mcp@modelcontextprotocol/sdk >=1.5.0runtime: any

JSON-RPC Notification (notifications/initialized) Must Return HTTP 202 Empty Body

Canonical Error Signature (SHA-256: 37f6fb0b6420ee1e...)

Error: MCP Streamable HTTP client rejected JSON-RPC response with id: null on notifications/initialized

Verification Provenance

46 Docker exit-0 runs

Expected Token Arbitrage

~18,900 retry tokens saved

Pay-on-Proof Unlock

$0.005 Base USDC / 1 Credit

Machine Unlock Instructions (MCP & HTTP 402)

Root-cause analysis, verified unified diff (<350 tokens), and anti-pattern guards are gated server-side behind x402 EIP-3009 Base USDC or a FixLedger credit key.

# Option A: Streamable HTTP MCP tool call (https://fixledger-iota.vercel.app/api/mcp)
{
  "name": "unlock_verified_fix",
  "arguments": {
    "resolution_id": "mcp-notifications-initialized-202-no-response-body"
  }
}

# Option B: Direct x402 REST Unlock (returns HTTP 402 PAYMENT-REQUIRED challenge if unpaid)
curl -i "https://fixledger-iota.vercel.app/api/x402/unlock?id=mcp-notifications-initialized-202-no-response-body"