From 383cb7d795f0061e6ca914150902950998510f2d Mon Sep 17 00:00:00 2001
From: Michael Bleigh <bleigh@google.com>
Date: Sat, 11 Apr 2026 19:01:57 -0700
Subject: [PATCH] wip: HistoryItemToolGroupDisplay

---
 .../src/ui/components/HistoryItemDisplay.tsx  |  1 +
 .../components/messages/ToolGroupMessage.tsx  |  1 +
 packages/cli/src/ui/types.ts                  |  6 +++
 packages/core/src/agent/types.ts              | 38 ++++++++++++++++++-
 4 files changed, 45 insertions(+), 1 deletion(-)

diff --git a/packages/cli/src/ui/components/HistoryItemDisplay.tsx b/packages/cli/src/ui/components/HistoryItemDisplay.tsx
index 0ceb70f8d7..414b6dcbe4 100644
--- a/packages/cli/src/ui/components/HistoryItemDisplay.tsx
+++ b/packages/cli/src/ui/components/HistoryItemDisplay.tsx
@@ -208,6 +208,7 @@ export const HistoryItemDisplay: React.FC<HistoryItemDisplayProps> = ({
           isToolGroupBoundary={isToolGroupBoundary}
         />
       )}
+      {/* TODO: tool_group_display goes here  */}
       {itemForDisplay.type === 'subagent' && (
         <SubagentHistoryMessage
           item={itemForDisplay}
diff --git a/packages/cli/src/ui/components/messages/ToolGroupMessage.tsx b/packages/cli/src/ui/components/messages/ToolGroupMessage.tsx
index cfec822f9d..b28acee83e 100644
--- a/packages/cli/src/ui/components/messages/ToolGroupMessage.tsx
+++ b/packages/cli/src/ui/components/messages/ToolGroupMessage.tsx
@@ -121,6 +121,7 @@ export const ToolGroupMessage: React.FC<ToolGroupMessageProps> = ({
   isToolGroupBoundary,
 }) => {
   const settings = useSettings();
+
   const isLowErrorVerbosity = settings.merged.ui?.errorVerbosity !== 'full';
   const isCompactModeEnabled = settings.merged.ui?.compactToolOutput === true;
 
diff --git a/packages/cli/src/ui/types.ts b/packages/cli/src/ui/types.ts
index 1ded2ae643..590b4e4ea8 100644
--- a/packages/cli/src/ui/types.ts
+++ b/packages/cli/src/ui/types.ts
@@ -260,6 +260,11 @@ export type HistoryItemToolGroup = HistoryItemBase & {
   borderDimColor?: boolean;
 };
 
+export type HistoryItemToolDisplayGroup = HistoryItemBase & {
+  type: 'tool_display_group';
+  tools: ToolDisplay[];
+};
+
 export type HistoryItemUserShell = HistoryItemBase & {
   type: 'user_shell';
   text: string;
@@ -393,6 +398,7 @@ export type HistoryItemWithoutId =
   | HistoryItemAbout
   | HistoryItemHelp
   | HistoryItemToolGroup
+  | HistoryItemToolDisplayGroup
   | HistoryItemStats
   | HistoryItemModelStats
   | HistoryItemToolStats
diff --git a/packages/core/src/agent/types.ts b/packages/core/src/agent/types.ts
index 0f7cad8a9b..d383c18c68 100644
--- a/packages/core/src/agent/types.ts
+++ b/packages/core/src/agent/types.ts
@@ -4,6 +4,7 @@
  * SPDX-License-Identifier: Apache-2.0
  */
 
+import type { AnsiOutput } from 'src/utils/terminalSerializer.js';
 import type { Kind } from '../tools/tools.js';
 
 export type WithMeta = { _meta?: Record<string, unknown> };
@@ -182,13 +183,48 @@ export type DisplayDiff = {
   beforeText: string;
   afterText: string;
 };
-export type DisplayContent = DisplayText | DisplayDiff;
+export type DisplayTerminal = {
+  type: 'terminal';
+  pid?: string;
+  exitCode?: number;
+  ansi?: AnsiOutput;
+};
+export type DisplayAgent = {
+  type: 'agent';
+  threadId: string;
+};
+
+export type DisplayContent =
+  | DisplayText
+  | DisplayDiff
+  | DisplayTerminal
+  | DisplayAgent;
+
+export type ToolDisplayFormat =
+  /**
+   * Displays as compact when user has enabled compact tools, box otherwise.
+   * This is the default format if none is selected.
+   **/
+  | 'auto'
+  /** Always display this tool in compact format. */
+  | 'compact'
+  /** Always display this tool in full box format. */
+  | 'box'
+  /** Hide this tool from the event history. */
+  | 'hidden'
+  /** Display this tool as a message-like notice. */
+  | 'notice';
 
 export interface ToolDisplay {
+  /** A display name for the tool. */
   name?: string;
+  /** A short description of what the tool is doing. */
   description?: string;
+  /** A short, one-line summary of the tool's results. */
   resultSummary?: string | null;
   result?: DisplayContent | null;
+  /** A tool may specify its preferred display format. */
+  format?: ToolDisplayFormat;
 }
 
 export interface ToolRequest {