# A2A-to-Settlement Identity Continuity Gate

> A2A-to-Settlement Identity Continuity Gate is a paid API for AI agents from k2so-8080.on.ascii.dev, paid per call via x402, $0.002/call, status unknown (last checked 2026-10-18).

Verifies that the agent identity that concluded an A2A negotiation is the same identity authorized to settle the outcome via x402 payment.

## Facts

- Endpoint: GET https://k2so-8080.on.ascii.dev/api/services/agent-stack-interop-binding-a2a-negotiation-outc?utm_source=zero.xyz
- Price: $0.002/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-18
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/a2a-to-settlement-identity-continuity-gate-a335acea
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_tbbzjQpX_TexeizZIQCrD

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 a2a-to-settlement-identity-continuity-gate-a335acea
```

Example prompt: Before we settle this x402 payment, check that the agent identity from our A2A negotiation — including the ERC-8004 claim and delegation scope — actually matches the payer address authorized to complete the settlement.

## When to prefer this

Use this endpoint when an AI agent needs to enforce identity continuity at the seam between an A2A negotiation phase and an x402 settlement phase — specifically when ERC-8004 identity claims and delegation scopes are in play. Prefer this over general authentication checks when you need deterministic, ordered verification covering claim extraction, issuer attestation, scope coverage, and payer address confirmation in a single gate call.

## Known failure modes

- ERC-8004 identity claim missing or malformed in A2A outcome — returns ok:false with explanation
- Delegation scope does not cover negotiated deliverable — gate blocks settlement
- Issuer attestation expired or revoked — identity check fails
- x402 payer address does not match negotiating party identity — continuity violation flagged
- Network or provider error from K-2SO backend — service unavailable response
- Payment not included for non-meta request — x402 payment required error

## How this service works

Deterministic gate for the agent-stack interop seam: verifying that the agent identity that concluded an A2A negotiation (ERC-8004 identity claim, delegation scope, capability offer) is the same identity authorized to settle the outcome via x402. Ordered checks: (1) extract the negotiating party's ERC-8004 identity claim from the A2A outcome, (2) verify the claim's issuer attestation and delegation scope still cover the negotiated deliverable, (3) confirm the x402 settlement payer address

## Output

Returns a structured decision object including a boolean success flag, a prose decision brief explaining the outcome of the identity continuity check, the service slug, generation source (llm/reasoning/deterministic), and an ISO-8601 timestamp. Also includes payment metadata confirming the x402 transaction details.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET",
      "HEAD",
      "DELETE"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "properties": {
      "meta": {
       "enum": [
        "0",
        "1"
       ],
       "type": "string",
       "description": "Set to 1 for free metadata JSON (no payment required)"
      },
      "topic": {
       "type": "string",
       "description": "Optional topic override for the decision procedure"
      }
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object",
     "title": "agent-stack interop: A2A-to-settlement identity continuity gate paid response",
     "$schema": "https://json-schema.org/draft/2020-12/schema",
     "required": [
      "ok",
      "paid",
      "service",
      "provider",
      "result"
     ],
     "properties": {
      "ok": {
       "type": "boolean"
      },
      "paid": {
       "type": "boolean"
      },
      "result": {
       "type": "object",
       "required": [
        "ok",
        "service"
       ],
       "properties": {
        "ok": {
         "type": "boolean",
         "description": "Handler success"
        },
        "brief": {
         "type": "string",
         "description": "Decision procedure prose for agents"
        },
        "model": {
         "type": "string"
        },
        "topic": {
         "type": "string"
        },
        "service": {
         "type": "string",
         "description": "Service slug"
        },
        "procedure": {
         "type": "string"
        },
        "generatedAt": {
         "type": "string",
         "description": "ISO-8601 timestamp"
        },
        "generationSource": {
         "enum": [
          "llm",
          "reasoning",
          "deterministic"
         ],
         "type": "string"
        }
       }
      },
      "payment": {
       "type": "object",
       "properties": {
        "code": {
         "type": "string"
        },
        "payer": {
         "type": "string"
        },
        "detail": {
         "type":
… (truncated)
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/a2a-to-settlement-identity-continuity-gate-a335acea/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from k2so-8080.on.ascii.dev](https://www.zero.xyz/host/k2so-8080.on.ascii.dev/llms.txt)