diff --git a/golang/cosmos/x/swingset/config.go b/golang/cosmos/x/swingset/config.go
index 3ebe9551cda6..1f8a8b063426 100644
--- a/golang/cosmos/x/swingset/config.go
+++ b/golang/cosmos/x/swingset/config.go
@@ -18,10 +18,18 @@ const (
 	ConfigPrefix = "swingset"
 	FlagSlogfile = ConfigPrefix + ".slogfile"
 
+	SnapshotRetentionOptionDebug       = "debug"
+	SnapshotRetentionOptionOperational = "operational"
+
 	TranscriptRetentionOptionArchival    = "archival"
 	TranscriptRetentionOptionOperational = "operational"
 )
 
+var snapshotRetentionValues []string = []string{
+	SnapshotRetentionOptionDebug,
+	SnapshotRetentionOptionOperational,
+}
+
 var transcriptRetentionValues []string = []string{
 	TranscriptRetentionOptionArchival,
 	TranscriptRetentionOptionOperational,
@@ -49,9 +57,16 @@ slogfile = "{{ .Swingset.SlogFile }}"
 # be frequently paged out to remain under this limit.
 max-vats-online = {{ .Swingset.MaxVatsOnline }}
 
+# Retention of vat snapshots, with values analogous to those of export
+# ` + "`artifactMode`" + ` (cf.
+# https://github.com/Agoric/agoric-sdk/blob/master/packages/swing-store/docs/data-export.md#optional--historical-data ).
+# * "debug": keep all snapshots
+# * "operational": keep only the last snapshot
+vat-snapshot-retention = "{{ .Swingset.VatSnapshotRetention }}"
+
 # Retention of vat transcript spans, with values analogous to those of export
 # ` + "`artifactMode`" + ` (cf.
-# https://github.com/Agoric/agoric-sdk/blob/master/packages/swing-store/docs/data-export.md#optional--historical-data
+# https://github.com/Agoric/agoric-sdk/blob/master/packages/swing-store/docs/data-export.md#optional--historical-data ).
 # * "archival": keep all transcript spans
 # * "operational": keep only necessary transcript spans (i.e., since the
 #   last snapshot of their vat)
@@ -70,9 +85,18 @@ type SwingsetConfig struct {
 	// SlogFile is the path at which a SwingSet log "slog" file should be written.
 	// If relative, it is interpreted against the application home directory
 	SlogFile string `mapstructure:"slogfile" json:"slogfile,omitempty"`
+
 	// MaxVatsOnline is the maximum number of vats that the SwingSet kernel will have online
 	// at any given time.
 	MaxVatsOnline int `mapstructure:"max-vats-online" json:"maxVatsOnline,omitempty"`
+
+	// VatSnapshotRetention controls retention of vat snapshots,
+	// and has values analogous to those of export `artifactMode` (cf.
+	// ../../../../packages/swing-store/docs/data-export.md#optional--historical-data ).
+	// * "debug": keep all snapshots
+	// * "operational": keep only the last snapshot
+	VatSnapshotRetention string `mapstructure:"vat-snapshot-retention" json:"vatSnapshotRetention,omitempty"`
+
 	// VatTranscriptRetention controls retention of vat transcript spans,
 	// and has values analogous to those of export `artifactMode` (cf.
 	// ../../../../packages/swing-store/docs/data-export.md#optional--historical-data ).
@@ -87,6 +111,7 @@ type SwingsetConfig struct {
 var DefaultSwingsetConfig = SwingsetConfig{
 	SlogFile:               "",
 	MaxVatsOnline:          50,
+	VatSnapshotRetention:   "operational",
 	VatTranscriptRetention: "default",
 }
 
@@ -114,7 +139,18 @@ func SwingsetConfigFromViper(resolvedConfig servertypes.AppOptions) (*SwingsetCo
 	}
 	ssConfig := &extendedConfig.Swingset
 
-	// Default/validate transcript retention.
+	if ssConfig.VatSnapshotRetention != "" {
+		// Validate vat snapshot retention.
+		if util.IndexOf(snapshotRetentionValues, ssConfig.VatSnapshotRetention) == -1 {
+			err := fmt.Errorf(
+				"value for vat-snapshot-retention must be in %q",
+				snapshotRetentionValues,
+			)
+			return nil, err
+		}
+	}
+
+	// Default/validate vat transcript retention.
 	if ssConfig.VatTranscriptRetention == "" || ssConfig.VatTranscriptRetention == "default" {
 		if extendedConfig.Pruning == pruningtypes.PruningOptionNothing {
 			ssConfig.VatTranscriptRetention = TranscriptRetentionOptionArchival
diff --git a/packages/cosmic-swingset/src/chain-main.js b/packages/cosmic-swingset/src/chain-main.js
index bb32233e176d..dff36fe872fb 100644
--- a/packages/cosmic-swingset/src/chain-main.js
+++ b/packages/cosmic-swingset/src/chain-main.js
@@ -74,6 +74,7 @@ const toNumber = specimen => {
  * @typedef {object} CosmosSwingsetConfig
  * @property {string} [slogfile]
  * @property {number} [maxVatsOnline]
+ * @property {'debug' | 'operational'} [vatSnapshotRetention]
  * @property {'archival' | 'operational'} [vatTranscriptRetention]
  */
 const SwingsetConfigShape = M.splitRecord(
@@ -81,6 +82,7 @@ const SwingsetConfigShape = M.splitRecord(
   {
     slogfile: M.string(),
     maxVatsOnline: M.number(),
+    vatSnapshotRetention: M.or('debug', 'operational'),
     vatTranscriptRetention: M.or('archival', 'operational'),
   },
   M.any(),
@@ -307,10 +309,16 @@ export default async function main(progname, args, { env, homedir, agcc }) {
   // here so 'sendToChainStorage' can close over the single mutable instance,
   // when we updated the 'portNums.storage' value each time toSwingSet was called.
   async function launchAndInitializeSwingSet(initAction) {
+    const { XSNAP_KEEP_SNAPSHOTS, NODE_HEAP_SNAPSHOTS = -1 } = env;
+
     /** @type {CosmosSwingsetConfig} */
     const swingsetConfig = harden(initAction.resolvedConfig || {});
     validateSwingsetConfig(swingsetConfig);
-    const { slogfile, vatTranscriptRetention } = swingsetConfig;
+    const { slogfile, vatSnapshotRetention, vatTranscriptRetention } =
+      swingsetConfig;
+    const keepSnapshots =
+      vatSnapshotRetention === 'debug' ||
+      (!vatSnapshotRetention && ['1', 'true'].includes(XSNAP_KEEP_SNAPSHOTS));
     const keepTranscripts = vatTranscriptRetention === 'archival';
 
     // As a kludge, back-propagate selected configuration into environment variables.
@@ -451,7 +459,6 @@ export default async function main(progname, args, { env, homedir, agcc }) {
       serviceName: TELEMETRY_SERVICE_NAME,
     });
 
-    const { XSNAP_KEEP_SNAPSHOTS, NODE_HEAP_SNAPSHOTS = -1 } = env;
     const slogSender = await makeSlogSender({
       stateDir: stateDBDir,
       env,
@@ -464,10 +471,6 @@ export default async function main(progname, args, { env, homedir, agcc }) {
       trueValue: pathResolve(stateDBDir, 'store-trace.log'),
     });
 
-    // TODO: Add to SwingsetConfig (#9386)
-    const keepSnapshots =
-      XSNAP_KEEP_SNAPSHOTS === '1' || XSNAP_KEEP_SNAPSHOTS === 'true';
-
     const nodeHeapSnapshots = Number.parseInt(NODE_HEAP_SNAPSHOTS, 10);
 
     let lastCommitTime = 0;