EM-A2A: Agent-to-Agent Payment Protocol#

Agent-to-Agent payments, escrow, credit scoring, and identity on the TRON blockchain.

When to Use This Skill#

Use em-a2a when:

• One agent needs to pay another agent for services, data, or compute
• Funds need to be held in escrow until work is delivered and accepted
• You need to check an agent's credit score before trusting them
• You need to verify an agent's on-chain identity (DID + KYA)
• You want to calculate protocol fees before initiating a payment

Not for: Paying API endpoints (use paybot) or HTTP 402 interception (use x402).

Tools#

This skill provides 4 MCP tools via @poisonpyf/a2a-mcp:

ToolWhen to Calla2a_payTransfer USDC/USDT from one agent to anothera2a_escrowLock funds before work starts, release on completion, refund on disputea2a_creditCheck credit score, level, trend, and leaderboard for an agenta2a_revenueCalculate protocol fee before initiating a transaction

Typical Workflow#

Hiring Another Agent#

text

1. a2a_credit(agentId)           → Check seller's reputation
2. a2a_revenue(amount, mode)     → Understand the fee structure
3. a2a_escrow(action="lock")     → Lock payment in escrow
4. [Seller delivers work]
5. a2a_escrow(action="release")  → Release funds on acceptance

Direct Payment (no escrow)#

text

1. a2a_credit(agentId)           → Check counterparty reputation
2. a2a_revenue(amount, mode)     → Preview fees
3. a2a_pay(from, to, amount)     → Execute direct transfer

Setup#

Add to your MCP client configuration:

json

{
  "mcpServers": {
    "a2a": {
      "command": "npx",
      "args": ["-y", "@poisonpyf/a2a-mcp"],
      "env": {
        "A2A_NETWORK": "shasta",
        "A2A_PRIVATE_KEY": "your-tron-private-key"
      }
    }
  }
}

Network: Use shasta for testnet, mainnet for production.

Tool Reference#

a2a_pay#

Transfer tokens between agents. Handles AML screening, revenue calculation, and on-chain execution.

json

{
  "from": "did:bai:tron:TBu...",
  "to": "did:bai:tron:TSa...",
  "token": "USDC",
  "amount": "1000000",
  "memo": "Payment for smart contract audit"
}

a2a_escrow#

Lock/release/refund funds between agents.

json

// Lock
{ "from": "...", "to": "...", "amount": "500000000", "action": "lock", "task": "Code review" }

// Release (use escrowId from lock result)
{ "from": "...", "to": "...", "amount": "500000000", "action": "release", "escrowId": "esc_abc123" }

// Refund
{ "from": "...", "to": "...", "amount": "500000000", "action": "refund", "escrowId": "esc_abc123" }

a2a_credit#

Check agent reputation and creditworthiness.

json

{ "agentId": "did:bai:tron:TSa..." }

Returns score (300-950), level (excellent/good/fair/poor/none), trend history, and leaderboard.

a2a_revenue#

Preview protocol fees. Two modes:

• fixed_tier: Volume-based fixed rates (1.0% default, decreases with volume)
• variable_float: Risk-adjusted rates (lower risk + higher credit = lower fees)

json

{ "amount": "100000000", "mode": "fixed_tier" }

Architecture#

text

Agent A (Client)                    Agent B (Server)
     │                                    │
     ├─ a2a_credit(agentB) ──→ credit score
     ├─ a2a_revenue(amount) ─→ fee preview
     ├─ a2a_escrow(lock) ────→ funds locked
     │                                    │
     │         [Agent B delivers work]    │
     │                                    │
     ├─ a2a_escrow(release) ──→ funds released + credit updated
     │                                    │
     └────────── TRON blockchain ─────────┘

Links#

• GitHub: https://github.com/ypeng1620-beep/EM-A2A
• npm: https://www.npmjs.com/package/@poisonpyf/a2a-mcp
• TRON Shasta Faucet: https://www.trongrid.io/shasta