diff --git a/pkg/server/admin/admin.go b/pkg/server/admin/admin.go
index db0c78a..3e552c6 100644
--- a/pkg/server/admin/admin.go
+++ b/pkg/server/admin/admin.go
@@ -96,7 +96,7 @@ func (admin *Admin) getFreeId(publicId models.RendezVousId) (models.RendezVousId
 	if admin.agents[publicId] == nil {
 		return publicId, nil
 	}
-	for i := 0; i < 100; i++ {
+	for i := range 100 {
 		candidate := models.RendezVousId(string(publicId) + "-" + strconv.Itoa(i))
 		if admin.agents[candidate] == nil {
 			return candidate, nil
@@ -130,6 +130,8 @@ func (admin *Admin) AddAgent(hostKey []byte, publicId models.RendezVousId, agent
 			Ok:      false,
 			Message: err.Error(),
 		})
+		return nil, fmt.Errorf(
+			"Agent requested id '%s' which is already taken anc could not allocate a new unique id", publicId)
 	}
 	agentCheck := admin.agents[publicId]
 	if agentCheck != nil {
diff --git a/pkg/server/admin/admin_test.go b/pkg/server/admin/admin_test.go
index 2035484..e2f3c38 100644
--- a/pkg/server/admin/admin_test.go
+++ b/pkg/server/admin/admin_test.go
@@ -10,6 +10,7 @@ import (
 	"github.com/stretchr/testify/suite"
 	"io"
 	"net/http"
+	"strings"
 	"testing"
 	"time"
 )
@@ -62,7 +63,7 @@ func (s *AdminTestSuite) SetupTest() {
 
 	s.admin = NewAdmin()
 	s.hostKey = make([]byte, 100)
-	rand.Read(s.hostKey)
+	s.NotNil(rand.Read(s.hostKey))
 }
 
 func (suite *AdminTestSuite) TearDownTest() {
@@ -72,21 +73,43 @@ func TestAdminTestSuite(t *testing.T) {
 	suite.Run(t, &AdminTestSuite{})
 }
 
-func (s *AdminTestSuite) agentRegisters(requestedPublicId, assignedPublicId string) *agentConnection {
+type AddAgentResult struct {
+	agentConn *agentConnection
+	err       error
+}
+
+type AgentRegisterResult struct {
+	registration comms.AgentRegistration
+	err          error
+}
+
+func (s *AdminTestSuite) agentRegisters(requestedPublicId, assignedPublicId string) (AddAgentResult, AgentRegisterResult) {
 	agentRW, serverRW := s.createPipe()
 	res := testsupport.RunAndWait(
 		&s.Suite,
 		func() any {
-			return s.addAgent(requestedPublicId, assignedPublicId, serverRW)
+			agentConn, err := s.addAgent(requestedPublicId, assignedPublicId, serverRW)
+			return AddAgentResult{
+				agentConn: agentConn,
+				err:       err,
+			}
 		},
 		func() any {
-			return s.agentRegistration(assignedPublicId, agentRW)
+			res := s.agentRegistration(assignedPublicId, agentRW)
+			if assignedPublicId != "" {
+				s.Nil(res.err)
+				s.True(res.registration.Ok)
+				s.Equal(s.hostKey, res.registration.HostPrivateKey)
+			}
+			return res
 		})
-	return res[0].(*agentConnection)
+	return res[0].(AddAgentResult), res[1].(AgentRegisterResult)
 }
 
 func (s *AdminTestSuite) Test_AgentRegisters() {
-	agentConn := s.agentRegisters("abc", "abc")
+	res, _ := s.agentRegisters("abc", "abc")
+	s.Nil(res.err)
+	agentConn := res.agentConn
 	state := s.admin.CreateNotifification()
 	s.Equal(1, len(state.Agents))
 	s.Equal(0, len(state.Clients))
@@ -99,7 +122,9 @@ func (s *AdminTestSuite) Test_ManyAgentsRegister() {
 	for i := range N {
 		publicId := fmt.Sprintf("abc%d", i)
 		agentRegistrations[i] = func() any {
-			return s.agentRegisters(publicId, publicId)
+			res, _ := s.agentRegisters(publicId, publicId)
+			s.Nil(res.err)
+			return res.agentConn
 		}
 	}
 	res := testsupport.RunAndWait(
@@ -115,30 +140,40 @@ func (s *AdminTestSuite) Test_ManyAgentsRegister() {
 }
 
 func (s *AdminTestSuite) Test_agentDuplicateId() {
-	s.agentRegisters("abc", "abc")
-	s.agentRegisters("abc", "abc-0")
+	res, _ := s.agentRegisters("abc", "abc")
+	s.Nil(res.err)
+	for i := range 100 {
+		res, _ = s.agentRegisters("abc", fmt.Sprintf("abc-%d", i))
+		s.Nil(res.err)
+	}
+	res, agentSideResult := s.agentRegisters("abc", "")
+	s.NotNil(res.err)
+	// verify it is the correct error an dnot an id mismatch.
+	s.True(strings.Contains(res.err.Error(), "could not allocate a new unique id"))
+	s.False(agentSideResult.registration.Ok)
 }
 
-func (s *AdminTestSuite) agentRegistration(expectedPublicId string, agentRW io.ReadWriteCloser) any {
+func (s *AdminTestSuite) agentRegistration(expectedPublicId string, agentRW io.ReadWriteCloser) AgentRegisterResult {
 	// verify registration message received
 	agentRegistration, err := comms.ReceiveRegistrationMessage(agentRW)
-	s.Nil(err)
-	s.True(agentRegistration.Ok)
-	s.Equal(expectedPublicId, agentRegistration.Id)
-	s.Equal(s.hostKey, agentRegistration.HostPrivateKey)
-
+	if err != nil {
+		return AgentRegisterResult{err: err}
+	}
 	commChannel, err := comms.NewCommChannel(comms.Agent, agentRW)
-	s.Nil(err)
+	if err != nil {
+		return AgentRegisterResult{registration: agentRegistration, err: err}
+	}
 	s.NotNil(commChannel)
-	return nil
+	return AgentRegisterResult{registration: agentRegistration, err: nil}
 }
 
-func (s *AdminTestSuite) addAgent(publicId string, assignedPublicId string, serverRW io.ReadWriteCloser) any {
+func (s *AdminTestSuite) addAgent(publicId string, assignedPublicId string, serverRW io.ReadWriteCloser) (*agentConnection, error) {
 	agentConn, err := s.admin.AddAgent(
 		s.hostKey, models.RendezVousId(publicId), comms.EnvironmentInfo{},
 		serverRW)
-	s.Nil(err)
+	if err != nil {
+		return nil, err
+	}
 	s.Equal(assignedPublicId, string(agentConn.Info.PublicId))
-
-	return agentConn
+	return agentConn, nil
 }