Basket Create

Create a new prediction basket on PolyBaskets via vara-wallet.

Setup

MAINNET ONLY. Run vara-wallet config set network mainnet before anything else. NEVER switch to testnet — there are no contracts there.

vara-wallet config set network mainnet
BASKET_MARKET="0x1fa6fd12433accef350a68da4555a2a71acab261c4ae9eb713033023fc0775ea"
_PB="${POLYBASKETS_SKILLS_DIR:-skills}"
IDL="$_PB/idl/polymarket-mirror.idl"

Ensure you have a wallet and VARA for gas:

vara-wallet wallet list
vara-wallet balance

Finding Polymarket Markets

Search for active markets on Polymarket to use as basket items. Use order=volume24hr&ascending=false to get the most active markets, and add end_date_max to find markets ending soon:

# Fetch high-volume markets ending within 48 hours (fastest resolution)
# end_date_min=now filters out markets that already ended (closed=false does NOT filter these!)
curl -s "https://gamma-api.polymarket.com/markets?closed=false&order=volume24hr&ascending=false&end_date_min=$(date -u +%Y-%m-%dT%H:%M:%SZ)&end_date_max=$(date -u -v+48H +%Y-%m-%dT%H:%M:%SZ)&limit=20"
# On Linux use: date -u -d '+48 hours' +%Y-%m-%dT%H:%M:%SZ

# Or fetch all active markets sorted by volume (still filter out ended ones!)
curl -s "https://gamma-api.polymarket.com/markets?closed=false&order=volume24hr&ascending=false&end_date_min=$(date -u +%Y-%m-%dT%H:%M:%SZ)&limit=20"

WARNING: closed=false does NOT mean the market hasn't ended. Markets past their endDate still appear. Always use end_date_min set to the current time, or check endDate > now before selecting a market.

Parse with jq:

# Show market id, question, YES/NO prices, and hours remaining
curl -s "https://gamma-api.polymarket.com/markets?closed=false&order=volume24hr&ascending=false&end_date_min=$(date -u +%Y-%m-%dT%H:%M:%SZ)&limit=20" \
  | jq '[.[] | {id, question, yes: (.outcomePrices | fromjson | .[0]), no: (.outcomePrices | fromjson | .[1]), endDate, liquidity}]'

CRITICAL: outcomePrices is a JSON-encoded string, not an array. The API returns "[\"0.52\", \"0.48\"]" (a string), not ["0.52", "0.48"] (an array).

• jq: .outcomePrices | fromjson | .[0] for YES price
• Python: json.loads(m['outcomePrices'])[0]
• Node.js: JSON.parse(m.outcomePrices)[0]
• Wrong: m['outcomePrices'][0] gives [ (first character of the string), NOT the price!

Important: poly_market_id is the numeric Polymarket ID (e.g. "540816"), not the hex conditionId. Use the id field from the API response.

The slug field is already included in every market response. Do NOT re-fetch markets to look up slugs — use the slug from the same response where you got the id. If you need details for a specific market ID, fetch it directly:

curl -s "https://gamma-api.polymarket.com/markets/540816"

Pre-Check

Most deployments run in CHIP-only mode. Check VARA status:

vara-wallet call $BASKET_MARKET BasketMarket/IsVaraEnabled --args '[]' --idl $IDL

If false (typical), create a "Bet" basket (CHIP lane).

Validation Rules

Before sending the transaction, validate locally:

Rule	Constraint
Name	Non-empty, max 48 characters
Description	Max 256 characters
Items	1 to 10 items
Weights	All weight_bps must sum to exactly 10000 (= 100%). Each weight is in basis points: 50% = 5000, 30% = 3000, etc.
No duplicates	Same poly_market_id + selected_outcome cannot appear twice
poly_market_id	Max 128 characters
poly_slug	Max 128 characters
asset_kind	"Vara" or "Bet"

Create Basket

Arguments

CreateBasket(name: str, description: str, items: vec BasketItem, asset_kind: BasketAssetKind) -> u64

Each BasketItem:

{
  "poly_market_id": "540816",
  "poly_slug": "will-btc-hit-100k",
  "weight_bps": 5000,
  "selected_outcome": "YES"
}

• poly_market_id — the numeric Polymarket ID from the API id field (e.g. "540816"), NOT the hex conditionId
• weight_bps — weight in basis points. 50% = 5000, 30% = 3000, etc. All weights must sum to 10000 (= 100%)

Example: 3-item basket

vara-wallet --account agent call $BASKET_MARKET BasketMarket/CreateBasket --voucher $VOUCHER_ID \
  --args '[
    "AI Regulation Bundle",
    "Outcomes related to AI policy",
    [
      {
        "poly_market_id": "540816",
        "poly_slug": "ai-regulation-2025",
        "weight_bps": 4000,
        "selected_outcome": "YES"
      },
      {
        "poly_market_id": "540817",
        "poly_slug": "openai-ipo-2025",
        "weight_bps": 3500,
        "selected_outcome": "YES"
      },
      {
        "poly_market_id": "540818",
        "poly_slug": "eu-ai-act-enforcement",
        "weight_bps": 2500,
        "selected_outcome": "NO"
      }
    ],
    "Bet"
  ]' \
  --idl $IDL

Weights: 40% + 35% + 25% = 100% (4000 + 3500 + 2500 = 10000 bps).

Parse Result

The call returns a u64 basket ID:

RESULT=$(vara-wallet --account agent call $BASKET_MARKET BasketMarket/CreateBasket --voucher $VOUCHER_ID \
  --args '[...]' --idl $IDL)
BASKET_ID=$(echo $RESULT | jq -r '.result // .ok // .')
echo "Created basket: $BASKET_ID"

After Creation

• Verify: vara-wallet call $BASKET_MARKET BasketMarket/GetBasket --args "[$BASKET_ID]" --idl $IDL
• Place a bet: see ../basket-bet/SKILL.md
• Share the basket ID for others to bet on

Common Errors

Error	Cause	Fix
InvalidWeights	Weights don't sum to 100%	Adjust weight_bps so they sum to 10000 (= 100%)
NoItems	Empty items array	Add at least 1 item
TooManyItems	More than 10 items	Remove items
DuplicateBasketItem	Same market+outcome twice	Remove duplicate
VaraDisabled	VARA mode off	Use "Bet" asset_kind instead
NameTooLong	Name > 48 chars	Shorten name

See ../references/error-codes.md for all error variants.