diff --git a/client/alloc_endpoint.go b/client/alloc_endpoint.go
index f24326b95..6b1e4eec0 100644
--- a/client/alloc_endpoint.go
+++ b/client/alloc_endpoint.go
@@ -1,7 +1,6 @@
 package client
 
 import (
-	"fmt"
 	"time"
 
 	metrics "github.com/armon/go-metrics"
@@ -19,7 +18,7 @@ type Allocations struct {
 func (a *Allocations) GarbageCollectAll(args *nstructs.NodeSpecificRequest, reply *nstructs.GenericResponse) error {
 	defer metrics.MeasureSince([]string{"client", "allocations", "garbage_collect_all"}, time.Now())
 
-	// Check node read permissions
+	// Check node write permissions
 	if aclObj, err := a.c.ResolveToken(args.AuthToken); err != nil {
 		return err
 	} else if aclObj != nil && !aclObj.AllowNodeWrite() {
@@ -34,7 +33,7 @@ func (a *Allocations) GarbageCollectAll(args *nstructs.NodeSpecificRequest, repl
 func (a *Allocations) GarbageCollect(args *nstructs.AllocSpecificRequest, reply *nstructs.GenericResponse) error {
 	defer metrics.MeasureSince([]string{"client", "allocations", "garbage_collect"}, time.Now())
 
-	// Check node read permissions
+	// Check submit job permissions
 	if aclObj, err := a.c.ResolveToken(args.AuthToken); err != nil {
 		return err
 	} else if aclObj != nil && !aclObj.AllowNsOp(args.Namespace, acl.NamespaceCapabilitySubmitJob) {
@@ -43,7 +42,7 @@ func (a *Allocations) GarbageCollect(args *nstructs.AllocSpecificRequest, reply
 
 	if !a.c.CollectAllocation(args.AllocID) {
 		// Could not find alloc
-		return fmt.Errorf("unknown allocation %q", args.AllocID)
+		return nstructs.NewErrUnknownAllocation(args.AllocID)
 	}
 
 	return nil
@@ -53,7 +52,7 @@ func (a *Allocations) GarbageCollect(args *nstructs.AllocSpecificRequest, reply
 func (a *Allocations) Stats(args *cstructs.AllocStatsRequest, reply *cstructs.AllocStatsResponse) error {
 	defer metrics.MeasureSince([]string{"client", "allocations", "stats"}, time.Now())
 
-	// Check node read permissions
+	// Check read job permissions
 	if aclObj, err := a.c.ResolveToken(args.AuthToken); err != nil {
 		return err
 	} else if aclObj != nil && !aclObj.AllowNsOp(args.Namespace, acl.NamespaceCapabilityReadJob) {
diff --git a/client/alloc_endpoint_test.go b/client/alloc_endpoint_test.go
index 6b57da70b..bccff0c77 100644
--- a/client/alloc_endpoint_test.go
+++ b/client/alloc_endpoint_test.go
@@ -149,7 +149,7 @@ func TestAllocations_GarbageCollect_ACL(t *testing.T) {
 
 		var resp nstructs.GenericResponse
 		err := client.ClientRPC("Allocations.GarbageCollect", &req, &resp)
-		require.Contains(err.Error(), "unknown allocation")
+		require.True(nstructs.IsErrUnknownAllocation(err))
 	}
 
 	// Try request with a management token
@@ -159,7 +159,7 @@ func TestAllocations_GarbageCollect_ACL(t *testing.T) {
 
 		var resp nstructs.GenericResponse
 		err := client.ClientRPC("Allocations.GarbageCollect", &req, &resp)
-		require.Contains(err.Error(), "unknown allocation")
+		require.True(nstructs.IsErrUnknownAllocation(err))
 	}
 }
 
@@ -239,7 +239,7 @@ func TestAllocations_Stats_ACL(t *testing.T) {
 
 		var resp cstructs.AllocStatsResponse
 		err := client.ClientRPC("Allocations.Stats", &req, &resp)
-		require.Contains(err.Error(), "unknown allocation")
+		require.True(nstructs.IsErrUnknownAllocation(err))
 	}
 
 	// Try request with a management token
@@ -249,6 +249,6 @@ func TestAllocations_Stats_ACL(t *testing.T) {
 
 		var resp cstructs.AllocStatsResponse
 		err := client.ClientRPC("Allocations.Stats", &req, &resp)
-		require.Contains(err.Error(), "unknown allocation")
+		require.True(nstructs.IsErrUnknownAllocation(err))
 	}
 }
diff --git a/command/agent/alloc_endpoint.go b/command/agent/alloc_endpoint.go
index aa07d8910..422f8906c 100644
--- a/command/agent/alloc_endpoint.go
+++ b/command/agent/alloc_endpoint.go
@@ -164,7 +164,7 @@ func (s *HTTPServer) allocGC(allocID string, resp http.ResponseWriter, req *http
 	}
 
 	if rpcErr != nil {
-		if structs.IsErrNoNodeConn(rpcErr) || strings.Contains(rpcErr.Error(), "unknown allocation") {
+		if structs.IsErrNoNodeConn(rpcErr) || structs.IsErrUnknownAllocation(rpcErr) {
 			rpcErr = CodedError(404, rpcErr.Error())
 		}
 	}
@@ -216,7 +216,7 @@ func (s *HTTPServer) allocStats(allocID string, resp http.ResponseWriter, req *h
 	}
 
 	if rpcErr != nil {
-		if structs.IsErrNoNodeConn(rpcErr) || strings.Contains(rpcErr.Error(), "unknown allocation") {
+		if structs.IsErrNoNodeConn(rpcErr) || structs.IsErrUnknownAllocation(rpcErr) {
 			rpcErr = CodedError(404, rpcErr.Error())
 		}
 	}
diff --git a/command/agent/alloc_endpoint_test.go b/command/agent/alloc_endpoint_test.go
index f9db9a872..e005753ba 100644
--- a/command/agent/alloc_endpoint_test.go
+++ b/command/agent/alloc_endpoint_test.go
@@ -277,7 +277,7 @@ func TestHTTP_AllocStats(t *testing.T) {
 			// Make the request
 			_, err = s.Server.ClientAllocRequest(respW, req)
 			require.NotNil(err)
-			require.Contains(err.Error(), "unknown allocation")
+			require.True(structs.IsErrUnknownAllocation(err))
 		}
 
 		// Local node, server resp
@@ -291,7 +291,7 @@ func TestHTTP_AllocStats(t *testing.T) {
 			respW := httptest.NewRecorder()
 			_, err = s.Server.ClientAllocRequest(respW, req)
 			require.NotNil(err)
-			require.Contains(err.Error(), "unknown allocation")
+			require.True(structs.IsErrUnknownAllocation(err))
 
 			s.server = srv
 		}
@@ -317,7 +317,7 @@ func TestHTTP_AllocStats(t *testing.T) {
 			respW := httptest.NewRecorder()
 			_, err = s.Server.ClientAllocRequest(respW, req)
 			require.NotNil(err)
-			require.Contains(err.Error(), "unknown allocation")
+			require.True(structs.IsErrUnknownAllocation(err))
 
 			s.client = c
 		}
@@ -551,7 +551,7 @@ func TestHTTP_AllocGC(t *testing.T) {
 
 			respW := httptest.NewRecorder()
 			_, err = s.Server.ClientAllocRequest(respW, req)
-			if err == nil || !strings.Contains(err.Error(), "unknown allocation") {
+			if !structs.IsErrUnknownAllocation(err) {
 				t.Fatalf("unexpected err: %v", err)
 			}
 		}
@@ -568,7 +568,7 @@ func TestHTTP_AllocGC(t *testing.T) {
 
 			respW := httptest.NewRecorder()
 			_, err = s.Server.ClientAllocRequest(respW, req)
-			if err == nil || !strings.Contains(err.Error(), "unknown allocation") {
+			if !structs.IsErrUnknownAllocation(err) {
 				t.Fatalf("unexpected err: %v", err)
 			}
 
@@ -598,7 +598,7 @@ func TestHTTP_AllocGC(t *testing.T) {
 			respW := httptest.NewRecorder()
 			_, err = s.Server.ClientAllocRequest(respW, req)
 			require.NotNil(err)
-			if err == nil || !strings.Contains(err.Error(), "unknown allocation") {
+			if !structs.IsErrUnknownAllocation(err) {
 				t.Fatalf("unexpected err: %v", err)
 			}
 
diff --git a/nomad/client_alloc_endpoint.go b/nomad/client_alloc_endpoint.go
index e174811df..bb28d2d39 100644
--- a/nomad/client_alloc_endpoint.go
+++ b/nomad/client_alloc_endpoint.go
@@ -2,7 +2,6 @@ package nomad
 
 import (
 	"errors"
-	"fmt"
 	"time"
 
 	metrics "github.com/armon/go-metrics"
@@ -95,7 +94,7 @@ func (a *ClientAllocations) GarbageCollect(args *structs.AllocSpecificRequest, r
 	}
 
 	if alloc == nil {
-		return fmt.Errorf("unknown allocation %q", args.AllocID)
+		return structs.NewErrUnknownAllocation(args.AllocID)
 	}
 
 	// Get the connection to the client
@@ -145,7 +144,7 @@ func (a *ClientAllocations) Stats(args *cstructs.AllocStatsRequest, reply *cstru
 	}
 
 	if alloc == nil {
-		return fmt.Errorf("unknown allocation %q", args.AllocID)
+		return structs.NewErrUnknownAllocation(args.AllocID)
 	}
 
 	// Get the connection to the client
diff --git a/nomad/client_alloc_endpoint_test.go b/nomad/client_alloc_endpoint_test.go
index 4f18942c5..1886aab1c 100644
--- a/nomad/client_alloc_endpoint_test.go
+++ b/nomad/client_alloc_endpoint_test.go
@@ -295,12 +295,12 @@ func TestClientAllocations_GarbageCollect_Local_ACL(t *testing.T) {
 		{
 			Name:          "good token",
 			Token:         tokenGood.SecretID,
-			ExpectedError: "unknown allocation",
+			ExpectedError: structs.ErrUnknownAllocationPrefix,
 		},
 		{
 			Name:          "root token",
 			Token:         root.SecretID,
-			ExpectedError: "unknown allocation",
+			ExpectedError: structs.ErrUnknownAllocationPrefix,
 		},
 	}
 
@@ -526,12 +526,12 @@ func TestClientAllocations_Stats_Local_ACL(t *testing.T) {
 		{
 			Name:          "good token",
 			Token:         tokenGood.SecretID,
-			ExpectedError: "unknown allocation",
+			ExpectedError: structs.ErrUnknownAllocationPrefix,
 		},
 		{
 			Name:          "root token",
 			Token:         root.SecretID,
-			ExpectedError: "unknown allocation",
+			ExpectedError: structs.ErrUnknownAllocationPrefix,
 		},
 	}