diff --git a/src/discord/monitor/native-command-context.test.ts b/src/discord/monitor/native-command-context.test.ts
new file mode 100644
index 00000000000..e20c9d9c778
--- /dev/null
+++ b/src/discord/monitor/native-command-context.test.ts
@@ -0,0 +1,95 @@
+import { describe, expect, it } from "vitest";
+import { buildDiscordNativeCommandContext } from "./native-command-context.js";
+
+describe("buildDiscordNativeCommandContext", () => {
+  it("builds direct-message slash command context", () => {
+    const ctx = buildDiscordNativeCommandContext({
+      prompt: "/status",
+      commandArgs: {},
+      sessionKey: "agent:codex:discord:slash:user-1",
+      commandTargetSessionKey: "agent:codex:discord:direct:user-1",
+      accountId: "default",
+      interactionId: "interaction-1",
+      channelId: "dm-1",
+      commandAuthorized: true,
+      isDirectMessage: true,
+      isGroupDm: false,
+      isGuild: false,
+      isThreadChannel: false,
+      user: {
+        id: "user-1",
+        username: "tester",
+        globalName: "Tester",
+      },
+      sender: {
+        id: "user-1",
+        tag: "tester#0001",
+      },
+      timestampMs: 123,
+    });
+
+    expect(ctx.From).toBe("discord:user-1");
+    expect(ctx.To).toBe("slash:user-1");
+    expect(ctx.ChatType).toBe("direct");
+    expect(ctx.ConversationLabel).toBe("Tester");
+    expect(ctx.SessionKey).toBe("agent:codex:discord:slash:user-1");
+    expect(ctx.CommandTargetSessionKey).toBe("agent:codex:discord:direct:user-1");
+    expect(ctx.OriginatingTo).toBe("user:user-1");
+    expect(ctx.UntrustedContext).toBeUndefined();
+    expect(ctx.GroupSystemPrompt).toBeUndefined();
+    expect(ctx.Timestamp).toBe(123);
+  });
+
+  it("builds guild slash command context with owner allowlist and channel metadata", () => {
+    const ctx = buildDiscordNativeCommandContext({
+      prompt: "/status",
+      commandArgs: { model: "gpt-5.2" },
+      sessionKey: "agent:codex:discord:slash:user-1",
+      commandTargetSessionKey: "agent:codex:discord:channel:chan-1",
+      accountId: "default",
+      interactionId: "interaction-1",
+      channelId: "chan-1",
+      threadParentId: "parent-1",
+      guildName: "Ops",
+      channelTopic: "Production alerts only",
+      channelConfig: {
+        allowed: true,
+        users: ["discord:user-1"],
+        systemPrompt: "Use the runbook.",
+      },
+      guildInfo: {
+        id: "guild-1",
+      },
+      allowNameMatching: false,
+      commandAuthorized: true,
+      isDirectMessage: false,
+      isGroupDm: false,
+      isGuild: true,
+      isThreadChannel: true,
+      user: {
+        id: "user-1",
+        username: "tester",
+      },
+      sender: {
+        id: "user-1",
+        name: "tester",
+        tag: "tester#0001",
+      },
+      timestampMs: 456,
+    });
+
+    expect(ctx.From).toBe("discord:channel:chan-1");
+    expect(ctx.ChatType).toBe("channel");
+    expect(ctx.ConversationLabel).toBe("chan-1");
+    expect(ctx.GroupSubject).toBe("Ops");
+    expect(ctx.GroupSystemPrompt).toBe("Use the runbook.");
+    expect(ctx.OwnerAllowFrom).toEqual(["user-1"]);
+    expect(ctx.MessageThreadId).toBe("chan-1");
+    expect(ctx.ThreadParentId).toBe("parent-1");
+    expect(ctx.OriginatingTo).toBe("channel:chan-1");
+    expect(ctx.UntrustedContext).toEqual([
+      expect.stringContaining("Discord channel topic:\nProduction alerts only"),
+    ]);
+    expect(ctx.Timestamp).toBe(456);
+  });
+});
diff --git a/src/discord/monitor/native-command-context.ts b/src/discord/monitor/native-command-context.ts
new file mode 100644
index 00000000000..938e7b3e1c4
--- /dev/null
+++ b/src/discord/monitor/native-command-context.ts
@@ -0,0 +1,124 @@
+import type { CommandArgs } from "../../auto-reply/commands-registry.js";
+import { finalizeInboundContext } from "../../auto-reply/reply/inbound-context.js";
+import { buildUntrustedChannelMetadata } from "../../security/channel-metadata.js";
+import {
+  resolveDiscordOwnerAllowFrom,
+  type DiscordChannelConfigResolved,
+  type DiscordGuildEntryResolved,
+} from "./allow-list.js";
+
+export type BuildDiscordNativeCommandContextParams = {
+  prompt: string;
+  commandArgs: CommandArgs;
+  sessionKey: string;
+  commandTargetSessionKey: string;
+  accountId?: string | null;
+  interactionId: string;
+  channelId: string;
+  threadParentId?: string;
+  guildName?: string;
+  channelTopic?: string;
+  channelConfig?: DiscordChannelConfigResolved | null;
+  guildInfo?: DiscordGuildEntryResolved | null;
+  allowNameMatching?: boolean;
+  commandAuthorized: boolean;
+  isDirectMessage: boolean;
+  isGroupDm: boolean;
+  isGuild: boolean;
+  isThreadChannel: boolean;
+  user: {
+    id: string;
+    username: string;
+    globalName?: string | null;
+  };
+  sender: {
+    id: string;
+    name?: string;
+    tag?: string;
+  };
+  timestampMs?: number;
+};
+
+function buildDiscordNativeCommandSystemPrompt(
+  channelConfig?: DiscordChannelConfigResolved | null,
+): string | undefined {
+  const systemPromptParts = [channelConfig?.systemPrompt?.trim() || null].filter(
+    (entry): entry is string => Boolean(entry),
+  );
+  return systemPromptParts.length > 0 ? systemPromptParts.join("\n\n") : undefined;
+}
+
+function buildDiscordNativeCommandUntrustedContext(params: {
+  isGuild: boolean;
+  channelTopic?: string;
+}): string[] | undefined {
+  if (!params.isGuild) {
+    return undefined;
+  }
+  const untrustedChannelMetadata = buildUntrustedChannelMetadata({
+    source: "discord",
+    label: "Discord channel topic",
+    entries: [params.channelTopic],
+  });
+  return untrustedChannelMetadata ? [untrustedChannelMetadata] : undefined;
+}
+
+export function buildDiscordNativeCommandContext(params: BuildDiscordNativeCommandContextParams) {
+  const conversationLabel = params.isDirectMessage
+    ? (params.user.globalName ?? params.user.username)
+    : params.channelId;
+  const ownerAllowFrom = resolveDiscordOwnerAllowFrom({
+    channelConfig: params.channelConfig,
+    guildInfo: params.guildInfo,
+    sender: params.sender,
+    allowNameMatching: params.allowNameMatching,
+  });
+
+  return finalizeInboundContext({
+    Body: params.prompt,
+    BodyForAgent: params.prompt,
+    RawBody: params.prompt,
+    CommandBody: params.prompt,
+    CommandArgs: params.commandArgs,
+    From: params.isDirectMessage
+      ? `discord:${params.user.id}`
+      : params.isGroupDm
+        ? `discord:group:${params.channelId}`
+        : `discord:channel:${params.channelId}`,
+    To: `slash:${params.user.id}`,
+    SessionKey: params.sessionKey,
+    CommandTargetSessionKey: params.commandTargetSessionKey,
+    AccountId: params.accountId ?? undefined,
+    ChatType: params.isDirectMessage ? "direct" : params.isGroupDm ? "group" : "channel",
+    ConversationLabel: conversationLabel,
+    GroupSubject: params.isGuild ? params.guildName : undefined,
+    GroupSystemPrompt: params.isGuild
+      ? buildDiscordNativeCommandSystemPrompt(params.channelConfig)
+      : undefined,
+    UntrustedContext: buildDiscordNativeCommandUntrustedContext({
+      isGuild: params.isGuild,
+      channelTopic: params.channelTopic,
+    }),
+    OwnerAllowFrom: ownerAllowFrom,
+    SenderName: params.user.globalName ?? params.user.username,
+    SenderId: params.user.id,
+    SenderUsername: params.user.username,
+    SenderTag: params.sender.tag,
+    Provider: "discord" as const,
+    Surface: "discord" as const,
+    WasMentioned: true,
+    MessageSid: params.interactionId,
+    MessageThreadId: params.isThreadChannel ? params.channelId : undefined,
+    Timestamp: params.timestampMs ?? Date.now(),
+    CommandAuthorized: params.commandAuthorized,
+    CommandSource: "native" as const,
+    // Native slash contexts use To=slash:<user> for interaction routing.
+    // For follow-up delivery (for example subagent completion announces),
+    // preserve the real Discord target separately.
+    OriginatingChannel: "discord" as const,
+    OriginatingTo: params.isDirectMessage
+      ? `user:${params.user.id}`
+      : `channel:${params.channelId}`,
+    ThreadParentId: params.isThreadChannel ? params.threadParentId : undefined,
+  });
+}
diff --git a/src/discord/monitor/native-command.ts b/src/discord/monitor/native-command.ts
index 987fa39cfe1..3ec8bfa03fd 100644
--- a/src/discord/monitor/native-command.ts
+++ b/src/discord/monitor/native-command.ts
@@ -37,7 +37,6 @@ import {
   resolveCommandArgMenu,
   serializeCommandArgs,
 } from "../../auto-reply/commands-registry.js";
-import { finalizeInboundContext } from "../../auto-reply/reply/inbound-context.js";
 import { resolveStoredModelOverride } from "../../auto-reply/reply/model-selection.js";
 import { dispatchReplyWithDispatcher } from "../../auto-reply/reply/provider-dispatcher.js";
 import type { ReplyPayload } from "../../auto-reply/types.js";
@@ -53,7 +52,6 @@ import { getAgentScopedMediaLocalRoots } from "../../media/local-roots.js";
 import { buildPairingReply } from "../../pairing/pairing-messages.js";
 import { executePluginCommand, matchPluginCommand } from "../../plugins/commands.js";
 import type { ResolvedAgentRoute } from "../../routing/resolve-route.js";
-import { buildUntrustedChannelMetadata } from "../../security/channel-metadata.js";
 import { chunkItems } from "../../utils/chunk-items.js";
 import { withTimeout } from "../../utils/with-timeout.js";
 import { loadWebMedia } from "../../web/media.js";
@@ -65,7 +63,6 @@ import {
   resolveDiscordGuildEntry,
   resolveDiscordMemberAccessState,
   resolveDiscordOwnerAccess,
-  resolveDiscordOwnerAllowFrom,
 } from "./allow-list.js";
 import { resolveDiscordDmCommandAccess } from "./dm-command-auth.js";
 import { handleDiscordDmCommandDecision } from "./dm-command-decision.js";
@@ -85,6 +82,7 @@ import {
   toDiscordModelPickerMessagePayload,
   type DiscordModelPickerCommandContext,
 } from "./model-picker.js";
+import { buildDiscordNativeCommandContext } from "./native-command-context.js";
 import {
   buildDiscordRoutePeer,
   resolveDiscordConversationRoute,
@@ -1653,70 +1651,31 @@ async function dispatchDiscordCommandInteraction(params: {
     configuredRoute,
     matchedBy: configuredBinding ? "binding.channel" : undefined,
   });
-  const conversationLabel = isDirectMessage ? (user.globalName ?? user.username) : channelId;
-  const ownerAllowFrom = resolveDiscordOwnerAllowFrom({
+  const ctxPayload = buildDiscordNativeCommandContext({
+    prompt,
+    commandArgs,
+    sessionKey: boundSessionKey ?? `agent:${effectiveRoute.agentId}:${sessionPrefix}:${user.id}`,
+    commandTargetSessionKey: boundSessionKey ?? effectiveRoute.sessionKey,
+    accountId: effectiveRoute.accountId,
+    interactionId,
+    channelId,
+    threadParentId,
+    guildName: interaction.guild?.name,
+    channelTopic: channel && "topic" in channel ? (channel.topic ?? undefined) : undefined,
     channelConfig,
     guildInfo,
-    sender: { id: sender.id, name: sender.name, tag: sender.tag },
     allowNameMatching,
-  });
-  const ctxPayload = finalizeInboundContext({
-    Body: prompt,
-    BodyForAgent: prompt,
-    RawBody: prompt,
-    CommandBody: prompt,
-    CommandArgs: commandArgs,
-    From: isDirectMessage
-      ? `discord:${user.id}`
-      : isGroupDm
-        ? `discord:group:${channelId}`
-        : `discord:channel:${channelId}`,
-    To: `slash:${user.id}`,
-    SessionKey: boundSessionKey ?? `agent:${effectiveRoute.agentId}:${sessionPrefix}:${user.id}`,
-    CommandTargetSessionKey: boundSessionKey ?? effectiveRoute.sessionKey,
-    AccountId: effectiveRoute.accountId,
-    ChatType: isDirectMessage ? "direct" : isGroupDm ? "group" : "channel",
-    ConversationLabel: conversationLabel,
-    GroupSubject: isGuild ? interaction.guild?.name : undefined,
-    GroupSystemPrompt: isGuild
-      ? (() => {
-          const systemPromptParts = [channelConfig?.systemPrompt?.trim() || null].filter(
-            (entry): entry is string => Boolean(entry),
-          );
-          return systemPromptParts.length > 0 ? systemPromptParts.join("\n\n") : undefined;
-        })()
-      : undefined,
-    UntrustedContext: isGuild
-      ? (() => {
-          const channelTopic =
-            channel && "topic" in channel ? (channel.topic ?? undefined) : undefined;
-          const untrustedChannelMetadata = buildUntrustedChannelMetadata({
-            source: "discord",
-            label: "Discord channel topic",
-            entries: [channelTopic],
-          });
-          return untrustedChannelMetadata ? [untrustedChannelMetadata] : undefined;
-        })()
-      : undefined,
-    OwnerAllowFrom: ownerAllowFrom,
-    SenderName: user.globalName ?? user.username,
-    SenderId: user.id,
-    SenderUsername: user.username,
-    SenderTag: sender.tag,
-    Provider: "discord" as const,
-    Surface: "discord" as const,
-    WasMentioned: true,
-    MessageSid: interactionId,
-    MessageThreadId: isThreadChannel ? channelId : undefined,
-    Timestamp: Date.now(),
-    CommandAuthorized: commandAuthorized,
-    CommandSource: "native" as const,
-    // Native slash contexts use To=slash:<user> for interaction routing.
-    // For follow-up delivery (for example subagent completion announces),
-    // preserve the real Discord target separately.
-    OriginatingChannel: "discord" as const,
-    OriginatingTo: isDirectMessage ? `user:${user.id}` : `channel:${channelId}`,
-    ThreadParentId: isThreadChannel ? threadParentId : undefined,
+    commandAuthorized,
+    isDirectMessage,
+    isGroupDm,
+    isGuild,
+    isThreadChannel,
+    user: {
+      id: user.id,
+      username: user.username,
+      globalName: user.globalName,
+    },
+    sender: { id: sender.id, name: sender.name, tag: sender.tag },
   });
 
   const { onModelSelected, ...prefixOptions } = createReplyPrefixOptions({