Skill Version: 0.0.4

SettlementWitness

Deterministic verification gate for agent execution and x402 settlement.

SettlementWitness provides replay-stable proof-of-delivery receipts that allow agents, tools, and orchestrators to safely gate downstream execution based on whether a claimed outcome actually satisfies predefined conditions.

It does not coordinate, enforce, or hold funds. It answers one question only:

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

What This Skill Does

SettlementWitness evaluates a claimed result against a deterministic specification and returns a signed verification receipt.

The receipt is:

• Deterministic (same inputs → => same receipt_id + signature)
• Replayable
• Neutral
• Safe to cache, forward, and audit

This allows agent systems to halt, continue, or settle based on objective verification rather than trust or heuristics.

Canonical Endpoints

MCP Adapter (install this): https://defaultverifier.com/mcp

REST Witness Endpoint: https://defaultverifier.com/settlement-witness

Public MCP Health: https://defaultverifier.com/mcp-healthz

Tool

settlement_witness

Verifies that an output satisfies a deterministic specification and returns a signed receipt.

Inputs

• task_id — stable identifier for the task
• spec – deterministic conditions expected to be satisfied
• output – claimed result to be verified

Outputs

• verdict — PASS or FAIL
• confidence — numeric confidence score
• receipt_id – deterministic receipt identifier
• signature – cryptographic proof
• timestamp – verification time

Gating Semantics (Important)

This skill is designed to be used as a verification gate.

• PASS – downstream execution may proceed
• FAIL – execution SHOULD halt or roll back

SettlementWitness does not retry, repair, or reinterpret results. A FAIL is an explicit signal that conditions were not satisfied.

Common Use Cases

x402 Payment Gating

Verify that a task completed correctly before releasing or settling payment.

Post-Task Verification

Confirm that an agent actually produced what it claimed before chaining further actions.

Proof-of-Delivery Receipts

Generate deterministic receipts that can be replayed, audited, or shared across systems.

Malicious or Broken Skill Mitigation

Prevent downstream agents from acting on incorrect, partial, or fabricated outputs.

Agent Orchestration Safety

Use objective verification instead of trust when coordinating multi-agent workflows.

Determinism Guarantee

SettlementWitness is fully deterministic.

Given the same:

• task_id
• spec
• output

It will always return:

• the same receipt_id
• the same signature
• the same verdict

This makes receipts safe for caching, replay, and dispute resolution.

What This Is Not

• Not a malware scanner
• Not an LLM judge
• Not a coordinator or enforcer
• Not a payment processor

It is neutral verification infrastructure.

Identity vs Delivery Proof

SettlementWitness provides delivery proof, not identity.

It complements ERC-8004 and identity systems by answering:

“Did this outcome satisfy the rules?”

— not:

“Who is this agent?”

When to Use SettlementWitness

Use this skill when truth must be established before action, settlement, or escalation.

If correctness matters, verify first.

Provenance

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

This skill invokes a public deterministic verification oracle. It performs no settlement, custody, enforcement, or execution.