fix(media): match all channel image placeholders in injectPathTags

Different channels emit different placeholder formats — Telegram/Feishu
use [image: photo], WeCom/WeChat/Line use bare [image], QQ/Discord use
[image: <filename>]. The previous string-match code only handled
[image: photo], so for the other channels the path tag was appended as
a duplicate, producing content like "[image] [image:/path]".

Switch to per-type regex that matches all generic placeholder shapes
while leaving path tags ([image:/path]) untouched. Also fixes the same
issue for [audio], [video], [file] tags. Added test coverage for the
various placeholder shapes.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

pkg/agent/agent_media.go

@@ -11,6 +11,7 @@ import (
 	"encoding/base64"
 	"io"
 	"os"
+	"regexp"
 	"strings"
 
 	"github.com/h2non/filetype"
@@ -20,12 +21,23 @@ import (
 	"github.com/sipeed/picoclaw/pkg/providers"
 )
 
+// genericPlaceholderRegex matches generic media placeholders emitted by various
+// channels: [image], [image: photo], [image: filename.jpg] — but NOT path tags
+// like [image:/path/to/file] (path tags have no space after the colon).
+var (
+	imagePlaceholderRegex = regexp.MustCompile(`\[image(:\s+[^\]]*)?\]`)
+	audioPlaceholderRegex = regexp.MustCompile(`\[audio(:\s+[^\]]*)?\]`)
+	videoPlaceholderRegex = regexp.MustCompile(`\[video(:\s+[^\]]*)?\]`)
+	filePlaceholderRegex  = regexp.MustCompile(`\[file(:\s+[^\]]*)?\]`)
+)
+
 // resolveMediaRefs resolves media:// refs in messages.
 // For user messages: images get path tags only ([image:/path]) so the LLM
 // can decide whether to view them via load_image or operate on the file.
 // For tool messages: images are base64-encoded and appended as a synthetic
-// user message after the contiguous tool-message block ends, preserving
-// the required assistant→tool ordering for LLM APIs.
+// user message only after the contiguous tool-message block ends, so we don't
+// break the tool-results-must-immediately-follow-assistant constraint that
+// LLM APIs enforce.
 // Non-image files always get path tags regardless of role.
 // Returns a new slice; original messages are not mutated.
 func resolveMediaRefs(messages []providers.Message, store media.MediaStore, maxSize int) []providers.Message {
@@ -227,24 +239,31 @@ func buildPathTag(mime, localPath string) string {
 }
 
 // injectPathTags replaces generic media tags in content with path-bearing versions,
-// or appends if no matching generic tag is found.
+// or appends if no matching generic tag is found. Channels emit a few different
+// placeholder formats — [image], [image: photo], [image: filename.jpg] — so we
+// match all of them via regex while leaving path tags ([image:/path]) untouched.
 func injectPathTags(content string, tags []string) string {
 	for _, tag := range tags {
-		var generic string
+		var pattern *regexp.Regexp
 		switch {
 		case strings.HasPrefix(tag, "[image:"):
-			generic = "[image: photo]"
+			pattern = imagePlaceholderRegex
 		case strings.HasPrefix(tag, "[audio:"):
-			generic = "[audio]"
+			pattern = audioPlaceholderRegex
 		case strings.HasPrefix(tag, "[video:"):
-			generic = "[video]"
+			pattern = videoPlaceholderRegex
 		case strings.HasPrefix(tag, "[file:"):
-			generic = "[file]"
+			pattern = filePlaceholderRegex
 		}
 
-		if generic != "" && strings.Contains(content, generic) {
-			content = strings.Replace(content, generic, tag, 1)
-		} else if content == "" {
+		if pattern != nil {
+			if loc := pattern.FindStringIndex(content); loc != nil {
+				content = content[:loc[0]] + tag + content[loc[1]:]
+				continue
+			}
+		}
+
+		if content == "" {
 			content = tag
 		} else {
 			content += " " + tag

pkg/agent/agent_test.go

@@ -4992,6 +4992,54 @@ func TestResolveMediaRefs_NoGenericTagAppendsPath(t *testing.T) {
 	}
 }
 
+func TestInjectPathTags_HandlesVariousChannelPlaceholders(t *testing.T) {
+	cases := []struct {
+		name    string
+		content string
+		tag     string
+		want    string
+	}{
+		// Telegram / Feishu format
+		{"image_photo", "[image: photo]", "[image:/tmp/p.png]", "[image:/tmp/p.png]"},
+		// WeCom / WeChat / Line format
+		{"bare_image", "[image]", "[image:/tmp/p.png]", "[image:/tmp/p.png]"},
+		// QQ / Discord format with filename
+		{"image_filename", "[image: pic.jpg]", "[image:/tmp/p.png]", "[image:/tmp/p.png]"},
+		{"audio_with_filename", "[audio: voice.m4a]", "[audio:/tmp/a.m4a]", "[audio:/tmp/a.m4a]"},
+		{"bare_audio", "[audio]", "[audio:/tmp/a.m4a]", "[audio:/tmp/a.m4a]"},
+		{"bare_video", "[video]", "[video:/tmp/v.mp4]", "[video:/tmp/v.mp4]"},
+		{"bare_file", "[file]", "[file:/tmp/f.pdf]", "[file:/tmp/f.pdf]"},
+		// Mixed surrounding text
+		{
+			"with_text",
+			"hello [image] world",
+			"[image:/tmp/p.png]",
+			"hello [image:/tmp/p.png] world",
+		},
+		// No placeholder — append
+		{"no_placeholder", "hello world", "[image:/tmp/p.png]", "hello world [image:/tmp/p.png]"},
+	}
+
+	for _, tc := range cases {
+		t.Run(tc.name, func(t *testing.T) {
+			got := injectPathTags(tc.content, []string{tc.tag})
+			if got != tc.want {
+				t.Errorf("expected %q, got %q", tc.want, got)
+			}
+		})
+	}
+}
+
+func TestInjectPathTags_DoesNotReplacePathTag(t *testing.T) {
+	// If content already contains a path tag, we must not touch it.
+	content := "see [image:/already/placed.png] thanks"
+	got := injectPathTags(content, []string{"[image:/new/path.png]"})
+	want := "see [image:/already/placed.png] thanks [image:/new/path.png]"
+	if got != want {
+		t.Fatalf("expected %q, got %q", want, got)
+	}
+}
+
 func TestResolveMediaRefs_EmptyContentGetsPathTag(t *testing.T) {
 	store := media.NewFileMediaStore()
 	dir := t.TempDir()