# agent.alexweb.space Adversarial Output Verifier

> agent.alexweb.space Adversarial Output Verifier is a paid API for AI agents from agent.alexweb.space, paid per call via x402, $0.08/call, status unknown (last checked 2026-09-15).

Runs a fast two-pass adversarial verification of an autonomous agent's output against its original task and optional hard constraints.

## Facts

- Endpoint: POST https://agent.alexweb.space/v1/verify
- Price: $0.08/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-15
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/agent-alexweb-space-adversarial-output-verifier-75bb81f7
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_LQ_IxOEauOEO2DhruX9KV

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 agent-alexweb-space-adversarial-output-verifier-75bb81f7 -d '<json body>'
```

Example prompt: Adversarially verify this agent output — the original task was 'Write a Python function to reverse a linked list', the candidate answer is the code block the agent produced, and the hard constraints are: must not use recursion, must handle empty lists.

## When to prefer this

Choose this endpoint when you need a fast, lightweight adversarial QA pass on a single agent output before acting on it, especially when a four-pass deep review would be overkill. Prefer it over the sibling four-pass verifier when latency matters and the task is well-scoped. Best suited for high-throughput agent pipelines where each output needs a quick sanity check with optional hard constraint enforcement.

## Known failure modes

- Missing or empty task/candidate fields returning a 400 validation error
- Candidate output too long causing context or token limit errors
- Ambiguous task description leading to low-confidence or inconclusive verdicts
- Network timeout on slow inference for very long inputs
- Incorrect constraint format causing constraints to be ignored

## How this service works

Fast two-pass adversarial verification of an autonomous agent output.

## Output

A structured adversarial verification result indicating whether the candidate output correctly satisfies the original task, along with critique details, identified failures or constraint violations, and an overall pass/fail judgment produced by the two-pass adversarial review process.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "task": {
   "type": "string",
   "description": "Original task or requirement"
  },
  "candidate": {
   "type": "string",
   "description": "Candidate output to verify"
  },
  "constraints": {
   "type": "array",
   "items": {
    "type": "string"
   },
   "description": "Optional hard constraints"
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/agent-alexweb-space-adversarial-output-verifier-75bb81f7/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from agent.alexweb.space](https://www.zero.xyz/host/agent.alexweb.space/llms.txt)