Discord: add fetch message action

skills/discord/SKILL.md

@@ -12,6 +12,7 @@ Use `discord` to manage messages, reactions, threads, polls, and moderation. You
 ## Inputs to collect
 
 - For reactions: `channelId`, `messageId`, and an `emoji`.
+- For fetchMessage: `guildId`, `channelId`, `messageId`, or a `messageLink` like `https://discord.com/channels/<guildId>/<channelId>/<messageId>`.
 - For stickers/polls/sendMessage: a `to` target (`channel:<id>` or `user:<id>`). Optional `content` text.
 - Polls also need a `question` plus 2–10 `answers`.
 - For media: `mediaUrl` with `file:///path` for local files or `https://...` for remote.
@@ -21,6 +22,7 @@ Use `discord` to manage messages, reactions, threads, polls, and moderation. You
 Message context lines include `discord message id` and `channel` fields you can reuse directly.
 
 **Note:** `sendMessage` uses `to: "channel:<id>"` format, not `channelId`. Other actions like `react`, `readMessages`, `editMessage` use `channelId` directly.
+**Note:** `fetchMessage` accepts message IDs or full links like `https://discord.com/channels/<guildId>/<channelId>/<messageId>`.
 
 ## Actions
 
@@ -144,6 +146,24 @@ Use `discord.actions.*` to disable action groups:
 }
 ```
 
+### Fetch a single message
+
+```json
+{
+  "action": "fetchMessage",
+  "guildId": "999",
+  "channelId": "123",
+  "messageId": "456"
+}
+```
+
+```json
+{
+  "action": "fetchMessage",
+  "messageLink": "https://discord.com/channels/999/123/456"
+}
+```
+
 ### Send/edit/delete a message
 
 ```json

src/agents/tools/discord-actions-messaging.ts

@@ -5,6 +5,7 @@ import {
   deleteMessageDiscord,
   editMessageDiscord,
   fetchChannelPermissionsDiscord,
+  fetchMessageDiscord,
   fetchReactionsDiscord,
   listPinsDiscord,
   listThreadsDiscord,
@@ -53,6 +54,23 @@ function formatDiscordTimestamp(ts?: string | null): string | undefined {
   return `${yyyy}-${mm}-${dd}T${hh}:${min}${sign}${offsetH}:${offsetM}${tzSuffix}`;
 }
 
+function parseDiscordMessageLink(link: string) {
+  const normalized = link.trim();
+  const match = normalized.match(
+    /^(?:https?:\/\/)?(?:ptb\.|canary\.)?discord(?:app)?\.com\/channels\/(\d+)\/(\d+)\/(\d+)(?:\/?|\?.*)$/i,
+  );
+  if (!match) {
+    throw new Error(
+      "Invalid Discord message link. Expected https://discord.com/channels/<guildId>/<channelId>/<messageId>.",
+    );
+  }
+  return {
+    guildId: match[1],
+    channelId: match[2],
+    messageId: match[3],
+  };
+}
+
 export async function handleDiscordMessagingAction(
   action: string,
   params: Record<string, unknown>,
@@ -157,6 +175,28 @@ export async function handleDiscordMessagingAction(
       const permissions = await fetchChannelPermissionsDiscord(channelId);
       return jsonResult({ ok: true, permissions });
     }
+    case "fetchMessage": {
+      if (!isActionEnabled("messages")) {
+        throw new Error("Discord message reads are disabled.");
+      }
+      const messageLink = readStringParam(params, "messageLink");
+      let guildId = readStringParam(params, "guildId");
+      let channelId = readStringParam(params, "channelId");
+      let messageId = readStringParam(params, "messageId");
+      if (messageLink) {
+        const parsed = parseDiscordMessageLink(messageLink);
+        guildId = parsed.guildId;
+        channelId = parsed.channelId;
+        messageId = parsed.messageId;
+      }
+      if (!guildId || !channelId || !messageId) {
+        throw new Error(
+          "Discord message fetch requires guildId, channelId, and messageId (or a valid messageLink).",
+        );
+      }
+      const message = await fetchMessageDiscord(channelId, messageId);
+      return jsonResult({ ok: true, message, guildId, channelId, messageId });
+    }
     case "readMessages": {
       if (!isActionEnabled("messages")) {
         throw new Error("Discord message reads are disabled.");

src/agents/tools/discord-actions.ts

@@ -11,6 +11,7 @@ const messagingActions = new Set([
   "sticker",
   "poll",
   "permissions",
+  "fetchMessage",
   "readMessages",
   "sendMessage",
   "editMessage",

src/agents/tools/discord-schema.ts

@@ -35,6 +35,21 @@ export const DiscordToolSchema = Type.Union([
     action: Type.Literal("permissions"),
     channelId: Type.String(),
   }),
+  Type.Union([
+    Type.Object({
+      action: Type.Literal("fetchMessage"),
+      messageLink: Type.String(),
+      guildId: Type.Optional(Type.String()),
+      channelId: Type.Optional(Type.String()),
+      messageId: Type.Optional(Type.String()),
+    }),
+    Type.Object({
+      action: Type.Literal("fetchMessage"),
+      guildId: Type.String(),
+      channelId: Type.String(),
+      messageId: Type.String(),
+    }),
+  ]),
   Type.Object({
     action: Type.Literal("readMessages"),
     channelId: Type.String(),

src/discord/send.ts

@@ -903,6 +903,17 @@ export async function readMessagesDiscord(
   )) as APIMessage[];
 }
 
+export async function fetchMessageDiscord(
+  channelId: string,
+  messageId: string,
+  opts: DiscordReactOpts = {},
+): Promise<APIMessage> {
+  const rest = resolveDiscordRest(opts);
+  return (await rest.get(
+    Routes.channelMessage(channelId, messageId),
+  )) as APIMessage;
+}
+
 export async function editMessageDiscord(
   channelId: string,
   messageId: string,