Verify an action

Create an API key

Open harness.chance.cc/keys and click Create key. The key starts with chance_sk_live_ and is shown once. Keep it in a server-side secret, not in client code.

Verify an action

Send the user’s rules as intent and the proposed action as action. Authenticate with x-api-key: <key> or Authorization: Bearer <key>.

curl -X POST https://harness.chance.cc/api/v1/intent \
  -H "x-api-key: $CHANCE_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "intent": "Only buy favorites priced at 95c or more. Reject longshots.",
    "action": "Buy YES on the Will-X-win market at 21c for $10."
  }'

const res = await fetch("https://harness.chance.cc/api/v1/intent", {
  method: "POST",
  headers: {
    Authorization: `Bearer ${process.env.CHANCE_API_KEY}`,
    "Content-Type": "application/json",
  },
  body: JSON.stringify({
    intent: "Only buy favorites priced at 95c or more. Reject longshots.",
    action: "Buy YES on the Will-X-win market at 21c for $10.",
  }),
});

const body = await res.json();
if (!res.ok) throw new Error(`${res.status} ${body.error}`);
if (body.verdict !== "ALLOW") {
  // Do not execute. body.reasoning says why.
}

import os, requests

r = requests.post(
    "https://harness.chance.cc/api/v1/intent",
    headers={"x-api-key": os.environ["CHANCE_API_KEY"]},
    json={
        "intent": "Only buy favorites priced at 95c or more. Reject longshots.",
        "action": "Buy YES on the Will-X-win market at 21c for $10.",
    },
)
r.raise_for_status()
print(r.json()["verdict"])  # expected: BLOCK

The response

A completed verification returns 201:

{
  "id": "3f6c2a0e-7b1d-4c5e-9a2f-1d4b8e6c0a91",
  "requestHash": "0x…",
  "status": "COMPLETED",
  "verdict": "BLOCK",
  "reasoning": "The action buys a 21c contract, below the 95c floor the intent sets.",
  "mode": "semantic",
  "venue": null,
  "actionFamily": null,
  "actionType": null,
  "proof": {
    "transcriptRoot": "0x…",
    "outputHash": "0x…",
    "signature": "0x…",
    "judge": "0x…",
    "attested": true,
    "anchorTx": "0x…",
    "anchorVerified": false,
    "transcriptUri": "https://harness.chance.cc/api/runs/…/transcript",
    "explorerTx": "https://…/tx/0x…"
  },
  "creditsRemaining": 49
}

Field	Meaning
`id`	The verification id. Pass it to `GET /api/v1/intent/{id}`.
`requestHash`	An identifier for this run. `GET /api/v1/intent/{id}` also accepts it.
`verdict`	`ALLOW`, `BLOCK`, `ESCALATE`, or `null` when the judge produced no decision.
`reasoning`	The judge’s explanation.
`mode`	`structured` when `action` is an object a venue adapter recognized, otherwise `semantic`.
`venue`, `actionFamily`, `actionType`	What the venue adapter classified. `null` for a plain-text action with no `venue`.
`proof`	The receipt. `anchorTx` and `explorerTx` are `null` when the run was not anchored. See Receipts.
`creditsRemaining`	Your balance after this call.

Execute the action only when verdict is "ALLOW". Treat every other value, including null and any non-201 response, as do not execute.

Errors

Status	Body	What to do
`400`	`{"error": "invalid JSON body"}`, `{"error": "intent is required"}` or `{"error": "action is required"}`	Fix the request. No credit is charged.
`401`	`{"error": "missing API key (send x-api-key)"}` or `{"error": "invalid or revoked API key"}`	Send a valid key.
`402`	`{"error": "out_of_credits", "message": "…", "topup": {…}}`	Add credits. `topup` is present when top-ups are enabled. See Credits.
`502`	`{"error": "verification_failed", "message": "…"}`	The run failed and the credit was refunded. Retry.

Next steps

Send the exact payload the venue will receive as action (a JSON object) and set venue. The judge then sees exactly what will be submitted, and the receipt records it. See Venues.
Fetch a past result with GET /api/v1/intent/{id}. Its response has a different shape: no mode, venue, actionFamily, actionType or creditsRemaining, a proof with anchorStatus (verified, pending or skipped) in place of anchorVerified, transcriptUri and explorerTx, and a createdAt. See Verification request.
Give an agent the same check as an MCP tool. See Connectors.

Integrate

Chance verification

Payload adapters

HTTP endpoints

Verify an action

The response

Errors

Next steps

​The response

​Errors

​Next steps

The response

Errors

Next steps