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A2A Agent Card Validator
x402
A2A Agent Card Validator is a paid API for AI agents from agent.halowerk.com, paid per call via x402, $0.002/call, status unknown (last checked 2026-09-13).
Validates an Agent Card document against the A2A convention, returning findings categorized by severity (error, warning, info) covering required fields, URL format, skill definitions, and security schemes.
Price / call$0.002
Success—
StatusUnknown
How this service works
Validates an Agent Card document against the A2A convention and returns findings by severity: error (the card is unusable as published), warning (works, but a consuming agent will guess), info (recommended field absent). Checked: the required fields name, description, url, version, capabilities and skills; that url is absolute and https; that every skill carries id, name, description and tags and that skill ids are unique; that declared securitySchemes use a known type and that every entry in…
Output
A structured report of validation findings grouped into three severity levels: errors (card is unusable as published, e.g. missing required fields like name, description, url, version, capabilities, or skills; non-absolute or non-HTTPS url), warnings (card works but consuming agents will have to guess), and info (recommended but absent fields). Each finding identifies the specific field or skill at issue.
Example use cases
Pre-publish agent card audit
“Before I publish this agent card, run it through A2A validation and tell me every error, warning, and info-level issue so I can fix them before other agents try to consume it.”
Debugging unusable agent card
“My agent card keeps getting rejected by consuming agents — can you validate it against the A2A convention and show me exactly which required fields are missing or malformed?”
Security scheme compliance check
“I added securitySchemes to my agent card and I want to make sure they use a recognized type and that every skill references a valid scheme — can you validate the whole card and flag anything wrong?”
Technical details
Endpoint
POSThttps://agent.halowerk.com/v1/a2a-card-validateWhen to prefer
Use this endpoint when you need to verify that an Agent Card document strictly conforms to the A2A interoperability convention before publishing or sharing it. Prefer it over manual review when you need machine-readable, severity-graded findings covering field presence, URL format, skill schema completeness, unique skill IDs, and security scheme correctness in a single call.
Side effects
- Malformed JSON input returns a parse error before validation begins
- Agent card missing the outer wrapper structure may produce unexpected findings
- Very large or deeply nested cards may exceed payload limits
- Unknown or future A2A spec fields not yet recognized by the validator may be silently ignored
- Payment failure (x402) if USDC balance is insufficient
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| card | object | The Agent Card document as JSON. |
| strict | boolean | If true, recommended-field findings count as warnings and lower the verdict. |
Tags
x402
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