diff --git a/packages/boot/test/fast-usdc/fast-usdc.test.ts b/packages/boot/test/fast-usdc/fast-usdc.test.ts
index 73d8b4e6baf..e13f95849e7 100644
--- a/packages/boot/test/fast-usdc/fast-usdc.test.ts
+++ b/packages/boot/test/fast-usdc/fast-usdc.test.ts
@@ -8,6 +8,7 @@ import { documentStorageSchema } from '@agoric/governance/tools/storageDoc.js';
 import { Fail } from '@endo/errors';
 import { unmarshalFromVstorage } from '@agoric/internal/src/marshal.js';
 import { makeMarshal } from '@endo/marshal';
+import { defaultMarshaller } from '@agoric/internal/src/storage-test-utils.js';
 import {
   makeWalletFactoryContext,
   type WalletFactoryTestContext,
@@ -110,11 +111,12 @@ test.serial(
 
 test.serial('writes feed policy to vstorage', async t => {
   const { storage } = t.context;
-  const doc = {
+  const opts = {
     node: 'fastUsdc.feedPolicy',
     owner: 'the general and chain-specific policies for the Fast USDC feed',
+    showValue: JSON.parse,
   };
-  await documentStorageSchema(t, storage, doc);
+  await documentStorageSchema(t, storage, opts);
 });
 
 test.serial('writes fee config to vstorage', async t => {
@@ -122,6 +124,7 @@ test.serial('writes fee config to vstorage', async t => {
   const doc = {
     node: 'fastUsdc.feeConfig',
     owner: 'the fee configuration for Fast USDC',
+    showValue: v => defaultMarshaller.fromCapData(JSON.parse(v)),
   };
   await documentStorageSchema(t, storage, doc);
 });
diff --git a/packages/boot/test/fast-usdc/snapshots/fast-usdc.test.ts.md b/packages/boot/test/fast-usdc/snapshots/fast-usdc.test.ts.md
index 08400eda5f5..f953f9ea514 100644
--- a/packages/boot/test/fast-usdc/snapshots/fast-usdc.test.ts.md
+++ b/packages/boot/test/fast-usdc/snapshots/fast-usdc.test.ts.md
@@ -14,7 +14,18 @@ Generated by [AVA](https://avajs.dev).
     [
       [
         'published.fastUsdc.feedPolicy',
-        '{"blockHeight":"0","values":["{\\"chainPolicies\\":{\\"Arbitrum\\":{\\"cctpTokenMessengerAddress\\":\\"0x19330d10D9Cc8751218eaf51E8885D058642E08A\\",\\"chainId\\":42161,\\"confirmations\\":2,\\"nobleContractAddress\\":\\"0x19330d10D9Cc8751218eaf51E8885D058642E08A\\"}},\\"nobleAgoricChannelId\\":\\"channel-21\\",\\"nobleDomainId\\":4}"]}',
+        {
+          chainPolicies: {
+            Arbitrum: {
+              cctpTokenMessengerAddress: '0x19330d10D9Cc8751218eaf51E8885D058642E08A',
+              chainId: 42161,
+              confirmations: 2,
+              nobleContractAddress: '0x19330d10D9Cc8751218eaf51E8885D058642E08A',
+            },
+          },
+          nobleAgoricChannelId: 'channel-21',
+          nobleDomainId: 4,
+        },
       ],
     ]
 
@@ -28,7 +39,36 @@ Generated by [AVA](https://avajs.dev).
     [
       [
         'published.fastUsdc.feeConfig',
-        '{"blockHeight":"0","values":["{\\"body\\":\\"#{\\\\\\"contractRate\\\\\\":{\\\\\\"denominator\\\\\\":{\\\\\\"brand\\\\\\":\\\\\\"$0.Alleged: USDC brand\\\\\\",\\\\\\"value\\\\\\":\\\\\\"+10\\\\\\"},\\\\\\"numerator\\\\\\":{\\\\\\"brand\\\\\\":\\\\\\"$0\\\\\\",\\\\\\"value\\\\\\":\\\\\\"+2\\\\\\"}},\\\\\\"flat\\\\\\":{\\\\\\"brand\\\\\\":\\\\\\"$0\\\\\\",\\\\\\"value\\\\\\":\\\\\\"+10000\\\\\\"},\\\\\\"maxVariable\\\\\\":{\\\\\\"brand\\\\\\":\\\\\\"$0\\\\\\",\\\\\\"value\\\\\\":\\\\\\"+5000000\\\\\\"},\\\\\\"variableRate\\\\\\":{\\\\\\"denominator\\\\\\":{\\\\\\"brand\\\\\\":\\\\\\"$0\\\\\\",\\\\\\"value\\\\\\":\\\\\\"+100\\\\\\"},\\\\\\"numerator\\\\\\":{\\\\\\"brand\\\\\\":\\\\\\"$0\\\\\\",\\\\\\"value\\\\\\":\\\\\\"+1\\\\\\"}}}\\",\\"slots\\":[\\"board01029\\"]}"]}',
+        {
+          contractRate: {
+            denominator: {
+              brand: Object @Alleged: USDC brand {},
+              value: 10n,
+            },
+            numerator: {
+              brand: Object @Alleged: USDC brand {},
+              value: 2n,
+            },
+          },
+          flat: {
+            brand: Object @Alleged: USDC brand {},
+            value: 10000n,
+          },
+          maxVariable: {
+            brand: Object @Alleged: USDC brand {},
+            value: 5000000n,
+          },
+          variableRate: {
+            denominator: {
+              brand: Object @Alleged: USDC brand {},
+              value: 100n,
+            },
+            numerator: {
+              brand: Object @Alleged: USDC brand {},
+              value: 1n,
+            },
+          },
+        },
       ],
     ]
 
@@ -42,10 +82,10 @@ Generated by [AVA](https://avajs.dev).
     [
       [
         'published.fastUsdc.status.0xc81bc6105b60a234c7c50ac17816ebcd5561d366df8bf3be59ff387552761702',
-        '{"blockHeight":"0","values":["OBSERVED"]}',
+        'OBSERVED',
       ],
       [
         'published.fastUsdc.status.0xd81bc6105b60a234c7c50ac17816ebcd5561d366df8bf3be59ff387552761799',
-        '{"blockHeight":"0","values":["OBSERVED"]}',
+        'OBSERVED',
       ],
     ]
diff --git a/packages/boot/test/fast-usdc/snapshots/fast-usdc.test.ts.snap b/packages/boot/test/fast-usdc/snapshots/fast-usdc.test.ts.snap
index 2a1d52ca9c2..9489b8bc7ff 100644
Binary files a/packages/boot/test/fast-usdc/snapshots/fast-usdc.test.ts.snap and b/packages/boot/test/fast-usdc/snapshots/fast-usdc.test.ts.snap differ
diff --git a/packages/internal/src/storage-test-utils.js b/packages/internal/src/storage-test-utils.js
index f224c47ad93..143a6bbd444 100644
--- a/packages/internal/src/storage-test-utils.js
+++ b/packages/internal/src/storage-test-utils.js
@@ -7,6 +7,7 @@ import { makeTracer } from './debug.js';
 import { isStreamCell, makeChainStorageRoot } from './lib-chainStorage.js';
 import { bindAllMethods } from './method-tools.js';
 import { eventLoopIteration } from './testing-utils.js';
+import { NonNullish } from './errors.js';
 
 /**
  * @import {TotalMap} from './types.js';
@@ -250,30 +251,48 @@ export const makeMockChainStorageRoot = () => {
  * @param {import('ava').ExecutionContext<unknown>} t
  * @param {MockChainStorageRoot | FakeStorageKit} storage
  * @param {({ note: string } | { node: string; owner: string }) &
- *   ({ pattern: string; replacement: string } | {})} opts
+ *   ({ pattern: string; replacement: string } | {}) & {
+ *     showValue?: (v: string) => unknown;
+ *   }} opts
  */
 export const documentStorageSchema = async (t, storage, opts) => {
   // chainStorage publication is unsynchronized
   await eventLoopIteration();
 
+  const getLast = (/** @type {string} */ cell) =>
+    JSON.parse(cell).values.at(-1) || assert.fail();
+  const { showValue = s => s } = opts;
+  /** @type {(d: Map<string, string>, k: string) => unknown} */
+  const getBodyDefault = (d, k) => showValue(getLast(NonNullish(d.get(k))));
+
   const [keys, getBody] =
     'keys' in storage
       ? [storage.keys(), (/** @type {string} */ k) => storage.getBody(k)]
-      : [storage.data.keys(), (/** @type {string} */ k) => storage.data.get(k)];
+      : [
+          storage.data.keys(),
+          (/** @type {string} */ k) => getBodyDefault(storage.data, k),
+        ];
 
   const { pattern, replacement } =
     'pattern' in opts
       ? opts
       : { pattern: 'mockChainStorageRoot.', replacement: 'published.' };
-  const illustration = [...keys].sort().map(
+
+  const pruned = [...keys]
+    .sort()
+    .filter(
+      'node' in opts
+        ? key =>
+            key
+              .replace(pattern, replacement)
+              .startsWith(`published.${opts.node}`)
+        : _entry => true,
+    );
+
+  const illustration = pruned.map(
     /** @type {(k: string) => [string, unknown]} */
     key => [key.replace(pattern, replacement), getBody(key)],
   );
-  const pruned = illustration.filter(
-    'node' in opts
-      ? ([key, _]) => key.startsWith(`published.${opts.node}`)
-      : _entry => true,
-  );
 
   const note =
     'note' in opts
@@ -283,5 +302,5 @@ export const documentStorageSchema = async (t, storage, opts) => {
 The example below illustrates the schema of the data published there.
 
 See also board marshalling conventions (_to appear_).`;
-  t.snapshot(pruned, note + boilerplate);
+  t.snapshot(illustration, note + boilerplate);
 };