Facts

A fact is a claim about a subject: Acme’s contract is $120k, Bob works at Y, the handbook says PTO starts on day one. Every fact carries a warrant — either a source (a record you can go and read) or ground: "assertion" (you stake the claim; the principal is the key, never a field you send). Never neither. Never both.

curl -X POST "$API/v1/brains/tenant:acme/statements" \
  -H "authorization: Bearer $NICIA_KEY" \
  -H "content-type: application/json" \
  -H "idempotency-key: stmt-salesforce-arr" \
  -d '{
    "subject": "acme",
    "predicate": "contract_value_usd",
    "value": 120000,
    "source": "salesforce-renewal"
  }'

{
  "data": {
    "statementIds": ["stmt_91ab01"],
    "outcome": {
      "kind": "admitted",
      "batchId": "batch_44a1e0",
      "policyVersionId": "pol_nicia_open",
      "acceptedSnapshot": "snap_6f1e4d6b",
      "eventIds": ["chg_44a1e0"]
    },
    "statements": [
      {
        "id": "stmt_91ab01",
        "subject": "acme",
        "predicate": "contract_value_usd",
        "value": 120000,
        "validFrom": "2026-08-14T09:20:00.000Z",
        "source": "salesforce-renewal",
        "assertedBy": { "kind": "service", "id": "key_7f3a1c" },
        "status": "active"
      }
    ]
  }
}

source is a record id — the same kebab rule as PATCH /records/{id}. A document id with colons (hubspot:deal:412) is not a source; write or address the record first. assertedBy is projected from the change event. You cannot set it.

The other warrant is a stake:

curl -X POST "$API/v1/brains/tenant:acme/statements" \
  -H "authorization: Bearer $NICIA_KEY" \
  -H "content-type: application/json" \
  -H "idempotency-key: stmt-handbook-pto" \
  -d '{
    "subject": "acme",
    "predicate": "pto_starts_on",
    "value": "day-one",
    "ground": "assertion"
  }'

Sources disagree

A later fact from the same source supersedes. A different source disagreeing over an overlapping window does not: both facts stay, and the next /context names it. You do not call GET /conflicts to find out. That list is the operator inbox.

curl -X POST "$API/v1/brains/tenant:acme/statements" \
  -H "authorization: Bearer $NICIA_KEY" \
  -H "content-type: application/json" \
  -H "idempotency-key: stmt-netsuite-arr" \
  -d '{
    "subject": "acme",
    "predicate": "contract_value_usd",
    "value": 145000,
    "source": "netsuite-renewal"
  }'

curl -X POST "$API/v1/brains/tenant:acme/context" \
  -H "authorization: Bearer $NICIA_KEY" \
  -H "content-type: application/json" \
  -d '{
    "prompt": "What is the Acme contract value?",
    "maxTokens": 2000,
    "format": "items"
  }'

{
  "data": {
    "text": "",
    "citations": [],
    "items": [
      {
        "kind": "record",
        "id": "stmt-salesforce-arr",
        "fields": { "contract_value_usd": 120000 },
        "status": "contested"
      },
      {
        "kind": "record",
        "id": "stmt-netsuite-arr",
        "fields": { "contract_value_usd": 145000 },
        "status": "contested"
      }
    ],
    "staged": 0,
    "warnings": [
      {
        "kind": "contested",
        "subject": "acme",
        "predicate": "contract_value_usd",
        "count": 2,
        "detail": "Two sources disagree about acme.contract_value_usd."
      }
    ],
    "receipt": "rcp_contested",
    "truncated": false
  }
}

warnings[] kind contested names the subject and predicate. Per-item status: "contested" marks the facts in this answer. There is no conflicts[] field on /context.

Resolve

GET /conflicts is the inbox. POST /conflicts/{id}/resolve keeps one fact or writes a corrected value. The loser is retained, not deleted. The call needs review and an Idempotency-Key.

curl "$API/v1/brains/tenant:acme/conflicts?resolved=false" \
  -H "authorization: Bearer $NICIA_KEY"

{
  "data": {
    "conflicts": [
      {
        "id": "cfl_91ab",
        "subject": "acme",
        "predicate": "contract_value_usd",
        "statements": [
          {
            "id": "stmt_91ab01",
            "subject": "acme",
            "predicate": "contract_value_usd",
            "value": 120000,
            "validFrom": "2026-08-14T09:20:00.000Z",
            "source": "salesforce-renewal",
            "assertedBy": { "kind": "service", "id": "key_7f3a1c" },
            "status": "conflicted"
          },
          {
            "id": "stmt_91ab02",
            "subject": "acme",
            "predicate": "contract_value_usd",
            "value": 145000,
            "validFrom": "2026-08-14T09:21:00.000Z",
            "source": "netsuite-renewal",
            "assertedBy": { "kind": "service", "id": "key_7f3a1c" },
            "status": "conflicted"
          }
        ],
        "detectedAt": "2026-08-14T09:21:01.000Z"
      }
    ],
    "receipt": "rcp_conflicts"
  }
}

curl -X POST "$API/v1/brains/tenant:acme/conflicts/cfl_91ab/resolve" \
  -H "authorization: Bearer $NICIA_KEY" \
  -H "content-type: application/json" \
  -H "idempotency-key: resolve-acme-arr" \
  -d '{ "keep": "stmt_91ab02" }'

{
  "data": {
    "outcome": {
      "kind": "admitted",
      "batchId": "batch_91ab03",
      "policyVersionId": "pol_nicia_open",
      "acceptedSnapshot": "snap_91ab03",
      "eventIds": ["chg_91ab03"]
    }
  }
}

Or send "value": 145000 instead of keep to supersede both with a corrected number.

Next

• Context — how a contested fact shows up on the read.
• Receipts — who was told, and whether a receipt is stale.
• Review — Open vs Reviewed, and settling the queue.
• Records — the subjects and sources facts point at.