API reference

Screwtape.ai

Screwtape.ai returns a pass, fail, or retry verdict on another agent's output, and scores consensus across several agents, including false-consensus risk. It is the agent validation API, not the arXiv paper also named Screwtape. Authenticate with Authorization: Bearer or, for a single call, an x402 PAYMENT-SIGNATURE header. That payment is $0.005 USDC on Base (eip155:8453) to 0x028Bb9A57B8C27c22f6B39dd00e7eFF1FB60344B, verified and settled through a facilitator. The worker does not hold a private key. When a model key is configured, the default model is openai/gpt-oss-120b, with qwen/qwen3.8-27b tried once if the primary model returns 404 or 5xx. Judged content is not stored unless retain is true. The public spec omits operator-only routes.

This page is generated from openapi.json. Base URL: https://screwtape.ai.

`/v1/health`

GET Health

Liveness. Does not require an API key and does not report secrets.

200 Service is up.

`/v1/judge`

POST Judge one agent output

Returns a verdict, a confidence score, reasons, and a request id. Free keys include 100 calls per UTC day. Prepaid credits are used after that. With no API key, the response is 402 and describes an x402 payment of $0.005 USDC on Base, which is verified and settled through a facilitator.

{
  "task": "State the crew size and launch site.",
  "agent_output": "The crew size was 4. The mission launched from Cape Canaveral.",
  "evidence": [
    "The mission launched on 2024-03-01 from Cape Canaveral.",
    "The crew size was 4."
  ],
  "criteria": [
    "crew size",
    "Cape Canaveral"
  ]
}

200 Verdict.
400 Invalid request.
401 API key was not recognized.
402 Payment required. PAYMENT-REQUIRED carries the x402 requirements. A valid payment is verified and settled through a facilitator.
429 Daily quota or rate limit exceeded.

`/v1/consensus`

POST Score consensus across agents

Returns the consensus answer, an agreement score, false-consensus risk, and a request id.

{
  "task": "State the crew size.",
  "answers": [
    {
      "agent_id": "alpha",
      "output": "The crew size was 4."
    },
    {
      "agent_id": "beta",
      "output": "The crew size was 4."
    },
    {
      "agent_id": "gamma",
      "output": "The crew size was 4."
    }
  ]
}

200 Consensus.
400 Invalid request.
401 API key was not recognized.
402 Payment required. A valid payment is verified and settled through a facilitator.
429 Daily quota or rate limit exceeded.

`/v1/keys`

POST Create a free API key

Returns the secret key once. Only a hash is stored. Limited to three active keys per email.

{
  "email": "dev@example.com",
  "name": "Local dev"
}

201 Key created.
400 Invalid signup.
429 Signup rate limit or email cap.

`/v1/keys/me`

GET Current key

Usage and credit balance for the Bearer key. The secret is not returned.

200 Key metadata.
401 API key was not recognized.

DELETE Delete the current key and its data

Deletes the key hash, daily counters, payment records, and any opt-in retained judgments.

200 Deleted.
401 API key was not recognized.

`/v1/retention`

GET List opt-in retained calls

Returns calls this key asked to retain. Rows expire after 24 hours.

200 Retained rows.
401 API key was not recognized.

`/v1/retention/{id}`

DELETE Delete one retained call

id Retention id returned when retain was true.

200 Deleted.
401 API key was not recognized.
404 No such row for this key.

`/v1/billing/checkout`

POST Start a Stripe test-mode checkout

Starter is $30 for 10,000 calls. Builder is $100 for 50,000 calls. Requires a Bearer key. Live-mode Stripe keys are refused. Credits are applied by the webhook, not by the success page.

{
  "pack": "starter"
}

200 Checkout URL.
401 API key was not recognized.
503 Stripe test checkout is not configured, or a live key was refused.

`/mcp`

POST MCP Streamable HTTP

JSON-RPC for initialize, tools/list, and tools/call. Tools are judge and consensus. tools/call uses the same auth and quota as the REST API. GET is reserved and returns 405 because this server does not open an SSE stream.

{
  "jsonrpc": "2.0",
  "id": 1,
  "method": "tools/list"
}

200 JSON-RPC result.
202 Notification accepted.
402 tools/call requires a key or an x402 payment, which is verified and settled through a facilitator.