From 96b4c543f4d8f3f48f3568205d0f78c5e952cfe1 Mon Sep 17 00:00:00 2001
From: hschne <hello@hansschnedlitz.com>
Date: Fri, 22 May 2026 19:27:48 +0200
Subject: [PATCH] fix(discord): download attachments for vision pipeline

Discord only downloaded audio attachments before passing them to the agent. Non-audio attachments (images, videos, files) were passed as raw Discord CDN URLs, which do not flow through resolveMediaRefs and are not serialized as vision inputs.

Download every attachment, store it in the MediaStore with Discord's filename and content type metadata, and emit a media placeholder tag that matches the attachment kind. This lets resolveMediaRefs replace the placeholder with the local path-bearing tag and encode supported images for vision-capable providers. If a download fails, keep the previous raw URL fallback.
---
 pkg/channels/discord/discord.go | 54 ++++++++++++++++++++++-----------
 1 file changed, 37 insertions(+), 17 deletions(-)

diff --git a/pkg/channels/discord/discord.go b/pkg/channels/discord/discord.go
index 514b9b3b1..394a06ad2 100644
--- a/pkg/channels/discord/discord.go
+++ b/pkg/channels/discord/discord.go
@@ -7,6 +7,7 @@ import (
 	"net/http"
 	"net/url"
 	"os"
+	"path/filepath"
 	"regexp"
 	"strings"
 	"sync"
@@ -605,10 +606,11 @@ func (c *DiscordChannel) handleMessage(s *discordgo.Session, m *discordgo.Messag
 	scope := channels.BuildMediaScope("discord", m.ChannelID, m.ID)
 
 	// Helper to register a local file with the media store
-	storeMedia := func(localPath, filename string) string {
+	storeMedia := func(localPath string, attachment *discordgo.MessageAttachment) string {
 		if store := c.GetMediaStore(); store != nil {
 			ref, err := store.Store(localPath, media.MediaMeta{
-				Filename:      filename,
+				Filename:      attachment.Filename,
+				ContentType:   attachment.ContentType,
 				Source:        "discord",
 				CleanupPolicy: media.CleanupPolicyDeleteOnCleanup,
 			}, scope)
@@ -620,22 +622,16 @@ func (c *DiscordChannel) handleMessage(s *discordgo.Session, m *discordgo.Messag
 	}
 
 	for _, attachment := range m.Attachments {
-		isAudio := utils.IsAudioFile(attachment.Filename, attachment.ContentType)
-
-		if isAudio {
-			localPath := c.downloadAttachment(attachment.URL, attachment.Filename)
-			if localPath != "" {
-				mediaPaths = append(mediaPaths, storeMedia(localPath, attachment.Filename))
-				content = appendContent(content, fmt.Sprintf("[audio: %s]", attachment.Filename))
-			} else {
-				logger.WarnCF("discord", "Failed to download audio attachment", map[string]any{
-					"url":      attachment.URL,
-					"filename": attachment.Filename,
-				})
-				mediaPaths = append(mediaPaths, attachment.URL)
-				content = appendContent(content, fmt.Sprintf("[attachment: %s]", attachment.URL))
-			}
+		localPath := c.downloadAttachment(attachment.URL, attachment.Filename)
+		if localPath != "" {
+			mediaPaths = append(mediaPaths, storeMedia(localPath, attachment))
+			tag := attachmentMediaTag(attachment.Filename, attachment.ContentType)
+			content = appendContent(content, fmt.Sprintf("[%s: %s]", tag, attachment.Filename))
 		} else {
+			logger.WarnCF("discord", "Failed to download attachment", map[string]any{
+				"url":      attachment.URL,
+				"filename": attachment.Filename,
+			})
 			mediaPaths = append(mediaPaths, attachment.URL)
 			content = appendContent(content, fmt.Sprintf("[attachment: %s]", attachment.URL))
 		}
@@ -748,6 +744,30 @@ func (c *DiscordChannel) downloadAttachment(url, filename string) string {
 	})
 }
 
+func attachmentMediaTag(filename, contentType string) string {
+	ct := strings.ToLower(contentType)
+	switch {
+	case strings.HasPrefix(ct, "image/"):
+		return "image"
+	case strings.HasPrefix(ct, "audio/"), ct == "application/ogg", ct == "application/x-ogg":
+		return "audio"
+	case strings.HasPrefix(ct, "video/"):
+		return "video"
+	}
+
+	ext := strings.ToLower(filepath.Ext(filename))
+	switch ext {
+	case ".jpg", ".jpeg", ".png", ".gif", ".webp", ".bmp":
+		return "image"
+	case ".mp3", ".wav", ".ogg", ".m4a", ".flac", ".aac", ".wma":
+		return "audio"
+	case ".mp4", ".avi", ".mov", ".webm", ".mkv":
+		return "video"
+	}
+
+	return "file"
+}
+
 func applyDiscordProxy(session *discordgo.Session, proxyAddr string) error {
 	var proxyFunc func(*http.Request) (*url.URL, error)
 	if proxyAddr != "" {