diff --git a/packages/SwingSet/test/test-state.js b/packages/SwingSet/test/test-state.js
index e5946c367e5a..72932c659aa6 100644
--- a/packages/SwingSet/test/test-state.js
+++ b/packages/SwingSet/test/test-state.js
@@ -145,13 +145,15 @@ function duplicateKeeper(serialize) {
 
 test('kernelStorage param guards', async t => {
   const { kvStore } = buildKeeperStorageInMemory();
-  const exp = { message: /true must be a string/ };
-  t.throws(() => kvStore.set('foo', true), exp);
-  t.throws(() => kvStore.set(true, 'foo'), exp);
-  t.throws(() => kvStore.has(true), exp);
-  t.throws(() => kvStore.getNextKey(true), exp);
-  t.throws(() => kvStore.get(true), exp);
-  t.throws(() => kvStore.delete(true), exp);
+  const expv = { message: /value must be a string/ };
+  const expk = { message: /key must be a string/ };
+  const exppk = { message: /previousKey must be a string/ };
+  t.throws(() => kvStore.set('foo', true), expv);
+  t.throws(() => kvStore.set(true, 'foo'), expk);
+  t.throws(() => kvStore.has(true), expk);
+  t.throws(() => kvStore.getNextKey(true), exppk);
+  t.throws(() => kvStore.get(true), expk);
+  t.throws(() => kvStore.delete(true), expk);
 });
 
 test('kernel state', async t => {
diff --git a/packages/swing-store/src/hasher.js b/packages/swing-store/src/hasher.js
index 4907745a94a7..17153494b35c 100644
--- a/packages/swing-store/src/hasher.js
+++ b/packages/swing-store/src/hasher.js
@@ -1,4 +1,4 @@
-import { assert } from '@agoric/assert';
+import { Fail } from '@agoric/assert';
 
 import { createHash } from 'crypto';
 
@@ -19,12 +19,12 @@ function createSHA256(initial = undefined) {
   // eslint-disable-next-line no-use-before-define
   const self = harden({ add, finish, sample });
   function add(more) {
-    assert(!done);
+    !done || Fail`hash already finished`;
     hash.update(more);
     return self;
   }
   function finish() {
-    assert(!done);
+    !done || Fail`hash already finished`;
     done = true;
     return hash.digest('hex');
   }
diff --git a/packages/swing-store/src/snapStore.js b/packages/swing-store/src/snapStore.js
index dc2c8fe340ac..d0bea79d2a66 100644
--- a/packages/swing-store/src/snapStore.js
+++ b/packages/swing-store/src/snapStore.js
@@ -4,7 +4,7 @@ import { createHash } from 'crypto';
 import { finished as finishedCallback, Readable } from 'stream';
 import { promisify } from 'util';
 import { createGzip, createGunzip } from 'zlib';
-import { assert, details as d } from '@agoric/assert';
+import { Fail, q } from '@agoric/assert';
 import { aggregateTryFinally, PromiseAllOrErrors } from '@agoric/internal';
 import { fsStreamReady } from '@agoric/internal/src/fs-stream.js';
 
@@ -297,7 +297,7 @@ export function makeSnapStore(
     return aggregateTryFinally(
       async () => {
         const loadInfo = sqlLoadSnapshot.get(vatID);
-        assert(loadInfo, `no snapshot available for vat ${vatID}`);
+        loadInfo || Fail`no snapshot available for vat ${q(vatID)}`;
         const { hash, compressedSnapshot } = loadInfo;
         const gzReader = Readable.from(compressedSnapshot);
         cleanup.push(() => gzReader.destroy());
@@ -322,7 +322,7 @@ export function makeSnapStore(
 
         await Promise.all([finished(gzReader), finished(snapWriter)]);
         const h = hashStream.digest('hex');
-        h === hash || assert.fail(d`actual hash ${h} !== expected ${hash}`);
+        h === hash || Fail`actual hash ${q(h)} !== expected ${q(hash)}`;
         const snapWriterClose = cleanup.pop();
         snapWriterClose();
 
@@ -457,19 +457,16 @@ export function makeSnapStore(
   async function importSnapshot(name, exporter, info) {
     const parts = name.split('.');
     const [type, vatID, rawEndPos] = parts;
-    assert(
-      parts.length === 3 && type === 'snapshot',
-      `expected snapshot name of the form 'snapshot.{vatID}.{endPos}', saw '${name}'`,
-    );
-    assert(
-      info.vatID === vatID,
-      `snapshot name says vatID ${vatID}, metadata says ${info.vatID}`,
-    );
+    // prettier-ignore
+    parts.length === 3 && type === 'snapshot' ||
+      Fail`expected snapshot name of the form 'snapshot.{vatID}.{endPos}', saw '${q(name)}'`;
+    // prettier-ignore
+    info.vatID === vatID ||
+      Fail`snapshot name says vatID ${q(vatID)}, metadata says ${q(info.vatID)}`;
     const endPos = Number(rawEndPos);
-    assert(
-      info.endPos === endPos,
-      `snapshot name says endPos ${endPos}, metadata says ${info.endPos}`,
-    );
+    // prettier-ignore
+    info.endPos === endPos ||
+      Fail`snapshot name says endPos ${q(endPos)}, metadata says ${q(info.endPos)}`;
 
     const artifactChunks = exporter.getArtifact(name);
     const inStream = Readable.from(artifactChunks);
@@ -482,10 +479,9 @@ export function makeSnapStore(
     const compressedArtifact = await buffer(gzip);
     await finished(inStream);
     const hash = hashStream.digest('hex');
-    assert(
-      info.hash === hash,
-      `snapshot ${name} hash is ${hash}, metadata says ${info.hash}`,
-    );
+    // prettier-ignore
+    info.hash === hash ||
+      Fail`snapshot ${q(name)} hash is ${q(hash)}, metadata says ${q(info.hash)}`;
     sqlSaveSnapshot.run(
       vatID,
       endPos,
diff --git a/packages/swing-store/src/transcriptStore.js b/packages/swing-store/src/transcriptStore.js
index 720c3ef1852d..68527e381e54 100644
--- a/packages/swing-store/src/transcriptStore.js
+++ b/packages/swing-store/src/transcriptStore.js
@@ -2,7 +2,7 @@
 import ReadlineTransform from 'readline-transform';
 import { Readable } from 'stream';
 import { Buffer } from 'buffer';
-import { assert, Fail, q } from '@agoric/assert';
+import { Fail, q } from '@agoric/assert';
 import { createSHA256 } from './hasher.js';
 
 /**
@@ -34,13 +34,13 @@ function* empty() {
 }
 
 /**
- * @param {unknown} position
+ * @param {number} position
  * @returns {asserts position is number}
  */
 
 function insistTranscriptPosition(position) {
-  assert.typeof(position, 'number');
-  assert(position >= 0);
+  typeof position === 'number' || Fail`position must be a number`;
+  position >= 0 || Fail`position must not be negative`;
 }
 
 /**
@@ -170,7 +170,7 @@ export function makeTranscriptStore(db, ensureTxn, noteExport) {
    */
   function getCurrentSpanBounds(vatID) {
     const bounds = sqlGetCurrentSpanBounds.get(vatID);
-    assert(bounds, `no current transcript for ${vatID}`);
+    bounds || Fail`no current transcript for ${q(vatID)}`;
     return bounds;
   }
 
@@ -300,13 +300,10 @@ export function makeTranscriptStore(db, ensureTxn, noteExport) {
     if (startPos === undefined) {
       ({ startPos, endPos } = getCurrentSpanBounds(vatID));
     } else {
-      assert.typeof(startPos, 'number');
+      insistTranscriptPosition(startPos);
       endPos = sqlGetSpanEndPos.get(vatID, startPos);
-      assert.typeof(
-        endPos,
-        'number',
-        `no transcript span for ${vatID} at ${startPos}`,
-      );
+      typeof endPos === 'number' ||
+        Fail`no transcript span for ${q(vatID)} at ${q(startPos)}`;
     }
     insistTranscriptPosition(startPos);
     startPos <= endPos || Fail`${q(startPos)} <= ${q(endPos)}}`;
@@ -384,24 +381,20 @@ export function makeTranscriptStore(db, ensureTxn, noteExport) {
   async function importSpan(name, exporter, info) {
     const parts = name.split('.');
     const [type, vatID, rawStartPos, rawEndPos] = parts;
-    assert(
-      parts.length === 4 && type === 'transcript',
-      `expected artifact name of the form 'transcript.{vatID}.{startPos}.{endPos}', saw '${name}'`,
-    );
-    assert(
-      info.vatID === vatID,
-      `artifact name says vatID ${vatID}, metadata says ${info.vatID}`,
-    );
+    // prettier-ignore
+    parts.length === 4 && type === 'transcript' ||
+      Fail`expected artifact name of the form 'transcript.{vatID}.{startPos}.{endPos}', saw '${q(name)}'`;
+    // prettier-ignore
+    info.vatID === vatID ||
+      Fail`artifact name says vatID ${q(vatID)}, metadata says ${q(info.vatID)}`;
     const startPos = Number(rawStartPos);
-    assert(
-      info.startPos === startPos,
-      `artifact name says startPos ${startPos}, metadata says ${info.startPos}`,
-    );
+    // prettier-ignore
+    info.startPos === startPos ||
+      Fail`artifact name says startPos ${q(startPos)}, metadata says ${q(info.startPos)}`;
     const endPos = Number(rawEndPos);
-    assert(
-      info.endPos === endPos,
-      `artifact name says endPos ${endPos}, metadata says ${info.endPos}`,
-    );
+    // prettier-ignore
+    info.endPos === endPos ||
+      Fail`artifact name says endPos ${q(endPos)}, metadata says ${q(info.endPos)}`;
     const artifactChunks = exporter.getArtifact(name);
     const inStream = Readable.from(artifactChunks);
     const lineTransform = new ReadlineTransform();
@@ -413,10 +406,8 @@ export function makeTranscriptStore(db, ensureTxn, noteExport) {
       hash = computeItemHash(hash, item);
       pos += 1;
     }
-    assert(
-      info.hash === hash,
-      `artifact ${name} hash is ${hash}, metadata says ${info.hash}`,
-    );
+    info.hash === hash ||
+      Fail`artifact ${name} hash is ${q(hash)}, metadata says ${q(info.hash)}`;
     sqlWriteSpan.run(
       info.vatID,
       info.startPos,
diff --git a/packages/swing-store/test/test-state.js b/packages/swing-store/test/test-state.js
index 68534a200f38..fc53d03efea2 100644
--- a/packages/swing-store/test/test-state.js
+++ b/packages/swing-store/test/test-state.js
@@ -172,7 +172,7 @@ async function testTranscriptStore(t, dbDir) {
   t.deepEqual(Array.from(reader2), ['oneth', 'twoth', 'threeth', 'fourst']);
 
   t.throws(() => transcriptStore.readSpan('st2', 3), {
-    message: 'no transcript span for st2 at 3',
+    message: 'no transcript span for "st2" at 3',
   });
 
   const reader1alt = transcriptStore.readSpan('st1');
@@ -185,7 +185,7 @@ async function testTranscriptStore(t, dbDir) {
   t.deepEqual(Array.from(readerEmpty), []);
 
   t.throws(() => transcriptStore.readSpan('nonexistent'), {
-    message: 'no current transcript for nonexistent',
+    message: 'no current transcript for "nonexistent"',
   });
 
   await commit();