evmscope

Instructions

Implementation Reference

• src/tools/getApprovalStatus.ts:64-140 (handler)

  The core handler logic that fetches allowance data from the blockchain for a given owner, token, and spender(s), calculates risk, and caches the result.

  async function handler(args: z.infer<typeof inputSchema>): Promise<ToolResult<ApprovalStatusData>> {
    const { owner, token, spender, chain } = args;
  
    // 토큰 주소 확인
    let tokenAddress = token;
    if (!isValidAddress(token)) {
      const meta = resolveTokenMeta(token, chain);
      if (!meta) return makeError(`Token '${token}' not found on ${chain}`, "TOKEN_NOT_FOUND");
      const addresses = meta.addresses;
      const addr = addresses[chain];
      if (!addr) return makeError(`Token '${token}' not available on ${chain}`, "TOKEN_NOT_FOUND");
      tokenAddress = addr;
    }
  
    const cacheKey = `approval:${chain}:${owner}:${tokenAddress.toLowerCase()}:${spender ?? "auto"}`;
    const cached = cache.get<ApprovalStatusData>(cacheKey);
    if (cached.hit) return makeSuccess(chain, cached.data, true);
  
    try {
      const client = getClient(chain);
      const spendersToCheck = spender
        ? [{ name: "custom", address: spender }]
        : getProtocolSpenders(chain);
  
      if (spendersToCheck.length === 0) {
        return makeError(`No known protocol spenders for ${chain}`, "INVALID_INPUT");
      }
  
      const results = await Promise.allSettled(
        spendersToCheck.map(async (s) => {
          const allowance = await client.readContract({
            address: tokenAddress as `0x${string}`,
            abi: ERC20_ALLOWANCE_ABI,
            functionName: "allowance",
            args: [owner as `0x${string}`, s.address as `0x${string}`],
          });
          return { ...s, allowance: allowance as bigint };
        }),
      );
  
      const approvals: ApprovalEntry[] = [];
      for (const result of results) {
        if (result.status === "fulfilled") {
          const { name, address, allowance: raw } = result.value;
          if (raw > 0n) {
            approvals.push({
              protocol: name,
              spender: address,
              allowance: raw >= UNLIMITED_THRESHOLD ? "unlimited" : raw.toString(),
              isUnlimited: raw >= UNLIMITED_THRESHOLD,
            });
          }
        }
      }
  
      // 리스크 레벨 결정
      const unlimitedCount = approvals.filter((a) => a.isUnlimited).length;
      let riskLevel: "safe" | "moderate" | "high" = "safe";
      if (unlimitedCount >= 3) riskLevel = "high";
      else if (unlimitedCount >= 1 || approvals.length >= 3) riskLevel = "moderate";
  
      const tokenMeta = resolveTokenMeta(token);
      const data: ApprovalStatusData = {
        owner,
        token: tokenMeta?.symbol ?? token,
        tokenAddress,
        approvals,
        riskLevel,
      };
  
      cache.set(cacheKey, data, CACHE_TTL);
      return makeSuccess(chain, data, false);
    } catch (err) {
      const message = sanitizeError(err);
      return makeError(`Failed to check approvals: ${message}`, "RPC_ERROR");
    }
  }

• src/tools/getApprovalStatus.ts:43-48 (schema)

  Input validation schema for the getApprovalStatus tool using zod.

  const inputSchema = z.object({
    owner: z.string().describe("지갑 주소"),
    token: z.string().describe("토큰 심볼 (USDC, USDT) 또는 contract address"),
    spender: z.string().optional().describe("특정 spender 주소 (미지정 시 주요 프로토콜 자동 조회)"),
    chain: z.enum(SUPPORTED_CHAINS).default("ethereum").describe("EVM 체인"),
  });

• src/tools/getApprovalStatus.ts:142-152 (registration)

  Registration of the getApprovalStatus tool with the McpServer.

  export function register(server: McpServer) {
    server.tool(
      "getApprovalStatus",
      "ERC-20 토큰 승인(allowance) 상태를 조회합니다. 주요 프로토콜 자동 체크, 리스크 레벨 판정",
      inputSchema.shape,
      async (args) => {
        const result = await handler(args as z.infer<typeof inputSchema>);
        return { content: [{ type: "text" as const, text: JSON.stringify(result, null, 2) }] };
      },
    );
  }