diff --git a/packages/internal/src/action-types.js b/packages/internal/src/action-types.js
index 18d4ad2b8a9..87e6af2e1e2 100644
--- a/packages/internal/src/action-types.js
+++ b/packages/internal/src/action-types.js
@@ -1,5 +1,7 @@
 // @jessie-check
 
+import { keyMirror } from './keyMirror.js';
+
 /**
  * Types of messages used for communication between a cosmos-sdk blockchain node
  * and its paired swingset VM, especially for the ABCI lifecycle. See:
@@ -14,13 +16,13 @@
  *
  * @enum {(typeof SwingsetMessageType)[keyof typeof SwingsetMessageType]}
  */
-export const SwingsetMessageType = /** @type {const} */ ({
-  AG_COSMOS_INIT: 'AG_COSMOS_INIT', // used to synchronize at process launch
-  BEGIN_BLOCK: 'BEGIN_BLOCK',
-  END_BLOCK: 'END_BLOCK',
-  COMMIT_BLOCK: 'COMMIT_BLOCK',
-  AFTER_COMMIT_BLOCK: 'AFTER_COMMIT_BLOCK',
-  SWING_STORE_EXPORT: 'SWING_STORE_EXPORT', // used to synchronize data export
+export const SwingsetMessageType = keyMirror({
+  AG_COSMOS_INIT: null, // used to synchronize at process launch
+  BEGIN_BLOCK: null,
+  END_BLOCK: null,
+  COMMIT_BLOCK: null,
+  AFTER_COMMIT_BLOCK: null,
+  SWING_STORE_EXPORT: null, // used to synchronize data export
 });
 harden(SwingsetMessageType);
 
@@ -47,17 +49,17 @@ export const {
  *
  * @enum {(typeof QueuedActionType)[keyof typeof QueuedActionType]}
  */
-export const QueuedActionType = /** @type {const} */ ({
-  CORE_EVAL: 'CORE_EVAL',
-  DELIVER_INBOUND: 'DELIVER_INBOUND',
-  IBC_EVENT: 'IBC_EVENT',
-  INSTALL_BUNDLE: 'INSTALL_BUNDLE',
-  PLEASE_PROVISION: 'PLEASE_PROVISION',
-  VBANK_BALANCE_UPDATE: 'VBANK_BALANCE_UPDATE',
-  WALLET_ACTION: 'WALLET_ACTION',
-  WALLET_SPEND_ACTION: 'WALLET_SPEND_ACTION',
-  VTRANSFER_IBC_EVENT: 'VTRANSFER_IBC_EVENT',
-  KERNEL_UPGRADE_EVENTS: 'KERNEL_UPGRADE_EVENTS',
+export const QueuedActionType = keyMirror({
+  CORE_EVAL: null,
+  DELIVER_INBOUND: null,
+  IBC_EVENT: null,
+  INSTALL_BUNDLE: null,
+  PLEASE_PROVISION: null,
+  VBANK_BALANCE_UPDATE: null,
+  WALLET_ACTION: null,
+  WALLET_SPEND_ACTION: null,
+  VTRANSFER_IBC_EVENT: null,
+  KERNEL_UPGRADE_EVENTS: null,
 });
 harden(QueuedActionType);
 
diff --git a/packages/internal/src/config.js b/packages/internal/src/config.js
index 2a05de87f21..f753619af81 100644
--- a/packages/internal/src/config.js
+++ b/packages/internal/src/config.js
@@ -1,6 +1,8 @@
 // @ts-check
 // @jessie-check
 
+import { keyMirror } from './keyMirror.js';
+
 /**
  * @file
  *
@@ -38,8 +40,8 @@ export const CosmosInitKeyToBridgeId = {
 };
 harden(CosmosInitKeyToBridgeId);
 
-export const WalletName = /** @type {const} */ ({
-  depositFacet: 'depositFacet',
+export const WalletName = keyMirror({
+  depositFacet: null,
 });
 harden(WalletName);
 
diff --git a/packages/internal/src/index.js b/packages/internal/src/index.js
index 8c1269028be..4c4ea3e0ebf 100644
--- a/packages/internal/src/index.js
+++ b/packages/internal/src/index.js
@@ -15,6 +15,7 @@ export * from './config.js';
 export * from './debug.js';
 export * from './errors.js';
 export * from './js-utils.js';
+export * from './keyMirror.js';
 export { pureDataMarshaller } from './marshal.js';
 export * from './method-tools.js';
 export * from './metrics.js';
diff --git a/packages/internal/src/keyMirror.js b/packages/internal/src/keyMirror.js
new file mode 100644
index 00000000000..0816184503e
--- /dev/null
+++ b/packages/internal/src/keyMirror.js
@@ -0,0 +1,45 @@
+// @ts-check
+// @jessie-check
+
+const { freeze, keys } = Object;
+
+/**
+ * @template {Record<string, string | null>} Init
+ * @typedef {{ readonly [K in keyof Init]: K }} KeyMirrorResult
+ */
+
+/**
+ * Mirror the keys of an object to string values that match the key names.
+ *
+ * The provided record must only map property names to either `null` or the
+ * property name itself. The returned object has identical keys whose values are
+ * the string form of the key.
+ *
+ * @template {Record<string, string | null>} Init
+ * @param {Init & { readonly [K in keyof Init]: Init[K] extends null ? null : K }}
+ *   record
+ * @returns {KeyMirrorResult<Init>}
+ */
+export const keyMirror = record => {
+  if (record === null || typeof record !== 'object') {
+    throw TypeError('keyMirror expects a record of string keys.');
+  }
+
+  /** @type {Record<string, string>} */
+  const mirrored = {};
+  for (const key of keys(record)) {
+    const typedKey = /** @type {keyof Init & string} */ (key);
+    const value = record[typedKey];
+    const stringValue = /** @type {string | null} */ (value);
+    if (stringValue !== null && stringValue !== typedKey) {
+      throw TypeError(
+        `Value for key "${typedKey}" must be null or the key string; got ${String(value)}.`,
+      );
+    }
+    mirrored[typedKey] = typedKey;
+  }
+
+  return /** @type {KeyMirrorResult<Init>} */ (freeze(mirrored));
+};
+
+freeze(keyMirror);
diff --git a/packages/orchestration/src/chain-info.js b/packages/orchestration/src/chain-info.js
index 495b4bdabd5..34119b6d69a 100644
--- a/packages/orchestration/src/chain-info.js
+++ b/packages/orchestration/src/chain-info.js
@@ -7,6 +7,7 @@
 
 import { E } from '@endo/far';
 import { M, mustMatch } from '@endo/patterns';
+import { keyMirror } from '@agoric/internal';
 import cctpChainInfo from './cctp-chain-info.js';
 import { withChainCapabilities } from './chain-capabilities.js';
 import { HubName, normalizeConnectionInfo } from './exos/chain-hub.js';
@@ -25,10 +26,10 @@ import { ChainInfoShape, CosmosAssetInfoShape } from './typeGuards.js';
  * @enum {(typeof KnownNamespace)[keyof typeof KnownNamespace]}
  * @see {@link https://github.com/ChainAgnostic/CAIPs/blob/c599f7601d0ce83e6dd9f350c6c21d158d56fd6d/CAIPs/caip-2.md}
  */
-export const KnownNamespace = /** @type {const} */ ({
-  cosmos: 'cosmos',
-  eip155: 'eip155',
-  solana: 'solana',
+export const KnownNamespace = keyMirror({
+  cosmos: null,
+  eip155: null,
+  solana: null,
 });
 harden(KnownNamespace);
 
diff --git a/packages/portfolio-api/src/constants.js b/packages/portfolio-api/src/constants.js
index f9413c93685..5111abbae5a 100644
--- a/packages/portfolio-api/src/constants.js
+++ b/packages/portfolio-api/src/constants.js
@@ -2,40 +2,44 @@
 
 /// <reference types="ses" />
 
+import { keyMirror } from '@agoric/internal';
+
 /**
  * Yield protocols for Proof of Concept.
  *
  * @enum {(typeof YieldProtocol)[keyof typeof YieldProtocol]}
  */
-export const YieldProtocol = /** @type {const} */ ({
-  Aave: 'Aave',
-  Compound: 'Compound',
-  USDN: 'USDN',
-  Beefy: 'Beefy',
+export const YieldProtocol = keyMirror({
+  Aave: null,
+  Compound: null,
+  USDN: null,
+  Beefy: null,
 });
 harden(YieldProtocol);
 
 /**
  * @enum {(typeof AxelarChain)[keyof typeof AxelarChain]}
  */
-export const AxelarChain = /** @type {const} */ ({
-  Arbitrum: 'Arbitrum',
-  Avalanche: 'Avalanche',
-  Base: 'Base',
-  Ethereum: 'Ethereum',
-  Optimism: 'Optimism',
+export const AxelarChain = keyMirror({
+  Arbitrum: null,
+  Avalanche: null,
+  Base: null,
+  Ethereum: null,
+  Optimism: null,
 });
 harden(AxelarChain);
 
 /**
  * @enum {(typeof SupportedChain)[keyof typeof SupportedChain]}
  */
-export const SupportedChain = /** @type {const} */ ({
+export const SupportedChain = {
   ...AxelarChain,
-  agoric: 'agoric',
-  noble: 'noble',
-  // XXX: check privateArgs for chainInfo for all of these
-});
+  ...keyMirror({
+    agoric: null,
+    noble: null,
+    // XXX: check privateArgs for chainInfo for all of these
+  }),
+};
 harden(SupportedChain);
 
 /**
diff --git a/packages/portfolio-contract/src/resolver/constants.js b/packages/portfolio-contract/src/resolver/constants.js
index 35165518c05..3707fe6f853 100644
--- a/packages/portfolio-contract/src/resolver/constants.js
+++ b/packages/portfolio-contract/src/resolver/constants.js
@@ -2,6 +2,8 @@
 
 /// <reference types="ses" />
 
+import { keyMirror } from '@agoric/internal';
+
 /**
  * Tx statuses for published transactions. Exhaustive state machine flows:
  *   - pending -> success (when cross-chain operation completes successfully)
@@ -21,11 +23,11 @@ harden(TxStatus);
  *
  * @enum {(typeof TxType)[keyof typeof TxType]}
  */
-export const TxType = /** @type {const} */ ({
-  CCTP_TO_EVM: 'CCTP_TO_EVM',
-  GMP: 'GMP',
-  CCTP_TO_AGORIC: 'CCTP_TO_AGORIC',
+export const TxType = keyMirror({
+  CCTP_TO_EVM: null,
+  GMP: null,
+  CCTP_TO_AGORIC: null,
   /** @deprecated - only supports 20 byte addresses */
-  CCTP_TO_NOBLE: 'CCTP_TO_NOBLE',
+  CCTP_TO_NOBLE: null,
 });
 harden(TxType);
diff --git a/packages/vats/src/walletFlags.js b/packages/vats/src/walletFlags.js
index d0f2778565e..8db70aae3b2 100644
--- a/packages/vats/src/walletFlags.js
+++ b/packages/vats/src/walletFlags.js
@@ -1,11 +1,13 @@
 // XXX domain of @agoric/cosmic-proto
+import { keyMirror } from '@agoric/internal';
+
 /**
  * non-exhaustive list of powerFlags REMOTE_WALLET is currently a default.
  *
  * See also MsgProvision in golang/cosmos/proto/agoric/swingset/msgs.proto
  */
-export const PowerFlags = /** @type {const} */ ({
-  SMART_WALLET: 'SMART_WALLET',
+export const PowerFlags = keyMirror({
+  SMART_WALLET: null,
   /** The ag-solo wallet is remote. */
-  REMOTE_WALLET: 'REMOTE_WALLET',
+  REMOTE_WALLET: null,
 });