BaseAdapter {
  name = "my-source";
  priority = "P1" as const;

  constructor() {
    super({
      pollIntervalMs: 30 * 60 * 1000, // how often to poll
      rateLimitMs: 2000,               // min delay between requests
    });
  }

  protected async fetchItems(): Promise<RawItem[]> {
    const response = await fetch("https://api.example.com/items");
    if (!response.ok) throw new Error(`Fetch failed: ${response.status}`);

    const data = await response.json();
    return this.dedupeByUrl(
      data.map((item: any) => ({
        source: this.name,
        source_url: item.url,
        title: item.title,
        content: item.body,
        published_at: new Date(item.date).toISOString(),
        raw_metadata: { id: item.id },
      }))
    );
  }
}

Existing Adapters

Shortened. The full README is on GitHub.