0️⃣ Links to Check Out

1️⃣ A2A (Agent-to-Agent) — The Intent Layer

A2A answers: Who is talking to whom, and why?

What exists at this layer

  • Autonomous agents
    • Each agent has:
      • A role (planner, executor, verifier, etc.)
      • A wallet or payment authority
      • A policy engine (budget, trust rules)
  • Negotiation
    • Price
    • SLA
    • Execution guarantees
  • No humans in the execution path

Conceptual object 

  Agent {
  id
  capabilities
  payment_policy
  wallet_reference
}

Example A2A intent

“Agent A will pay Agent B 0.2 KAS if Agent B completes task X within 5 seconds.”

Important: At the A2A layer, no blockchain yet. This is pure intent + autonomy.

2️⃣ x402 — The Transport & Authorization Layer

x402 answers: How do agents ask for, authorize, and prove payment?

x402 adapts the familiar HTTP 402 Payment Required into an agent-native payment handshake.

How x402 fits A2A

Traditional HTTP 

  GET /resource
→ 401 Unauthorized

x402-style agent interaction 

  GET /task/execute
→ 402 Payment Required

With machine-readable metadata, not a PayPal link.

x402 responsibilities

x402 does NOT move money.

It:

  • Describes payment requirements
  • Establishes who must pay whom
  • Encodes conditions
  • References settlement proof

Think of x402 as:

“Authorization & negotiation glue” between agents and payment rails

x402 conceptual flow

Step 1: Request 

  POST /execute
Agent-ID: agent-A

Step 2: Challenge 

  402 Payment Required
X-Payment-Amount: 0.2 KAS
X-Payment-Recipient: kaspa:qxyz...
X-Payment-Condition: on-success
X-Payment-Deadline: 5s

Step 3: Proof submission 

  POST /execute
X-Payment-Proof: <signed tx | channel proof | escrow ref>

x402 is blockchain-agnostic. This is where Kaspa plugs in.

3️⃣ Kaspa BlockDAG — The Settlement Layer

Kaspa answers: How does value actually move, fast enough for agents?

Why Kaspa is unusually well-suited

Kaspa’s BlockDAG gives you:

  • High throughput
  • Low latency
  • Parallel blocks
  • Fast confirmations
  • No global bottleneck

This matters because A2A payments are frequent, small, and time-sensitive.

Kaspa’s role in the stack

Kaspa provides:

  • Final settlement
  • Cryptographic proof
  • Wallet ownership
  • Anti-double-spend guarantees

Kaspa objects 

  Transaction {
  from_address
  to_address
  amount
  fee
  timestamp
  dag_inclusion_proof
}

Two Kaspa payment modes for A2A

🔹 Mode A: Direct On-Chain Micropayment

  • Agent A signs a transaction
  • Agent B verifies DAG inclusion
  • Proof returned via x402

Good for:

  • Low frequency
  • High trust finality

🔹 Mode B: Pre-Funded / Escrow Pattern (recommended)

  • Agent A pre-funds a Kaspa address or UTXO
  • Agent B draws against it
  • Final settlement later

Good for:

  • Streaming payments
  • Per-token billing
  • Swarm agents

4️⃣ Full Stack Mapping (Side-by-Side)

Layer Role What it Defines
A2A Intent Who pays whom and why
x402 Protocol How payment is requested, authorized, and proven
Kaspa BlockDAG Settlement Where and how value actually moves

End-to-End Flow (Concrete) 

  Agent A (Planner)
  └─ Needs transcription

Agent B (Transcriber)
  └─ Responds with x402 challenge
     (0.1 KAS, on success)

Agent A
  └─ Signs Kaspa tx
  └─ Sends tx hash + signature

Agent B
  └─ Verifies DAG inclusion
  └─ Executes task
  └─ Returns result

5️⃣ Mental Model (Key Insight)

A2A is the “why” x402 is the “how” Kaspa is the “where value settles”

None replaces the others.

6️⃣ Why This Stack Is Compelling

Compared to Ethereum-centric stacks:

Ethereum Kaspa
Sequential blocks Parallel BlockDAG
Congestion sensitive Naturally scalable
Gas spikes Predictable fees
Slower finality Near-real-time confirmation

For agent swarms and micro-tasks, Kaspa’s architecture is a natural fit.