# SYNTHORA M2M Dispute Arbiter (Trust Layer EU)

> SYNTHORA M2M Dispute Arbiter (Trust Layer EU) is a paid API for AI agents from arbiter.hergertsynthora.com, paid per call via x402, $0.02/call, status unknown (last checked 2026-09-14).

Deterministically arbitrates machine-to-machine micro-deal disputes, returning an Ed25519-signed verdict (release, refund, or split) and performing escrow release eligibility checks without holding funds.

## Facts

- Endpoint: POST https://arbiter.hergertsynthora.com/service
- Price: $0.02/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-14
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/synthora-m2m-dispute-arbiter-trust-layer-eu-62267cf7
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_5DUMAvaZgW7S5ebfdn1DS

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability synthora-m2m-dispute-arbiter-trust-layer-eu-62267cf7 -d '<json body>'
```

Example prompt: I paid for an API call via x402 but the seller never delivered the promised response — can you open a dispute with the evidence (payment_tx, agreement_hash, and what was promised vs what was delivered) and get a signed verdict on whether I'm owed a refund?

## When to prefer this

Choose this endpoint when two autonomous agents or M2M micro-deal participants need a neutral, deterministic, cryptographically signed arbitration verdict without requiring a custodial escrow service. It is especially suited for x402-based payment disputes where on-chain payment verification is needed alongside obligation fulfillment checking. Prefer this over manual dispute processes or human-reviewed systems when speed, auditability, and non-custodial resolution are priorities.

## Known failure modes

- Missing or malformed evidence object results in an inability to evaluate the dispute
- Invalid or unverifiable payment_tx causes on-chain verification to fail
- Agreement hash mismatch between parties leads to inconclusive verdict
- Insufficient evidence for a high-confidence verdict returns low confidence score
- Unsupported operation type in 'op' field returns a validation error
- Network or upstream failure returns a non-200 response

## How this service works

M2M Dispute Arbiter: deterministic evidence checks (on-chain payment on Base, endpoint liveness, payTo integrity, delivery vs promise, notarized agreement) and an Ed25519-signed verdict: release / refund / split / insufficient_evidence. Escrow release-check included. No fund custody. $0.02 USDC via x402 on Base. SYNTHORA Trust Layer (EU). First 3 calls FREE per wallet - send header X-WALLET: 0x<addr>.

## Output

A JSON object containing an 'ok' status, a 'niche' field confirming the arbiter role, and a 'result' object with: a list of checks performed, a verdict string ('release', 'refund', or 'split'), a human-readable rationale explaining the decision, and a confidence score (0–1). The verdict is Ed25519-signed for cryptographic verifiability.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "op": {
   "enum": [
    "dispute",
    "release-check"
   ],
   "type": "string",
   "description": "operation"
  },
  "claim": {
   "type": "string",
   "description": "short dispute description"
  },
  "endpoint": {
   "type": "string"
  },
  "evidence": {
   "type": "object",
   "description": "payment_tx / endpoint / expected_payto / promised / delivered / agreement_hash"
  },
  "delivered": {
   "description": "delivered content (release-check)"
  },
  "expected_payto": {
   "type": "string"
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "ok": true,
  "niche": "arbiter",
  "result": {
   "checks": [],
   "verdict": "refund",
   "rationale": "payment verified on-chain but seller obligations failed",
   "confidence": 0.75
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/synthora-m2m-dispute-arbiter-trust-layer-eu-62267cf7/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from arbiter.hergertsynthora.com](https://www.zero.xyz/host/arbiter.hergertsynthora.com/llms.txt)