diff --git a/packages/ERTP/test/unitTests/test-inputValidation.js b/packages/ERTP/test/unitTests/test-inputValidation.js
index 791a03d47f2b..90124406701d 100644
--- a/packages/ERTP/test/unitTests/test-inputValidation.js
+++ b/packages/ERTP/test/unitTests/test-inputValidation.js
@@ -33,7 +33,7 @@ test('makeIssuerKit bad displayInfo.decimalPlaces', async t => {
       ),
     {
       message:
-        'displayInfo: optional-parts: decimalPlaces: "hello" - Must be >= -100',
+        'displayInfo: optional: decimalPlaces: "hello" - Must be >= -100',
     },
   );
 
@@ -61,8 +61,7 @@ test('makeIssuerKit bad displayInfo.decimalPlaces', async t => {
     () =>
       makeIssuerKit('myTokens', AssetKind.NAT, harden({ decimalPlaces: 101 })),
     {
-      message:
-        'displayInfo: optional-parts: decimalPlaces: 101 - Must be <= 100',
+      message: 'displayInfo: optional: decimalPlaces: 101 - Must be <= 100',
     },
   );
 
@@ -70,8 +69,7 @@ test('makeIssuerKit bad displayInfo.decimalPlaces', async t => {
     () =>
       makeIssuerKit('myTokens', AssetKind.NAT, harden({ decimalPlaces: -101 })),
     {
-      message:
-        'displayInfo: optional-parts: decimalPlaces: -101 - Must be >= -100',
+      message: 'displayInfo: optional: decimalPlaces: -101 - Must be >= -100',
     },
   );
 });
@@ -89,7 +87,7 @@ test('makeIssuerKit bad displayInfo.assetKind', async t => {
       ),
     {
       message:
-        'displayInfo: optional-parts: assetKind: "something" - Must match one of ["nat","set","copySet","copyBag"]',
+        'displayInfo: optional: assetKind: "something" - Must match one of ["nat","set","copySet","copyBag"]',
     },
   );
 });
@@ -106,8 +104,7 @@ test('makeIssuerKit bad displayInfo.whatever', async t => {
         }),
       ),
     {
-      message:
-        'displayInfo: rest-parts: {"whatever":"something"} - Must be: {}',
+      message: 'displayInfo: rest: {"whatever":"something"} - Must be: {}',
     },
   );
 });
@@ -144,7 +141,7 @@ test('brand.isMyIssuer bad issuer', async t => {
   // @ts-expect-error Intentional wrong type for testing
   t.throwsAsync(() => brand.isMyIssuer('not an issuer'), {
     message:
-      'In "isMyIssuer" method of (myTokens brand) arg 0: string "not an issuer" - Must be a remotable (Issuer)',
+      'In "isMyIssuer" method of (myTokens brand): args: [0]: string "not an issuer" - Must be a remotable (Issuer)',
   });
   const fakeIssuer = /** @type {Issuer} */ (
     /** @type {unknown} */ (Far('myTokens issuer', {}))
@@ -187,7 +184,7 @@ test('issuer.combine bad payments array', async t => {
   // @ts-expect-error Intentional wrong type for testing
   await t.throwsAsync(() => E(issuer).combine(notAnArray), {
     message:
-      'In "combine" method of (fungible issuer) arg 0: cannot serialize Remotables with non-methods like "length" in {"length":2,"split":"[Function split]"}',
+      'In "combine" method of (fungible issuer): cannot serialize Remotables with non-methods like "length" in {"length":2,"split":"[Function split]"}',
   });
 
   const notAnArray2 = Far('notAnArray2', {
@@ -197,7 +194,7 @@ test('issuer.combine bad payments array', async t => {
   // @ts-expect-error Intentional wrong type for testing
   await t.throwsAsync(() => E(issuer).combine(notAnArray2), {
     message:
-      'In "combine" method of (fungible issuer) arg 0: remotable "[Alleged: notAnArray2]" - Must be a copyArray',
+      'In "combine" method of (fungible issuer): args: [0]: remotable "[Alleged: notAnArray2]" - Must be a copyArray',
   });
 });
 
diff --git a/packages/ERTP/test/unitTests/test-issuerObj.js b/packages/ERTP/test/unitTests/test-issuerObj.js
index 532ee1114b8f..9c3ea754fa34 100644
--- a/packages/ERTP/test/unitTests/test-issuerObj.js
+++ b/packages/ERTP/test/unitTests/test-issuerObj.js
@@ -43,7 +43,7 @@ test('bad display info', t => {
   const displayInfo = harden({ somethingUnexpected: 3 });
   // @ts-expect-error deliberate invalid arguments for testing
   t.throws(() => makeIssuerKit('fungible', AssetKind.NAT, displayInfo), {
-    message: 'displayInfo: rest-parts: {"somethingUnexpected":3} - Must be: {}',
+    message: 'displayInfo: rest: {"somethingUnexpected":3} - Must be: {}',
   });
 });
 
@@ -199,7 +199,7 @@ test('purse.deposit promise', async t => {
     () => E(purse).deposit(exclusivePaymentP, fungible25),
     {
       message:
-        'In "deposit" method of (fungible Purse purse) arg 0: promise "[Promise]" - Must be a remotable (Payment)',
+        'In "deposit" method of (fungible Purse purse): args: [0]: promise "[Promise]" - Must be a remotable (Payment)',
     },
     'failed to reject a promise for a payment',
   );
@@ -334,7 +334,7 @@ test('issuer.split bad amount', async t => {
     _ => E(issuer).split(payment, AmountMath.make(otherBrand, 10n)),
     {
       message:
-        'In "split" method of (fungible issuer) arg 1: brand: "[Alleged: other fungible brand]" - Must be: "[Alleged: fungible brand]"',
+        'In "split" method of (fungible issuer): args: [1]: brand: "[Alleged: other fungible brand]" - Must be: "[Alleged: fungible brand]"',
     },
     'throws for bad amount',
   );
diff --git a/packages/ERTP/test/unitTests/test-mintObj.js b/packages/ERTP/test/unitTests/test-mintObj.js
index 5945b0b964e7..f16e8d6f1a61 100644
--- a/packages/ERTP/test/unitTests/test-mintObj.js
+++ b/packages/ERTP/test/unitTests/test-mintObj.js
@@ -45,7 +45,7 @@ test('mint.mintPayment set w strings AssetKind', async t => {
   const badAmount = AmountMath.make(brand, harden([['badElement']]));
   t.throws(() => mint.mintPayment(badAmount), {
     message:
-      'In "mintPayment" method of (items mint) arg 0: value: [0]: copyArray ["badElement"] - Must be a string',
+      'In "mintPayment" method of (items mint): args: [0]: value: [0]: copyArray ["badElement"] - Must be a string',
   });
 });
 
diff --git a/packages/governance/test/unitTests/test-paramGovernance.js b/packages/governance/test/unitTests/test-paramGovernance.js
index 5752bf9f81ba..34033f5d748d 100644
--- a/packages/governance/test/unitTests/test-paramGovernance.js
+++ b/packages/governance/test/unitTests/test-paramGovernance.js
@@ -218,7 +218,7 @@ test('multiple params bad change', async t => {
       ),
     {
       message:
-        'In "getAmountOf" method of (Zoe Invitation issuer) arg 0: bigint "[13n]" - Must be a remotable (Payment)',
+        'In "getAmountOf" method of (Zoe Invitation issuer): args: [0]: bigint "[13n]" - Must be a remotable (Payment)',
     },
   );
 });
diff --git a/packages/inter-protocol/test/psm/test-psm.js b/packages/inter-protocol/test/psm/test-psm.js
index 1917ba19a000..e129a7c4b756 100644
--- a/packages/inter-protocol/test/psm/test-psm.js
+++ b/packages/inter-protocol/test/psm/test-psm.js
@@ -622,7 +622,7 @@ test('wrong give giveMintedInvitation', async t => {
       ),
     {
       message:
-        '"giveMinted" proposal: required-parts: give: In: brand: "[Alleged: aUSD brand]" - Must be: "[Alleged: IST brand]"',
+        '"giveMinted" proposal: give: In: brand: "[Alleged: aUSD brand]" - Must be: "[Alleged: IST brand]"',
     },
   );
 });
@@ -652,7 +652,7 @@ test('wrong give wantMintedInvitation', async t => {
       ),
     {
       message:
-        '"wantMinted" proposal: required-parts: give: In: brand: "[Alleged: IST brand]" - Must be: "[Alleged: aUSD brand]"',
+        '"wantMinted" proposal: give: In: brand: "[Alleged: IST brand]" - Must be: "[Alleged: aUSD brand]"',
     },
   );
 });
@@ -674,7 +674,7 @@ test('extra give wantMintedInvitation', async t => {
       ),
     {
       message:
-        '"wantMinted" proposal: required-parts: give: {"Extra":{"brand":"[Alleged: aUSD brand]","value":"[200000000n]"},"In":{"brand":"[Seen]","value":"[200000000n]"}} - Must not have unexpected properties: ["Extra"]',
+        '"wantMinted" proposal: give: {"Extra":{"brand":"[Alleged: aUSD brand]","value":"[200000000n]"},"In":{"brand":"[Seen]","value":"[200000000n]"}} - Must not have unexpected properties: ["Extra"]',
     },
   );
 });
diff --git a/packages/inter-protocol/test/vaultFactory/test-vaultFactory.js b/packages/inter-protocol/test/vaultFactory/test-vaultFactory.js
index 055a04c67c13..d4adbbfa3cbd 100644
--- a/packages/inter-protocol/test/vaultFactory/test-vaultFactory.js
+++ b/packages/inter-protocol/test/vaultFactory/test-vaultFactory.js
@@ -2516,7 +2516,7 @@ test('addVaultType: extra, unexpected params', async t => {
     E(vaultFactory).addVaultType(chit.issuer, 'Chit', missingParams),
     {
       message:
-        /initialParamValues: required-parts: .* - Must have missing properties \["interestRate"\]/,
+        /initialParamValues: .* - Must have missing properties \["interestRate"\]/,
     },
   );
 
diff --git a/packages/store/test/test-heap-classes.js b/packages/store/test/test-heap-classes.js
index f8ea21e28e7d..a8c99ca6cdf4 100644
--- a/packages/store/test/test-heap-classes.js
+++ b/packages/store/test/test-heap-classes.js
@@ -38,13 +38,12 @@ test('test defineHeapFarClass', t => {
   t.is(upCounter.incr(5), 8);
   t.is(upCounter.incr(1), 9);
   t.throws(() => upCounter.incr(-3), {
-    message:
-      'In "incr" method of (UpCounter): optional args: [0]: -3 - Must be >= 0',
+    message: 'In "incr" method of (UpCounter) arg 0: -3 - Must be >= 0',
   });
   // @ts-expect-error bad arg
   t.throws(() => upCounter.incr('foo'), {
     message:
-      'In "incr" method of (UpCounter): optional args: [0]: string "foo" - Must be a number',
+      'In "incr" method of (UpCounter) arg 0: string "foo" - Must be a number',
   });
 });
 
@@ -76,13 +75,12 @@ test('test defineHeapFarClassKit', t => {
   t.is(downCounter.decr(), 7);
   t.is(upCounter.incr(3), 10);
   t.throws(() => upCounter.incr(-3), {
-    message:
-      'In "incr" method of (Counter up): optional args: [0]: -3 - Must be >= 0',
+    message: 'In "incr" method of (Counter up) arg 0: -3 - Must be >= 0',
   });
   // @ts-expect-error the type violation is what we're testing
   t.throws(() => downCounter.decr('foo'), {
     message:
-      'In "decr" method of (Counter down): optional args: [0]: string "foo" - Must be a number',
+      'In "decr" method of (Counter down) arg 0: string "foo" - Must be a number',
   });
   // @ts-expect-error bad arg
   t.throws(() => upCounter.decr(3), {
@@ -101,12 +99,11 @@ test('test makeHeapFarInstance', t => {
   t.is(upCounter.incr(5), 8);
   t.is(upCounter.incr(1), 9);
   t.throws(() => upCounter.incr(-3), {
-    message:
-      'In "incr" method of (upCounter): optional args: [0]: -3 - Must be >= 0',
+    message: 'In "incr" method of (upCounter) arg 0: -3 - Must be >= 0',
   });
   t.throws(() => upCounter.incr('foo'), {
     message:
-      'In "incr" method of (upCounter): optional args: [0]: string "foo" - Must be a number',
+      'In "incr" method of (upCounter) arg 0: string "foo" - Must be a number',
   });
 });
 
diff --git a/packages/store/test/test-patterns.js b/packages/store/test/test-patterns.js
index 0d55f28ec734..5b81bea0b00e 100644
--- a/packages/store/test/test-patterns.js
+++ b/packages/store/test/test-patterns.js
@@ -82,13 +82,13 @@ const runTests = (successCase, failCase) => {
     failCase(
       specimen,
       M.split([3, 4, 5, 6]),
-      'args: [3,4] - Must be: [3,4,5,6]',
+      'required-parts: [3,4] - Must be: [3,4,5,6]',
     );
-    failCase(specimen, M.split([5]), 'args: [3] - Must be: [5]');
+    failCase(specimen, M.split([5]), 'required-parts: [3] - Must be: [5]');
     failCase(specimen, M.split({}), 'copyArray [3,4] - Must be a copyRecord');
-    failCase(specimen, M.split([3], 'x'), 'rest args: [4] - Must be: "x"');
+    failCase(specimen, M.split([3], 'x'), 'rest-parts: [4] - Must be: "x"');
 
-    failCase(specimen, M.partial([5]), 'optional args: [0]: 3 - Must be: 5');
+    failCase(specimen, M.partial([5]), 'optional-parts: [3] - Must be: [5]');
 
     failCase(
       specimen,
@@ -194,19 +194,13 @@ const runTests = (successCase, failCase) => {
       '{"foo":3,"bar":4} - Must be >= {"baz":3}',
     );
 
-    failCase(
-      specimen,
-      M.splitRecord({ foo: M.number() }, { bar: M.string(), baz: M.number() }),
-      'optional: bar: number 4 - Must be a string',
-    );
-
     failCase(
       specimen,
       M.split(
         { foo: M.number() },
         M.and(M.partial({ bar: M.string() }), M.partial({ baz: M.number() })),
       ),
-      'rest: optional: bar: number 4 - Must be a string',
+      'rest-parts: optional-parts: bar: number 4 - Must be a string',
     );
 
     failCase(
@@ -217,22 +211,22 @@ const runTests = (successCase, failCase) => {
     failCase(
       specimen,
       M.split({ foo: 3, z: 4 }),
-      '{"foo":3} - Must be: {"foo":3,"z":4}',
+      'required-parts: {"foo":3} - Must be: {"foo":3,"z":4}',
     );
     failCase(
       specimen,
       M.split({ foo: 3 }, { foo: 3, bar: 4 }),
-      'rest: {"bar":4} - Must be: {"foo":3,"bar":4}',
+      'rest-parts: {"bar":4} - Must be: {"foo":3,"bar":4}',
     );
     failCase(
       specimen,
       M.split({ foo: 3 }, { foo: M.any(), bar: 4 }),
-      'rest: {"bar":4} - Must have missing properties ["foo"]',
+      'rest-parts: {"bar":4} - Must have missing properties ["foo"]',
     );
     failCase(
       specimen,
       M.partial({ foo: 7, zip: 5 }, { bar: 4 }),
-      'optional: foo: 3 - Must be: 7',
+      'optional-parts: {"foo":3} - Must be: {"foo":7}',
     );
 
     failCase(
diff --git a/packages/vat-data/test/test-durable-classes.js b/packages/vat-data/test/test-durable-classes.js
index 0509ade09da9..f54b68028106 100644
--- a/packages/vat-data/test/test-durable-classes.js
+++ b/packages/vat-data/test/test-durable-classes.js
@@ -42,12 +42,13 @@ test('test defineDurableFarClass', t => {
   t.is(upCounter.incr(5), 8);
   t.is(upCounter.incr(1), 9);
   t.throws(() => upCounter.incr(-3), {
-    message: 'In "incr" method of (UpCounter) arg 0: -3 - Must be >= 0',
+    message:
+      'In "incr" method of (UpCounter): optional args: [0]: -3 - Must be >= 0',
   });
   // @ts-expect-error the type violation is what we're testing
   t.throws(() => upCounter.incr('foo'), {
     message:
-      'In "incr" method of (UpCounter) arg 0: string "foo" - Must be a number',
+      'In "incr" method of (UpCounter): optional args: [0]: string "foo" - Must be a number',
   });
 });
 
@@ -80,12 +81,13 @@ test('test defineDurableFarClassKit', t => {
   t.is(downCounter.decr(), 7);
   t.is(upCounter.incr(3), 10);
   t.throws(() => upCounter.incr(-3), {
-    message: 'In "incr" method of (Counter up) arg 0: -3 - Must be >= 0',
+    message:
+      'In "incr" method of (Counter up): optional args: [0]: -3 - Must be >= 0',
   });
   // @ts-expect-error the type violation is what we're testing
   t.throws(() => downCounter.decr('foo'), {
     message:
-      'In "decr" method of (Counter down) arg 0: string "foo" - Must be a number',
+      'In "decr" method of (Counter down): optional args: [0]: string "foo" - Must be a number',
   });
   // @ts-expect-error the type violation is what we're testing
   t.throws(() => upCounter.decr(3), {
diff --git a/packages/vat-data/test/test-virtual-classes.js b/packages/vat-data/test/test-virtual-classes.js
index d4015cc126f1..62fa770a6b41 100644
--- a/packages/vat-data/test/test-virtual-classes.js
+++ b/packages/vat-data/test/test-virtual-classes.js
@@ -39,12 +39,13 @@ test('test defineVirtualFarClass', t => {
   t.is(upCounter.incr(5), 8);
   t.is(upCounter.incr(1), 9);
   t.throws(() => upCounter.incr(-3), {
-    message: 'In "incr" method of (UpCounter) arg 0: -3 - Must be >= 0',
+    message:
+      'In "incr" method of (UpCounter): optional args: [0]: -3 - Must be >= 0',
   });
   // @ts-expect-error the type violation is what we're testing
   t.throws(() => upCounter.incr('foo'), {
     message:
-      'In "incr" method of (UpCounter) arg 0: string "foo" - Must be a number',
+      'In "incr" method of (UpCounter): optional args: [0]: string "foo" - Must be a number',
   });
 });
 
@@ -75,12 +76,13 @@ test('test defineVirtualFarClassKit', t => {
   t.is(downCounter.decr(), 7);
   t.is(upCounter.incr(3), 10);
   t.throws(() => upCounter.incr(-3), {
-    message: 'In "incr" method of (Counter up) arg 0: -3 - Must be >= 0',
+    message:
+      'In "incr" method of (Counter up): optional args: [0]: -3 - Must be >= 0',
   });
   // @ts-expect-error the type violation is what we're testing
   t.throws(() => downCounter.decr('foo'), {
     message:
-      'In "decr" method of (Counter down) arg 0: string "foo" - Must be a number',
+      'In "decr" method of (Counter down): optional args: [0]: string "foo" - Must be a number',
   });
   // @ts-expect-error the type violation is what we're testing
   t.throws(() => upCounter.decr(3), {
diff --git a/packages/vat-data/test/test-vivify.js b/packages/vat-data/test/test-vivify.js
index 8b8090eb860f..2e1fd41591b4 100644
--- a/packages/vat-data/test/test-vivify.js
+++ b/packages/vat-data/test/test-vivify.js
@@ -43,12 +43,13 @@ test('test vivifyFarClass', t => {
   t.is(upCounter.incr(5), 8);
   t.is(upCounter.incr(1), 9);
   t.throws(() => upCounter.incr(-3), {
-    message: 'In "incr" method of (UpCounter) arg 0: -3 - Must be >= 0',
+    message:
+      'In "incr" method of (UpCounter): optional args: [0]: -3 - Must be >= 0',
   });
   // @ts-expect-error the type violation is what we're testing
   t.throws(() => upCounter.incr('foo'), {
     message:
-      'In "incr" method of (UpCounter) arg 0: string "foo" - Must be a number',
+      'In "incr" method of (UpCounter): optional args: [0]: string "foo" - Must be a number',
   });
 });
 
@@ -82,12 +83,13 @@ test('test vivifyFarClassKit', t => {
   t.is(downCounter.decr(), 7);
   t.is(upCounter.incr(3), 10);
   t.throws(() => upCounter.incr(-3), {
-    message: 'In "incr" method of (Counter up) arg 0: -3 - Must be >= 0',
+    message:
+      'In "incr" method of (Counter up): optional args: [0]: -3 - Must be >= 0',
   });
   // @ts-expect-error the type violation is what we're testing
   t.throws(() => downCounter.decr('foo'), {
     message:
-      'In "decr" method of (Counter down) arg 0: string "foo" - Must be a number',
+      'In "decr" method of (Counter down): optional args: [0]: string "foo" - Must be a number',
   });
   // @ts-expect-error the type violation is what we're testing
   t.throws(() => upCounter.decr(3), {
@@ -108,11 +110,12 @@ test('test vivifyFarInstance', t => {
   t.is(upCounter.incr(5), 8);
   t.is(upCounter.incr(1), 9);
   t.throws(() => upCounter.incr(-3), {
-    message: 'In "incr" method of (upCounter) arg 0: -3 - Must be >= 0',
+    message:
+      'In "incr" method of (upCounter): optional args: [0]: -3 - Must be >= 0',
   });
   t.throws(() => upCounter.incr('foo'), {
     message:
-      'In "incr" method of (upCounter) arg 0: string "foo" - Must be a number',
+      'In "incr" method of (upCounter): optional args: [0]: string "foo" - Must be a number',
   });
 });
 
diff --git a/packages/zoe/test/unitTests/test-cleanProposal.js b/packages/zoe/test/unitTests/test-cleanProposal.js
index 9579034c7710..fd55473b2b48 100644
--- a/packages/zoe/test/unitTests/test-cleanProposal.js
+++ b/packages/zoe/test/unitTests/test-cleanProposal.js
@@ -226,7 +226,7 @@ test('cleanProposal - other wrong stuff', t => {
     t,
     { exit: { onDemand: 'foo' } },
     'nat',
-    'proposal: exit: optional-parts: {"onDemand":"foo"} - Must be: {"onDemand":null}',
+    'proposal: exit: optional: onDemand: "foo" - Must be: null',
   );
   proposeBad(
     t,
@@ -238,43 +238,43 @@ test('cleanProposal - other wrong stuff', t => {
     t,
     { exit: { afterDeadline: { timer: 'foo', deadline: 3n } } },
     'nat',
-    'proposal: exit: optional-parts: afterDeadline: timer: "foo" - Must match one of ["[match:remotable]","[match:kind]"]',
+    'proposal: exit: optional: afterDeadline: timer: "foo" - Must match one of ["[match:remotable]","[match:kind]"]',
   );
   proposeBad(
     t,
     { exit: { afterDeadline: { timer, deadline: 'foo' } } },
     'nat',
-    'proposal: exit: optional-parts: afterDeadline: deadline: string "foo" - Must be a bigint',
+    'proposal: exit: optional: afterDeadline: deadline: string "foo" - Must be a bigint',
   );
   proposeBad(
     t,
     { exit: { afterDeadline: { timer, deadline: 3n, extra: 'foo' } } },
     'nat',
-    'proposal: exit: optional-parts: afterDeadline: {"timer":"[Alleged: ManualTimer]","deadline":"[3n]","extra":"foo"} - Must not have unexpected properties: ["extra"]',
+    'proposal: exit: optional: afterDeadline: {"timer":"[Alleged: ManualTimer]","deadline":"[3n]","extra":"foo"} - Must not have unexpected properties: ["extra"]',
   );
   proposeBad(
     t,
     { exit: { afterDeadline: { timer } } },
     'nat',
-    'proposal: exit: optional-parts: afterDeadline: {"timer":"[Alleged: ManualTimer]"} - Must have missing properties ["deadline"]',
+    'proposal: exit: optional: afterDeadline: {"timer":"[Alleged: ManualTimer]"} - Must have missing properties ["deadline"]',
   );
   proposeBad(
     t,
     { exit: { afterDeadline: { deadline: 3n } } },
     'nat',
-    'proposal: exit: optional-parts: afterDeadline: {"deadline":"[3n]"} - Must have missing properties ["timer"]',
+    'proposal: exit: optional: afterDeadline: {"deadline":"[3n]"} - Must have missing properties ["timer"]',
   );
   proposeBad(
     t,
     { exit: { afterDeadline: { timer, deadline: 3 } } },
     'nat',
-    'proposal: exit: optional-parts: afterDeadline: deadline: number 3 - Must be a bigint',
+    'proposal: exit: optional: afterDeadline: deadline: number 3 - Must be a bigint',
   );
   proposeBad(
     t,
     { exit: { afterDeadline: { timer, deadline: -3n } } },
     'nat',
-    'proposal: exit: optional-parts: afterDeadline: deadline: "[-3n]" - Must be non-negative',
+    'proposal: exit: optional: afterDeadline: deadline: "[-3n]" - Must be non-negative',
   );
   proposeBad(t, { exit: {} }, 'nat', /exit {} should only have one key/);
   proposeBad(
diff --git a/packages/zoe/test/unitTests/zcf/test-zoeHelpersWZcf.js b/packages/zoe/test/unitTests/zcf/test-zoeHelpersWZcf.js
index 2b19381fd5ef..b5321ea63721 100644
--- a/packages/zoe/test/unitTests/zcf/test-zoeHelpersWZcf.js
+++ b/packages/zoe/test/unitTests/zcf/test-zoeHelpersWZcf.js
@@ -304,7 +304,7 @@ test(`zoeHelper with zcf - fit proposal patterns`, async t => {
     () => fit(proposal, M.split({ want: { C: M.any() } })),
     {
       message:
-        'required-parts: want: {"A":{"brand":"[Alleged: moola brand]","value":"[20n]"}} - Must have missing properties ["C"]',
+        'want: {"A":{"brand":"[Alleged: moola brand]","value":"[20n]"}} - Must have missing properties ["C"]',
     },
     'empty keywordRecord does not match',
   );
@@ -314,14 +314,14 @@ test(`zoeHelper with zcf - fit proposal patterns`, async t => {
     () => fit(proposal, M.split({ give: { c: M.any() } })),
     {
       message:
-        'required-parts: give: {"B":{"brand":"[Alleged: simoleans brand]","value":"[3n]"}} - Must have missing properties ["c"]',
+        'give: {"B":{"brand":"[Alleged: simoleans brand]","value":"[3n]"}} - Must have missing properties ["c"]',
     },
     'wrong key in keywordRecord does not match',
   );
   t.throws(
     () => fit(proposal, M.split({ exit: { onDemaind: M.any() } })),
     {
-      message: 'required-parts: {} - Must have missing properties ["exit"]',
+      message: '{} - Must have missing properties ["exit"]',
     },
     'missing exit rule',
   );