diff --git a/CHANGELOG.md b/CHANGELOG.md
index 569a3f1ee..449555623 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -8,6 +8,7 @@
 - CLI: add `sandbox list` and `sandbox recreate` commands for managing Docker sandbox containers after image/config updates. (#563) — thanks @pasogott
 - Providers: add Microsoft Teams provider with polling, attachments, and CLI send support. (#404) — thanks @onutc
 - Slack: honor reply tags + replyToMode while keeping threaded replies in-thread. (#574) — thanks @bolismauro
+- Discord: fix forum thread starters and cache channel lookups for thread context. (#585) — thanks @thewilloftheshadow
 - Commands: accept /models as an alias for /model.
 - Commands: add `/usage` as an alias for `/status`. (#492) — thanks @lc0rp
 - Models/Auth: show per-agent auth candidates in `/model status`, and add `clawdbot models auth order {get,set,clear}` (per-agent auth rotation overrides). — thanks @steipete
diff --git a/src/discord/monitor.tool-result.test.ts b/src/discord/monitor.tool-result.test.ts
index e85e8c4f0..952bfda15 100644
--- a/src/discord/monitor.tool-result.test.ts
+++ b/src/discord/monitor.tool-result.test.ts
@@ -1,7 +1,7 @@
 import type { Client } from "@buape/carbon";
 import { ChannelType, MessageType } from "@buape/carbon";
-import { beforeEach, describe, expect, it, vi } from "vitest";
 import { Routes } from "discord-api-types/v10";
+import { beforeEach, describe, expect, it, vi } from "vitest";
 
 const sendMock = vi.fn();
 const reactMock = vi.fn();
@@ -120,6 +120,79 @@ describe("discord tool result dispatch", () => {
     expect(sendMock.mock.calls[0]?.[1]).toMatch(/^PFX /);
   }, 10000);
 
+  it("caches channel info lookups between messages", async () => {
+    const { createDiscordMessageHandler } = await import("./monitor.js");
+    const cfg = {
+      agents: {
+        defaults: {
+          model: "anthropic/claude-opus-4-5",
+          workspace: "/tmp/clawd",
+        },
+      },
+      session: { store: "/tmp/clawdbot-sessions.json" },
+      discord: { dm: { enabled: true, policy: "open" } },
+    } as ReturnType<typeof import("../config/config.js").loadConfig>;
+
+    const handler = createDiscordMessageHandler({
+      cfg,
+      discordConfig: cfg.discord,
+      accountId: "default",
+      token: "token",
+      runtime: {
+        log: vi.fn(),
+        error: vi.fn(),
+        exit: (code: number): never => {
+          throw new Error(`exit ${code}`);
+        },
+      },
+      botUserId: "bot-id",
+      guildHistories: new Map(),
+      historyLimit: 0,
+      mediaMaxBytes: 10_000,
+      textLimit: 2000,
+      replyToMode: "off",
+      dmEnabled: true,
+      groupDmEnabled: false,
+    });
+
+    const fetchChannel = vi.fn().mockResolvedValue({
+      type: ChannelType.DM,
+      name: "dm",
+    });
+    const client = { fetchChannel } as unknown as Client;
+    const baseMessage = {
+      content: "hello",
+      channelId: "cache-channel-1",
+      timestamp: new Date().toISOString(),
+      type: MessageType.Default,
+      attachments: [],
+      embeds: [],
+      mentionedEveryone: false,
+      mentionedUsers: [],
+      mentionedRoles: [],
+      author: { id: "u-cache", bot: false, username: "Ada" },
+    };
+
+    await handler(
+      {
+        message: { ...baseMessage, id: "m-cache-1" },
+        author: baseMessage.author,
+        guild_id: null,
+      },
+      client,
+    );
+    await handler(
+      {
+        message: { ...baseMessage, id: "m-cache-2" },
+        author: baseMessage.author,
+        guild_id: null,
+      },
+      client,
+    );
+
+    expect(fetchChannel).toHaveBeenCalledTimes(1);
+  });
+
   it("replies with pairing code and sender id when dmPolicy is pairing", async () => {
     const { createDiscordMessageHandler } = await import("./monitor.js");
     const cfg = {
@@ -483,9 +556,7 @@ describe("discord tool result dispatch", () => {
     );
     expect(capturedCtx?.ThreadStarterBody).toContain("starter message");
     expect(capturedCtx?.ThreadLabel).toContain("Discord thread #support");
-    expect(restGet).toHaveBeenCalledWith(
-      Routes.channelMessage("t1", "t1"),
-    );
+    expect(restGet).toHaveBeenCalledWith(Routes.channelMessage("t1", "t1"));
   });
 
   it("scopes thread sessions to the routed agent", async () => {
diff --git a/src/discord/monitor.ts b/src/discord/monitor.ts
index bee9b5e38..59ef8e910 100644
--- a/src/discord/monitor.ts
+++ b/src/discord/monitor.ts
@@ -113,7 +113,20 @@ type DiscordThreadStarter = {
   timestamp?: number;
 };
 
+type DiscordChannelInfo = {
+  type: ChannelType;
+  name?: string;
+  topic?: string;
+  parentId?: string;
+};
+
 const DISCORD_THREAD_STARTER_CACHE = new Map<string, DiscordThreadStarter>();
+const DISCORD_CHANNEL_INFO_CACHE_TTL_MS = 5 * 60 * 1000;
+const DISCORD_CHANNEL_INFO_NEGATIVE_CACHE_TTL_MS = 30 * 1000;
+const DISCORD_CHANNEL_INFO_CACHE = new Map<
+  string,
+  { value: DiscordChannelInfo | null; expiresAt: number }
+>();
 const DISCORD_SLOW_LISTENER_THRESHOLD_MS = 1000;
 
 function logSlowDiscordListener(params: {
@@ -684,13 +697,14 @@ export function createDiscordMessageHandler(params: {
         message.channel.isThread();
       const isThreadByType =
         isGuildMessage && isDiscordThreadType(channelInfo?.type);
-      const threadChannel = isThreadChannel
+      const threadChannel: DiscordThreadChannel | null = isThreadChannel
         ? (message.channel as DiscordThreadChannel)
         : isThreadByType
           ? {
               id: message.channelId,
               name: channelInfo?.name ?? undefined,
               parentId: channelInfo?.parentId ?? undefined,
+              parent: undefined,
             }
           : null;
       const threadParentId =
@@ -1721,19 +1735,42 @@ async function deliverDiscordReply(params: {
 async function resolveDiscordChannelInfo(
   client: Client,
   channelId: string,
-): Promise<
-  { type: ChannelType; name?: string; topic?: string; parentId?: string } | null
-> {
+): Promise<DiscordChannelInfo | null> {
+  const cached = DISCORD_CHANNEL_INFO_CACHE.get(channelId);
+  if (cached) {
+    if (cached.expiresAt > Date.now()) return cached.value;
+    DISCORD_CHANNEL_INFO_CACHE.delete(channelId);
+  }
   try {
     const channel = await client.fetchChannel(channelId);
-    if (!channel) return null;
+    if (!channel) {
+      DISCORD_CHANNEL_INFO_CACHE.set(channelId, {
+        value: null,
+        expiresAt: Date.now() + DISCORD_CHANNEL_INFO_NEGATIVE_CACHE_TTL_MS,
+      });
+      return null;
+    }
     const name = "name" in channel ? (channel.name ?? undefined) : undefined;
     const topic = "topic" in channel ? (channel.topic ?? undefined) : undefined;
     const parentId =
       "parentId" in channel ? (channel.parentId ?? undefined) : undefined;
-    return { type: channel.type, name, topic, parentId };
+    const payload: DiscordChannelInfo = {
+      type: channel.type,
+      name,
+      topic,
+      parentId,
+    };
+    DISCORD_CHANNEL_INFO_CACHE.set(channelId, {
+      value: payload,
+      expiresAt: Date.now() + DISCORD_CHANNEL_INFO_CACHE_TTL_MS,
+    });
+    return payload;
   } catch (err) {
     logVerbose(`discord: failed to fetch channel ${channelId}: ${String(err)}`);
+    DISCORD_CHANNEL_INFO_CACHE.set(channelId, {
+      value: null,
+      expiresAt: Date.now() + DISCORD_CHANNEL_INFO_NEGATIVE_CACHE_TTL_MS,
+    });
     return null;
   }
 }