Documentation

mosaic-sdk exports MosaicClient and metadata helpers.

Import

from mosaic_sdk import MosaicClient, canonical_metadata_hash, load_metadata

Configure

client = MosaicClient(
    rpc_url="https://mainnet.base.org",
    contract_address="0x0c7fad7C9bBaD0BE62aAc867c6069d7Aad7Cb361",
)

Defaults:

Field	Value
`chain_id`	`8453`
`usdc_address`	`0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913`

MosaicClient rejects non-Base chain_id values and non-Base-USDC usdc_address values.

Build Bounty Transaction

metadata = {
    "version": 1,
    "title": "Find a reproducible bug",
    "brief": "Submit a minimal reproduction and a fix suggestion.",
}

tx = client.create_bounty(
    metadata_uri="ar://bounty-json",
    metadata_hash=canonical_metadata_hash(metadata),
    reward_amount=50_000_000,
    duration=86_400,
)

Returned transaction dict:

{
    "chainId": 8453,
    "to": "0x...",
    "data": "0x...",
    "value": 0,
}

Transaction Helpers

Method	Contract Call
`approve_usdc(amount)`	USDC `approve(contractAddress, amount)`
`create_bounty(metadata_uri, metadata_hash, reward_amount, duration)`	`createBounty(string,bytes32,uint256,uint64)`
`submit(bounty_id, metadata_uri, metadata_hash)`	`submit(uint256,string,bytes32)`
`dispute(submission_id, metadata_uri, metadata_hash)`	`dispute(uint256,string,bytes32)`
`finalize(bounty_id)`	`finalize(uint256)`
`advance_review_cursor(bounty_id)`	`advanceReviewCursor(uint256)`
`refund_expired(bounty_id)`	`refundExpired(uint256)`
`refund_submission_bond(submission_id)`	`refundSubmissionBond(uint256)`
`cancel_resolved_dispute(challenge_id)`	`cancelResolvedDispute(uint256)`
`withdraw()`	`withdraw()`
`withdraw_to(recipient)`	`withdrawTo(address)`

Metadata Helpers

metadata = await load_metadata(
    "ar://bounty-json",
    expected_hash="0x1111111111111111111111111111111111111111111111111111111111111111",
)

canonical_metadata_hash(metadata) hashes sorted compact JSON with Keccak.

load_metadata(uri, expected_hash=None, gateway="https://arweave.net") fetches HTTP URLs directly. For ar:// URIs, it prefixes the configured gateway. When expected_hash is set, it raises ValueError("metadata hash mismatch") on mismatch.

Inputs

Amount arguments are integers in USDC base units.
Metadata hash arguments must encode to 32 bytes.

Python SDK