diff --git a/apps/daemon/internal/cli/agent_discovery.go b/apps/daemon/internal/cli/agent_discovery.go
index 9c28fb45d..83c5d2bae 100644
--- a/apps/daemon/internal/cli/agent_discovery.go
+++ b/apps/daemon/internal/cli/agent_discovery.go
@@ -1,8 +1,11 @@
 package cli
 
 import (
+	"bytes"
 	"context"
 	"fmt"
+	"sync"
+
 	"github.com/MiniMax-AI/OpenAgentCore/apps/daemon/internal/agent"
 	"github.com/MiniMax-AI/OpenAgentCore/apps/daemon/internal/paths"
 )
@@ -25,18 +28,35 @@ func discoverAgentCLIs(parent context.Context, rc *runContext, profile string, d
 	if err != nil {
 		return nil, err
 	}
-	var out agentCLIDiscovery
-	available := false
-	for _, declaration := range declarations {
+	// Preflights are independent and sit on every cold start, so they run
+	// concurrently; their output is replayed in declaration order.
+	type probe struct {
+		runtime        *agent.Runtime
+		stdout, stderr bytes.Buffer
+	}
+	probes := make([]probe, len(declarations))
+	var running sync.WaitGroup
+	for i, declaration := range declarations {
 		if rc.installedKinds != nil && !rc.installedKinds[declaration.Kind] {
 			continue
 		}
-		runtime := declaration.Discover(parent, agent.DiscoveryOptions{Profile: profile, StateRoot: stateRoot, RuntimeRoot: runtimeRoot, Stdout: rc.stdout, Stderr: rc.stderr}, declaration.Info())
-		if runtime == nil {
+		running.Go(func() {
+			p := &probes[i]
+			p.runtime = declaration.Discover(parent, agent.DiscoveryOptions{Profile: profile, StateRoot: stateRoot, RuntimeRoot: runtimeRoot, Stdout: &p.stdout, Stderr: &p.stderr}, declaration.Info())
+		})
+	}
+	running.Wait()
+	var out agentCLIDiscovery
+	available := false
+	for i := range probes {
+		p := &probes[i]
+		_, _ = rc.stdout.Write(p.stdout.Bytes())
+		_, _ = rc.stderr.Write(p.stderr.Bytes())
+		if p.runtime == nil {
 			continue
 		}
-		out = append(out, discoveredHarness{declaration, *runtime})
-		available = available || runtime.Info.Available
+		out = append(out, discoveredHarness{declarations[i], *p.runtime})
+		available = available || p.runtime.Info.Available
 	}
 	if err := parent.Err(); err != nil {
 		return out, err
diff --git a/apps/daemon/internal/cli/native_discovery_test.go b/apps/daemon/internal/cli/native_discovery_test.go
index e3894f84d..389ecdbe3 100644
--- a/apps/daemon/internal/cli/native_discovery_test.go
+++ b/apps/daemon/internal/cli/native_discovery_test.go
@@ -3,9 +3,13 @@ package cli
 import (
 	"context"
 	"errors"
+	"fmt"
 	"io"
 	"reflect"
+	"strings"
+	"sync"
 	"testing"
+	"time"
 
 	"github.com/MiniMax-AI/OpenAgentCore/apps/daemon/internal/agent"
 	"github.com/MiniMax-AI/OpenAgentCore/internal/agentdaemon/proto"
@@ -17,31 +21,44 @@ func TestDiscoveryAndRegistration(t *testing.T) {
 			runtimeRoot, stateRoot := t.TempDir(), t.TempDir()
 			t.Setenv("OAC_RUNTIME_HOME", runtimeRoot)
 			t.Setenv("OAC_RUNTIME_STATE_DIRECTORY", stateRoot)
-			called := []string{}
+			rc := &runContext{stdout: io.Discard, stderr: io.Discard}
+			expected := []string{"claude_sdk", "codex", "mcode"}
+			if selected != "" {
+				rc.installedKinds = map[string]bool{selected: true}
+				expected = []string{selected}
+			}
+			// Each probe waits for all selected probes to start, so a sequential
+			// discovery fails here instead of passing slowly.
+			var started sync.WaitGroup
+			started.Add(len(expected))
+			all := make(chan struct{})
+			go func() { started.Wait(); close(all) }()
 			declarations := append([]agent.Declaration(nil), harnessDeclarations...)
 			for i := range declarations {
 				declarations[i].Discover = func(_ context.Context, options agent.DiscoveryOptions, info proto.SupportedAgentKind) *agent.Runtime {
 					if options.RuntimeRoot != runtimeRoot || options.StateRoot != stateRoot {
-						t.Fatal("discovery lost explicit directory context")
+						t.Error("discovery lost explicit directory context")
+					}
+					started.Done()
+					select {
+					case <-all:
+					case <-time.After(5 * time.Second):
+						t.Error("preflights did not run concurrently")
 					}
-					called = append(called, info.Kind)
+					fmt.Fprintln(options.Stdout, info.Kind)
 					info.Available = true
 					info.Version = "test"
 					return &agent.Runtime{Info: info}
 				}
 			}
-			rc := &runContext{stdout: io.Discard, stderr: io.Discard}
-			expected := []string{"claude_sdk", "codex", "mcode"}
-			if selected != "" {
-				rc.installedKinds = map[string]bool{selected: true}
-				expected = []string{selected}
-			}
+			var stdout strings.Builder
+			rc.stdout = &stdout
 			discovery, err := discoverAgentCLIs(t.Context(), rc, "default", declarations)
 			if err != nil {
 				t.Fatal(err)
 			}
-			if !reflect.DeepEqual(called, expected) {
-				t.Fatalf("probes %v, want %v", called, expected)
+			if got := strings.Fields(stdout.String()); !reflect.DeepEqual(got, expected) {
+				t.Fatalf("preflight output %v, want %v", got, expected)
 			}
 			registry := agent.NewRegistry()
 			registerAgentKinds(registry, discovery)
diff --git a/services/core/internal/execution/runtime_initialization.go b/services/core/internal/execution/runtime_initialization.go
index 3b9762901..2dd4f9d86 100644
--- a/services/core/internal/execution/runtime_initialization.go
+++ b/services/core/internal/execution/runtime_initialization.go
@@ -33,6 +33,7 @@ func (w *Worker) runEnvironmentInitializations(ctx context.Context) error {
 			return ctx.Err()
 		case id := <-done:
 			delete(active, id)
+		case <-w.dispatcher.Registry.Announced():
 		case <-ticker.C:
 		}
 		rows, err := w.dispatcher.SessionsReader.ListEnvironmentInitializations(ctx, cursor)
diff --git a/services/core/internal/runtimegateway/capabilities_test.go b/services/core/internal/runtimegateway/capabilities_test.go
index a6c26c69b..54baa1774 100644
--- a/services/core/internal/runtimegateway/capabilities_test.go
+++ b/services/core/internal/runtimegateway/capabilities_test.go
@@ -48,3 +48,25 @@ func TestInvalidHeartbeatDiscardsPreviousDeclarationAndClosesTransport(t *testin
 		t.Fatal("old declaration survived invalid heartbeat")
 	}
 }
+
+func TestFirstHeartbeatAnnouncesAgentKinds(t *testing.T) {
+	registry := NewRegistry()
+	session := newTestSession(newFakeConn(), "runtime", "workspace", proto.Version, registry, nil)
+	heartbeat, err := proto.NewEnvelope(proto.TypeHeartbeat, "", proto.HeartbeatPayload{SupportedAgentKinds: []proto.SupportedAgentKind{{Kind: "fixture", Available: true, Capabilities: prototest.Capabilities(proto.AgentKindCapabilities{})}}})
+	if err != nil {
+		t.Fatal(err)
+	}
+	for _, want := range []bool{true, false} {
+		session.handleHeartbeat(heartbeat)
+		select {
+		case <-registry.Announced():
+			if !want {
+				t.Fatal("repeated heartbeat announced again")
+			}
+		default:
+			if want {
+				t.Fatal("first agent kinds not announced")
+			}
+		}
+	}
+}
diff --git a/services/core/internal/runtimegateway/registry.go b/services/core/internal/runtimegateway/registry.go
index 29ef0ddcf..45111df43 100644
--- a/services/core/internal/runtimegateway/registry.go
+++ b/services/core/internal/runtimegateway/registry.go
@@ -37,15 +37,31 @@ type Registry struct {
 	// happens between WaitForDevice registering and selecting on the
 	// chan still wakes the waiter.
 	waiters map[string][]chan *Session
+
+	// announced coalesces "a session reported its agent kinds for the first
+	// time" for the one owner that waits on known kinds.
+	announced chan struct{}
 }
 
 // NewRegistry returns an empty registry. The zero value would also
 // work but the constructor avoids accidental nil-map panics.
 func NewRegistry() *Registry {
 	return &Registry{
-		byDevice: map[string]*Session{},
-		byRun:    map[string]*Session{},
-		waiters:  map[string][]chan *Session{},
+		byDevice:  map[string]*Session{},
+		byRun:     map[string]*Session{},
+		waiters:   map[string][]chan *Session{},
+		announced: make(chan struct{}, 1),
+	}
+}
+
+// Announced signals after a session first reports its agent kinds. Polling
+// recovers a coalesced signal.
+func (r *Registry) Announced() <-chan struct{} { return r.announced }
+
+func (r *Registry) announce() {
+	select {
+	case r.announced <- struct{}{}:
+	default:
 	}
 }
 
diff --git a/services/core/internal/runtimegateway/session.go b/services/core/internal/runtimegateway/session.go
index 1ec05993d..a2e48df53 100644
--- a/services/core/internal/runtimegateway/session.go
+++ b/services/core/internal/runtimegateway/session.go
@@ -209,13 +209,16 @@ func (s *Session) AgentKindStatus(kind string) (info runtimedevice.SupportedAgen
 	return runtimedevice.SupportedAgentKind{}, false, true
 }
 
-func (s *Session) setSupportedAgentKinds(kinds []runtimedevice.SupportedAgentKind) {
+// setSupportedAgentKinds reports whether these are the session's first kinds.
+func (s *Session) setSupportedAgentKinds(kinds []runtimedevice.SupportedAgentKind) (first bool) {
 	copyKinds := make([]runtimedevice.SupportedAgentKind, len(kinds))
 	copy(copyKinds, kinds)
 	s.kindsMu.Lock()
+	first = !s.kindsSeen
 	s.kindsSeen = true
 	s.supportedKinds = copyKinds
 	s.kindsMu.Unlock()
+	return first
 }
 
 // Close closes the transport and subscriptions with ErrSessionClosed, then
@@ -396,7 +399,9 @@ func (s *Session) handleHeartbeat(env proto.Envelope) {
 		return
 	}
 	kinds := deviceKindsFromHeartbeat(p)
-	s.setSupportedAgentKinds(kinds)
+	if s.setSupportedAgentKinds(kinds) {
+		s.reg.announce()
+	}
 	if s.heartbeat == nil {
 		return
 	}