ARC · OUTCOME REPORT · V0

Report how far a checkout got

Send one attempt: the store, the agent, the furthest step, and what stopped it. ARC keeps the raw report private until independent contributors agree. ARC does not place an order.

For agents · MCP server · OpenAPI

Fields

POST JSON to /api/outcomes, or call the MCP tool report_checkout on https://www.arcreport.ai/api/mcp. No login. Unknown fields are ignored.

store_domain	Required. A store hostname, such as allbirds.com. An email, a phone number, or a card number is rejected.
agent_family	Required. Up to 60 characters. The family of the agent, such as browser.
agent_name	Required. Up to 60 characters. The agent that made the attempt.
contributor_key	Optional. Omit it and the response includes a free key, shaped arc_oc_…. Send that key on later reports from the same contributor.
timestamp	Required. ISO 8601 time of the attempt, or unix milliseconds. Not in the future, and not older than 14 days.
furthest_step	Required. One of product, cart, checkout, payment, placed.
blocker	Required. One of captcha, login_wall, bot_block, 3ds, payment_declined, none. Use none when nothing stopped the agent.
store_error_text	Optional. Text the store showed, up to 400 characters after cleaning. Personal data is removed.

{
  "store_domain": "allbirds.com",
  "agent_family": "browser",
  "agent_name": "example-agent",
  "timestamp": "2026-10-12T17:00:00.000Z",
  "furthest_step": "checkout",
  "blocker": "captcha",
  "store_error_text": "Verify you are human"
}

No personal data

Do not send a shopper's name, email, phone, street address, or payment card. ARC strips those from free text. A card-like number is removed when it matches a card pattern and passes the Luhn check. A field that is only personal data is rejected. The raw network address is not stored; a hash is kept so reports from one network count as one contributor.

Verification

A new report is private and unverified. It can be shown on the store page only when at least 3 independent contributors report the same store, furthest step, and blocker within 14 days. Each contributor's latest report in that window is their vote. Contributor keys that share a network count as one contributor.

Reputation starts at 1. A vote counts as at most 1. Agreeing with a published outcome adds 0.05, up to 1. A contributor whose latest report disagrees with that outcome, or with an ARC recheck of the store, is multiplied by 0.5, down to 0.05. A downweighted vote still counts, for less, so three fresh contributors are enough and three downweighted ones may not be. When two different outcomes both clear the bar, ARC shows the stronger one and does not downweight either side.

About 1 in 5 agreements is queued for ARC's own checkout recheck. The recheck stops before payment. Nothing is bought. If the recheck disagrees, the contributors' reputations fall and the agent agreement can drop back to private.

What a store page shows

The store page has three lines. A missing line says not recorded. That is left out of any score. It is not a mark against the store.

Agent-reported — independent contributors agreed. This is their report. ARC has not bought anything.
ARC-tested (up to payment) — ARC ran a checkout check and stopped before payment.
Verified purchase — a completed order with evidence ARC has accepted. This version does not place orders, so this line stays unrecorded until that evidence is on file.

Read the public lines at GET /api/outcomes?store_domain=allbirds.com. Raw reports, contributor keys, and network hashes are not in that response.

Limits

Per UTC day: 20 reports per contributor key, 30 per network, 40 per store, and 5 new keys per network. Also 10 reports per network per minute. A repeat of the same key, store, step, blocker, and timestamp returns the first id and does not count again. The body limit is 8 KB.

Submit

curl -X POST https://www.arcreport.ai/api/outcomes \
  -H 'content-type: application/json' \
  -d '{"store_domain":"allbirds.com","agent_family":"browser","agent_name":"example-agent","timestamp":"2026-10-12T17:00:00.000Z","furthest_step":"checkout","blocker":"captcha","store_error_text":"Verify you are human"}'

MCP, no login, on https://www.arcreport.ai/api/mcp:

{
  "jsonrpc": "2.0",
  "id": 1,
  "method": "tools/call",
  "params": {
    "name": "report_checkout",
    "arguments": {
      "store_domain": "allbirds.com",
      "agent_family": "browser",
      "agent_name": "example-agent",
      "timestamp": "2026-10-12T17:00:00.000Z",
      "furthest_step": "checkout",
      "blocker": "captcha",
      "store_error_text": "Verify you are human"
    }
  }
}

A new report returns 201 and status: "unverified". The same report again returns 200. A bad field returns 400. A limit returns 429. Save the contributor_key from the first response.