---
title: "A2A Agent-Card Trust-Chain Validator"
method: POST
path: "/v1/tools/validate_a2a_trust_chain"
tags: ["A2A", "Agent2Agent", "agent card", "trust chain", "delegated authority", "KYA-OS", "spend policy", "scope escalation", "OpenChainGraph", "compliance_mandate"]
---

# A2A Agent-Card Trust-Chain Validator

`POST /v1/tools/validate_a2a_trust_chain`

## Request

- Base URL: `https://ainumbers.co`
- URL: `https://ainumbers.co/v1/tools/validate_a2a_trust_chain`
- Auth: none declared

The horizontal agent-to-agent trust complement. Validates an A2A v1.0 agent card (schema, signature, extension URIs) then assesses the delegated-authority trust chain into KYA-OS attestation + spend policy: chain depth <= 4, no scope escalation, validity windows <= 90 days. Trust PASS/WARN/FAIL determination + execution_hash.

**Tool URL:** https://ainumbers.co/chaingraph/art-32-a2a-agent-card-trust-chain-validator.html
**AP2/Policy Mandate export:** yes

## Request body

- object
  - `agent_card` unknown, required
  - `delegation_chain` unknown[], required
    - unknown
  - `spend_policy` unknown, required

## Response `200`

Successful tool execution result

- object
  - `card_schema_ok` boolean
  - `checks` object[]
    - `code` string
    - `note` string
    - `status` string
  - `fail_count` integer
  - `no_expired_links` boolean
  - `no_scope_escalation` boolean
  - `pass_count` integer
  - `signature_block_present` boolean
  - `trust_determination` string
  - `warn_count` integer

---

[API](https://skmtc.dev/ainumbers/apis/ainumbers-co-fintech-intelligence-suite.md) · [All operations](https://skmtc.dev/ainumbers/apis/ainumbers-co-fintech-intelligence-suite/llms.txt) · [OpenAPI document](https://skmtc.dev/ainumbers/apis/ainumbers-co-fintech-intelligence-suite/revisions/b462e4f5bb28?raw)