fix(staking-cli): truncate balance display instead of rounding up

.changeset/fix-balance-truncation.md

@@ -0,0 +1,5 @@
+---
+"@walletconnect/staking-cli": patch
+---
+
+Fix balance display rounding up, causing full-balance stake to revert. `formatWCT` now truncates to 2 decimal places instead of rounding. `stake` checks on-chain balance before approving to avoid wasting gas.

packages/staking-cli/src/commands.ts

@@ -62,6 +62,16 @@ export async function stake(
 
   console.log(`\nAdding ${amount} WCT${extendingTime ? `, extending lock to ${formatDate(Number(effectiveUnlockTime))}` : ""}...`);
 
+  // Check balance before approving to avoid wasting gas on a doomed stake
+  const bal = await readUint256(buildBalanceOfCallData(address));
+  if (bal < amountWei) {
+    console.error(
+      `\nInsufficient balance: you have ${formatWCT(bal)} WCT but tried to stake ${amount} WCT.` +
+      `\nUse the displayed balance (or less) to avoid a reverted transaction.`,
+    );
+    return;
+  }
+
   // Check allowance and approve if needed
   const allowance = await readUint256(buildAllowanceCallData(address, STAKE_WEIGHT_ADDRESS));
   if (allowance < amountWei) {

packages/staking-cli/src/format.ts

@@ -7,10 +7,17 @@ import {
   MAX_LOCK_WEEKS,
 } from "./constants.js";
 
-/** Format a bigint WCT amount as a human-readable string with 2 decimals */
+/** Format a bigint WCT amount as a human-readable string with 2 decimals (truncated, never rounded up) */
 export function formatWCT(amount: bigint): string {
   const raw = formatUnits(amount, WCT_DECIMALS);
-  const num = parseFloat(raw);
+  // Truncate to 2 decimal places instead of rounding to avoid displaying
+  // a value larger than the actual on-chain balance
+  const dotIndex = raw.indexOf(".");
+  const truncated =
+    dotIndex === -1
+      ? `${raw}.00`
+      : raw.slice(0, dotIndex + 3).padEnd(dotIndex + 3, "0");
+  const num = parseFloat(truncated);
   return num.toLocaleString("en-US", {
     minimumFractionDigits: 2,
     maximumFractionDigits: 2,

packages/staking-cli/test/format.test.ts

@@ -19,6 +19,16 @@ describe("formatWCT", () => {
     // 1.5 WCT
     expect(formatWCT(1500000000000000000n)).toBe("1.50");
   });
+
+  it("truncates instead of rounding up", () => {
+    // 112.887964254423744364 WCT — must display 112.88, not 112.89
+    expect(formatWCT(112887964254423744364n)).toBe("112.88");
+  });
+
+  it("truncates .999 without rounding to next integer", () => {
+    // 9.999 WCT — must display 9.99, not 10.00
+    expect(formatWCT(9999000000000000000n)).toBe("9.99");
+  });
 });
 
 describe("formatDate", () => {