x402-native, pay-per-call. Two HTTP tools an agent pays for inline — no accounts, no keys held. Live on Base, Polygon & Arbitrum.
x402-nativemultichaindecision-grade
the gap
A wallet guard like Blockaid tells an agent whether a transaction is malicious — can I sign this? It can't tell the agent should I trade this? — what price actually fills under size, and whether the token is an economic trap. Plexa answers the economic question.
two endpoints, one engine
POST /v1/quote$0.02
Executable liquidity under a given size: real fill price (not mid/spot), price impact (bps), realizable depth, per-leg route, worst-case slippage, confidence. Priced from canonical on-chain quoters, on Base, Polygon & Arbitrum.
POST /v1/pretrade/check$0.05
Economic-safety verdict — ok / caution / avoid — with reasons and confidence. Weighs liquidity structure, holder concentration, token age, fee-on-transfer / honeypot fingerprints, oracle sanity, in context. Plus an executable quote.
Add the Plexa MCP server to any agent (Claude Code / Claude Desktop / any MCP host). It exposes plexa_quote and plexa_pretrade_check. Payment is handled automatically via x402 from a wallet you configure — Plexa never sees the key.
Direct HTTP (x402)
Any x402 client works (e.g. @x402/fetch). Call the endpoint; on 402 the client signs a USDC payment (EIP-3009) and retries — the response is served only after on-chain settle. Pass chain: base / polygon / arbitrum.
// MCP client config (claude_desktop_config.json or any host){"mcpServers": {"plexa": {"command": "npx",
"args": ["-y", "@plexa/mcp"],
"env": {"PLEXA_PAYER_KEY": "0x<your funded wallet key>"}}}}
The @plexa/mcp package and public API endpoint ship with distribution (coming soon).
open-source reference agent
See Plexa in action
A complete, MIT-licensed reference agent — a dust consolidator that discovers small token balances, checks each through Plexa, and swaps the safe ones. Client-only: it uses nothing but the public API, so it doubles as a working integration pattern you can fork.