SettlementWitness MCP

SettlementWitness is a stateless MCP verification tool that returns replay-stable settlement receipts (PASS/FAIL) by forwarding task_id, spec, and output to the Default Settlement Verifier. Designed for agent execution gating and x402 settlement flows.

GitHub

Default Settlement Verifier

Deterministic, neutral verification for agent-to-agent and programmatic settlements.

Landing page: https://defaultverifier.com

SAR v0.1 Specification

Spec: https://defaultverifier.com/spec/sar-v0.1

Public Keys: https://defaultverifier.com/.well-known/sar-keys.json

Fixtures: https://defaultverifier.com/spec/sar-v0.1/fixtures/README

Overview

The Default Settlement Verifier is a stateless verification service that evaluates whether a claimed settlement outcome satisfies predefined conditions under deterministic rules.

It answers one question only:

“Given this claim and these conditions, does it verify?”

It produces signed, replayable truth, not coordination, custody, or enforcement.

What It Does

The verifier accepts a structured verification request describing a settlement claim and evaluates it against deterministic rules. It returns:

  • A binary verdict (PASS / FAIL)
  • A confidence score
  • A cryptographic signature
  • Optional fee metadata (fee-aware; currently not enforced)

The verifier:

  • Does not hold funds
  • Does not initiate payments
  • Does not maintain session state
  • Does not rely on identity, reputation, or trust assumptions

Core Properties

  • Deterministic — Identical inputs always produce identical signed results
  • Stateless — Every call is independent
  • Neutral — No buyer/seller bias, no incentives, no governance layer
  • Composable — Plugs into agent frameworks, payment rails, and settlement protocols
  • Auditable — Signed responses allow downstream verification and logging

Intended Use Cases

  • Agent-to-agent payments requiring post-condition verification
  • x402-style pay-after-execution flows
  • Automated escrow or conditional release systems
  • Buyer protection primitives without custody
  • Programmatic settlement validation in AI workflows

Canonical Verification Endpoint (POST)

POST https://defaultverifier.com/verify

Important:
This endpoint accepts POST requests only.
Browsers will show “Cannot GET /verify”. This is expected behavior.

Example request:

{
  "task_id": "example-001",
  "spec": { "expected_output": "hash_or_descriptor" },
  "output": { "expected_output": "hash_or_descriptor" }
}

SettlementWitness (v0)

SettlementWitness is a thin, stateless wrapper that calls the Default Settlement Verifier and returns a replay-stable receipt for agent workflows.

It adds:

  • no state
  • no judgment
  • no retries
  • no facilitation logic

Canonical Endpoints

Notes:

  • POST /settlement-witness is POST-only.
  • GET /settlement-witness returns 405 by design.

Example (PASS)

curl -s -X POST https://defaultverifier.com/settlement-witness \
  -H "Content-Type: application/json" \
  -d '{
    "task_id": "example-002",
    "spec": { "expected": "foo" },
    "output": { "expected": "foo" }
  }'

Minimal response shape (trimmed):

{
  "witness": "SettlementWitness",
  "witness_version": "v0",
  "task_id": "example-002",
  "verifier_response": {
    "verdict": "PASS",
    "reason_code": "MATCH",
    "signature": "..."
  },
  "witness_timestamp": "...",
  "receipt_id": "..."
}

MCP (Canonical)

SettlementWitness is available via MCP for agent-native workflows.

Determinism guarantee: Identical inputs produce the same receipt_id and verifier signature. Timestamps may differ.

Security & Settlement Gating

Default Settlement Verifier can serve as a lightweight mitigation layer in autonomous workflows:

  • Proof-of-Delivery — Deterministic PASS/FAIL verdicts verify outputs match task specifications before settlement.
  • Settlement Gating — Payments or downstream actions can be conditioned on verifiable completion.
  • Dispute Reduction — Signed receipts provide replayable evidence for post-task settlement decisions.

The verifier does not enforce outcomes or custody funds; it produces neutral, signed verification receipts.

Determinism & Signatures (Replay Stability)

  • timestamp and witness_timestamp may change on each call (observability).
  • For identical inputs (task_id, spec, output), the verifier signature is stable.
  • receipt_id is derived from the verifier signature and is stable for identical inputs.

Endpoint Behavior (Expected)

  • POST /verify → works (GET not supported)
  • POST /settlement-witness → works (GET returns 405)
  • GET /manifest → works

OpenClaw Compatibility

SettlementWitness is compatible with OpenClaw via a drop-in skill definition included in this repository:

openclaw/skills/settlement-witness/SKILL.md

The skill calls the public HTTPS endpoint:

POST https://defaultverifier.com/settlement-witness

No local services are required.

Agent Wrappers & Skills

SettlementWitness is a stateless witness wrapper that issues replay-stable verification receipts for post-task settlement workflows.

It is compatible with:

  • Heurist Mesh (submission pending)
  • MCP invocation patterns
  • OpenClaw skills (drop-in wrapper included)

Deployment Notes (Factual)

  • Verifier and SettlementWitness are served via HTTPS behind NGINX on defaultverifier.com
  • SettlementWitness runs persistently and is proxied via NGINX (no raw port exposure)
  • Cloudflare cache bypass is enabled for API routes (/verify, /settlement-witness, /manifest)

Non-Goals

The Default Settlement Verifier explicitly does not:

  • Act as an oracle of subjective truth
  • Resolve disputes
  • Store or escrow funds
  • Enforce payment
  • Provide reputation or identity services

Those layers belong upstream or downstream.

Roadmap (Non-Commitment)

  • Expanded claim schemas
  • Optional replay-safe receipts
  • Public verification key endpoint
  • Optional metrics endpoint

No timelines are guaranteed.

License

MIT License

Contact

Project discussions and updates:

https://x.com/defaultsettle

Operator & Provenance

SettlementWitness is operated as part of the Default Settlement Verifier infrastructure.

Operator: Default Settlement Verifier
Repository: https://github.com/nutstrut/default-settlement-verifier
Homepage: https://defaultverifier.com

SettlementWitness is a stateless deterministic attestation service. It does not hold funds, execute payments, enforce settlements, or trigger on-chain actions.

Receipt verification: see docs/signature-verification.md (added in this repo).

Support

If Default Settlement Verifier or SettlementWitness saved you time, reduced risk, or helped you ship faster, you can support ongoing infrastructure work.

Support via GitHub Sponsors:
https://github.com/sponsors/nutstrut

Infrastructure is operated independently and remains free to use.

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