diff --git a/CHANGELOG.md b/CHANGELOG.md
index 189c088d2..b0897c57b 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -16,6 +16,7 @@
 - Agent runtime: accept legacy `Z_AI_API_KEY` for Z.AI provider auth (maps to `ZAI_API_KEY`).
 - Signal: add `signal-cli` JSON-RPC support for send/receive via the Signal provider.
 - Chat UI: add recent-session dropdown switcher (main first) in macOS/iOS/Android + Control UI.
+- Discord: allow agent-triggered reactions via `clawdis_discord` when enabled, and surface message ids in context.
 - Tests: add a Z.AI live test gate for smoke validation when keys are present.
 - macOS Debug: add app log verbosity and rolling file log toggle for swift-log-backed app logs.
 - CLI: add onboarding wizard (gateway + workspace + skills) with daemon installers and Anthropic/Minimax setup paths.
diff --git a/docs/configuration.md b/docs/configuration.md
index 7ef6bbd74..c7ca94330 100644
--- a/docs/configuration.md
+++ b/docs/configuration.md
@@ -179,7 +179,8 @@ Configure the Discord bot by setting the bot token and optional gating:
     },
     requireMention: true,                   // require @bot mentions in guilds
     mediaMaxMb: 8,                          // clamp inbound media size
-    historyLimit: 20                        // include last N guild messages as context
+    historyLimit: 20,                       // include last N guild messages as context
+    enableReactions: false                  // allow agent-triggered reactions
   }
 }
 ```
diff --git a/docs/discord.md b/docs/discord.md
index 5fcb5445f..7bd17715f 100644
--- a/docs/discord.md
+++ b/docs/discord.md
@@ -24,6 +24,7 @@ Status: ready for DM and guild text channels via the official Discord bot gatewa
 7. Optional DM allowlist: reuse `discord.allowFrom` with user ids (`1234567890` or `discord:1234567890`). Use `"*"` to allow all DMs.
 8. Optional guild allowlist: set `discord.guildAllowFrom` with `guilds` and/or `users` to gate who can invoke the bot in servers.
 9. Optional guild context history: set `discord.historyLimit` (default 20) to include the last N guild messages as context when replying to a mention. Set `0` to disable.
+10. Optional reactions: set `discord.enableReactions = true` to allow the agent to react to Discord messages via the `clawdis_discord` tool.
 
 Note: Discord does not provide a simple username → id lookup without extra guild context, so prefer ids or `<@id>` mentions for DM delivery targets.
 
@@ -47,7 +48,8 @@ Note: Discord does not provide a simple username → id lookup without extra gui
     },
     requireMention: true,
     mediaMaxMb: 8,
-    historyLimit: 20
+    historyLimit: 20,
+    enableReactions: false
   }
 }
 ```
@@ -57,6 +59,14 @@ Note: Discord does not provide a simple username → id lookup without extra gui
 - `requireMention`: when `true`, messages in guild channels must mention the bot.
 - `mediaMaxMb`: clamp inbound media saved to disk.
 - `historyLimit`: number of recent guild messages to include as context when replying to a mention (default 20, `0` disables).
+- `enableReactions`: allow agent-triggered reactions via the `clawdis_discord` tool (default `false`).
+
+## Reactions
+When `discord.enableReactions = true`, the agent can call `clawdis_discord` with:
+- `action: "react"`
+- `channelId`, `messageId`, `emoji`
+
+Discord message ids are surfaced in the injected context (`[discord message id: …]` and history lines) so the agent can target them.
 
 ## Safety & ops
 - Treat the bot token like a password; prefer the `DISCORD_BOT_TOKEN` env var on supervised hosts or lock down the config file permissions.
diff --git a/src/agents/clawdis-tools.ts b/src/agents/clawdis-tools.ts
index e77a66472..38cf1c32a 100644
--- a/src/agents/clawdis-tools.ts
+++ b/src/agents/clawdis-tools.ts
@@ -41,6 +41,7 @@ import {
 } from "../cli/nodes-screen.js";
 import { parseDurationMs } from "../cli/parse-duration.js";
 import { loadConfig } from "../config/config.js";
+import { reactMessageDiscord } from "../discord/send.js";
 import { callGateway } from "../gateway/call.js";
 import { detectMime } from "../media/mime.js";
 import { sanitizeToolResultImages } from "./tool-images.js";
@@ -1422,6 +1423,48 @@ const GatewayToolSchema = Type.Union([
   }),
 ]);
 
+const DiscordToolSchema = Type.Union([
+  Type.Object({
+    action: Type.Literal("react"),
+    channelId: Type.String(),
+    messageId: Type.String(),
+    emoji: Type.String(),
+  }),
+]);
+
+function createDiscordTool(): AnyAgentTool {
+  return {
+    label: "Clawdis Discord",
+    name: "clawdis_discord",
+    description:
+      "React to Discord messages. Requires discord.enableReactions=true in config.",
+    parameters: DiscordToolSchema,
+    execute: async (_toolCallId, args) => {
+      const params = args as Record<string, unknown>;
+      const action = readStringParam(params, "action", { required: true });
+      if (action !== "react") throw new Error(`Unknown action: ${action}`);
+
+      const cfg = loadConfig();
+      if (!cfg.discord?.enableReactions) {
+        throw new Error(
+          "Discord reactions are disabled (set discord.enableReactions=true).",
+        );
+      }
+
+      const channelId = readStringParam(params, "channelId", {
+        required: true,
+      });
+      const messageId = readStringParam(params, "messageId", {
+        required: true,
+      });
+      const emoji = readStringParam(params, "emoji", { required: true });
+
+      await reactMessageDiscord(channelId, messageId, emoji);
+      return jsonResult({ ok: true });
+    },
+  };
+}
+
 function createGatewayTool(): AnyAgentTool {
   return {
     label: "Clawdis Gateway",
@@ -1470,6 +1513,7 @@ export function createClawdisTools(): AnyAgentTool[] {
     createCanvasTool(),
     createNodesTool(),
     createCronTool(),
+    createDiscordTool(),
     createGatewayTool(),
   ];
 }
diff --git a/src/config/config.ts b/src/config/config.ts
index 2539aeb3d..803d16a62 100644
--- a/src/config/config.ts
+++ b/src/config/config.ts
@@ -171,6 +171,8 @@ export type DiscordConfig = {
   mediaMaxMb?: number;
   /** Number of recent guild messages to include for context (default: 20). */
   historyLimit?: number;
+  /** Allow agent-triggered Discord reactions (default: false). */
+  enableReactions?: boolean;
 };
 
 export type SignalConfig = {
@@ -879,6 +881,7 @@ const ClawdisSchema = z.object({
       requireMention: z.boolean().optional(),
       mediaMaxMb: z.number().positive().optional(),
       historyLimit: z.number().int().min(0).optional(),
+      enableReactions: z.boolean().optional(),
     })
     .optional(),
   signal: z
diff --git a/src/discord/monitor.ts b/src/discord/monitor.ts
index 04e3c9ea5..0ad4e4247 100644
--- a/src/discord/monitor.ts
+++ b/src/discord/monitor.ts
@@ -44,6 +44,7 @@ type DiscordHistoryEntry = {
   sender: string;
   body: string;
   timestamp?: number;
+  messageId?: string;
 };
 
 export async function monitorDiscordProvider(opts: MonitorDiscordOpts = {}) {
@@ -122,6 +123,7 @@ export async function monitorDiscordProvider(opts: MonitorDiscordOpts = {}) {
           sender: message.member?.displayName ?? message.author.tag,
           body: baseText,
           timestamp: message.createdTimestamp,
+          messageId: message.id,
         });
         while (history.length > historyLimit) history.shift();
         guildHistories.set(message.channelId, history);
@@ -196,11 +198,12 @@ export async function monitorDiscordProvider(opts: MonitorDiscordOpts = {}) {
       const fromLabel = isDirectMessage
         ? buildDirectLabel(message)
         : buildGuildLabel(message);
+      const textWithId = `${text}\n[discord message id: ${message.id} channel: ${message.channelId}]`;
       let combinedBody = formatAgentEnvelope({
         surface: "Discord",
         from: fromLabel,
         timestamp: message.createdTimestamp,
-        body: text,
+        body: textWithId,
       });
       let shouldClearHistory = false;
       if (!isDirectMessage) {
@@ -215,7 +218,7 @@ export async function monitorDiscordProvider(opts: MonitorDiscordOpts = {}) {
                 surface: "Discord",
                 from: fromLabel,
                 timestamp: entry.timestamp,
-                body: `${entry.sender}: ${entry.body}`,
+                body: `${entry.sender}: ${entry.body} [id:${entry.messageId ?? "unknown"} channel:${message.channelId}]`,
               }),
             )
             .join("\n");
diff --git a/src/discord/send.ts b/src/discord/send.ts
index 430dc38df..1afd90bd0 100644
--- a/src/discord/send.ts
+++ b/src/discord/send.ts
@@ -29,6 +29,11 @@ export type DiscordSendResult = {
   channelId: string;
 };
 
+export type DiscordReactOpts = {
+  token?: string;
+  rest?: REST;
+};
+
 function resolveToken(explicit?: string) {
   const cfgToken = loadConfig().discord?.token;
   const token = normalizeDiscordToken(
@@ -42,6 +47,16 @@ function resolveToken(explicit?: string) {
   return token;
 }
 
+function normalizeReactionEmoji(raw: string) {
+  const trimmed = raw.trim();
+  if (!trimmed) {
+    throw new Error("emoji required");
+  }
+  const customMatch = trimmed.match(/^<a?:([^:>]+):(\d+)>$/);
+  const identifier = customMatch ? `${customMatch[1]}:${customMatch[2]}` : trimmed;
+  return encodeURIComponent(identifier);
+}
+
 function parseRecipient(raw: string): DiscordRecipient {
   const trimmed = raw.trim();
   if (!trimmed) {
@@ -164,3 +179,16 @@ export async function sendMessageDiscord(
     channelId: String(result.channel_id ?? channelId),
   };
 }
+
+export async function reactMessageDiscord(
+  channelId: string,
+  messageId: string,
+  emoji: string,
+  opts: DiscordReactOpts = {},
+) {
+  const token = resolveToken(opts.token);
+  const rest = opts.rest ?? new REST({ version: "10" }).setToken(token);
+  const encoded = normalizeReactionEmoji(emoji);
+  await rest.put(Routes.channelMessageReaction(channelId, messageId, encoded));
+  return { ok: true };
+}