# Verity Fact-Checker by BaseChainLabs

> Verity Fact-Checker by BaseChainLabs is a paid API for AI agents from verity.basechainlabs.com, paid per call via x402, $0.1/call, status unknown (last checked 2026-09-15).

Verifies claims, URLs, or content and returns a verdict (CURRENT/OUTDATED/DISPUTED/UNVERIFIABLE) with confidence score and sources, with persistent memory to skip repeat lookups across sessions.

## Facts

- Endpoint: POST https://verity.basechainlabs.com/api/verify
- Price: $0.1/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-15
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/verity-basechainlabs-com-2766bea7
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_mSN5CG4d1T0Mx3kGqzFRz

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 verity-basechainlabs-com-2766bea7 -d '<json body>'
```

Example prompt: Can you fact-check this claim for me: 'OpenAI is currently valued at $157 billion'? I want to know if it's still current, disputed, or outdated, along with a confidence score and your sources.

## When to prefer this

Use Verity when your agent needs to fact-check claims, articles, or URLs across multiple sessions with memory persistence to avoid redundant lookups and token waste. Ideal for agents that repeatedly verify the same domain of claims (e.g. financial valuations, political statements) and want structured verdicts with sourcing rather than a raw web search result.

## Known failure modes

- Claim is too vague or ambiguous to verify — returns UNVERIFIABLE verdict
- URL provided is inaccessible or behind a paywall — may return UNVERIFIABLE
- Payment of 0.10 USDC not received — request rejected with 402
- Claim is highly niche with no indexed sources — low confidence UNVERIFIABLE
- Rate limiting or service unavailability — 503 or timeout error

## How this service works

Fact-checking with persistent memory — VERITY remembers prior claims your agent has checked and skips repeat lookups, saving tokens across sessions. Returns CURRENT/OUTDATED/DISPUTED/UNVERIFIABLE verdicts with confidence score, sources, and what changed. 0.10 USDC.

## Output

A verdict of CURRENT, OUTDATED, DISPUTED, or UNVERIFIABLE; a confidence score (0–1); a list of supporting sources; and a summary of what has changed if the claim is outdated. If the same claim was previously checked under the same caller_id, the cached result is returned to save tokens.

## Example request

```json
{
 "query": "Is artificial intelligence currently being regulated by the EU AI Act?",
 "caller_id": "qa-test-agent-001"
}
```

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "query": {
   "type": "string",
   "description": "The claim, URL, or content to verify. E.g. 'Is OpenAI still valued at $157B?' or 'https://example.com/article'"
  },
  "caller_id": {
   "type": "string",
   "description": "Optional agent or user ID for persistent memory."
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/verity-basechainlabs-com-2766bea7/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from verity.basechainlabs.com](https://www.zero.xyz/host/verity.basechainlabs.com/llms.txt)