diff --git a/src/slack/monitor/message-handler/prepare.ts b/src/slack/monitor/message-handler/prepare.ts
index 7e3ccf5f9..72b7d9271 100644
--- a/src/slack/monitor/message-handler/prepare.ts
+++ b/src/slack/monitor/message-handler/prepare.ts
@@ -35,7 +35,6 @@ import { buildPairingReply } from "../../../pairing/pairing-messages.js";
 import { upsertChannelPairingRequest } from "../../../pairing/pairing-store.js";
 import { resolveAgentRoute } from "../../../routing/resolve-route.js";
 import { resolveThreadSessionKeys } from "../../../routing/session-key.js";
-import { buildUntrustedChannelMetadata } from "../../../security/channel-metadata.js";
 import { reactSlackMessage } from "../../actions.js";
 import { sendMessageSlack } from "../../send.js";
 import { resolveSlackThreadContext } from "../../threading.js";
@@ -49,6 +48,7 @@ import {
   resolveSlackThreadHistory,
   resolveSlackThreadStarter,
 } from "../media.js";
+import { resolveSlackRoomContextHints } from "../room-context.js";
 
 export async function prepareSlackMessage(params: {
   ctx: SlackMonitorContext;
@@ -452,18 +452,11 @@ export async function prepareSlackMessage(params: {
 
   const slackTo = isDirectMessage ? `user:${message.user}` : `channel:${message.channel}`;
 
-  const untrustedChannelMetadata = isRoomish
-    ? buildUntrustedChannelMetadata({
-        source: "slack",
-        label: "Slack channel description",
-        entries: [channelInfo?.topic, channelInfo?.purpose],
-      })
-    : undefined;
-  const systemPromptParts = [channelConfig?.systemPrompt?.trim() || null].filter(
-    (entry): entry is string => Boolean(entry),
-  );
-  const groupSystemPrompt =
-    systemPromptParts.length > 0 ? systemPromptParts.join("\n\n") : undefined;
+  const { untrustedChannelMetadata, groupSystemPrompt } = resolveSlackRoomContextHints({
+    isRoomish,
+    channelInfo,
+    channelConfig,
+  });
 
   let threadStarterBody: string | undefined;
   let threadHistoryBody: string | undefined;
diff --git a/src/slack/monitor/room-context.ts b/src/slack/monitor/room-context.ts
new file mode 100644
index 000000000..653591362
--- /dev/null
+++ b/src/slack/monitor/room-context.ts
@@ -0,0 +1,31 @@
+import { buildUntrustedChannelMetadata } from "../../security/channel-metadata.js";
+
+export function resolveSlackRoomContextHints(params: {
+  isRoomish: boolean;
+  channelInfo?: { topic?: string; purpose?: string };
+  channelConfig?: { systemPrompt?: string | null } | null;
+}): {
+  untrustedChannelMetadata?: ReturnType<typeof buildUntrustedChannelMetadata>;
+  groupSystemPrompt?: string;
+} {
+  if (!params.isRoomish) {
+    return {};
+  }
+
+  const untrustedChannelMetadata = buildUntrustedChannelMetadata({
+    source: "slack",
+    label: "Slack channel description",
+    entries: [params.channelInfo?.topic, params.channelInfo?.purpose],
+  });
+
+  const systemPromptParts = [params.channelConfig?.systemPrompt?.trim() || null].filter(
+    (entry): entry is string => Boolean(entry),
+  );
+  const groupSystemPrompt =
+    systemPromptParts.length > 0 ? systemPromptParts.join("\n\n") : undefined;
+
+  return {
+    untrustedChannelMetadata,
+    groupSystemPrompt,
+  };
+}
diff --git a/src/slack/monitor/slash.ts b/src/slack/monitor/slash.ts
index 3ee2b3083..61046ede9 100644
--- a/src/slack/monitor/slash.ts
+++ b/src/slack/monitor/slash.ts
@@ -26,7 +26,6 @@ import {
   upsertChannelPairingRequest,
 } from "../../pairing/pairing-store.js";
 import { resolveAgentRoute } from "../../routing/resolve-route.js";
-import { buildUntrustedChannelMetadata } from "../../security/channel-metadata.js";
 import {
   normalizeAllowList,
   normalizeAllowListLower,
@@ -38,6 +37,7 @@ import { buildSlackSlashCommandMatcher, resolveSlackSlashCommandConfig } from ".
 import { normalizeSlackChannelType } from "./context.js";
 import { isSlackChannelAllowedByPolicy } from "./policy.js";
 import { deliverSlackSlashReplies } from "./replies.js";
+import { resolveSlackRoomContextHints } from "./room-context.js";
 
 type SlackBlock = { type: string; [key: string]: unknown };
 
@@ -387,18 +387,11 @@ export function registerSlackMonitorSlashCommands(params: {
         },
       });
 
-      const untrustedChannelMetadata = isRoomish
-        ? buildUntrustedChannelMetadata({
-            source: "slack",
-            label: "Slack channel description",
-            entries: [channelInfo?.topic, channelInfo?.purpose],
-          })
-        : undefined;
-      const systemPromptParts = [channelConfig?.systemPrompt?.trim() || null].filter(
-        (entry): entry is string => Boolean(entry),
-      );
-      const groupSystemPrompt =
-        systemPromptParts.length > 0 ? systemPromptParts.join("\n\n") : undefined;
+      const { untrustedChannelMetadata, groupSystemPrompt } = resolveSlackRoomContextHints({
+        isRoomish,
+        channelInfo,
+        channelConfig,
+      });
 
       const ctxPayload = finalizeInboundContext({
         Body: prompt,