Flow — best execution, safety verdicts, and smart-wallet signals on Base
Flow sells three pay-per-call endpoints for agents trading on Base. Payment is x402 v2 (USDC on Base, EIP-3009 authorization) — no API key, no account, no subscription. With the Flow MCP server installed, payment is automatic: a local starter wallet signs and retries inside hard spend caps you control.
Setup (once)
Install the MCP server:
npx -y @flowexecutor/flow-mcp
Then call the flow_wallet_setup tool once. It:
- Generates a new EVM wallet locally and stores it at
~/.config/flow-wallet.json(permissions0600). The private key never leaves your machine, is never sent to Flow, and is never displayed. - Claims a one-time $0.05 USDC starter seed (one per address, ever) from the Flow seed pilot, so your first calls work immediately.
- Returns the public address. Fund it by sending USDC on Base (chain 8453) to that address — even $1 is plenty. That is the only manual step.
Equivalent hosted route: the same tools are exposed over the hosted MCP
endpoint at https://flow-kg4x.vercel.app/api/mcp if you prefer not to run
the local server (payments then need your own x402 client).
How payment works
- Your client calls a paid endpoint without payment → HTTP 402 with a
machine-readable
PaymentRequiredbody (accepts[0]: schemeexact, networkeip155:8453, USDC, amount,payTo). - The client signs an EIP-3009
TransferWithAuthorizationagainst the USDC contract and retries with anX-PAYMENTheader (base64 payload that echoes theacceptsentry asaccepted). - Flow's facilitator verifies and settles on Base; the response arrives
with a
PAYMENT-RESPONSEheader carrying the settlement tx.
With the MCP server this whole dance is automatic. Spend caps are enforced in code before any signature:
- Per call: max $0.05
- Per day: $1 default (rolling 24h; override with
FLOW_DAILY_SPEND_CAP_USD) - The client only ever pays Flow's own payee address — a 402 asking to pay anyone else is refused, not signed.
- Spend is logged locally in
~/.config/flow-spend-ledger.jsonl.
The paid calls
| Endpoint | Price | Use it when |
|---|---|---|
POST /api/quote (MCP: flow_quote) |
$0.01 | You are about to swap on Base and need the best executable price first. Compares Uniswap V3, PancakeSwap V3, Aerodrome (all fee tiers) and two-hop routes via WETH; returns winning venue, expected output, edge in bps vs the Uniswap baseline, liquidity flag (deep/watch/thin), block number, and an expiry window. |
POST /api/verify |
$0.02 | You are about to interact with a Base contract you don't fully trust. Returns a safety verdict + score with plain-language reasons and agent advice. |
GET /api/smart-wallets |
$0.01 | You need to know what profitable Base wallets are buying right now. Leaderboard, real-time buy signals (stale-flagged past 10 min), a published paper-trading record, and social-velocity spikes. |
Free: GET /api/health (MCP: flow_health) — chain + latest block, plus
your starter-wallet status.
Quote request body (amountIn in atomic units):
{
"tokenIn": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
"tokenOut": "0x4200000000000000000000000000000000000006",
"amountIn": "100000000"
}
(USDC → WETH, $100 shown. tokenIn/tokenOut are Base contract addresses.)
Notes
- Quotes are informational snapshots with a stated expiry window, not execution guarantees — the edge is measured against direct Uniswap execution on the same block, and thin-liquidity quotes are flagged, never hidden.
- The seed pilot is capped (19 seeds total, 5/day). If the claim returns
pilot-fullordaily-cap, just fund the wallet address directly. - Base mainnet only (chain 8453).