From edd0ee537dfcbb9f8fcb14cd39b272b5eab85a0d Mon Sep 17 00:00:00 2001
From: Hui-Sang Kim <102507786+Hiksang@users.noreply.github.com>
Date: Thu, 7 May 2026 15:20:39 +0900
Subject: [PATCH] fix(swap): raise default --slippage from 50 to 100 bps for
 thin-liquidity broadcasts
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Pre-fix behaviour: `defi --chain monad swap --from MON --to USDC --provider kyber
--broadcast` reverted on-chain inside the KyberSwap MetaAggregator's minOut
check, even though the dry-run simulation succeeded. Reproduced live on
Monad on 2026-05-07 (tx 0x4fe39977eab47de942e7aefd540f12d4f9c56ae340813e6a46bd63c8f0a30e7f).

Root cause: the default --slippage of 50 bps (0.5%) is too tight for
thin-liquidity chains and high-volatility moments. The dry-run uses
eth_call against the current block; the real broadcast lands one or
more blocks later when the spot price has drifted past the 50 bps
floor encoded in the kyber-built calldata.

Fix:
  - Raise the default --slippage from 50 to 100 bps. 100 bps is the
    SSOT 7.3 ceiling for "safe default" defined by qa/slippage.test.ts:
    "user-facing slippage knobs default to <= 100 bps (1%)". This
    change keeps the default at the ceiling, which the slippage guard
    explicitly allows.
  - Users wanting tighter control still pass --slippage explicitly;
    the lower bound is unchanged.
  - Comment block above the option documents the rationale + the
    Monad failure tx for future archaeology.

Live re-verification post-fix (same swap, same wallet, default
slippage now 100 bps):
  pre  : tx 0x4fe39977…  status=failed,    gas_used=69095   (revert)
  post : tx 0x35310bb3…  status=confirmed, gas_used=427255  (success)

Verified:
  - pnpm -C ts -r build  — clean.
  - pnpm -C ts -r lint   — 3 packages, tsc --noEmit clean.
  - pnpm -C ts -r test   — defi-core 32/32, defi-protocols 43/43,
                           defi-cli 102/102 (the existing
                           qa/slippage.test.ts ceiling check still passes
                           because 100 == ceiling).
  - Live on-chain kyber broadcast on Monad (above): success.
---
 ts/packages/defi-cli/src/commands/swap.ts | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/ts/packages/defi-cli/src/commands/swap.ts b/ts/packages/defi-cli/src/commands/swap.ts
index 7c5c85e..e97ca9c 100644
--- a/ts/packages/defi-cli/src/commands/swap.ts
+++ b/ts/packages/defi-cli/src/commands/swap.ts
@@ -219,7 +219,14 @@ export function registerSwap(
     .requiredOption("--to <token>", "Output token symbol or address")
     .requiredOption("--amount <amount>", "Amount of input token in wei")
     .option("--provider <name>", "Aggregator: kyber, openocean, liquid, lifi, relay", "kyber")
-    .option("--slippage <bps>", "Slippage tolerance in bps", "50")
+    // Default 100 bps (1%) is the SSOT 7.3 ceiling for "safe default" and
+    // the sweet spot for thin-liquidity chains like Monad where the previous
+    // 50 bps default produced revert-on-broadcast even when the dry-run
+    // simulated successfully. Live re-verification on 2026-05-07 reproduced
+    // the issue: kyber dry-run succeeded but the actual on-chain tx reverted
+    // inside the router's minOut check (Monad tx 0x4fe39977…). Users wanting
+    // tighter control still pass --slippage explicitly.
+    .option("--slippage <bps>", "Slippage tolerance in bps", "100")
     .action(async (opts) => {
       const executor = makeExecutor();
       const chainName = requireChain(parent, getOpts);