diff --git a/tools/src/cts/expectations/update.go b/tools/src/cts/expectations/update.go
index 0d24fda..43fe72f 100644
--- a/tools/src/cts/expectations/update.go
+++ b/tools/src/cts/expectations/update.go
@@ -207,9 +207,13 @@
 	// expectation.
 	consumed result.Status = "<<consumed>>"
 	// Chunk comment for new flakes
-	newFlakesComment = "# New flakes. Please triage:"
+	newFlakesComment = "# New flakes. Please triage - will be discarded/regenerated by the next roll:"
 	// Chunk comment for new failures
-	newFailuresComment = "# New failures. Please triage:"
+	newFailuresComment = "# New failures. Please triage - will be discarded/regenerated by the next roll:"
+	// Chunk comment for expectations the roller is allowed to mutate
+	ROLLER_MUTABLE = "# ##ROLLER_MUTABLE##"
+	// Chunk comment for expectations the roller should discard and rewrite
+	ROLLER_DISCARD_AND_REWRITE = "# ##ROLLER_DISCARD_AND_REWRITE##"
 )
 
 // resultQueryTree holds tree of queries to all results (no filtering by tag or
@@ -354,13 +358,11 @@
 func (u *updater) build() error {
 	progress := Progress{}
 
-	// All chunks other than the ones for untriaged flakes/failures produced by
-	// the CTS roller are considered immutable unless they are explicitly
-	// declared as mutable.
+	// Chunks are considered immutable by default, unless annotated as
+	// ROLLER_MUTABLE or ROLLER_DISCARD_AND_REWRITE.
 	mutableTokens := []string{
-		newFlakesComment,
-		newFailuresComment,
-		"MUTABLE",
+		ROLLER_MUTABLE,
+		ROLLER_DISCARD_AND_REWRITE,
 	}
 
 	// Bin the chunks into those that contain any of the strings in
@@ -428,11 +430,10 @@
 		return in // Just a comment / blank line
 	}
 
-	// Skip over any untriaged failures / flake chunks.
+	// Skip over ROLLER_DISCARD_AND_REWRITE chunks (untriaged failures/flakes).
 	// We'll just rebuild them at the end.
 	for _, line := range in.Comments {
-		if strings.HasPrefix(line, newFailuresComment) ||
-			strings.HasPrefix(line, newFlakesComment) {
+		if strings.HasPrefix(line, ROLLER_DISCARD_AND_REWRITE) {
 			return Chunk{}
 		}
 	}
@@ -611,6 +612,7 @@
 				Comments: []string{
 					"################################################################################",
 					group.comment,
+					ROLLER_DISCARD_AND_REWRITE,
 					"################################################################################",
 				},
 				Expectations: group.results,
diff --git a/tools/src/cts/expectations/update_test.go b/tools/src/cts/expectations/update_test.go
index c138c3a..aba4925 100644
--- a/tools/src/cts/expectations/update_test.go
+++ b/tools/src/cts/expectations/update_test.go
@@ -67,7 +67,7 @@
 		{ //////////////////////////////////////////////////////////////////////
 			name: "no results found",
 			expectations: `
-# MUTABLE
+# ##ROLLER_MUTABLE##
 crbug.com/a/123 a:missing,test,result:* [ Failure ]
 crbug.com/a/123 [ tag ] another:missing,test,result:* [ Failure ]
 some:other,test:* [ Failure ]
@@ -85,7 +85,7 @@
 				},
 			},
 			updated: `
-# MUTABLE
+# ##ROLLER_MUTABLE##
 some:other,test:* [ Failure ]
 crbug.com/a/123 a:missing,test,result:* [ Failure ]
 crbug.com/a/123 [ tag ] another:missing,test,result:* [ Failure ]
@@ -138,7 +138,7 @@
 		{ //////////////////////////////////////////////////////////////////////
 			name: "unknown test",
 			expectations: `
-# MUTABLE
+# ##ROLLER_MUTABLE##
 crbug.com/a/123 an:unknown,test:* [ Failure ]
 crbug.com/a/123 [ tag ] another:unknown:test [ Failure ]
 
@@ -205,7 +205,7 @@
 		{ //////////////////////////////////////////////////////////////////////
 			name: "simple expectation with tags",
 			expectations: `
-# MUTABLE
+# ##ROLLER_MUTABLE##
 [ os-a ] a:b,c:* [ Failure ]
 [ gpu-b ] a:b,c:* [ Failure ]
 `,
@@ -217,7 +217,7 @@
 				},
 			},
 			updated: `
-# MUTABLE
+# ##ROLLER_MUTABLE##
 a:b,c:* [ Failure ]
 `,
 			diagnostics: expectations.Diagnostics{
@@ -232,7 +232,8 @@
 			name: "simple expectation with tags new flakes implicitly mutable",
 			expectations: `
 ################################################################################
-# New flakes. Please triage:
+# New flakes. Please triage - will be discarded/regenerated by the next roll:
+# ##ROLLER_DISCARD_AND_REWRITE##
 ################################################################################
 [ os-a ] a:b,c:* [ RetryOnFailure ]
 [ gpu-b ] a:b,c:* [ RetryOnFailure ]
@@ -246,7 +247,8 @@
 			},
 			updated: `
 ################################################################################
-# New flakes. Please triage:
+# New flakes. Please triage - will be discarded/regenerated by the next roll:
+# ##ROLLER_DISCARD_AND_REWRITE##
 ################################################################################
 crbug.com/dawn/0000 a:* [ RetryOnFailure ]
 `,
@@ -255,7 +257,8 @@
 			name: "simple expectation with tags new failures implicitly mutable",
 			expectations: `
 ################################################################################
-# New failures. Please triage:
+# New failures. Please triage - will be discarded/regenerated by the next roll:
+# ##ROLLER_DISCARD_AND_REWRITE##
 ################################################################################
 [ os-a ] a:b,c:* [ Failure ]
 [ gpu-b ] a:b,c:* [ Failure ]
@@ -269,7 +272,8 @@
 			},
 			updated: `
 ################################################################################
-# New failures. Please triage:
+# New failures. Please triage - will be discarded/regenerated by the next roll:
+# ##ROLLER_DISCARD_AND_REWRITE##
 ################################################################################
 crbug.com/dawn/0000 a:* [ Failure ]
 `,
@@ -295,7 +299,7 @@
 		{ //////////////////////////////////////////////////////////////////////
 			name: "expectation test now passes",
 			expectations: `
-# MUTABLE
+# ##ROLLER_MUTABLE##
 crbug.com/a/123 [ gpu-a os-a ] a:b,c:* [ Failure ]
 crbug.com/a/123 [ gpu-b os-b ] a:b,c:* [ Failure ]
 `,
@@ -312,7 +316,7 @@
 				},
 			},
 			updated: `
-# MUTABLE
+# ##ROLLER_MUTABLE##
 crbug.com/a/123 [ os-b ] a:b,c:* [ Failure ]
 `,
 			diagnostics: expectations.Diagnostics{
@@ -326,7 +330,7 @@
 		{ //////////////////////////////////////////////////////////////////////
 			name: "expectation case now passes",
 			expectations: `
-# MUTABLE
+# ##ROLLER_MUTABLE##
 crbug.com/a/123 [ gpu-a os-a ] a:b,c:d:* [ Failure ]
 crbug.com/a/123 [ gpu-b os-b ] a:b,c:d:* [ Failure ]
 `,
@@ -343,7 +347,7 @@
 				},
 			},
 			updated: `
-# MUTABLE
+# ##ROLLER_MUTABLE##
 crbug.com/a/123 [ os-b ] a:b,c:d:* [ Failure ]
 `,
 			diagnostics: expectations.Diagnostics{
@@ -502,13 +506,15 @@
 			updated: `# A comment
 
 ################################################################################
-# New flakes. Please triage:
+# New flakes. Please triage - will be discarded/regenerated by the next roll:
+# ##ROLLER_DISCARD_AND_REWRITE##
 ################################################################################
 crbug.com/dawn/0000 [ gpu-a os-a ] suite:dir_a,dir_b:test_c:case=6;* [ RetryOnFailure ]
 crbug.com/dawn/0000 [ gpu-b os-b ] suite:dir_a,dir_b:test_c:case=5;* [ RetryOnFailure ]
 
 ################################################################################
-# New failures. Please triage:
+# New failures. Please triage - will be discarded/regenerated by the next roll:
+# ##ROLLER_DISCARD_AND_REWRITE##
 ################################################################################
 crbug.com/dawn/0000 [ gpu-a os-a ] suite:dir_a,dir_b:test_a:* [ Failure ]
 crbug.com/dawn/0000 [ gpu-a os-a ] suite:dir_a,dir_b:test_b:* [ Slow ]
@@ -558,7 +564,8 @@
 			updated: `# A comment
 
 ################################################################################
-# New failures. Please triage:
+# New failures. Please triage - will be discarded/regenerated by the next roll:
+# ##ROLLER_DISCARD_AND_REWRITE##
 ################################################################################
 crbug.com/dawn/0000 [ os-a ] a:b,c:d:* [ Failure ]
 crbug.com/dawn/0000 [ os-b ] a:b,c:d:x,* [ Failure ]
@@ -596,7 +603,8 @@
 			},
 			updated: `
 ################################################################################
-# New failures. Please triage:
+# New failures. Please triage - will be discarded/regenerated by the next roll:
+# ##ROLLER_DISCARD_AND_REWRITE##
 ################################################################################
 crbug.com/dawn/0000 [ gpu-a ] a:* [ Failure ]
 crbug.com/dawn/0000 [ gpu-b ] a:* [ Failure ]
@@ -626,7 +634,8 @@
 			},
 			updated: `
 ################################################################################
-# New failures. Please triage:
+# New failures. Please triage - will be discarded/regenerated by the next roll:
+# ##ROLLER_DISCARD_AND_REWRITE##
 ################################################################################
 crbug.com/dawn/0000 [ gpu-b os-c ] a:* [ Failure ]
 crbug.com/dawn/0000 [ gpu-c os-b ] a:* [ Failure ]
@@ -649,7 +658,8 @@
 			},
 			updated: `
 ################################################################################
-# New failures. Please triage:
+# New failures. Please triage - will be discarded/regenerated by the next roll:
+# ##ROLLER_DISCARD_AND_REWRITE##
 ################################################################################
 crbug.com/dawn/0000 a:* [ Failure ]
 `,
@@ -671,7 +681,8 @@
 			},
 			updated: `
 ################################################################################
-# New failures. Please triage:
+# New failures. Please triage - will be discarded/regenerated by the next roll:
+# ##ROLLER_DISCARD_AND_REWRITE##
 ################################################################################
 crbug.com/dawn/0000 a:b,c:0:* [ Failure ]
 crbug.com/dawn/0000 a:b,c:2:* [ Failure ]
@@ -717,7 +728,8 @@
 			},
 			updated: `
 ################################################################################
-# New failures. Please triage:
+# New failures. Please triage - will be discarded/regenerated by the next roll:
+# ##ROLLER_DISCARD_AND_REWRITE##
 ################################################################################
 crbug.com/dawn/0000 a:* [ Failure ]
 `,
@@ -759,7 +771,8 @@
 			},
 			updated: `
 ################################################################################
-# New failures. Please triage:
+# New failures. Please triage - will be discarded/regenerated by the next roll:
+# ##ROLLER_DISCARD_AND_REWRITE##
 ################################################################################
 crbug.com/dawn/0000 a:b,c:00:* [ Failure ]
 crbug.com/dawn/0000 a:b,c:05:* [ Failure ]
diff --git a/webgpu-cts/compat-expectations.txt b/webgpu-cts/compat-expectations.txt
index eaa7700..a17c322 100644
--- a/webgpu-cts/compat-expectations.txt
+++ b/webgpu-cts/compat-expectations.txt
@@ -485,7 +485,8 @@
 [ intel-0x9bc5 ] webgpu:api,operation,resource_init,texture_zero:uninitialized_texture_is_zero:dimension="3d";readMethod="CopyToTexture";format="rgba8snorm" [ Failure ]
 
 ################################################################################
-# New flakes. Please triage:
+# New flakes. Please triage - will be discarded/regenerated by the next roll:
+# ##ROLLER_DISCARD_AND_REWRITE##
 ################################################################################
 crbug.com/dawn/0000 [ intel-0x9bc5 ] webgpu:api,operation,resource_init,texture_zero:uninitialized_texture_is_zero:dimension="1d";readMethod="CopyToTexture";format="r8snorm" [ RetryOnFailure ]
 crbug.com/dawn/0000 [ intel-0x9bc5 ] webgpu:api,operation,resource_init,texture_zero:uninitialized_texture_is_zero:dimension="1d";readMethod="CopyToTexture";format="rgba8snorm" [ RetryOnFailure ]
@@ -499,7 +500,8 @@
 crbug.com/dawn/0000 [ nvidia-0x2184 ] webgpu:shader,execution,expression,call,builtin,cross:f32:inputSource="storage_rw" [ RetryOnFailure ]
 
 ################################################################################
-# New failures. Please triage:
+# New failures. Please triage - will be discarded/regenerated by the next roll:
+# ##ROLLER_DISCARD_AND_REWRITE##
 ################################################################################
 crbug.com/dawn/0000 webgpu:api,operation,adapter,requestDevice:always_returns_device:compatibilityMode=false [ Failure ]
 crbug.com/dawn/0000 webgpu:api,operation,uncapturederror:iff_uncaptured:errorType="out-of-memory" [ Failure ]
diff --git a/webgpu-cts/expectations.txt b/webgpu-cts/expectations.txt
index e23e91c..190f5d6 100644
--- a/webgpu-cts/expectations.txt
+++ b/webgpu-cts/expectations.txt
@@ -1935,7 +1935,8 @@
 crbug.com/dawn/0000 [ nvidia-0x2184 ] webgpu:shader,execution,expression,call,builtin,fwidthFine:f32:vectorize=4;non_uniform_discard=true [ Failure ]
 
 ################################################################################
-# New flakes. Please triage:
+# New flakes. Please triage - will be discarded/regenerated by the next roll:
+# ##ROLLER_DISCARD_AND_REWRITE##
 ################################################################################
 crbug.com/dawn/0000 [ amd-0x67ef dawn-backend-validation ] webgpu:shader,validation,expression,call,builtin,sin:values:stage="override";type="vec2%3Cf32%3E" [ RetryOnFailure ]
 crbug.com/dawn/0000 [ amd-0x67ef dawn-backend-validation mac webgpu-adapter-default webgpu-no-worker ] webgpu:api,operation,rendering,3d_texture_slices:multiple_color_attachments,same_mip_level:sameTexture=true [ RetryOnFailure ]
@@ -1979,7 +1980,8 @@
 crbug.com/dawn/0000 [ nvidia-0x2184 webgpu-adapter-default webgpu-dedicated-worker win10 ] webgpu:web_platform,copyToTexture,canvas:copy_contents_from_gpu_context_canvas:canvasType="offscreen";srcAndDstInSameGPUDevice=false;dstColorFormat="bgra8unorm-srgb";srcAlphaMode="premultiplied";dstAlphaMode="premultiplied";srcDoFlipYDuringCopy=false [ RetryOnFailure ]
 
 ################################################################################
-# New failures. Please triage:
+# New failures. Please triage - will be discarded/regenerated by the next roll:
+# ##ROLLER_DISCARD_AND_REWRITE##
 ################################################################################
 crbug.com/dawn/0000 webgpu:shader,validation,decl,var:address_space_access_mode:address_space="storage";access_mode="read";trailing_comma=true [ Failure ]
 crbug.com/dawn/0000 webgpu:shader,validation,decl,var:address_space_access_mode:address_space="storage";access_mode="read_write";trailing_comma=true [ Failure ]