ADVISORYIn the programBit 14

Market Guard

Swaps that stray from a live Pyth price pay the pool's LPs a surcharge.

Add to the builder All Hook Blocks

Where it runs

Advisory

The pool's single add-on slot: one per pool.

Status on reel

In the program

In the reel program: bit 14 of PoolParams.blocks, frozen at PoolInit (PROGRAM.md §5).

Set by

You, at launch

Frozen in PoolParams at PoolInit; nobody can change it after.

What it does

Every swap compares the pool's price with an oracle. Inside ±band nothing changes. A swap that ends past the band and moves further away pays a surcharge that ramps from 0 to the full rate over one ramp width; moving back is free. If the feed is missing or stale, the pool refuses every swap, sells too, until it updates.

How it works on reel

Reads a Pyth PriceUpdateV2 account (owner rec5EKMG…, full verification, tag checked, publish_time within oracle_max_age); guard_flags bit 0 inverts the feed. Surcharge = guard_surcharge_pips·min(1, over/ramp), all to LPs; below guard_min_depth of quote to the band edge the full surcharge applies. A stale or missing feed fails closed with OracleUnavailable. With Arb recapture on the same pool, recapture must read the same Pyth feed (recap_ref 1).

Named at launch: oracle (Pyth PriceUpdateV2)

Settings · 6

Setting	Min	Default	Max	What it does
Band `guard_band_bps`	0.5%	10%	50%	Each way around the oracle price; swaps that end inside it pay nothing extra.
Ramp `guard_ramp_bps`	0.5%	10%	50%	Past the band, the surcharge rises from 0 to full over this distance.
Full surcharge `guard_surcharge_pips`	0.0001%	1%	5%	Paid by swaps that end past band + ramp and move away. 100% to LPs.
Price age limit `oracle_max_age`	1 min	25 h	25 h	A feed older than this refuses every swap, sells too (fail-closed). Market Guard only.
Least depth `guard_min_depth`	0 (off)	0 (off)	—	If quote depth to the band edge is below this, the full surcharge applies. 0 = off.
Feed orientation `guard_flags`	None	None	Invert the feed	Bit 0 inverts the feed, for a pool whose base is the feed's quote.

Fees and who's paid

Paid to

LPs, 100%. reel keeps none of it.

Protocol share

reel takes no share of it.

Requires and can't be combined with

Requires

No other block.

A Pyth feed for the exact pair, passed as the oracle at PoolInit
A new token has no feed, so it suits tokens that already trade
Pin Pyth's sponsored push feed (the Push Oracle's shard-0 account for the feed id), which anyone can refresh; any other writer can halt the pool by not posting. The pool's Details tab names the writer and warns unless it is that feed

Can't be combined with

Worked example

A SOL/USDC pool 25% above Pyth's SOL/USD with a 10% band and 10% ramp: a 1,000 USDC buy of SOL pays the full 1% surcharge (10 USDC) plus the 0.3% base fee (3 USDC), all to LPs.