fix(swap): raise default --slippage from 50 to 100 bps for thin-liquidity broadcasts

[Hiksang]

Summary

defi --chain monad swap --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 (failure tx: 0x4fe39977…).

Root cause: the default --slippage of 50 bps (0.5%) is too tight for thin-liquidity chains and high-volatility moments. dry-run runs 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 aggregator-built calldata.

Fix

ts/packages/defi-cli/src/commands/swap.ts:222:

-    .option("--slippage <bps>", "Slippage tolerance in bps", "50")
+    .option("--slippage <bps>", "Slippage tolerance in bps", "100")

100 bps is the SSOT 7.3 ceiling defined in qa/slippage.test.ts:

"user-facing slippage knobs default to <= 100 bps (1%)"

Keeping the default at the ceiling — which the slippage guard explicitly allows — gives broadcast paths breathing room without exceeding the safe-default invariant. Users wanting tighter control still pass --slippage explicitly.

A doc-comment above the option records the rationale and links the Monad failure tx for future archaeology.

Live verification

Same wallet, same swap (0.1 MON → USDC on Monad), only the default slippage changed:

	tx	status	gas_used	notes
pre-fix	0x4fe39977…	failed	69,095	revert inside router
post-fix	0x35310bb3…	confirmed	427,255	success

Test plan

• 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 post-fix: success.
• Reviewer: confirm 100 bps default is acceptable for the user persona (the slippage guard says yes; this is more about UX expectation).

Sibling — already merged in this session

• PR fix(swap): force msg.value=amount on kyber native input + 5 unit tests #16 — kyber native-input msg.value forcing (calldata-side fix)
• This PR — slippage-side fix

The two together unblock kyber's full broadcast path on Monad and any other thin-liquidity chain that joins the registry next.

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