TrustAtom MCP Server

Instructions

Implementation Reference

• src/sign.ts:175-201 (handler)

  The core logic that verifies the Ed25519 signature of a TrustAtom receipt.

  export function verifyTrustAtom(
    receipt: TrustAtomReceipt,
  ): VerifyResult {
    try {
      const sig = naclUtil.decodeBase64(receipt.signature_b64);
      const pubKey = naclUtil.decodeBase64(receipt.public_key_b64);
      const msg = naclUtil.decodeUTF8(receipt.evidence_hash);
  
      const valid = nacl.sign.detached.verify(msg, sig, pubKey);
  
      return {
        valid,
        reason: valid
          ? "Ed25519 signature verified — receipt is authentic"
          : "Signature mismatch — receipt may have been tampered with",
        receipt_id: receipt.id,
        public_key_b64: receipt.public_key_b64,
      };
    } catch (e: unknown) {
      return {
        valid: false,
        reason: `Verification failed: ${e instanceof Error ? e.message : String(e)}`,
        receipt_id: receipt.id,
        public_key_b64: receipt.public_key_b64,
      };
    }
  }

• src/server.ts:193-217 (registration)

  The MCP tool handler case for "verify_trustatom" in src/server.ts, which calls the verification logic.

  case "verify_trustatom": {
    const receiptId = String(args?.receipt_id ?? "");
    const found = ledger.find((r) => r.id === receiptId);
  
    if (!found) {
      return {
        content: [
          {
            type: "text",
            text: JSON.stringify({
              valid: false,
              reason: `Receipt ${receiptId} not found in ledger`,
            }),
          },
        ],
      };
    }
  
    const result = verifyTrustAtom(found);
    return {
      content: [
        {
          type: "text",
          text: JSON.stringify(result, null, 2),
        },