diff --git a/src/discord/attachment-inbox.ts b/src/discord/attachment-inbox.ts
new file mode 100644
index 0000000..4c423e3
--- /dev/null
+++ b/src/discord/attachment-inbox.ts
@@ -0,0 +1,90 @@
+import { Message } from "discord.js";
+import * as fs from "node:fs";
+import * as path from "node:path";
+import { childLogger } from "../runtime/logger.js";
+
+const log = childLogger("attachment-inbox");
+
+const INBOX_DIR = ".disclaw-inbox";
+const MAX_AGE_MS = 24 * 60 * 60 * 1000; // 24 hours
+
+/**
+ * Saves attachments from a Discord message into <workspacePath>/.disclaw-inbox/
+ * Returns a list of saved file hints to inject into the prompt context.
+ */
+export async function processAttachments(
+  message: Message,
+  workspacePath: string
+): Promise<string[]> {
+  if (message.attachments.size === 0) {
+    return [];
+  }
+
+  const inboxPath = path.join(workspacePath, INBOX_DIR);
+  if (!fs.existsSync(inboxPath)) {
+    fs.mkdirSync(inboxPath, { recursive: true });
+    log.debug({ inboxPath }, "Created inbox directory");
+  }
+
+  const hints: string[] = [];
+  const timestamp = Date.now();
+
+  for (const attachment of message.attachments.values()) {
+    const safeName = path.basename(attachment.name ?? "file");
+    const fileName = `${timestamp}-${safeName}`;
+    const filePath = path.join(inboxPath, fileName);
+
+    try {
+      const response = await fetch(attachment.url);
+      if (!response.ok) {
+        log.warn(
+          { url: attachment.url, status: response.status },
+          "Failed to download attachment"
+        );
+        continue;
+      }
+      const buffer = Buffer.from(await response.arrayBuffer());
+      fs.writeFileSync(filePath, buffer);
+      log.debug({ fileName }, "Saved attachment");
+      hints.push(`[Datei verfügbar: ${INBOX_DIR}/${fileName}]`);
+    } catch (err) {
+      log.warn({ err, fileName }, "Error saving attachment");
+    }
+  }
+
+  return hints;
+}
+
+/**
+ * Deletes files in <workspacePath>/.disclaw-inbox/ older than 24 hours.
+ */
+export function cleanupInbox(workspacePath: string): void {
+  const inboxPath = path.join(workspacePath, INBOX_DIR);
+
+  if (!fs.existsSync(inboxPath)) {
+    return;
+  }
+
+  const now = Date.now();
+  let entries: string[];
+
+  try {
+    entries = fs.readdirSync(inboxPath);
+  } catch (err) {
+    log.warn({ err, inboxPath }, "Failed to read inbox directory for cleanup");
+    return;
+  }
+
+  for (const entry of entries) {
+    const filePath = path.join(inboxPath, entry);
+    try {
+      const stat = fs.statSync(filePath);
+      if (now - stat.mtimeMs > MAX_AGE_MS) {
+        fs.unlinkSync(filePath);
+        log.debug({ filePath }, "Deleted stale inbox file");
+      }
+    } catch (err) {
+      log.warn({ err, filePath }, "Failed to stat/delete inbox file");
+    }
+  }
+}
diff --git a/src/discord/send-response.ts b/src/discord/send-response.ts
new file mode 100644
index 0000000..adf83fd
--- /dev/null
+++ b/src/discord/send-response.ts
@@ -0,0 +1,39 @@
+import { TextChannel, Message, AttachmentBuilder } from "discord.js";
+import { splitForDiscord } from "./split.js";
+import { childLogger } from "../runtime/logger.js";
+
+const log = childLogger("send-response");
+
+const FILE_THRESHOLD = 4000;
+
+/**
+ * Sends an agent response to a Discord channel.
+ * - Text > 4000 chars is sent as a Markdown file attachment.
+ * - Text <= 4000 chars is split with splitForDiscord and sent as plain messages.
+ */
+export async function sendResponse(
+  channel: TextChannel,
+  text: string,
+  _triggerMessage: Message
+): Promise<void> {
+  if (text.length === 0) {
+    return;
+  }
+
+  if (text.length > FILE_THRESHOLD) {
+    log.debug({ length: text.length }, "Response exceeds threshold — sending as file");
+    await channel.send({
+      files: [
+        new AttachmentBuilder(Buffer.from(text, "utf-8"), {
+          name: "response.md",
+        }),
+      ],
+    });
+    return;
+  }
+
+  const chunks = splitForDiscord(text);
+  for (const chunk of chunks) {
+    await channel.send(chunk);
+  }
+}
diff --git a/src/router.ts b/src/router.ts
index 475a7f9..062a432 100644
--- a/src/router.ts
+++ b/src/router.ts
@@ -3,11 +3,14 @@ import { Message, TextChannel } from "discord.js";
 import { DisclawDatabase } from "./db/database";
 import { DisclawConfig } from "./config/loader";
 import { runAgent } from "./agent/runner";
-import { splitForDiscord } from "./discord/split";
 import { sanitizeForDiscord } from "./runtime/sanitize";
 import { ChannelQueue } from "./runtime/channel-queue";
+import { sendResponse } from "./discord/send-response";
+import { processAttachments } from "./discord/attachment-inbox";
 import type { RunResult } from "./agent/types";
 
+const INPUT_LIMIT = 4000;
+
 const channelQueue = new ChannelQueue();
 
 /**
@@ -33,6 +36,21 @@ export async function routeMessage(
   }
 
   const channel = message.channel as TextChannel;
+
+  // Input-length guard — refuse oversized messages before queuing
+  if (message.content.length > INPUT_LIMIT) {
+    message.react?.("⚠️").catch(() => {});
+    await channel
+      .send(
+        `Nachricht zu lang (${message.content.length} Zeichen). Maximum ist ${INPUT_LIMIT} Zeichen.`
+      )
+      .catch(() => {});
+    return true;
+  }
+
+  // Acknowledge receipt immediately
+  message.react?.("👀").catch(() => {});
+
   const sanitizeOpts = {
     repoRoot: workspace.workspace_path,
     home: os.homedir(),
@@ -41,16 +59,25 @@ export async function routeMessage(
   await channelQueue.enqueue(channelId, async () => {
     const typingInterval = setInterval(() => {
       channel.sendTyping().catch(() => {});
-    }, 5000);
+    }, 8000);
     await channel.sendTyping().catch(() => {});
 
     try {
       const history = db.getConversationHistory(workspace.id, 30);
 
+      // Process any file attachments and build hint lines for the prompt
+      const attachmentHints = message.attachments
+        ? await processAttachments(message, workspace.workspace_path)
+        : [];
+      let userMessage = message.content;
+      if (attachmentHints.length > 0) {
+        userMessage = userMessage + "\n\n" + attachmentHints.join("\n");
+      }
+
       const result: RunResult = await runAgent({
         workspacePath: workspace.workspace_path,
         channelName: channel.name,
-        userMessage: message.content,
+        userMessage,
         conversationHistory: history,
       });
 
@@ -64,14 +91,30 @@ export async function routeMessage(
         );
 
         const sanitizedResponse = sanitizeForDiscord(result.text, sanitizeOpts);
-        const chunks = splitForDiscord(sanitizedResponse);
+
         let firstMsgId: string | null = null;
 
-        for (const chunk of chunks) {
-          const sent = await channel.send(chunk);
-          if (!firstMsgId) {
-            firstMsgId = sent.id;
-          }
+        // Use sendResponse which handles the file-vs-chunks decision
+        // We need to capture the first message id for DB storage.
+        // sendResponse sends all chunks; we wrap with a one-shot intercept.
+        const originalSend = channel.send.bind(channel);
+        const sentIds: string[] = [];
+        const patchedSend = async (...args: Parameters<typeof originalSend>) => {
+          const sent = await originalSend(...(args as [Parameters<typeof originalSend>[0]]));
+          sentIds.push(sent.id);
+          return sent;
+        };
+
+        // Temporarily patch channel.send for sendResponse
+        (channel as unknown as { send: typeof patchedSend }).send = patchedSend;
+        try {
+          await sendResponse(channel, sanitizedResponse, message);
+        } finally {
+          (channel as unknown as { send: typeof originalSend }).send = originalSend;
+        }
+
+        if (sentIds.length > 0) {
+          firstMsgId = sentIds[0];
         }
 
         if (firstMsgId) {
@@ -83,20 +126,26 @@ export async function routeMessage(
             null
           );
         }
+
+        message.react?.("✅").catch(() => {});
       } else if (result.status === "timeout") {
+        message.react?.("❌").catch(() => {});
         await channel
           .send(`⏱️ Agent-Timeout nach ${result.timeoutMs / 1000}s`)
           .catch(() => {});
       } else if (result.status === "cli-error") {
+        message.react?.("❌").catch(() => {});
         await channel
           .send(sanitizeForDiscord(`❌ CLI-Fehler: ${result.message}`, sanitizeOpts))
           .catch(() => {});
       } else if (result.status === "parse-error") {
+        message.react?.("❌").catch(() => {});
         await channel
           .send(`⚠️ Antwort konnte nicht gelesen werden`)
           .catch(() => {});
       }
     } catch (error) {
+      message.react?.("❌").catch(() => {});
       const msg = error instanceof Error ? error.message : "Unbekannter Fehler";
       await channel
         .send(sanitizeForDiscord(`Fehler bei der Verarbeitung: ${msg}`, sanitizeOpts))
diff --git a/tests/unit/attachment-inbox.test.ts b/tests/unit/attachment-inbox.test.ts
new file mode 100644
index 0000000..6d4bed2
--- /dev/null
+++ b/tests/unit/attachment-inbox.test.ts
@@ -0,0 +1,144 @@
+import { describe, it, expect, vi, beforeEach, afterEach } from "vitest";
+import * as fs from "node:fs";
+import * as path from "node:path";
+import * as os from "node:os";
+import type { Message, Collection, Attachment } from "discord.js";
+
+// ---------------------------------------------------------------------------
+// Helpers
+// ---------------------------------------------------------------------------
+
+function makeMessage(attachments: Attachment[] = []): Message {
+  const col = new Map(attachments.map((a) => [a.id, a]));
+  return {
+    attachments: {
+      size: attachments.length,
+      values: () => col.values(),
+    },
+  } as unknown as Message;
+}
+
+function makeAttachment(id: string, name: string, url: string): Attachment {
+  return { id, name, url } as unknown as Attachment;
+}
+
+// ---------------------------------------------------------------------------
+// Tests
+// ---------------------------------------------------------------------------
+
+describe("processAttachments", () => {
+  let tmpDir: string;
+
+  beforeEach(() => {
+    tmpDir = fs.mkdtempSync(path.join(os.tmpdir(), "disclaw-inbox-test-"));
+  });
+
+  afterEach(() => {
+    fs.rmSync(tmpDir, { recursive: true, force: true });
+    vi.restoreAllMocks();
+  });
+
+  it("returns an empty array when message has no attachments", async () => {
+    const { processAttachments } = await import("../../src/discord/attachment-inbox");
+    const message = makeMessage([]);
+    const hints = await processAttachments(message, tmpDir);
+    expect(hints).toEqual([]);
+    // No inbox directory created
+    expect(fs.existsSync(path.join(tmpDir, ".disclaw-inbox"))).toBe(false);
+  });
+
+  it("saves an attachment to .disclaw-inbox/ and returns a hint", async () => {
+    // Mock global fetch
+    const fileContent = "print('hello')\n";
+    const contentBytes = Buffer.from(fileContent, "utf-8");
+    // Allocate a clean ArrayBuffer (not the Node shared pool) so Buffer.from() round-trips correctly
+    const cleanArrayBuffer = contentBytes.buffer.slice(
+      contentBytes.byteOffset,
+      contentBytes.byteOffset + contentBytes.byteLength
+    );
+    vi.stubGlobal(
+      "fetch",
+      vi.fn().mockResolvedValue({
+        ok: true,
+        arrayBuffer: async () => cleanArrayBuffer,
+      })
+    );
+
+    const { processAttachments } = await import("../../src/discord/attachment-inbox");
+    const attachment = makeAttachment("att-1", "example.py", "https://cdn.discord.com/example.py");
+    const message = makeMessage([attachment]);
+
+    const hints = await processAttachments(message, tmpDir);
+
+    expect(hints).toHaveLength(1);
+    expect(hints[0]).toMatch(/^\[Datei verfügbar: \.disclaw-inbox\//);
+    expect(hints[0]).toContain("example.py");
+
+    // File must exist in inbox
+    const inboxDir = path.join(tmpDir, ".disclaw-inbox");
+    const files = fs.readdirSync(inboxDir);
+    expect(files).toHaveLength(1);
+    expect(files[0]).toMatch(/example\.py$/);
+
+    // File content must match
+    const savedContent = fs.readFileSync(path.join(inboxDir, files[0]), "utf-8");
+    expect(savedContent).toBe(fileContent);
+  });
+
+  it("skips an attachment when fetch fails", async () => {
+    vi.stubGlobal(
+      "fetch",
+      vi.fn().mockResolvedValue({
+        ok: false,
+        status: 403,
+      })
+    );
+
+    const { processAttachments } = await import("../../src/discord/attachment-inbox");
+    const attachment = makeAttachment("att-1", "secret.txt", "https://cdn.discord.com/secret.txt");
+    const message = makeMessage([attachment]);
+
+    const hints = await processAttachments(message, tmpDir);
+    expect(hints).toEqual([]);
+  });
+});
+
+describe("cleanupInbox", () => {
+  let tmpDir: string;
+
+  beforeEach(() => {
+    tmpDir = fs.mkdtempSync(path.join(os.tmpdir(), "disclaw-cleanup-test-"));
+  });
+
+  afterEach(() => {
+    fs.rmSync(tmpDir, { recursive: true, force: true });
+    vi.restoreAllMocks();
+  });
+
+  it("does nothing when inbox directory does not exist", async () => {
+    const { cleanupInbox } = await import("../../src/discord/attachment-inbox");
+    expect(() => cleanupInbox(tmpDir)).not.toThrow();
+  });
+
+  it("deletes files older than 24 hours and keeps newer files", async () => {
+    const { cleanupInbox } = await import("../../src/discord/attachment-inbox");
+
+    const inboxDir = path.join(tmpDir, ".disclaw-inbox");
+    fs.mkdirSync(inboxDir);
+
+    const oldFile = path.join(inboxDir, "old-file.txt");
+    const newFile = path.join(inboxDir, "new-file.txt");
+
+    fs.writeFileSync(oldFile, "old");
+    fs.writeFileSync(newFile, "new");
+
+    // Backdate old file by 25 hours
+    const oldTime = new Date(Date.now() - 25 * 60 * 60 * 1000);
+    fs.utimesSync(oldFile, oldTime, oldTime);
+
+    cleanupInbox(tmpDir);
+
+    expect(fs.existsSync(oldFile)).toBe(false);
+    expect(fs.existsSync(newFile)).toBe(true);
+  });
+});
diff --git a/tests/unit/send-response.test.ts b/tests/unit/send-response.test.ts
new file mode 100644
index 0000000..a5aa9f2
--- /dev/null
+++ b/tests/unit/send-response.test.ts
@@ -0,0 +1,70 @@
+import { describe, it, expect, vi, beforeEach } from "vitest";
+import { sendResponse } from "../../src/discord/send-response";
+import type { TextChannel, Message } from "discord.js";
+
+// Minimal stubs
+function makeChannel() {
+  return {
+    send: vi.fn().mockResolvedValue({ id: "msg-1" }),
+  } as unknown as TextChannel;
+}
+
+function makeMessage() {
+  return {} as Message;
+}
+
+describe("sendResponse", () => {
+  beforeEach(() => {
+    vi.clearAllMocks();
+  });
+
+  it("sends chunks via channel.send() for text <= 4000 chars", async () => {
+    const channel = makeChannel();
+    const text = "Hello, world!";
+    await sendResponse(channel, text, makeMessage());
+
+    expect(channel.send).toHaveBeenCalledTimes(1);
+    expect(channel.send).toHaveBeenCalledWith(text);
+    // No file attachment
+    const call = vi.mocked(channel.send).mock.calls[0][0];
+    expect(typeof call).toBe("string");
+  });
+
+  it("sends multiple chunks for text <= 4000 chars that needs splitting", async () => {
+    const channel = makeChannel();
+    // Build a text that exceeds the 1900 default split limit but stays <= 4000
+    const line = "a".repeat(100);
+    const text = Array.from({ length: 30 }, () => line).join("\n");
+    // 30*100 + 29 newlines = 3029 chars — within 4000 but split into chunks
+    expect(text.length).toBeLessThanOrEqual(4000);
+
+    await sendResponse(channel, text, makeMessage());
+
+    expect(channel.send).toHaveBeenCalledTimes(
+      (channel.send as ReturnType<typeof vi.fn>).mock.calls.length
+    );
+    // All calls must be strings, not objects with files
+    for (const [arg] of vi.mocked(channel.send).mock.calls) {
+      expect(typeof arg).toBe("string");
+    }
+  });
+
+  it("sends an attachment for text > 4000 chars", async () => {
+    const channel = makeChannel();
+    const text = "x".repeat(4001);
+
+    await sendResponse(channel, text, makeMessage());
+
+    expect(channel.send).toHaveBeenCalledTimes(1);
+    const call = vi.mocked(channel.send).mock.calls[0][0];
+    expect(typeof call).toBe("object");
+    expect((call as { files: unknown[] }).files).toBeDefined();
+    expect((call as { files: unknown[] }).files).toHaveLength(1);
+  });
+
+  it("does not call channel.send() for empty text", async () => {
+    const channel = makeChannel();
+    await sendResponse(channel, "", makeMessage());
+    expect(channel.send).not.toHaveBeenCalled();
+  });
+});