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SYNTHORA Agent Card Validator (A2A)
x402
SYNTHORA Agent Card Validator (A2A) is a paid API for AI agents from api.hergertsynthora.com, paid per call via x402, $0.01/call, status unknown (last checked 2026-09-13).
Validates an A2A Agent Card (by URL or raw JSON) against the A2A spec, returning a compatibility score, schema errors, and warnings
Price / call$0.01
Success—
StatusUnknown
How this service works
Agent Card Validator (A2A): given an Agent Card URL or JSON, deterministically validates it against the A2A spec — required fields, skill schemas, endpoint reachability, security schemes, provider transparency — and returns a compatibility_score, schema_errors and warnings. The trust layer for the agent economy. Deterministic, Ed25519-signed. 0.01 USDC via x402 on Base. SYNTHORA.
Output
Returns a compatibility_score (0–1 numeric rating of A2A spec conformance), a list of schema_errors (specific field-level violations), and warnings (non-blocking issues such as missing optional fields, reachability problems, or weak security schemes). The response is Ed25519-signed for tamper-proof auditability.
Example use cases
Pre-publish agent card compliance check
“Before I list my new agent on the marketplace, validate the agent card at https://myagent.example.com/.well-known/agent-card.json and tell me if it's A2A compliant — I want the compatibility score and a list of any errors I need to fix.”
Debugging a broken agent card JSON
“I have this agent card JSON I wrote by hand and I'm not sure it's correct — can you run it through the A2A validator and show me all the schema errors and warnings?”
Trust check on a third-party agent
“I'm thinking of integrating with this external agent at https://partner-agent.io/.well-known/agent-card.json — can you validate their agent card against the A2A spec and give me a compatibility score so I know if their setup is trustworthy?”
Technical details
Endpoint
POSThttps://api.hergertsynthora.com/v1/agentcardWhen to prefer
Choose this endpoint when you need deterministic, cryptographically signed validation of an A2A Agent Card — whether authored locally or fetched from a live URL — especially before listing an agent on a marketplace, integrating with a third-party agent, or auditing agent cards in an automated pipeline. Prefer this over manual spec review or generic JSON schema validators because it checks endpoint reachability and security scheme compliance in addition to structural correctness, and its Ed25519-signed response provides a verifiable audit trail.
Side effects
- Unreachable URL — if the provided Agent Card URL is not publicly accessible, endpoint reachability check fails and an error is returned
- Invalid JSON — if the pasted card is malformed JSON, a parse error is returned before schema validation begins
- Missing both inputs — if neither url nor card is provided, the request is rejected with a validation error
- Non-A2A document — if the URL resolves to a non-agent-card document, schema errors will cover all required fields as missing
- Payment failure — if the x402 payment of 0.05 USDC on Base is not completed, the request is rejected
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| url | string | URL of the A2A Agent Card (.well-known/agent-card.json) |
| card | object | Or paste the Agent Card JSON directly |
Tags
x402
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