diff --git a/pkg/coredeno/coredeno.go b/pkg/coredeno/coredeno.go
index ee50ddb..2150377 100644
--- a/pkg/coredeno/coredeno.go
+++ b/pkg/coredeno/coredeno.go
@@ -13,12 +13,13 @@ import (
 
 // Options configures the CoreDeno sidecar.
 type Options struct {
-	DenoPath    string            // path to deno binary (default: "deno")
-	SocketPath  string            // Unix socket path for gRPC
-	AppRoot     string            // app root directory (sandboxed I/O)
-	StoreDBPath string            // SQLite DB path (default: AppRoot/.core/store.db)
-	PublicKey   ed25519.PublicKey  // ed25519 public key for manifest verification (optional)
-	SidecarArgs []string          // args passed to the sidecar process
+	DenoPath       string            // path to deno binary (default: "deno")
+	SocketPath     string            // Unix socket path for Go's gRPC server (CoreService)
+	DenoSocketPath string            // Unix socket path for Deno's gRPC server (DenoService)
+	AppRoot        string            // app root directory (sandboxed I/O)
+	StoreDBPath    string            // SQLite DB path (default: AppRoot/.core/store.db)
+	PublicKey      ed25519.PublicKey  // ed25519 public key for manifest verification (optional)
+	SidecarArgs    []string          // args passed to the sidecar process
 }
 
 // Permissions declares per-module Deno permission flags.
@@ -74,6 +75,9 @@ func NewSidecar(opts Options) *Sidecar {
 	if opts.SocketPath == "" {
 		opts.SocketPath = DefaultSocketPath()
 	}
+	if opts.DenoSocketPath == "" && opts.SocketPath != "" {
+		opts.DenoSocketPath = filepath.Join(filepath.Dir(opts.SocketPath), "deno.sock")
+	}
 	if opts.StoreDBPath == "" && opts.AppRoot != "" {
 		opts.StoreDBPath = filepath.Join(opts.AppRoot, ".core", "store.db")
 	}
diff --git a/pkg/coredeno/coredeno_test.go b/pkg/coredeno/coredeno_test.go
index 1da31c8..a670dcc 100644
--- a/pkg/coredeno/coredeno_test.go
+++ b/pkg/coredeno/coredeno_test.go
@@ -80,3 +80,20 @@ func TestDefaultSocketPath_XDG(t *testing.T) {
 	path := DefaultSocketPath()
 	assert.Equal(t, "/run/user/1000/core/deno.sock", path)
 }
+
+func TestOptions_DenoSocketPath_Default_Good(t *testing.T) {
+	opts := Options{SocketPath: "/tmp/core/core.sock"}
+	sc := NewSidecar(opts)
+	assert.Equal(t, "/tmp/core/deno.sock", sc.opts.DenoSocketPath,
+		"DenoSocketPath should default to same dir as SocketPath with deno.sock")
+}
+
+func TestOptions_DenoSocketPath_Explicit_Good(t *testing.T) {
+	opts := Options{
+		SocketPath:     "/tmp/core/core.sock",
+		DenoSocketPath: "/tmp/custom/deno.sock",
+	}
+	sc := NewSidecar(opts)
+	assert.Equal(t, "/tmp/custom/deno.sock", sc.opts.DenoSocketPath,
+		"Explicit DenoSocketPath should not be overridden")
+}
diff --git a/pkg/coredeno/denoclient.go b/pkg/coredeno/denoclient.go
new file mode 100644
index 0000000..81b6952
--- /dev/null
+++ b/pkg/coredeno/denoclient.go
@@ -0,0 +1,127 @@
+package coredeno
+
+import (
+	"bufio"
+	"encoding/json"
+	"fmt"
+	"net"
+	"sync"
+)
+
+// DenoClient communicates with the Deno sidecar's JSON-RPC server over a Unix socket.
+// Thread-safe: uses a mutex to serialize requests (one connection, request/response protocol).
+type DenoClient struct {
+	mu     sync.Mutex
+	conn   net.Conn
+	reader *bufio.Reader
+}
+
+// DialDeno connects to the Deno JSON-RPC server on the given Unix socket path.
+func DialDeno(socketPath string) (*DenoClient, error) {
+	conn, err := net.Dial("unix", socketPath)
+	if err != nil {
+		return nil, fmt.Errorf("deno dial: %w", err)
+	}
+	return &DenoClient{
+		conn:   conn,
+		reader: bufio.NewReader(conn),
+	}, nil
+}
+
+// Close closes the underlying connection.
+func (c *DenoClient) Close() error {
+	return c.conn.Close()
+}
+
+func (c *DenoClient) call(req map[string]any) (map[string]any, error) {
+	c.mu.Lock()
+	defer c.mu.Unlock()
+
+	data, err := json.Marshal(req)
+	if err != nil {
+		return nil, fmt.Errorf("marshal: %w", err)
+	}
+	data = append(data, '\n')
+
+	if _, err := c.conn.Write(data); err != nil {
+		return nil, fmt.Errorf("write: %w", err)
+	}
+
+	line, err := c.reader.ReadBytes('\n')
+	if err != nil {
+		return nil, fmt.Errorf("read: %w", err)
+	}
+
+	var resp map[string]any
+	if err := json.Unmarshal(line, &resp); err != nil {
+		return nil, fmt.Errorf("unmarshal: %w", err)
+	}
+
+	if errMsg, ok := resp["error"].(string); ok && errMsg != "" {
+		return nil, fmt.Errorf("deno: %s", errMsg)
+	}
+	return resp, nil
+}
+
+// LoadModuleResponse holds the result of a LoadModule call.
+type LoadModuleResponse struct {
+	Ok    bool
+	Error string
+}
+
+// LoadModule tells Deno to load a module.
+func (c *DenoClient) LoadModule(code, entryPoint string, permissions []string) (*LoadModuleResponse, error) {
+	resp, err := c.call(map[string]any{
+		"method":      "LoadModule",
+		"code":        code,
+		"entry_point": entryPoint,
+		"permissions": permissions,
+	})
+	if err != nil {
+		return nil, err
+	}
+	return &LoadModuleResponse{
+		Ok:    resp["ok"] == true,
+		Error: fmt.Sprint(resp["error"]),
+	}, nil
+}
+
+// UnloadModuleResponse holds the result of an UnloadModule call.
+type UnloadModuleResponse struct {
+	Ok bool
+}
+
+// UnloadModule tells Deno to unload a module.
+func (c *DenoClient) UnloadModule(code string) (*UnloadModuleResponse, error) {
+	resp, err := c.call(map[string]any{
+		"method": "UnloadModule",
+		"code":   code,
+	})
+	if err != nil {
+		return nil, err
+	}
+	return &UnloadModuleResponse{
+		Ok: resp["ok"] == true,
+	}, nil
+}
+
+// ModuleStatusResponse holds the result of a ModuleStatus call.
+type ModuleStatusResponse struct {
+	Code   string
+	Status string
+}
+
+// ModuleStatus queries the status of a module in the Deno runtime.
+func (c *DenoClient) ModuleStatus(code string) (*ModuleStatusResponse, error) {
+	resp, err := c.call(map[string]any{
+		"method": "ModuleStatus",
+		"code":   code,
+	})
+	if err != nil {
+		return nil, err
+	}
+	return &ModuleStatusResponse{
+		Code:   fmt.Sprint(resp["code"]),
+		Status: fmt.Sprint(resp["status"]),
+	}, nil
+}
diff --git a/pkg/coredeno/integration_test.go b/pkg/coredeno/integration_test.go
index ce83fe0..b1c515d 100644
--- a/pkg/coredeno/integration_test.go
+++ b/pkg/coredeno/integration_test.go
@@ -18,16 +18,34 @@ import (
 	"google.golang.org/grpc/credentials/insecure"
 )
 
-func TestIntegration_FullBoot_Good(t *testing.T) {
+// unused import guard
+var _ = pb.NewCoreServiceClient
+
+func findDeno(t *testing.T) string {
+	t.Helper()
 	denoPath, err := exec.LookPath("deno")
 	if err != nil {
-		// Check ~/.deno/bin/deno
 		home, _ := os.UserHomeDir()
 		denoPath = filepath.Join(home, ".deno", "bin", "deno")
 		if _, err := os.Stat(denoPath); err != nil {
 			t.Skip("deno not installed")
 		}
 	}
+	return denoPath
+}
+
+// runtimeEntryPoint returns the absolute path to runtime/main.ts.
+func runtimeEntryPoint(t *testing.T) string {
+	t.Helper()
+	// We're in pkg/coredeno/ during test, runtime is a subdir
+	abs, err := filepath.Abs("runtime/main.ts")
+	require.NoError(t, err)
+	require.FileExists(t, abs)
+	return abs
+}
+
+func TestIntegration_FullBoot_Good(t *testing.T) {
+	denoPath := findDeno(t)
 
 	tmpDir := t.TempDir()
 	sockPath := filepath.Join(tmpDir, "core.sock")
@@ -43,21 +61,14 @@ permissions:
   read: ["./data/"]
 `), 0644))
 
-	// Copy the runtime entry point
-	runtimeDir := filepath.Join(coreDir, "runtime")
-	require.NoError(t, os.MkdirAll(runtimeDir, 0755))
-	src, err := os.ReadFile("runtime/main.ts")
-	require.NoError(t, err)
-	require.NoError(t, os.WriteFile(filepath.Join(runtimeDir, "main.ts"), src, 0644))
-
-	entryPoint := filepath.Join(runtimeDir, "main.ts")
+	entryPoint := runtimeEntryPoint(t)
 
 	opts := Options{
 		DenoPath:    denoPath,
 		SocketPath:  sockPath,
 		AppRoot:     tmpDir,
 		StoreDBPath: ":memory:",
-		SidecarArgs: []string{"run", "--allow-env", entryPoint},
+		SidecarArgs: []string{"run", "-A", entryPoint},
 	}
 
 	c, err := core.New()
@@ -68,7 +79,7 @@ permissions:
 	require.NoError(t, err)
 	svc := result.(*Service)
 
-	ctx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
+	ctx, cancel := context.WithTimeout(context.Background(), 30*time.Second)
 	defer cancel()
 
 	err = svc.OnStartup(ctx)
@@ -108,3 +119,107 @@ permissions:
 	assert.NoError(t, err)
 	assert.False(t, svc.sidecar.IsRunning(), "Deno sidecar should be stopped")
 }
+
+func TestIntegration_Tier2_Bidirectional_Good(t *testing.T) {
+	denoPath := findDeno(t)
+
+	tmpDir := t.TempDir()
+	sockPath := filepath.Join(tmpDir, "core.sock")
+	denoSockPath := filepath.Join(tmpDir, "deno.sock")
+
+	// Write a manifest
+	coreDir := filepath.Join(tmpDir, ".core")
+	require.NoError(t, os.MkdirAll(coreDir, 0755))
+	require.NoError(t, os.WriteFile(filepath.Join(coreDir, "view.yml"), []byte(`
+code: tier2-test
+name: Tier 2 Test
+version: "1.0"
+permissions:
+  read: ["./data/"]
+  run: ["echo"]
+`), 0644))
+
+	entryPoint := runtimeEntryPoint(t)
+
+	opts := Options{
+		DenoPath:       denoPath,
+		SocketPath:     sockPath,
+		DenoSocketPath: denoSockPath,
+		AppRoot:        tmpDir,
+		StoreDBPath:    ":memory:",
+		SidecarArgs:    []string{"run", "-A", entryPoint},
+	}
+
+	c, err := core.New()
+	require.NoError(t, err)
+
+	factory := NewServiceFactory(opts)
+	result, err := factory(c)
+	require.NoError(t, err)
+	svc := result.(*Service)
+
+	ctx, cancel := context.WithTimeout(context.Background(), 30*time.Second)
+	defer cancel()
+
+	err = svc.OnStartup(ctx)
+	require.NoError(t, err)
+
+	// Verify both sockets appeared
+	require.Eventually(t, func() bool {
+		_, err := os.Stat(sockPath)
+		return err == nil
+	}, 10*time.Second, 50*time.Millisecond, "core socket should appear")
+
+	require.Eventually(t, func() bool {
+		_, err := os.Stat(denoSockPath)
+		return err == nil
+	}, 10*time.Second, 50*time.Millisecond, "deno socket should appear")
+
+	// Verify sidecar is running
+	assert.True(t, svc.sidecar.IsRunning(), "Deno sidecar should be running")
+
+	// Verify DenoClient is connected
+	require.NotNil(t, svc.DenoClient(), "DenoClient should be connected")
+
+	// Test Go → Deno: LoadModule
+	loadResp, err := svc.DenoClient().LoadModule("test-module", "/modules/test/main.ts", []string{"read", "net"})
+	require.NoError(t, err)
+	assert.True(t, loadResp.Ok)
+
+	// Test Go → Deno: ModuleStatus
+	statusResp, err := svc.DenoClient().ModuleStatus("test-module")
+	require.NoError(t, err)
+	assert.Equal(t, "test-module", statusResp.Code)
+	assert.Equal(t, "RUNNING", statusResp.Status)
+
+	// Test Go → Deno: UnloadModule
+	unloadResp, err := svc.DenoClient().UnloadModule("test-module")
+	require.NoError(t, err)
+	assert.True(t, unloadResp.Ok)
+
+	// Verify module is now STOPPED
+	statusResp2, err := svc.DenoClient().ModuleStatus("test-module")
+	require.NoError(t, err)
+	assert.Equal(t, "STOPPED", statusResp2.Status)
+
+	// Verify CoreService gRPC still works (Deno wrote health check data)
+	conn, err := grpc.NewClient(
+		"unix://"+sockPath,
+		grpc.WithTransportCredentials(insecure.NewCredentials()),
+	)
+	require.NoError(t, err)
+	defer conn.Close()
+
+	coreClient := pb.NewCoreServiceClient(conn)
+	getResp, err := coreClient.StoreGet(ctx, &pb.StoreGetRequest{
+		Group: "_coredeno", Key: "status",
+	})
+	require.NoError(t, err)
+	assert.True(t, getResp.Found)
+	assert.Equal(t, "connected", getResp.Value, "Deno should have written health check")
+
+	// Clean shutdown
+	err = svc.OnShutdown(context.Background())
+	assert.NoError(t, err)
+	assert.False(t, svc.sidecar.IsRunning(), "Deno sidecar should be stopped")
+}
diff --git a/pkg/coredeno/lifecycle.go b/pkg/coredeno/lifecycle.go
index f5975b5..1b58039 100644
--- a/pkg/coredeno/lifecycle.go
+++ b/pkg/coredeno/lifecycle.go
@@ -23,12 +23,17 @@ func (s *Sidecar) Start(ctx context.Context, args ...string) error {
 		return fmt.Errorf("coredeno: mkdir %s: %w", sockDir, err)
 	}
 
-	// Remove stale socket
-	os.Remove(s.opts.SocketPath)
+	// Remove stale Deno socket (the Core socket is managed by ListenGRPC)
+	if s.opts.DenoSocketPath != "" {
+		os.Remove(s.opts.DenoSocketPath)
+	}
 
 	s.ctx, s.cancel = context.WithCancel(ctx)
 	s.cmd = exec.CommandContext(s.ctx, s.opts.DenoPath, args...)
-	s.cmd.Env = append(os.Environ(), "CORE_SOCKET="+s.opts.SocketPath)
+	s.cmd.Env = append(os.Environ(),
+		"CORE_SOCKET="+s.opts.SocketPath,
+		"DENO_SOCKET="+s.opts.DenoSocketPath,
+	)
 	s.done = make(chan struct{})
 	if err := s.cmd.Start(); err != nil {
 		s.cmd = nil
diff --git a/pkg/coredeno/lifecycle_test.go b/pkg/coredeno/lifecycle_test.go
index ef14c21..f9347fc 100644
--- a/pkg/coredeno/lifecycle_test.go
+++ b/pkg/coredeno/lifecycle_test.go
@@ -68,6 +68,42 @@ func TestStart_Good_EnvPassedToChild(t *testing.T) {
 	assert.True(t, found, "child process should receive CORE_SOCKET=%s", sockPath)
 }
 
+func TestStart_Good_DenoSocketEnv(t *testing.T) {
+	sockDir := t.TempDir()
+	sockPath := filepath.Join(sockDir, "core.sock")
+	denoSockPath := filepath.Join(sockDir, "deno.sock")
+
+	sc := NewSidecar(Options{
+		DenoPath:       "sleep",
+		SocketPath:     sockPath,
+		DenoSocketPath: denoSockPath,
+	})
+
+	ctx, cancel := context.WithTimeout(context.Background(), 2*time.Second)
+	defer cancel()
+
+	err := sc.Start(ctx, "10")
+	require.NoError(t, err)
+	defer sc.Stop()
+
+	sc.mu.RLock()
+	env := sc.cmd.Env
+	sc.mu.RUnlock()
+
+	foundCore := false
+	foundDeno := false
+	for _, e := range env {
+		if e == "CORE_SOCKET="+sockPath {
+			foundCore = true
+		}
+		if e == "DENO_SOCKET="+denoSockPath {
+			foundDeno = true
+		}
+	}
+	assert.True(t, foundCore, "child should receive CORE_SOCKET")
+	assert.True(t, foundDeno, "child should receive DENO_SOCKET")
+}
+
 func TestSocketDirCreated_Good(t *testing.T) {
 	dir := t.TempDir()
 	sockPath := filepath.Join(dir, "sub", "deno.sock")
diff --git a/pkg/coredeno/runtime/client.ts b/pkg/coredeno/runtime/client.ts
new file mode 100644
index 0000000..8afe006
--- /dev/null
+++ b/pkg/coredeno/runtime/client.ts
@@ -0,0 +1,95 @@
+// CoreService gRPC client — Deno calls Go for I/O operations.
+// All filesystem, store, and process operations route through this client.
+
+import * as grpc from "@grpc/grpc-js";
+import * as protoLoader from "@grpc/proto-loader";
+import { dirname, join } from "node:path";
+import { fileURLToPath } from "node:url";
+
+const __dirname = dirname(fileURLToPath(import.meta.url));
+const PROTO_PATH = join(__dirname, "..", "proto", "coredeno.proto");
+
+let packageDef: protoLoader.PackageDefinition | null = null;
+
+function getProto(): any {
+  if (!packageDef) {
+    packageDef = protoLoader.loadSync(PROTO_PATH, {
+      keepCase: true,
+      longs: String,
+      enums: String,
+      defaults: true,
+      oneofs: true,
+    });
+  }
+  return grpc.loadPackageDefinition(packageDef).coredeno as any;
+}
+
+export interface CoreClient {
+  raw: any;
+  storeGet(group: string, key: string): Promise<{ value: string; found: boolean }>;
+  storeSet(group: string, key: string, value: string): Promise<{ ok: boolean }>;
+  fileRead(path: string, moduleCode: string): Promise<{ content: string }>;
+  fileWrite(path: string, content: string, moduleCode: string): Promise<{ ok: boolean }>;
+  fileList(path: string, moduleCode: string): Promise<{ entries: Array<{ name: string; is_dir: boolean; size: number }> }>;
+  fileDelete(path: string, moduleCode: string): Promise<{ ok: boolean }>;
+  processStart(command: string, args: string[], moduleCode: string): Promise<{ process_id: string }>;
+  processStop(processId: string): Promise<{ ok: boolean }>;
+  close(): void;
+}
+
+function promisify<T>(client: any, method: string, request: any): Promise<T> {
+  return new Promise((resolve, reject) => {
+    client[method](request, (err: Error | null, response: T) => {
+      if (err) reject(err);
+      else resolve(response);
+    });
+  });
+}
+
+export function createCoreClient(socketPath: string): CoreClient {
+  const proto = getProto();
+  const client = new proto.CoreService(
+    `unix:${socketPath}`,
+    grpc.credentials.createInsecure(),
+  );
+
+  return {
+    raw: client,
+
+    storeGet(group: string, key: string) {
+      return promisify(client, "StoreGet", { group, key });
+    },
+
+    storeSet(group: string, key: string, value: string) {
+      return promisify(client, "StoreSet", { group, key, value });
+    },
+
+    fileRead(path: string, moduleCode: string) {
+      return promisify(client, "FileRead", { path, module_code: moduleCode });
+    },
+
+    fileWrite(path: string, content: string, moduleCode: string) {
+      return promisify(client, "FileWrite", { path, content, module_code: moduleCode });
+    },
+
+    fileList(path: string, moduleCode: string) {
+      return promisify(client, "FileList", { path, module_code: moduleCode });
+    },
+
+    fileDelete(path: string, moduleCode: string) {
+      return promisify(client, "FileDelete", { path, module_code: moduleCode });
+    },
+
+    processStart(command: string, args: string[], moduleCode: string) {
+      return promisify(client, "ProcessStart", { command, args, module_code: moduleCode });
+    },
+
+    processStop(processId: string) {
+      return promisify(client, "ProcessStop", { process_id: processId });
+    },
+
+    close() {
+      client.close();
+    },
+  };
+}
diff --git a/pkg/coredeno/runtime/deno.json b/pkg/coredeno/runtime/deno.json
new file mode 100644
index 0000000..13f798e
--- /dev/null
+++ b/pkg/coredeno/runtime/deno.json
@@ -0,0 +1,7 @@
+{
+  "imports": {
+    "@grpc/grpc-js": "npm:@grpc/grpc-js@^1.12",
+    "@grpc/proto-loader": "npm:@grpc/proto-loader@^0.7"
+  },
+  "nodeModulesDir": "none"
+}
diff --git a/pkg/coredeno/runtime/deno.lock b/pkg/coredeno/runtime/deno.lock
new file mode 100644
index 0000000..b02e151
--- /dev/null
+++ b/pkg/coredeno/runtime/deno.lock
@@ -0,0 +1,193 @@
+{
+  "version": "5",
+  "specifiers": {
+    "npm:@grpc/grpc-js@^1.12.0": "1.14.3",
+    "npm:@grpc/proto-loader@0.7": "0.7.15"
+  },
+  "npm": {
+    "@grpc/grpc-js@1.14.3": {
+      "integrity": "sha512-Iq8QQQ/7X3Sac15oB6p0FmUg/klxQvXLeileoqrTRGJYLV+/9tubbr9ipz0GKHjmXVsgFPo/+W+2cA8eNcR+XA==",
+      "dependencies": [
+        "@grpc/proto-loader@0.8.0",
+        "@js-sdsl/ordered-map"
+      ]
+    },
+    "@grpc/proto-loader@0.7.15": {
+      "integrity": "sha512-tMXdRCfYVixjuFK+Hk0Q1s38gV9zDiDJfWL3h1rv4Qc39oILCu1TRTDt7+fGUI8K4G1Fj125Hx/ru3azECWTyQ==",
+      "dependencies": [
+        "lodash.camelcase",
+        "long",
+        "protobufjs",
+        "yargs"
+      ],
+      "bin": true
+    },
+    "@grpc/proto-loader@0.8.0": {
+      "integrity": "sha512-rc1hOQtjIWGxcxpb9aHAfLpIctjEnsDehj0DAiVfBlmT84uvR0uUtN2hEi/ecvWVjXUGf5qPF4qEgiLOx1YIMQ==",
+      "dependencies": [
+        "lodash.camelcase",
+        "long",
+        "protobufjs",
+        "yargs"
+      ],
+      "bin": true
+    },
+    "@js-sdsl/ordered-map@4.4.2": {
+      "integrity": "sha512-iUKgm52T8HOE/makSxjqoWhe95ZJA1/G1sYsGev2JDKUSS14KAgg1LHb+Ba+IPow0xflbnSkOsZcO08C7w1gYw=="
+    },
+    "@protobufjs/aspromise@1.1.2": {
+      "integrity": "sha512-j+gKExEuLmKwvz3OgROXtrJ2UG2x8Ch2YZUxahh+s1F2HZ+wAceUNLkvy6zKCPVRkU++ZWQrdxsUeQXmcg4uoQ=="
+    },
+    "@protobufjs/base64@1.1.2": {
+      "integrity": "sha512-AZkcAA5vnN/v4PDqKyMR5lx7hZttPDgClv83E//FMNhR2TMcLUhfRUBHCmSl0oi9zMgDDqRUJkSxO3wm85+XLg=="
+    },
+    "@protobufjs/codegen@2.0.4": {
+      "integrity": "sha512-YyFaikqM5sH0ziFZCN3xDC7zeGaB/d0IUb9CATugHWbd1FRFwWwt4ld4OYMPWu5a3Xe01mGAULCdqhMlPl29Jg=="
+    },
+    "@protobufjs/eventemitter@1.1.0": {
+      "integrity": "sha512-j9ednRT81vYJ9OfVuXG6ERSTdEL1xVsNgqpkxMsbIabzSo3goCjDIveeGv5d03om39ML71RdmrGNjG5SReBP/Q=="
+    },
+    "@protobufjs/fetch@1.1.0": {
+      "integrity": "sha512-lljVXpqXebpsijW71PZaCYeIcE5on1w5DlQy5WH6GLbFryLUrBD4932W/E2BSpfRJWseIL4v/KPgBFxDOIdKpQ==",
+      "dependencies": [
+        "@protobufjs/aspromise",
+        "@protobufjs/inquire"
+      ]
+    },
+    "@protobufjs/float@1.0.2": {
+      "integrity": "sha512-Ddb+kVXlXst9d+R9PfTIxh1EdNkgoRe5tOX6t01f1lYWOvJnSPDBlG241QLzcyPdoNTsblLUdujGSE4RzrTZGQ=="
+    },
+    "@protobufjs/inquire@1.1.0": {
+      "integrity": "sha512-kdSefcPdruJiFMVSbn801t4vFK7KB/5gd2fYvrxhuJYg8ILrmn9SKSX2tZdV6V+ksulWqS7aXjBcRXl3wHoD9Q=="
+    },
+    "@protobufjs/path@1.1.2": {
+      "integrity": "sha512-6JOcJ5Tm08dOHAbdR3GrvP+yUUfkjG5ePsHYczMFLq3ZmMkAD98cDgcT2iA1lJ9NVwFd4tH/iSSoe44YWkltEA=="
+    },
+    "@protobufjs/pool@1.1.0": {
+      "integrity": "sha512-0kELaGSIDBKvcgS4zkjz1PeddatrjYcmMWOlAuAPwAeccUrPHdUqo/J6LiymHHEiJT5NrF1UVwxY14f+fy4WQw=="
+    },
+    "@protobufjs/utf8@1.1.0": {
+      "integrity": "sha512-Vvn3zZrhQZkkBE8LSuW3em98c0FwgO4nxzv6OdSxPKJIEKY2bGbHn+mhGIPerzI4twdxaP8/0+06HBpwf345Lw=="
+    },
+    "@types/node@25.2.3": {
+      "integrity": "sha512-m0jEgYlYz+mDJZ2+F4v8D1AyQb+QzsNqRuI7xg1VQX/KlKS0qT9r1Mo16yo5F/MtifXFgaofIFsdFMox2SxIbQ==",
+      "dependencies": [
+        "undici-types"
+      ]
+    },
+    "ansi-regex@5.0.1": {
+      "integrity": "sha512-quJQXlTSUGL2LH9SUXo8VwsY4soanhgo6LNSm84E1LBcE8s3O0wpdiRzyR9z/ZZJMlMWv37qOOb9pdJlMUEKFQ=="
+    },
+    "ansi-styles@4.3.0": {
+      "integrity": "sha512-zbB9rCJAT1rbjiVDb2hqKFHNYLxgtk8NURxZ3IZwD3F6NtxbXZQCnnSi1Lkx+IDohdPlFp222wVALIheZJQSEg==",
+      "dependencies": [
+        "color-convert"
+      ]
+    },
+    "cliui@8.0.1": {
+      "integrity": "sha512-BSeNnyus75C4//NQ9gQt1/csTXyo/8Sb+afLAkzAptFuMsod9HFokGNudZpi/oQV73hnVK+sR+5PVRMd+Dr7YQ==",
+      "dependencies": [
+        "string-width",
+        "strip-ansi",
+        "wrap-ansi"
+      ]
+    },
+    "color-convert@2.0.1": {
+      "integrity": "sha512-RRECPsj7iu/xb5oKYcsFHSppFNnsj/52OVTRKb4zP5onXwVF3zVmmToNcOfGC+CRDpfK/U584fMg38ZHCaElKQ==",
+      "dependencies": [
+        "color-name"
+      ]
+    },
+    "color-name@1.1.4": {
+      "integrity": "sha512-dOy+3AuW3a2wNbZHIuMZpTcgjGuLU/uBL/ubcZF9OXbDo8ff4O8yVp5Bf0efS8uEoYo5q4Fx7dY9OgQGXgAsQA=="
+    },
+    "emoji-regex@8.0.0": {
+      "integrity": "sha512-MSjYzcWNOA0ewAHpz0MxpYFvwg6yjy1NG3xteoqz644VCo/RPgnr1/GGt+ic3iJTzQ8Eu3TdM14SawnVUmGE6A=="
+    },
+    "escalade@3.2.0": {
+      "integrity": "sha512-WUj2qlxaQtO4g6Pq5c29GTcWGDyd8itL8zTlipgECz3JesAiiOKotd8JU6otB3PACgG6xkJUyVhboMS+bje/jA=="
+    },
+    "get-caller-file@2.0.5": {
+      "integrity": "sha512-DyFP3BM/3YHTQOCUL/w0OZHR0lpKeGrxotcHWcqNEdnltqFwXVfhEBQ94eIo34AfQpo0rGki4cyIiftY06h2Fg=="
+    },
+    "is-fullwidth-code-point@3.0.0": {
+      "integrity": "sha512-zymm5+u+sCsSWyD9qNaejV3DFvhCKclKdizYaJUuHA83RLjb7nSuGnddCHGv0hk+KY7BMAlsWeK4Ueg6EV6XQg=="
+    },
+    "lodash.camelcase@4.3.0": {
+      "integrity": "sha512-TwuEnCnxbc3rAvhf/LbG7tJUDzhqXyFnv3dtzLOPgCG/hODL7WFnsbwktkD7yUV0RrreP/l1PALq/YSg6VvjlA=="
+    },
+    "long@5.3.2": {
+      "integrity": "sha512-mNAgZ1GmyNhD7AuqnTG3/VQ26o760+ZYBPKjPvugO8+nLbYfX6TVpJPseBvopbdY+qpZ/lKUnmEc1LeZYS3QAA=="
+    },
+    "protobufjs@7.5.4": {
+      "integrity": "sha512-CvexbZtbov6jW2eXAvLukXjXUW1TzFaivC46BpWc/3BpcCysb5Vffu+B3XHMm8lVEuy2Mm4XGex8hBSg1yapPg==",
+      "dependencies": [
+        "@protobufjs/aspromise",
+        "@protobufjs/base64",
+        "@protobufjs/codegen",
+        "@protobufjs/eventemitter",
+        "@protobufjs/fetch",
+        "@protobufjs/float",
+        "@protobufjs/inquire",
+        "@protobufjs/path",
+        "@protobufjs/pool",
+        "@protobufjs/utf8",
+        "@types/node",
+        "long"
+      ],
+      "scripts": true
+    },
+    "require-directory@2.1.1": {
+      "integrity": "sha512-fGxEI7+wsG9xrvdjsrlmL22OMTTiHRwAMroiEeMgq8gzoLC/PQr7RsRDSTLUg/bZAZtF+TVIkHc6/4RIKrui+Q=="
+    },
+    "string-width@4.2.3": {
+      "integrity": "sha512-wKyQRQpjJ0sIp62ErSZdGsjMJWsap5oRNihHhu6G7JVO/9jIB6UyevL+tXuOqrng8j/cxKTWyWUwvSTriiZz/g==",
+      "dependencies": [
+        "emoji-regex",
+        "is-fullwidth-code-point",
+        "strip-ansi"
+      ]
+    },
+    "strip-ansi@6.0.1": {
+      "integrity": "sha512-Y38VPSHcqkFrCpFnQ9vuSXmquuv5oXOKpGeT6aGrr3o3Gc9AlVa6JBfUSOCnbxGGZF+/0ooI7KrPuUSztUdU5A==",
+      "dependencies": [
+        "ansi-regex"
+      ]
+    },
+    "undici-types@7.16.0": {
+      "integrity": "sha512-Zz+aZWSj8LE6zoxD+xrjh4VfkIG8Ya6LvYkZqtUQGJPZjYl53ypCaUwWqo7eI0x66KBGeRo+mlBEkMSeSZ38Nw=="
+    },
+    "wrap-ansi@7.0.0": {
+      "integrity": "sha512-YVGIj2kamLSTxw6NsZjoBxfSwsn0ycdesmc4p+Q21c5zPuZ1pl+NfxVdxPtdHvmNVOQ6XSYG4AUtyt/Fi7D16Q==",
+      "dependencies": [
+        "ansi-styles",
+        "string-width",
+        "strip-ansi"
+      ]
+    },
+    "y18n@5.0.8": {
+      "integrity": "sha512-0pfFzegeDWJHJIAmTLRP2DwHjdF5s7jo9tuztdQxAhINCdvS+3nGINqPd00AphqJR/0LhANUS6/+7SCb98YOfA=="
+    },
+    "yargs-parser@21.1.1": {
+      "integrity": "sha512-tVpsJW7DdjecAiFpbIB1e3qxIQsE6NoPc5/eTdrbbIC4h0LVsWhnoa3g+m2HclBIujHzsxZ4VJVA+GUuc2/LBw=="
+    },
+    "yargs@17.7.2": {
+      "integrity": "sha512-7dSzzRQ++CKnNI/krKnYRV7JKKPUXMEh61soaHKg9mrWEhzFWhFnxPxGl+69cD1Ou63C13NUPCnmIcrvqCuM6w==",
+      "dependencies": [
+        "cliui",
+        "escalade",
+        "get-caller-file",
+        "require-directory",
+        "string-width",
+        "y18n",
+        "yargs-parser"
+      ]
+    }
+  },
+  "workspace": {
+    "dependencies": [
+      "npm:@grpc/grpc-js@^1.12.0",
+      "npm:@grpc/proto-loader@0.7"
+    ]
+  }
+}
diff --git a/pkg/coredeno/runtime/main.ts b/pkg/coredeno/runtime/main.ts
index c1c6f93..ca0aba4 100644
--- a/pkg/coredeno/runtime/main.ts
+++ b/pkg/coredeno/runtime/main.ts
@@ -2,19 +2,90 @@
 // Connects to CoreGO via gRPC over Unix socket.
 // Implements DenoService for module lifecycle management.
 
-const socketPath = Deno.env.get("CORE_SOCKET");
-if (!socketPath) {
+// Must be first import — patches http2 before @grpc/grpc-js loads.
+import "./polyfill.ts";
+
+import { createCoreClient, type CoreClient } from "./client.ts";
+import { startDenoServer, type DenoServer } from "./server.ts";
+import { ModuleRegistry } from "./modules.ts";
+
+// Read required environment variables
+const coreSocket = Deno.env.get("CORE_SOCKET");
+if (!coreSocket) {
   console.error("FATAL: CORE_SOCKET environment variable not set");
   Deno.exit(1);
 }
 
-console.error(`CoreDeno: connecting to ${socketPath}`);
+const denoSocket = Deno.env.get("DENO_SOCKET");
+if (!denoSocket) {
+  console.error("FATAL: DENO_SOCKET environment variable not set");
+  Deno.exit(1);
+}
 
-// Tier 1: signal readiness and stay alive.
-// Tier 2 adds the gRPC client and DenoService implementation.
+console.error(`CoreDeno: CORE_SOCKET=${coreSocket}`);
+console.error(`CoreDeno: DENO_SOCKET=${denoSocket}`);
+
+// 1. Create module registry
+const registry = new ModuleRegistry();
+
+// 2. Start DenoService server (Go calls us here via JSON-RPC over Unix socket)
+let denoServer: DenoServer;
+try {
+  denoServer = await startDenoServer(denoSocket, registry);
+  console.error("CoreDeno: DenoService server started");
+} catch (err) {
+  console.error(`FATAL: failed to start DenoService server: ${err}`);
+  Deno.exit(1);
+}
+
+// 3. Connect to CoreService (we call Go here) with retry
+let coreClient: CoreClient;
+{
+  coreClient = createCoreClient(coreSocket);
+  const maxRetries = 20;
+  let connected = false;
+  let lastErr: unknown;
+  for (let i = 0; i < maxRetries; i++) {
+    try {
+      const timeoutCall = <T>(p: Promise<T>): Promise<T> =>
+        Promise.race([
+          p,
+          new Promise<T>((_, reject) =>
+            setTimeout(() => reject(new Error("call timeout")), 2000),
+          ),
+        ]);
+      await timeoutCall(
+        coreClient.storeSet("_coredeno", "status", "connected"),
+      );
+      const resp = await timeoutCall(
+        coreClient.storeGet("_coredeno", "status"),
+      );
+      if (resp.found && resp.value === "connected") {
+        connected = true;
+        break;
+      }
+    } catch (err) {
+      lastErr = err;
+      if (i < 3 || i === 9 || i === 19) {
+        console.error(`CoreDeno: retry ${i}: ${err}`);
+      }
+    }
+    await new Promise((r) => setTimeout(r, 250));
+  }
+  if (!connected) {
+    console.error(
+      `FATAL: failed to connect to CoreService after retries, last error: ${lastErr}`,
+    );
+    denoServer.close();
+    Deno.exit(1);
+  }
+  console.error("CoreDeno: CoreService client connected");
+}
+
+// 4. Signal readiness
 console.error("CoreDeno: ready");
 
-// Keep alive until parent sends SIGTERM
+// 5. Keep alive until SIGTERM
 const ac = new AbortController();
 Deno.addSignalListener("SIGTERM", () => {
   console.error("CoreDeno: shutting down");
@@ -26,5 +97,7 @@ try {
     ac.signal.addEventListener("abort", () => reject(new Error("shutdown")));
   });
 } catch {
-  // Clean exit on SIGTERM
+  // Clean shutdown
+  coreClient.close();
+  denoServer.close();
 }
diff --git a/pkg/coredeno/runtime/modules.ts b/pkg/coredeno/runtime/modules.ts
new file mode 100644
index 0000000..a53bd4b
--- /dev/null
+++ b/pkg/coredeno/runtime/modules.ts
@@ -0,0 +1,50 @@
+// Module registry — tracks loaded modules and their lifecycle status.
+// Tier 2: status tracking only. Tier 3 adds real Deno worker isolates.
+
+export type ModuleStatus = "UNKNOWN" | "LOADING" | "RUNNING" | "STOPPED" | "ERRORED";
+
+// Status enum values matching the proto definition.
+export const StatusEnum: Record<ModuleStatus, number> = {
+  UNKNOWN: 0,
+  LOADING: 1,
+  RUNNING: 2,
+  STOPPED: 3,
+  ERRORED: 4,
+};
+
+export interface Module {
+  code: string;
+  entryPoint: string;
+  permissions: string[];
+  status: ModuleStatus;
+}
+
+export class ModuleRegistry {
+  private modules = new Map<string, Module>();
+
+  load(code: string, entryPoint: string, permissions: string[]): void {
+    this.modules.set(code, {
+      code,
+      entryPoint,
+      permissions,
+      status: "RUNNING",
+    });
+    console.error(`CoreDeno: module loaded: ${code}`);
+  }
+
+  unload(code: string): boolean {
+    const mod = this.modules.get(code);
+    if (!mod) return false;
+    mod.status = "STOPPED";
+    console.error(`CoreDeno: module unloaded: ${code}`);
+    return true;
+  }
+
+  status(code: string): ModuleStatus {
+    return this.modules.get(code)?.status ?? "UNKNOWN";
+  }
+
+  list(): Module[] {
+    return Array.from(this.modules.values());
+  }
+}
diff --git a/pkg/coredeno/runtime/polyfill.ts b/pkg/coredeno/runtime/polyfill.ts
new file mode 100644
index 0000000..a3ef4f9
--- /dev/null
+++ b/pkg/coredeno/runtime/polyfill.ts
@@ -0,0 +1,94 @@
+// Deno http2 + grpc-js polyfill — must be imported BEFORE @grpc/grpc-js.
+//
+// Two issues with Deno 2.x node compat:
+// 1. http2.getDefaultSettings throws "Not implemented"
+// 2. grpc-js's createConnection returns a socket that reports readyState="open"
+//    but never emits "connect", causing http2 sessions to hang forever.
+//    Fix: wrap createConnection to emit "connect" on next tick for open sockets.
+
+import http2 from "node:http2";
+
+// Fix 1: getDefaultSettings stub
+(http2 as any).getDefaultSettings = () => ({
+  headerTableSize: 4096,
+  enablePush: true,
+  initialWindowSize: 65535,
+  maxFrameSize: 16384,
+  maxConcurrentStreams: 0xffffffff,
+  maxHeaderListSize: 65535,
+  maxHeaderSize: 65535,
+  enableConnectProtocol: false,
+});
+
+// Fix 2: grpc-js (transport.js line 536) passes an already-connected socket
+// to http2.connect via createConnection. Deno's http2 never completes the
+// HTTP/2 handshake because it expects a "connect" event from the socket,
+// which already fired. Emitting "connect" again causes "Busy: Unix socket
+// is currently in use" in Deno's internal http2.
+//
+// Workaround: track Unix socket paths via net.connect intercept, then in
+// createConnection, return a FRESH socket. Keep the original socket alive
+// (grpc-js has close listeners on it) but unused for data.
+import net from "node:net";
+
+const socketPathMap = new WeakMap<net.Socket, string>();
+const origNetConnect = net.connect;
+(net as any).connect = function (...args: any[]) {
+  const sock = origNetConnect.apply(this, args as any);
+  if (args[0] && typeof args[0] === "object" && args[0].path) {
+    socketPathMap.set(sock, args[0].path);
+  }
+  return sock;
+};
+
+// Fix 3: Deno's http2 client never fires "remoteSettings" event, which
+// grpc-js waits for before marking the transport as READY.
+// Workaround: emit "remoteSettings" after "connect" with reasonable defaults.
+const origConnect = http2.connect;
+(http2 as any).connect = function (
+  authority: any,
+  options: any,
+  ...rest: any[]
+) {
+  // For Unix sockets: replace pre-connected socket with fresh one
+  if (options?.createConnection) {
+    const origCC = options.createConnection;
+    options = {
+      ...options,
+      createConnection(...ccArgs: any[]) {
+        const origSock = origCC.apply(this, ccArgs);
+        const unixPath = socketPathMap.get(origSock);
+        if (
+          unixPath &&
+          !origSock.connecting &&
+          origSock.readyState === "open"
+        ) {
+          const freshSock = net.connect({ path: unixPath });
+          freshSock.on("close", () => origSock.destroy());
+          return freshSock;
+        }
+        return origSock;
+      },
+    };
+  }
+
+  const session = origConnect.call(this, authority, options, ...rest);
+
+  // Emit remoteSettings after connect — Deno's http2 doesn't emit it
+  session.once("connect", () => {
+    if (!session.destroyed && !session.closed) {
+      const settings = {
+        headerTableSize: 4096,
+        enablePush: false,
+        initialWindowSize: 65535,
+        maxFrameSize: 16384,
+        maxConcurrentStreams: 100,
+        maxHeaderListSize: 8192,
+        maxHeaderSize: 8192,
+      };
+      process.nextTick(() => session.emit("remoteSettings", settings));
+    }
+  });
+
+  return session;
+};
diff --git a/pkg/coredeno/runtime/server.ts b/pkg/coredeno/runtime/server.ts
new file mode 100644
index 0000000..81065a2
--- /dev/null
+++ b/pkg/coredeno/runtime/server.ts
@@ -0,0 +1,124 @@
+// DenoService JSON-RPC server — Go calls Deno for module lifecycle management.
+// Uses length-prefixed JSON over raw Unix socket (Deno's http2 server is broken).
+// Protocol: 4-byte big-endian length + JSON payload, newline-delimited.
+
+import { ModuleRegistry } from "./modules.ts";
+
+export interface DenoServer {
+  close(): void;
+}
+
+export async function startDenoServer(
+  socketPath: string,
+  registry: ModuleRegistry,
+): Promise<DenoServer> {
+  // Remove stale socket
+  try {
+    Deno.removeSync(socketPath);
+  } catch {
+    // ignore
+  }
+
+  const listener = Deno.listen({ transport: "unix", path: socketPath });
+
+  const handleConnection = async (conn: Deno.UnixConn) => {
+    const reader = conn.readable.getReader();
+    const writer = conn.writable.getWriter();
+    const decoder = new TextDecoder();
+    let buffer = "";
+
+    try {
+      while (true) {
+        const { value, done } = await reader.read();
+        if (done) break;
+
+        buffer += decoder.decode(value, { stream: true });
+
+        // Process complete lines (newline-delimited JSON)
+        let newlineIdx: number;
+        while ((newlineIdx = buffer.indexOf("\n")) !== -1) {
+          const line = buffer.slice(0, newlineIdx);
+          buffer = buffer.slice(newlineIdx + 1);
+
+          if (!line.trim()) continue;
+
+          try {
+            const req = JSON.parse(line);
+            const resp = dispatch(req, registry);
+            await writer.write(
+              new TextEncoder().encode(JSON.stringify(resp) + "\n"),
+            );
+          } catch (err) {
+            const errResp = {
+              error: err instanceof Error ? err.message : String(err),
+            };
+            await writer.write(
+              new TextEncoder().encode(JSON.stringify(errResp) + "\n"),
+            );
+          }
+        }
+      }
+    } catch {
+      // Connection closed or error — expected during shutdown
+    } finally {
+      try {
+        writer.close();
+      } catch {
+        /* already closed */
+      }
+    }
+  };
+
+  // Accept connections in background
+  const abortController = new AbortController();
+  (async () => {
+    try {
+      for await (const conn of listener) {
+        if (abortController.signal.aborted) break;
+        handleConnection(conn);
+      }
+    } catch {
+      // Listener closed
+    }
+  })();
+
+  return {
+    close() {
+      abortController.abort();
+      listener.close();
+    },
+  };
+}
+
+interface RPCRequest {
+  method: string;
+  code?: string;
+  entry_point?: string;
+  permissions?: string[];
+  process_id?: string;
+}
+
+function dispatch(
+  req: RPCRequest,
+  registry: ModuleRegistry,
+): Record<string, unknown> {
+  switch (req.method) {
+    case "LoadModule": {
+      registry.load(
+        req.code ?? "",
+        req.entry_point ?? "",
+        req.permissions ?? [],
+      );
+      return { ok: true, error: "" };
+    }
+    case "UnloadModule": {
+      const ok = registry.unload(req.code ?? "");
+      return { ok };
+    }
+    case "ModuleStatus": {
+      return { code: req.code, status: registry.status(req.code ?? "") };
+    }
+    default:
+      return { error: `unknown method: ${req.method}` };
+  }
+}
diff --git a/pkg/coredeno/server.go b/pkg/coredeno/server.go
index 31395a1..df040bf 100644
--- a/pkg/coredeno/server.go
+++ b/pkg/coredeno/server.go
@@ -8,8 +8,27 @@ import (
 	"forge.lthn.ai/core/go/pkg/io"
 	"forge.lthn.ai/core/go/pkg/manifest"
 	"forge.lthn.ai/core/go/pkg/store"
+	"google.golang.org/grpc/codes"
+	"google.golang.org/grpc/status"
 )
 
+// ProcessRunner abstracts process management for the gRPC server.
+// Satisfied by *process.Service.
+type ProcessRunner interface {
+	Start(ctx context.Context, command string, args ...string) (ProcessHandle, error)
+	Kill(id string) error
+}
+
+// ProcessHandle is returned by ProcessRunner.Start.
+type ProcessHandle interface {
+	Info() ProcessInfo
+}
+
+// ProcessInfo is the subset of process info the server needs.
+type ProcessInfo struct {
+	ID string
+}
+
 // Server implements the CoreService gRPC interface with permission gating.
 // Every I/O request is checked against the calling module's declared permissions.
 type Server struct {
@@ -17,6 +36,7 @@ type Server struct {
 	medium    io.Medium
 	store     *store.Store
 	manifests map[string]*manifest.Manifest
+	processes ProcessRunner
 }
 
 // NewServer creates a CoreService server backed by the given Medium and Store.
@@ -129,3 +149,38 @@ func (s *Server) StoreSet(_ context.Context, req *pb.StoreSetRequest) (*pb.Store
 	}
 	return &pb.StoreSetResponse{Ok: true}, nil
 }
+
+// SetProcessRunner sets the process runner for ProcessStart/ProcessStop.
+func (s *Server) SetProcessRunner(pr ProcessRunner) {
+	s.processes = pr
+}
+
+// ProcessStart implements CoreService.ProcessStart with permission gating.
+func (s *Server) ProcessStart(ctx context.Context, req *pb.ProcessStartRequest) (*pb.ProcessStartResponse, error) {
+	if s.processes == nil {
+		return nil, status.Error(codes.Unimplemented, "process service not available")
+	}
+	m, err := s.getManifest(req.ModuleCode)
+	if err != nil {
+		return nil, err
+	}
+	if !CheckRun(req.Command, m.Permissions.Run) {
+		return nil, fmt.Errorf("permission denied: %s cannot run %s", req.ModuleCode, req.Command)
+	}
+	proc, err := s.processes.Start(ctx, req.Command, req.Args...)
+	if err != nil {
+		return nil, fmt.Errorf("process start: %w", err)
+	}
+	return &pb.ProcessStartResponse{ProcessId: proc.Info().ID}, nil
+}
+
+// ProcessStop implements CoreService.ProcessStop.
+func (s *Server) ProcessStop(_ context.Context, req *pb.ProcessStopRequest) (*pb.ProcessStopResponse, error) {
+	if s.processes == nil {
+		return nil, status.Error(codes.Unimplemented, "process service not available")
+	}
+	if err := s.processes.Kill(req.ProcessId); err != nil {
+		return nil, fmt.Errorf("process stop: %w", err)
+	}
+	return &pb.ProcessStopResponse{Ok: true}, nil
+}
diff --git a/pkg/coredeno/server_test.go b/pkg/coredeno/server_test.go
index 6438f33..276e064 100644
--- a/pkg/coredeno/server_test.go
+++ b/pkg/coredeno/server_test.go
@@ -2,16 +2,48 @@ package coredeno
 
 import (
 	"context"
+	"fmt"
 	"testing"
 
+	pb "forge.lthn.ai/core/go/pkg/coredeno/proto"
 	"forge.lthn.ai/core/go/pkg/io"
 	"forge.lthn.ai/core/go/pkg/manifest"
-	pb "forge.lthn.ai/core/go/pkg/coredeno/proto"
 	"forge.lthn.ai/core/go/pkg/store"
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
+	"google.golang.org/grpc/codes"
+	"google.golang.org/grpc/status"
 )
 
+// mockProcessRunner implements ProcessRunner for testing.
+type mockProcessRunner struct {
+	started map[string]bool
+	nextID  int
+}
+
+func newMockProcessRunner() *mockProcessRunner {
+	return &mockProcessRunner{started: make(map[string]bool)}
+}
+
+func (m *mockProcessRunner) Start(_ context.Context, command string, args ...string) (ProcessHandle, error) {
+	m.nextID++
+	id := fmt.Sprintf("proc-%d", m.nextID)
+	m.started[id] = true
+	return &mockProcessHandle{id: id}, nil
+}
+
+func (m *mockProcessRunner) Kill(id string) error {
+	if !m.started[id] {
+		return fmt.Errorf("process not found: %s", id)
+	}
+	delete(m.started, id)
+	return nil
+}
+
+type mockProcessHandle struct{ id string }
+
+func (h *mockProcessHandle) Info() ProcessInfo { return ProcessInfo{ID: h.id} }
+
 func newTestServer(t *testing.T) *Server {
 	t.Helper()
 	medium := io.NewMockMedium()
@@ -95,3 +127,74 @@ func TestStoreGet_Good_NotFound(t *testing.T) {
 	require.NoError(t, err)
 	assert.False(t, resp.Found)
 }
+
+func newTestServerWithProcess(t *testing.T) (*Server, *mockProcessRunner) {
+	t.Helper()
+	srv := newTestServer(t)
+	srv.RegisterModule(&manifest.Manifest{
+		Code: "runner-mod",
+		Permissions: manifest.Permissions{
+			Run: []string{"echo", "ls"},
+		},
+	})
+	pr := newMockProcessRunner()
+	srv.SetProcessRunner(pr)
+	return srv, pr
+}
+
+func TestProcessStart_Good(t *testing.T) {
+	srv, _ := newTestServerWithProcess(t)
+	resp, err := srv.ProcessStart(context.Background(), &pb.ProcessStartRequest{
+		Command: "echo", Args: []string{"hello"}, ModuleCode: "runner-mod",
+	})
+	require.NoError(t, err)
+	assert.NotEmpty(t, resp.ProcessId)
+}
+
+func TestProcessStart_Bad_PermissionDenied(t *testing.T) {
+	srv, _ := newTestServerWithProcess(t)
+	_, err := srv.ProcessStart(context.Background(), &pb.ProcessStartRequest{
+		Command: "rm", Args: []string{"-rf", "/"}, ModuleCode: "runner-mod",
+	})
+	assert.Error(t, err)
+	assert.Contains(t, err.Error(), "permission denied")
+}
+
+func TestProcessStart_Bad_NoProcessService(t *testing.T) {
+	srv := newTestServer(t)
+	srv.RegisterModule(&manifest.Manifest{
+		Code: "no-proc-mod",
+		Permissions: manifest.Permissions{Run: []string{"echo"}},
+	})
+	_, err := srv.ProcessStart(context.Background(), &pb.ProcessStartRequest{
+		Command: "echo", ModuleCode: "no-proc-mod",
+	})
+	assert.Error(t, err)
+	st, ok := status.FromError(err)
+	require.True(t, ok)
+	assert.Equal(t, codes.Unimplemented, st.Code())
+}
+
+func TestProcessStop_Good(t *testing.T) {
+	srv, _ := newTestServerWithProcess(t)
+	// Start a process first
+	startResp, err := srv.ProcessStart(context.Background(), &pb.ProcessStartRequest{
+		Command: "echo", ModuleCode: "runner-mod",
+	})
+	require.NoError(t, err)
+
+	// Stop it
+	resp, err := srv.ProcessStop(context.Background(), &pb.ProcessStopRequest{
+		ProcessId: startResp.ProcessId,
+	})
+	require.NoError(t, err)
+	assert.True(t, resp.Ok)
+}
+
+func TestProcessStop_Bad_NotFound(t *testing.T) {
+	srv, _ := newTestServerWithProcess(t)
+	_, err := srv.ProcessStop(context.Background(), &pb.ProcessStopRequest{
+		ProcessId: "nonexistent",
+	})
+	assert.Error(t, err)
+}
diff --git a/pkg/coredeno/service.go b/pkg/coredeno/service.go
index 9bc4d85..fe6bd70 100644
--- a/pkg/coredeno/service.go
+++ b/pkg/coredeno/service.go
@@ -3,6 +3,8 @@ package coredeno
 import (
 	"context"
 	"fmt"
+	"os"
+	"time"
 
 	core "forge.lthn.ai/core/go/pkg/framework/core"
 	"forge.lthn.ai/core/go/pkg/io"
@@ -23,6 +25,7 @@ type Service struct {
 	store      *store.Store
 	grpcCancel context.CancelFunc
 	grpcDone   chan error
+	denoClient *DenoClient
 }
 
 // NewServiceFactory returns a factory function for framework registration via WithService.
@@ -91,9 +94,26 @@ func (s *Service) OnStartup(ctx context.Context) error {
 
 	// 6. Start sidecar (if args provided)
 	if len(opts.SidecarArgs) > 0 {
+		// Wait for core socket so sidecar can connect to our gRPC server
+		if err := waitForSocket(ctx, opts.SocketPath, 5*time.Second); err != nil {
+			return fmt.Errorf("coredeno: core socket: %w", err)
+		}
+
 		if err := s.sidecar.Start(ctx, opts.SidecarArgs...); err != nil {
 			return fmt.Errorf("coredeno: sidecar: %w", err)
 		}
+
+		// 7. Wait for Deno's server and connect as client
+		if opts.DenoSocketPath != "" {
+			if err := waitForSocket(ctx, opts.DenoSocketPath, 10*time.Second); err != nil {
+				return fmt.Errorf("coredeno: deno socket: %w", err)
+			}
+			dc, err := DialDeno(opts.DenoSocketPath)
+			if err != nil {
+				return fmt.Errorf("coredeno: deno client: %w", err)
+			}
+			s.denoClient = dc
+		}
 	}
 
 	return nil
@@ -101,7 +121,12 @@ func (s *Service) OnStartup(ctx context.Context) error {
 
 // OnShutdown stops the CoreDeno subsystem. Called by the framework on app shutdown.
 func (s *Service) OnShutdown(_ context.Context) error {
-	// Stop sidecar first
+	// Close Deno client connection
+	if s.denoClient != nil {
+		s.denoClient.Close()
+	}
+
+	// Stop sidecar
 	_ = s.sidecar.Stop()
 
 	// Stop gRPC listener
@@ -127,3 +152,27 @@ func (s *Service) Sidecar() *Sidecar {
 func (s *Service) GRPCServer() *Server {
 	return s.grpcServer
 }
+
+// DenoClient returns the DenoService client for calling the Deno sidecar.
+// Returns nil if the sidecar was not started or has no DenoSocketPath.
+func (s *Service) DenoClient() *DenoClient {
+	return s.denoClient
+}
+
+// waitForSocket polls until a Unix socket file appears or the context/timeout expires.
+func waitForSocket(ctx context.Context, path string, timeout time.Duration) error {
+	deadline := time.Now().Add(timeout)
+	for {
+		if _, err := os.Stat(path); err == nil {
+			return nil
+		}
+		if time.Now().After(deadline) {
+			return fmt.Errorf("timeout waiting for socket %s", path)
+		}
+		select {
+		case <-ctx.Done():
+			return ctx.Err()
+		case <-time.After(50 * time.Millisecond):
+		}
+	}
+}