Magneta Contract Risk MCP server

Magneta Contract Risk (x402)

A small production-oriented service that sells an on-chain smart-contract risk report to AI agents, paid per call with x402 micropayments (USDC, EIP-3009 exact scheme). One express process, two paid surfaces:

Both paid surfaces call the same analyzeContract(chainId, address) in src/risk/analyze.ts. The analysis is deterministic and uses public data only (RPC, Blockscout, Sourcify, a local aderyn binary). No LLM, no API key for analysis. Unknown chain or malformed address returns 400 before any payment is requested. If the analysis itself fails (not a contract, upstream error, timeout) the response is an error status and the buyer is not charged (x402 only settles successful responses).

Supported chains (v1, src/chains.ts): Base 8453, Base Sepolia 84532, Ethereum 1, Arbitrum One 42161. Override RPCs with RPCURL.

Report

{ chainId, address, analyzedAt, isContract, bytecodeSize, proxy, erc20, opcodes, selectors: { found },
  blockscout, sourcify?, aderyn, score, level, flags, notes }

• proxy: { type, implementation, admin? } from EIP-1967 (implementation/admin/beacon), legacy zeppelinos slot, EIP-1822, EIP-1167 clones, or Blockscout's detection. The implementation bytecode is analysed too.
• erc20: name, symbol, decimals, totalSupply, owner() (and whether it is the zero address), paused(). Each probe is individually try/catch.
• opcodes: SELFDESTRUCT / DELEGATECALL presence from a real opcode walk that skips PUSH data (no substring matching).
• selectors.found: risky signatures (mint, pause, blacklist, fee/tax setters, upgrade, ownership...) whose 4-byte selector appears as a PUSH4 in the bytecode. Heuristic: presence is not proof of reachability (also stated in notes).
• blockscout / sourcify: verification status, compiler, contract name, creator and creation tx. Blockscout has a 5 s timeout; on failure blockscout: { available: false }. Sourcify is only queried as a fallback when Blockscout is unreachable or reports "unverified". For proxies, the implementation's verification is what counts.
• aderyn: when verified Solidity source is available, sources are written to a temp dir (sanitised paths) and aderyn runs with a 15 s timeout: { ran, counts: { high, low }, top: [{ title, severity, instances }] }, else { ran: false, reason }. It never fails the request.
• Total budget: hard deadline 24 s per analysis. Results are cached in memory for 10 minutes per chainId+address (the payment still happens on every call).

Score rubric (src/risk/score.ts)

Score 0..100, higher = riskier, additive, capped at 100.

Level: 0-24 low, 25-49 medium, 50-74 high, 75-100 critical. A non-contract address is an error, not a score. The score is a triage signal, not an audit.

Supported chains

Shortened. The full README is on GitHub.