diff --git a/Cargo.lock b/Cargo.lock
index c19e362fd..f04970daa 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -1823,7 +1823,7 @@ checksum = "3640c1c38b8e4e43584d8df18be5fc6b0aa314ce6ebf51b53313d4306cca8e46"
 dependencies = [
  "hermit-abi",
  "libc",
- "windows-sys 0.52.0",
+ "windows-sys 0.61.2",
 ]
 
 [[package]]
@@ -2798,9 +2798,9 @@ dependencies = [
 
 [[package]]
 name = "serde_qs"
-version = "1.1.1"
+version = "1.1.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "c2316d01592c3382277c5062105510e35e0a6bfb2851e30028485f7af8cf1240"
+checksum = "67d525c8ff68aa99e5818302259bdd02d86d0303710616f39c0f44846ff6d332"
 dependencies = [
  "axum",
  "itoa",
@@ -3702,9 +3702,9 @@ checksum = "589f6da84c646204747d1270a2a5661ea66ed1cced2631d546fdfb155959f9ec"
 
 [[package]]
 name = "winnow"
-version = "1.0.2"
+version = "1.0.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "2ee1708bef14716a11bae175f579062d4554d95be2c6829f518df847b7b3fdd0"
+checksum = "0592e1c9d151f854e6fd382574c3a0855250e1d9b2f99d9281c6e6391af352f1"
 
 [[package]]
 name = "wio"
diff --git a/crates/brk_query/src/impl/addr.rs b/crates/brk_query/src/impl/addr.rs
index b1958ca57..08c7e1b67 100644
--- a/crates/brk_query/src/impl/addr.rs
+++ b/crates/brk_query/src/impl/addr.rs
@@ -208,7 +208,7 @@ impl Query {
     pub fn addr_mempool_hash(&self, addr: &Addr) -> Option<u64> {
         let mempool = self.mempool()?;
         let bytes = AddrBytes::from_str(addr).ok()?;
-        Some(mempool.addr_state_hash(&bytes))
+        mempool.addr_state_hash(&bytes)
     }
 
     pub fn addr_mempool_txs(&self, addr: &Addr, limit: usize) -> Result<Vec<Transaction>> {
diff --git a/crates/brk_query/src/impl/mempool.rs b/crates/brk_query/src/impl/mempool.rs
index 2dca0ac55..df1740680 100644
--- a/crates/brk_query/src/impl/mempool.rs
+++ b/crates/brk_query/src/impl/mempool.rs
@@ -1,6 +1,6 @@
 use crate::Query;
 use brk_error::{Error, Result};
-use brk_mempool::{Mempool, PrevoutResolver, RbfForTx, RbfNode};
+use brk_mempool::{Mempool, RbfForTx, RbfNode};
 use brk_types::{
     BlockTemplate, BlockTemplateDiff, CheckedSub, FeeRate, MempoolBlock, MempoolInfo,
     MempoolRecentTx, NextBlockHash, OutputType, RbfResponse, RbfTx, RecommendedFees,
@@ -32,8 +32,12 @@ impl Query {
         Ok(mempool.block_stats().iter().map(MempoolBlock::from).collect())
     }
 
-    /// Indexer-backed resolver for confirmed-parent prevouts.
-    pub fn indexer_prevout_resolver(&self) -> PrevoutResolver {
+    /// Indexer-backed resolver for confirmed-parent prevouts. Boxed so
+    /// the caller (typically [`Mempool::start_with`]) can stash one
+    /// resolver behind a stable type for the lifetime of the loop.
+    pub fn indexer_prevout_resolver(
+        &self,
+    ) -> Box<dyn Fn(&[(Txid, Vout)]) -> FxHashMap<(Txid, Vout), TxOut> + Send + Sync> {
         let indexer = self.0.indexer;
 
         Box::new(move |holes: &[(Txid, Vout)]| {
diff --git a/crates/brk_types/src/tx.rs b/crates/brk_types/src/tx.rs
index 67938d0ba..5cf5edc43 100644
--- a/crates/brk_types/src/tx.rs
+++ b/crates/brk_types/src/tx.rs
@@ -98,6 +98,14 @@ impl Transaction {
         FeeRate::from((self.fee, self.vsize()))
     }
 
+    /// Recompute `total_sigop_cost` from current inputs/outputs and
+    /// write it back into the field. Cheaper than rebuilding the
+    /// transaction when prevouts arrive; the only mutator paired with
+    /// [`Self::total_sigop_cost`].
+    pub fn refresh_sigops(&mut self) {
+        self.total_sigop_cost = self.total_sigop_cost();
+    }
+
     /// Total sigop cost (BIP-141 weight units).
     ///
     /// Mirrors `bitcoin::Transaction::total_sigop_cost`, but reads