diff --git a/pkg/agent/loop.go b/pkg/agent/loop.go
index 966668227..19d13b2bb 100644
--- a/pkg/agent/loop.go
+++ b/pkg/agent/loop.go
@@ -183,6 +183,17 @@ func registerSharedTools(
 			agent.Tools.Register(messageTool)
 		}
 
+		// Send file tool (outbound media via MediaStore — store injected later by SetMediaStore)
+		if cfg.Tools.IsToolEnabled("send_file") {
+			sendFileTool := tools.NewSendFileTool(
+				agent.Workspace,
+				cfg.Agents.Defaults.RestrictToWorkspace,
+				cfg.Agents.Defaults.GetMaxMediaSize(),
+				nil,
+			)
+			agent.Tools.Register(sendFileTool)
+		}
+
 		// Skill discovery and installation tools
 		skills_enabled := cfg.Tools.IsToolEnabled("skills")
 		find_skills_enable := cfg.Tools.IsToolEnabled("find_skills")
@@ -384,6 +395,13 @@ func (al *AgentLoop) SetChannelManager(cm *channels.Manager) {
 // SetMediaStore injects a MediaStore for media lifecycle management.
 func (al *AgentLoop) SetMediaStore(s media.MediaStore) {
 	al.mediaStore = s
+
+	// Propagate store to send_file tools in all agents.
+	al.registry.ForEachTool("send_file", func(t tools.Tool) {
+		if sf, ok := t.(*tools.SendFileTool); ok {
+			sf.SetMediaStore(s)
+		}
+	})
 }
 
 // SetTranscriber injects a voice transcriber for agent-level audio transcription.
@@ -1167,7 +1185,7 @@ func (al *AgentLoop) runLLMIteration(
 			}
 
 			// If tool returned media refs, publish them as outbound media
-			if len(r.result.Media) > 0 && opts.SendResponse {
+			if len(r.result.Media) > 0 {
 				parts := make([]bus.MediaPart, 0, len(r.result.Media))
 				for _, ref := range r.result.Media {
 					part := bus.MediaPart{Ref: ref}
diff --git a/pkg/agent/registry.go b/pkg/agent/registry.go
index 77b846832..0e7973dc3 100644
--- a/pkg/agent/registry.go
+++ b/pkg/agent/registry.go
@@ -7,6 +7,7 @@ import (
 	"github.com/sipeed/picoclaw/pkg/logger"
 	"github.com/sipeed/picoclaw/pkg/providers"
 	"github.com/sipeed/picoclaw/pkg/routing"
+	"github.com/sipeed/picoclaw/pkg/tools"
 )
 
 // AgentRegistry manages multiple agent instances and routes messages to them.
@@ -100,6 +101,19 @@ func (r *AgentRegistry) CanSpawnSubagent(parentAgentID, targetAgentID string) bo
 	return false
 }
 
+// ForEachTool calls fn for every tool registered under the given name
+// across all agents. This is useful for propagating dependencies (e.g.
+// MediaStore) to tools after registry construction.
+func (r *AgentRegistry) ForEachTool(name string, fn func(tools.Tool)) {
+	r.mu.RLock()
+	defer r.mu.RUnlock()
+	for _, agent := range r.agents {
+		if t, ok := agent.Tools.Get(name); ok {
+			fn(t)
+		}
+	}
+}
+
 // GetDefaultAgent returns the default agent instance.
 func (r *AgentRegistry) GetDefaultAgent() *AgentInstance {
 	r.mu.RLock()
diff --git a/pkg/config/config.go b/pkg/config/config.go
index cff81a3a7..72af3e2fb 100644
--- a/pkg/config/config.go
+++ b/pkg/config/config.go
@@ -640,6 +640,7 @@ type ToolsConfig struct {
 	ListDir         ToolConfig         `json:"list_dir"                                                 envPrefix:"PICOCLAW_TOOLS_LIST_DIR_"`
 	Message         ToolConfig         `json:"message"                                                  envPrefix:"PICOCLAW_TOOLS_MESSAGE_"`
 	ReadFile        ToolConfig         `json:"read_file"                                                envPrefix:"PICOCLAW_TOOLS_READ_FILE_"`
+	SendFile        ToolConfig         `json:"send_file"                                                envPrefix:"PICOCLAW_TOOLS_SEND_FILE_"`
 	Spawn           ToolConfig         `json:"spawn"                                                    envPrefix:"PICOCLAW_TOOLS_SPAWN_"`
 	SPI             ToolConfig         `json:"spi"                                                      envPrefix:"PICOCLAW_TOOLS_SPI_"`
 	Subagent        ToolConfig         `json:"subagent"                                                 envPrefix:"PICOCLAW_TOOLS_SUBAGENT_"`
@@ -913,6 +914,8 @@ func (t *ToolsConfig) IsToolEnabled(name string) bool {
 		return t.Subagent.Enabled
 	case "web_fetch":
 		return t.WebFetch.Enabled
+	case "send_file":
+		return t.SendFile.Enabled
 	case "write_file":
 		return t.WriteFile.Enabled
 	case "mcp":
diff --git a/pkg/config/defaults.go b/pkg/config/defaults.go
index c4c04d41a..1902480c5 100644
--- a/pkg/config/defaults.go
+++ b/pkg/config/defaults.go
@@ -404,6 +404,9 @@ func DefaultConfig() *Config {
 					TTLSeconds: 300,
 				},
 			},
+			SendFile: ToolConfig{
+				Enabled: true,
+			},
 			MCP: MCPConfig{
 				ToolConfig: ToolConfig{
 					Enabled: false,
diff --git a/pkg/tools/send_file.go b/pkg/tools/send_file.go
new file mode 100644
index 000000000..1a03e58ed
--- /dev/null
+++ b/pkg/tools/send_file.go
@@ -0,0 +1,150 @@
+package tools
+
+import (
+	"context"
+	"fmt"
+	"mime"
+	"os"
+	"path/filepath"
+	"strings"
+
+	"github.com/h2non/filetype"
+
+	"github.com/sipeed/picoclaw/pkg/config"
+	"github.com/sipeed/picoclaw/pkg/media"
+)
+
+// SendFileTool allows the LLM to send a local file (image, document, etc.)
+// to the user on the current chat channel via the MediaStore pipeline.
+type SendFileTool struct {
+	workspace   string
+	restrict    bool
+	maxFileSize int
+	mediaStore  media.MediaStore
+
+	defaultChannel string
+	defaultChatID  string
+}
+
+func NewSendFileTool(workspace string, restrict bool, maxFileSize int, store media.MediaStore) *SendFileTool {
+	if maxFileSize <= 0 {
+		maxFileSize = config.DefaultMaxMediaSize
+	}
+	return &SendFileTool{
+		workspace:   workspace,
+		restrict:    restrict,
+		maxFileSize: maxFileSize,
+		mediaStore:  store,
+	}
+}
+
+func (t *SendFileTool) Name() string { return "send_file" }
+func (t *SendFileTool) Description() string {
+	return "Send a local file (image, document, etc.) to the user on the current chat channel."
+}
+
+func (t *SendFileTool) Parameters() map[string]any {
+	return map[string]any{
+		"type": "object",
+		"properties": map[string]any{
+			"path": map[string]any{
+				"type":        "string",
+				"description": "Path to the local file. Relative paths are resolved from workspace.",
+			},
+			"filename": map[string]any{
+				"type":        "string",
+				"description": "Optional display filename. Defaults to the basename of path.",
+			},
+		},
+		"required": []string{"path"},
+	}
+}
+
+func (t *SendFileTool) SetContext(channel, chatID string) {
+	t.defaultChannel = channel
+	t.defaultChatID = chatID
+}
+
+func (t *SendFileTool) SetMediaStore(store media.MediaStore) {
+	t.mediaStore = store
+}
+
+func (t *SendFileTool) Execute(ctx context.Context, args map[string]any) *ToolResult {
+	path, _ := args["path"].(string)
+	if strings.TrimSpace(path) == "" {
+		return ErrorResult("path is required")
+	}
+
+	// Prefer context-injected channel/chatID (set by ExecuteWithContext), fall back to SetContext values.
+	channel := ToolChannel(ctx)
+	if channel == "" {
+		channel = t.defaultChannel
+	}
+	chatID := ToolChatID(ctx)
+	if chatID == "" {
+		chatID = t.defaultChatID
+	}
+	if channel == "" || chatID == "" {
+		return ErrorResult("no target channel/chat available")
+	}
+
+	if t.mediaStore == nil {
+		return ErrorResult("media store not configured")
+	}
+
+	resolved, err := validatePath(path, t.workspace, t.restrict)
+	if err != nil {
+		return ErrorResult(fmt.Sprintf("invalid path: %v", err))
+	}
+
+	info, err := os.Stat(resolved)
+	if err != nil {
+		return ErrorResult(fmt.Sprintf("file not found: %v", err))
+	}
+	if info.IsDir() {
+		return ErrorResult("path is a directory, expected a file")
+	}
+	if info.Size() > int64(t.maxFileSize) {
+		return ErrorResult(fmt.Sprintf(
+			"file too large: %d bytes (max %d bytes)",
+			info.Size(), t.maxFileSize,
+		))
+	}
+
+	filename, _ := args["filename"].(string)
+	if filename == "" {
+		filename = filepath.Base(resolved)
+	}
+
+	mediaType := detectMediaType(resolved)
+	scope := fmt.Sprintf("tool:send_file:%s:%s", channel, chatID)
+
+	ref, err := t.mediaStore.Store(resolved, media.MediaMeta{
+		Filename:    filename,
+		ContentType: mediaType,
+		Source:      "tool:send_file",
+	}, scope)
+	if err != nil {
+		return ErrorResult(fmt.Sprintf("failed to register media: %v", err))
+	}
+
+	return MediaResult(fmt.Sprintf("File %q sent to user", filename), []string{ref})
+}
+
+// detectMediaType determines the MIME type of a file.
+// Uses magic-bytes detection (h2non/filetype) first, then falls back to
+// extension-based lookup via mime.TypeByExtension.
+func detectMediaType(path string) string {
+	kind, err := filetype.MatchFile(path)
+	if err == nil && kind != filetype.Unknown {
+		return kind.MIME.Value
+	}
+
+	if ext := filepath.Ext(path); ext != "" {
+		if t := mime.TypeByExtension(ext); t != "" {
+			return t
+		}
+	}
+
+	return "application/octet-stream"
+}
diff --git a/pkg/tools/send_file_test.go b/pkg/tools/send_file_test.go
new file mode 100644
index 000000000..08d129674
--- /dev/null
+++ b/pkg/tools/send_file_test.go
@@ -0,0 +1,176 @@
+package tools
+
+import (
+	"context"
+	"os"
+	"path/filepath"
+	"strings"
+	"testing"
+
+	"github.com/sipeed/picoclaw/pkg/config"
+	"github.com/sipeed/picoclaw/pkg/media"
+)
+
+func TestSendFileTool_MissingPath(t *testing.T) {
+	store := media.NewFileMediaStore()
+	tool := NewSendFileTool("/tmp", false, 0, store)
+	tool.SetContext("feishu", "chat123")
+
+	result := tool.Execute(context.Background(), map[string]any{})
+	if !result.IsError {
+		t.Fatal("expected error for missing path")
+	}
+}
+
+func TestSendFileTool_NoContext(t *testing.T) {
+	store := media.NewFileMediaStore()
+	tool := NewSendFileTool("/tmp", false, 0, store)
+	// no SetContext call
+
+	result := tool.Execute(context.Background(), map[string]any{"path": "/tmp/test.txt"})
+	if !result.IsError {
+		t.Fatal("expected error when no channel context")
+	}
+}
+
+func TestSendFileTool_NoMediaStore(t *testing.T) {
+	tool := NewSendFileTool("/tmp", false, 0, nil)
+	tool.SetContext("feishu", "chat123")
+
+	result := tool.Execute(context.Background(), map[string]any{"path": "/tmp/test.txt"})
+	if !result.IsError {
+		t.Fatal("expected error when no media store")
+	}
+}
+
+func TestSendFileTool_Directory(t *testing.T) {
+	store := media.NewFileMediaStore()
+	tool := NewSendFileTool("/tmp", false, 0, store)
+	tool.SetContext("feishu", "chat123")
+
+	result := tool.Execute(context.Background(), map[string]any{"path": "/tmp"})
+	if !result.IsError {
+		t.Fatal("expected error for directory path")
+	}
+}
+
+func TestSendFileTool_FileTooLarge(t *testing.T) {
+	dir := t.TempDir()
+	testFile := filepath.Join(dir, "big.bin")
+	// Create a file larger than the limit
+	if err := os.WriteFile(testFile, make([]byte, 1024), 0o644); err != nil {
+		t.Fatal(err)
+	}
+
+	store := media.NewFileMediaStore()
+	tool := NewSendFileTool(dir, false, 512, store) // 512 byte limit
+	tool.SetContext("feishu", "chat123")
+
+	result := tool.Execute(context.Background(), map[string]any{"path": testFile})
+	if !result.IsError {
+		t.Fatal("expected error for oversized file")
+	}
+	if !strings.Contains(result.ForLLM, "too large") {
+		t.Errorf("expected 'too large' in error, got %q", result.ForLLM)
+	}
+}
+
+func TestSendFileTool_DefaultMaxSize(t *testing.T) {
+	tool := NewSendFileTool("/tmp", false, 0, nil)
+	if tool.maxFileSize != config.DefaultMaxMediaSize {
+		t.Errorf("expected default max size %d, got %d", config.DefaultMaxMediaSize, tool.maxFileSize)
+	}
+}
+
+func TestSendFileTool_Success(t *testing.T) {
+	dir := t.TempDir()
+	testFile := filepath.Join(dir, "photo.png")
+	if err := os.WriteFile(testFile, []byte("fake png"), 0o644); err != nil {
+		t.Fatal(err)
+	}
+
+	store := media.NewFileMediaStore()
+	tool := NewSendFileTool(dir, false, 0, store)
+	tool.SetContext("feishu", "chat123")
+
+	result := tool.Execute(context.Background(), map[string]any{"path": testFile})
+	if result.IsError {
+		t.Fatalf("unexpected error: %s", result.ForLLM)
+	}
+	if len(result.Media) != 1 {
+		t.Fatalf("expected 1 media ref, got %d", len(result.Media))
+	}
+	if result.Media[0][:8] != "media://" {
+		t.Errorf("expected media:// ref, got %q", result.Media[0])
+	}
+}
+
+func TestSendFileTool_CustomFilename(t *testing.T) {
+	dir := t.TempDir()
+	testFile := filepath.Join(dir, "img.jpg")
+	if err := os.WriteFile(testFile, []byte("fake jpg"), 0o644); err != nil {
+		t.Fatal(err)
+	}
+
+	store := media.NewFileMediaStore()
+	tool := NewSendFileTool(dir, false, 0, store)
+	tool.SetContext("telegram", "chat456")
+
+	result := tool.Execute(context.Background(), map[string]any{
+		"path":     testFile,
+		"filename": "my-photo.jpg",
+	})
+	if result.IsError {
+		t.Fatalf("unexpected error: %s", result.ForLLM)
+	}
+	if len(result.Media) != 1 {
+		t.Fatalf("expected 1 media ref, got %d", len(result.Media))
+	}
+}
+
+func TestDetectMediaType_MagicBytes(t *testing.T) {
+	dir := t.TempDir()
+
+	// Minimal valid PNG header
+	pngHeader := []byte{0x89, 0x50, 0x4E, 0x47, 0x0D, 0x0A, 0x1A, 0x0A}
+	pngFile := filepath.Join(dir, "image.dat") // wrong extension, but valid PNG bytes
+	if err := os.WriteFile(pngFile, pngHeader, 0o644); err != nil {
+		t.Fatal(err)
+	}
+
+	got := detectMediaType(pngFile)
+	if got != "image/png" {
+		t.Errorf("expected image/png from magic bytes, got %q", got)
+	}
+}
+
+func TestDetectMediaType_FallbackToExtension(t *testing.T) {
+	dir := t.TempDir()
+
+	// File with unrecognizable content but known extension
+	txtFile := filepath.Join(dir, "readme.txt")
+	if err := os.WriteFile(txtFile, []byte("hello world"), 0o644); err != nil {
+		t.Fatal(err)
+	}
+
+	got := detectMediaType(txtFile)
+	// text/plain or similar — just verify it's not application/octet-stream
+	if got == "application/octet-stream" {
+		t.Errorf("expected extension-based MIME for .txt, got %q", got)
+	}
+}
+
+func TestDetectMediaType_UnknownFallsToOctetStream(t *testing.T) {
+	dir := t.TempDir()
+
+	// File with no extension and random bytes
+	unknownFile := filepath.Join(dir, "mystery")
+	if err := os.WriteFile(unknownFile, []byte{0x00, 0x01, 0x02}, 0o644); err != nil {
+		t.Fatal(err)
+	}
+
+	got := detectMediaType(unknownFile)
+	if got != "application/octet-stream" {
+		t.Errorf("expected application/octet-stream, got %q", got)
+	}
+}