Default Settlement Verifier

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

Landing page: https://defaultverifier.com

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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

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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.

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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

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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

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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

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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" }
}

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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

• POST https://defaultverifier.com/settlement-witness
• GET https://defaultverifier.com/manifest

Notes:

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

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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": "..."
}

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MCP (Canonical)

SettlementWitness is available via MCP for agent-native workflows.

• MCP Server: https://defaultverifier.com/mcp
• Health: https://defaultverifier.com/mcp-healthz
• Tool: settlement_witness
• Arguments (required):
  • task_id (string)
  • spec (object)
  • output (object)
• Returns: receipt JSON (verbatim)

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

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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.

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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.

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Endpoint Behavior (Expected)

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

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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)

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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)

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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.

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Roadmap (Non-Commitment)

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

No timelines are guaranteed.

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License

MIT License

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Contact

Project discussions and updates:

https://x.com/defaultsettle

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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).

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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.