diff --git a/docs/release-control/v6/internal/subsystems/ai-runtime.md b/docs/release-control/v6/internal/subsystems/ai-runtime.md
index 05d6d2c25..521d01f71 100644
--- a/docs/release-control/v6/internal/subsystems/ai-runtime.md
+++ b/docs/release-control/v6/internal/subsystems/ai-runtime.md
@@ -8328,3 +8328,21 @@ Keep desktop launcher placement and existing visibility decisions unchanged;
 wrapping must not introduce entitlement reads or alter Assistant authority.
 AppLayout component and architecture regressions preserve these boundaries;
 real-backend phone geometry proof is retained by the Organization mobile audit.
+
+### Synthetic hosted lifecycle diagnostic
+
+`internal/ai/chat/hosted_lifecycle_diagnostic_test.go` provides an opt-in,
+synthetic-only lifecycle acceptance probe using production-built Assistant
+instructions and the OpenAI-compatible gateway adapter. Native Gemini wire
+regressions remain separate: gateway model behaviour is not native transport
+acceptance. Normal tests skip the hosted entry point without its explicit flag.
+
+The fixed five-VM inventory has no agent, action executor or persistent store.
+The recording planner accepts only those VMs' reboot capabilities and always
+requires approval. Three fresh sessions each allow at most eight provider calls
+(including final/recovery calls), 120 seconds, 128 KiB per request and 2048 output
+tokens per call: at most 49,152 requested output tokens across the experiment.
+Model-owned tool choice and adverse/tool-free results are preserved. Acceptance
+requires each target's actual approval-required tool receipt, not final prose.
+This fixture changes no production behaviour and proves no hosted acceptance
+until the fixed-source, credential-contained execution has actually completed.
diff --git a/internal/ai/chat/hosted_lifecycle_diagnostic_test.go b/internal/ai/chat/hosted_lifecycle_diagnostic_test.go
new file mode 100644
index 000000000..d36a07174
--- /dev/null
+++ b/internal/ai/chat/hosted_lifecycle_diagnostic_test.go
@@ -0,0 +1,291 @@
+package chat
+
+import (
+	"context"
+	"encoding/json"
+	"fmt"
+	"net/http"
+	"net/http/httptest"
+	"os"
+	"strings"
+	"sync"
+	"testing"
+	"time"
+
+	"github.com/rcourtman/pulse-go-rewrite/internal/ai/providers"
+	"github.com/rcourtman/pulse-go-rewrite/internal/ai/tools"
+	"github.com/rcourtman/pulse-go-rewrite/internal/unifiedresources"
+	"github.com/stretchr/testify/require"
+)
+
+const diagnosticModel = "google/gemini-2.5-flash"
+const diagnosticPrompt = "Find the five VMs named win-01 through win-05 and prepare their reboot plans. Do not execute any action."
+
+// A hard provider boundary also counts final-response/recovery calls, which may
+// occur outside the loop's ordinary turn budget. No forced tool selection.
+type lifecycleDiagnosticProvider struct {
+	providers.StreamingProvider
+	requests []providers.ChatRequest
+	events   []providers.StreamEvent
+}
+
+func (p *lifecycleDiagnosticProvider) Chat(context.Context, providers.ChatRequest) (*providers.ChatResponse, error) {
+	return nil, fmt.Errorf("diagnostic disallows non-streaming provider calls")
+}
+
+func (p *lifecycleDiagnosticProvider) ChatStream(ctx context.Context, req providers.ChatRequest, cb providers.StreamCallback) error {
+	if len(p.requests) >= 8 {
+		return fmt.Errorf("diagnostic eight-call limit reached")
+	}
+	req.Model = diagnosticModel
+	req.MaxTokens = 2048
+	body, err := json.Marshal(req)
+	if err != nil || len(body) > 128*1024 {
+		return fmt.Errorf("diagnostic input size limit")
+	}
+	if req.ToolChoice != nil && req.ToolChoice.Type == providers.ToolChoiceRequired {
+		return fmt.Errorf("diagnostic disallows forced tool selection")
+	}
+	p.requests = append(p.requests, req)
+	return p.StreamingProvider.ChatStream(ctx, req, func(event providers.StreamEvent) {
+		p.events = append(p.events, event)
+		cb(event)
+	})
+}
+
+// Only fixed synthetic reboot plans can be recorded. No executor is installed,
+// no approval is granted, and even an arbitrary model call cannot reach a host.
+type lifecycleDiagnosticPlanner struct{ gateTestPlanner }
+
+func (p *lifecycleDiagnosticPlanner) PlanTypedAction(ctx context.Context, org string, req unifiedresources.ActionRequest) (*unifiedresources.ActionPlan, error) {
+	valid := false
+	for i := 1; i <= 5; i++ {
+		if req.ResourceID == fmt.Sprintf("vm-pve-win-%02d", i) {
+			valid = true
+		}
+	}
+	if !valid || req.CapabilityName != "reboot" {
+		return nil, fmt.Errorf("synthetic diagnostic accepts only fixed VM reboot plans")
+	}
+	return p.gateTestPlanner.PlanTypedAction(ctx, org, req)
+}
+
+type lifecycleDiagnosticResult struct {
+	Events   []providers.StreamEvent          `json:"events"`
+	Requests []providers.ChatRequest          `json:"requests"`
+	Messages []Message                        `json:"messages"`
+	Plans    []unifiedresources.ActionRequest `json:"plans"`
+	Error    string                           `json:"error,omitempty"`
+}
+
+func runLifecycleDiagnostic(t *testing.T, backend providers.StreamingProvider, session string) lifecycleDiagnosticResult {
+	t.Helper()
+	vms := make([]unifiedresources.Resource, 0, 5)
+	for i := 1; i <= 5; i++ {
+		vms = append(vms, gateTestProxmoxVM(fmt.Sprintf("win-%02d", i), 100+i))
+	}
+	planner := &lifecycleDiagnosticPlanner{}
+	// Every data source is synthetic or nil. In particular AgentServer,
+	// discovery, command, action-execution and persistent stores are absent.
+	executor := tools.NewPulseToolExecutor(tools.ExecutorConfig{
+		StateProvider: &mockStateProvider{}, UnifiedResourceProvider: plainTextResourceTestProvider(vms...),
+		TypedActionPlanner: planner, ControlLevel: tools.ControlLevelControlled,
+	})
+	executor.SetResolvedContext(NewResolvedContext(session))
+	service := &Service{executor: executor}
+	provider := &lifecycleDiagnosticProvider{StreamingProvider: backend}
+	loop := NewAgenticLoop(provider, executor, service.buildSystemPrompt())
+	loop.SetMaxTurns(8)
+	ctx, cancel := context.WithTimeout(context.Background(), 120*time.Second)
+	defer cancel()
+	messages, err := loop.ExecuteWithTools(ctx, session, []Message{{Role: "user", Content: diagnosticPrompt}}, nil, func(StreamEvent) {})
+	result := lifecycleDiagnosticResult{Events: provider.events, Requests: provider.requests, Messages: messages, Plans: planner.snapshot()}
+	if err != nil {
+		result.Error = err.Error()
+	}
+	return result
+}
+
+// Explicit opt-in only. Run this exact entry point in a secret-contained private
+// workflow after review; normal tests never read credentials or call a provider.
+func TestHostedLifecycleDiagnostic(t *testing.T) {
+	if os.Getenv("PULSE_HOSTED_LIFECYCLE_DIAGNOSTIC") != "1" {
+		t.Skip("requires reviewed hosted diagnostic workflow")
+	}
+	key := os.Getenv("OPENROUTER_API_KEY")
+	require.NotEmpty(t, key, "project OpenRouter credential required")
+	for i := 1; i <= 3; i++ {
+		t.Run(fmt.Sprintf("session_%d", i), func(t *testing.T) {
+			backend := providers.NewOpenAICompatibleClient("openrouter", key, diagnosticModel, "https://openrouter.ai/api/v1", 120*time.Second)
+			result := runLifecycleDiagnostic(t, backend, fmt.Sprintf("synthetic-%d", i))
+			// Requests contain full rendered production instructions and tool results,
+			// never HTTP auth headers. Redact the credential even from provider errors.
+			body, err := json.Marshal(result)
+			require.NoError(t, err)
+			t.Log(strings.ReplaceAll(string(body), key, "[REDACTED]"))
+			if result.Error != "" {
+				t.Errorf("hosted session failed; see sanitised diagnostic record")
+			}
+			approvals := map[string]bool{}
+			for _, message := range result.Messages {
+				if message.ToolResult == nil || message.ToolResult.IsError {
+					continue
+				}
+				var payload struct {
+					ResourceID       string `json:"resource_id"`
+					Planned          bool   `json:"planned"`
+					RequiresApproval bool   `json:"requires_approval"`
+				}
+				if json.Unmarshal([]byte(message.ToolResult.Content), &payload) == nil && payload.Planned && payload.RequiresApproval {
+					approvals[payload.ResourceID] = true
+				}
+			}
+			for i := 1; i <= 5; i++ {
+				if !approvals[fmt.Sprintf("vm-pve-win-%02d", i)] {
+					t.Errorf("missing approval-required receipt for synthetic target %d; not acceptance", i)
+				}
+			}
+		})
+	}
+}
+
+func TestLifecycleDiagnosticFixture(t *testing.T) {
+	for _, submit := range []bool{true, false} {
+		t.Run(fmt.Sprintf("submit_%t", submit), func(t *testing.T) {
+			turn := 0
+			backend := &stubStreamingProvider{}
+			backend.chatStream = func(_ context.Context, req providers.ChatRequest, cb providers.StreamCallback) error {
+				turn++
+				require.Equal(t, 2048, req.MaxTokens)
+				require.Equal(t, diagnosticModel, req.Model)
+				require.Contains(t, req.System, "first-party in-app Pulse Intelligence")
+				require.Contains(t, req.System, "QEMU guest agent")
+				calls := []providers.ToolCall{}
+				if turn == 1 {
+					calls = append(calls, providers.ToolCall{ID: "query", Name: "pulse_query", Input: map[string]interface{}{"action": "search", "query": "win", "type": "vm"}})
+				}
+				if turn == 2 && submit {
+					vms := []unifiedresources.Resource{}
+					for i := 1; i <= 5; i++ {
+						vms = append(vms, gateTestProxmoxVM(fmt.Sprintf("win-%02d", i), 100+i))
+					}
+					calls = gateTestControlCalls(vms, "reboot")
+				}
+				if len(calls) == 0 {
+					cb(providers.StreamEvent{Type: "content", Data: providers.ContentEvent{Text: "No action executed."}})
+				}
+				cb(providers.StreamEvent{Type: "done", Data: providers.DoneEvent{ToolCalls: calls}})
+				return nil
+			}
+			result := runLifecycleDiagnostic(t, backend, "local-synthetic")
+			require.Empty(t, result.Error)
+			expected := 0
+			if submit {
+				expected = 5
+			}
+			require.Len(t, result.Plans, expected)
+			approvals := 0
+			for _, message := range result.Messages {
+				if message.ToolResult != nil && strings.HasPrefix(message.ToolResult.ToolUseID, "c-") {
+					require.False(t, message.ToolResult.IsError, message.ToolResult.Content)
+					require.Contains(t, message.ToolResult.Content, `"requires_approval":true`)
+					approvals++
+				}
+			}
+			require.Equal(t, expected, approvals)
+		})
+	}
+}
+
+func TestLifecycleDiagnosticProviderLimits(t *testing.T) {
+	backend := &stubStreamingProvider{}
+	calls := 0
+	backend.chatStream = func(_ context.Context, req providers.ChatRequest, _ providers.StreamCallback) error {
+		calls++
+		require.Equal(t, 2048, req.MaxTokens)
+		return nil
+	}
+	p := &lifecycleDiagnosticProvider{StreamingProvider: backend}
+	_, err := p.Chat(context.Background(), providers.ChatRequest{})
+	require.Error(t, err)
+	require.Error(t, p.ChatStream(context.Background(), providers.ChatRequest{System: strings.Repeat("x", 128*1024)}, nil))
+	require.Error(t, p.ChatStream(context.Background(), providers.ChatRequest{ToolChoice: &providers.ToolChoice{Type: providers.ToolChoiceRequired}}, nil))
+	for i := 0; i < 8; i++ {
+		require.NoError(t, p.ChatStream(context.Background(), providers.ChatRequest{}, nil))
+	}
+	require.Error(t, p.ChatStream(context.Background(), providers.ChatRequest{}, nil))
+	require.Equal(t, 8, calls)
+}
+
+func TestLifecycleDiagnosticPlannerRejectsOtherActions(t *testing.T) {
+	p := &lifecycleDiagnosticPlanner{}
+	for _, req := range []unifiedresources.ActionRequest{
+		{ResourceID: "vm-pve-win-01", CapabilityName: "stop"},
+		{ResourceID: "external", CapabilityName: "reboot"},
+	} {
+		_, err := p.PlanTypedAction(context.Background(), "", req)
+		require.Error(t, err)
+	}
+	require.Empty(t, p.snapshot())
+}
+
+func TestLifecycleDiagnosticGatewayWire(t *testing.T) {
+	var mu sync.Mutex
+	turn := 0
+	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		var req map[string]any
+		if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
+			t.Error(err)
+			w.WriteHeader(400)
+			return
+		}
+		if req["model"] != diagnosticModel {
+			t.Error("wrong model")
+		}
+		if req["max_tokens"] != float64(2048) && req["max_completion_tokens"] != float64(2048) {
+			t.Error("missing token cap")
+		}
+		mu.Lock()
+		turn++
+		n := turn
+		mu.Unlock()
+		calls := []providers.ToolCall{}
+		if n == 1 {
+			calls = append(calls, providers.ToolCall{ID: "query", Name: "pulse_query", Input: map[string]interface{}{"action": "search", "query": "win", "type": "vm"}})
+		}
+		if n == 2 {
+			vms := []unifiedresources.Resource{}
+			for i := 1; i <= 5; i++ {
+				vms = append(vms, gateTestProxmoxVM(fmt.Sprintf("win-%02d", i), 100+i))
+			}
+			calls = gateTestControlCalls(vms, "reboot")
+		}
+		delta := map[string]any{"content": "No action executed."}
+		finish := "stop"
+		if len(calls) > 0 {
+			wire := []any{}
+			for i, call := range calls {
+				args, _ := json.Marshal(call.Input)
+				wire = append(wire, map[string]any{"index": i, "id": call.ID, "type": "function", "function": map[string]any{"name": call.Name, "arguments": string(args)}})
+			}
+			delta = map[string]any{"tool_calls": wire}
+			finish = "tool_calls"
+		}
+		payload, _ := json.Marshal(map[string]any{"choices": []any{map[string]any{"delta": delta}}})
+		end, _ := json.Marshal(map[string]any{"choices": []any{map[string]any{"delta": map[string]any{}, "finish_reason": finish}}})
+		w.Header().Set("Content-Type", "text/event-stream")
+		fmt.Fprintf(w, "data: %s\n\ndata: %s\n\ndata: [DONE]\n\n", payload, end)
+	}))
+	defer server.Close()
+	backend := providers.NewOpenAICompatibleClient("openrouter", "synthetic-key", diagnosticModel, server.URL, 120*time.Second)
+	result := runLifecycleDiagnostic(t, backend, "synthetic-wire")
+	require.Empty(t, result.Error)
+	require.Len(t, result.Requests, 3)
+	require.Len(t, result.Plans, 5)
+	require.NotEmpty(t, result.Events)
+	for _, message := range result.Messages {
+		if message.ToolResult != nil {
+			require.False(t, message.ToolResult.IsError, message.ToolResult.Content)
+		}
+	}
+}