Provides tools to check active ERC-20 token approvals on Ethereum, identify risky allowances (unlimited, EOA spenders, upgradeable contracts), and generate revoke calldata.
Provides tools to check active ERC-20 token approvals on Polygon, identify risky allowances (unlimited, EOA spenders, upgradeable contracts), and generate revoke calldata.
Click on "Deploy Server".
Wait a few minutes for the server to deploy. Once ready, it will show a "Started" state.
In the chat, type @ followed by the MCP server name and your instructions, e.g., "@approval-guardian check approvals for 0xabc... on ethereum"
That's it! The server will respond to your query, and you can continue using it as needed.
Here is a step-by-step guide with screenshots.
Find the token approvals draining your wallet — and get the revoke calldata.
approval-guardian is an MCP server and a pay-per-call x402 HTTP API. Give it a wallet address + chain and it returns a CLEAN / REVIEW / AT_RISK verdict listing every active ERC-20 approval, worst first, with the exact approve(spender, 0) calldata to revoke each one.
Unlimited token approvals are the #1 way DeFi wallets get drained — a single bad approve() lets a spender move your entire balance of that token, forever, in one transaction.
⚠️ Read-only risk screen, not financial advice. approval-guardian never holds a key and never moves funds. Revoking is a transaction you sign. Absence of findings is not proof of safety.
To know what a wallet has approved, an agent that "just reads the chain" must:
Pull every ERC-20 Approval log the wallet ever emitted (paginated eth_getLogs with the right topic0 + owner topic, respecting per-RPC block-range caps).
For each (token, spender) pair, read the LIVE allowance() — because a later approve(0) or a spend may have changed it. Stale logs lie.
Read each token's decimals/symbol to turn a raw allowance into a human amount.
Classify the spender: is it a contract at all? a plain wallet (EOA)? an EIP-1967 upgradeable proxy whose code can be swapped behind your approval? a recognised router/permit/locker?
Score the blast radius and order the revokes.
approval-guardian batches all of that over public RPCs and returns one prioritized report. That live aggregation — not a static answer — is what an agent pays for.
Related MCP server: chain-signer
♻️ Live allowances | only approvals with |
👻 EOA spenders | approving a token to a plain wallet (not a contract) is the signature of a drainer phishing scam — flagged critical |
♾️ Unlimited | infinite ( |
🔗 Upgradeable | spender is an EIP-1967 proxy whose implementation can be replaced |
✅ Known routers | recognises Uniswap / Permit2 / 1inch / 0x / PancakeSwap so you aren't scared off safe infra |
🧾 Revoke calldata | every finding ships the exact |
{
"mcpServers": {
"approval-guardian": { "command": "npx", "args": ["-y", "approval-sentinel-mcp"] }
}
}Tools:
check_approvals — full approval-risk report. Params: chain, wallet, deep (optional, full history).
revoke_plan — just the ordered list of risky approvals + revoke calldata. Params: chain, wallet, minRisk.
Or connect over HTTP at POST /mcp.
GET /check?chain=base&wallet=0xYourWallet
GET /check?chain=ethereum&wallet=0x...Returns the active approvals worst-first, each with revokeCalldata.
The /pro/* routes are gated by x402. Your agent pays $0.20 USDC per call automatically — no sign-up, no API key. The pro scan covers full on-chain history; settles on-chain (Base) to the operator wallet.
GET /pro/check?chain=base&wallet=0x... # 402 → pay → deep report
GET /pro/revoke_plan?chain=base&wallet=0x...Ethereum · Base · BSC · Polygon · Arbitrum — all via public, key-free RPCs.
npm-guardian · contract-auditor · rug-check · approval-guardian
Source & docs: github.com/Baneado98/approval-guardian · MIT
Audit a wallet's ACTIVE ERC-20 token approvals (allowances) for drain risk — the #1 way DeFi wallets get emptied. Pulls every Approval event the wallet ever emitted, reads the LIVE allowance for each (token, spender) pair, classifies the spender (EOA / unknown contract / upgradeable proxy / known router) and returns a prioritized CLEAN / REVIEW / AT_RISK verdict listing exactly which approvals to revoke first — with the approve(spender,0) revoke calldata ready to sign. Read-only; never moves funds, never holds a key. Use this before/after a wallet interacts with unfamiliar dApps, when a user fears a drainer, or to harden any wallet. Chains: ethereum, base, bsc, polygon, arbitrum.
Inputs: chain (required), wallet (required), deep.
Return ONLY the revoke action plan for a wallet: the ordered list of risky approvals to cancel, each with the token, spender and the exact approve(spender,0) calldata the user signs to revoke it. Use after check_approvals to get a clean, signable to-do list. Read-only; the user signs each revoke themselves.
Inputs: chain (required), wallet (required), minRisk.
Recent tool additions, removals, and schema changes observed during successful MCP inspections.
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Scored across 2 tools
The two tools have distinct and complementary purposes: check_approvals performs an audit and provides a verdict, while revoke_plan generates a list of revoke actions. There is no overlap in functionality.
Both tool names follow a consistent verb_noun pattern: check_approvals and revoke_plan, making them predictable and easy to understand.
With only 2 tools, the server is minimal but well-scoped for its specific purpose of auditing and planning revocations. It covers the essential operations without unnecessary bloat.
The tools cover the core workflow of auditing approvals and generating a revocation plan. The lack of a tool for executing revocations is intentional (read-only design), so the surface is complete for its stated domain.
Check a Solana wallet for risky approvals and scam tokens, and find SOL you can take back.
Send a token/contract address (Base, Ethereum, BSC), get a deterministic verdict (LOW_RISK / CAUTION
Pre-trade safety + wallets: Solana/EVM token risk, honeypots, counterparties, balances, txs, CVEs.
Pre-trade safety + wallets: Solana/EVM token risk, honeypots, counterparties, balances, txs, CVEs.