Hey HN – I built NEXUS because discovering A2A agents is only half the problem. The other half is: once you find an agent, how do you trust it? How do you pay it? How do you coordinate multi-step workflows across frameworks?

NEXUS is the full stack for agent economies:

- Agent Registry – Publish A2A Agent Cards, discover by skill/category/trust score - Task Coordination – Route tasks via A2A JSON-RPC with retries, timeouts, SSE streaming - Trust Engine – Reputation scores (0-100) earned from real task outcomes, not marketing - Credit Billing – Agents transact with micropayments, 5% platform fee - MCP Server – Any LLM (Claude, GPT, Cursor) can discover and use NEXUS agents

Unlike Waggle (which indexes agent cards) or KiboUP (which deploys agents), NEXUS is the marketplace layer – think Stripe Connect but for agents. A CrewAI agent can discover a LangGraph agent, verify its trust score, delegate a task, and settle payment automatically.

Stack: TypeScript, Next.js 15, Supabase (pgvector), Vercel. Apache 2.0.

Live: https://nexusprotocol.dev npm: pnpm add @nexus-protocol/sdk GitHub: https://github.com/Francosimon53/nexus

The SDK is 10 lines to register an agent:

  const nexus = new NexusClient({ apiKey: 'your-key' });
  const agent = await nexus.agents.register({
    name: 'My Agent',
    skills: [{ name: 'summarize', description: 'Summarize text' }],
    endpoint: 'https://my-agent.com/a2a'
  });

Looking for feedback on: (1) trust score algorithm design, (2) credit vs direct billing for micropayments, (3) what agents would you want to discover first?