refactor(cli): migrate core tools to native ToolDisplay property and fix UI rendering (#25186)

packages/core/src/agent/event-translator.ts

@@ -236,6 +236,7 @@ export function translateEvent(
           requestId: event.value.callId,
           name: event.value.name,
           args: event.value.args,
+          display: event.value.display,
         }),
       );
       break;
@@ -243,13 +244,15 @@ export function translateEvent(
     case GeminiEventType.ToolCallResponse: {
       ensureStreamStart(state, out);
       const data = buildToolResponseData(event.value);
-      const display: ToolDisplay | undefined = event.value.resultDisplay
-        ? {
-            result: toolResultDisplayToDisplayContent(
-              event.value.resultDisplay,
-            ),
-          }
-        : undefined;
+      const display: ToolDisplay | undefined =
+        event.value.display ??
+        (event.value.resultDisplay
+          ? {
+              result: toolResultDisplayToDisplayContent(
+                event.value.resultDisplay,
+              ),
+            }
+          : undefined);
       out.push(
         makeEvent('tool_response', state, {
           requestId: event.value.callId,
@@ -279,7 +282,6 @@ export function translateEvent(
       ((x: never) => {
         throw new Error(`Unhandled event type: ${JSON.stringify(x)}`);
       })(event);
-      break;
   }
 
   return out;

packages/core/src/agent/legacy-agent-session.test.ts

@@ -102,7 +102,10 @@ function makeCompletedToolCall(
     response: {
       callId,
       responseParts: [{ text: responseText }],
-      resultDisplay: undefined,
+      resultDisplay: responseText,
+      display: {
+        result: { type: 'text', text: responseText },
+      },
       error: undefined,
       errorType: undefined,
     },
@@ -426,6 +429,12 @@ describe('LegacyAgentSession', () => {
         (e): e is AgentEvent<'tool_response'> => e.type === 'tool_response',
       );
       expect(toolResp?.name).toBe('read_file');
+      expect(toolResp?.display).toEqual(
+        expect.objectContaining({
+          name: 'read_file',
+          result: { type: 'text', text: 'file contents' },
+        }),
+      );
       expect(toolResp?.content).toEqual([
         { type: 'text', text: 'file contents' },
       ]);

packages/core/src/agent/legacy-agent-session.ts

@@ -266,6 +266,7 @@ export class LegacyAgentProtocol implements AgentProtocol {
           invocation: 'invocation' in tc ? tc.invocation : undefined,
           resultDisplay: response.resultDisplay,
           displayName: 'tool' in tc ? tc.tool?.displayName : undefined,
+          display: response.display,
         });
         const data = buildToolResponseData(response);
 

packages/core/src/agent/tool-display-utils.ts

@@ -21,18 +21,21 @@ export function populateToolDisplay({
   invocation,
   resultDisplay,
   displayName,
+  display: prevDisplay,
 }: {
   name: string;
   invocation?: ToolInvocation<object, ToolResult>;
   resultDisplay?: ToolResultDisplay;
   displayName?: string;
+  display?: ToolDisplay;
 }): ToolDisplay {
   const display: ToolDisplay = {
     name: displayName || name,
     description: invocation?.getDescription?.(),
+    ...prevDisplay,
   };
 
-  if (resultDisplay) {
+  if (resultDisplay !== undefined && display.result === undefined) {
     display.result = toolResultDisplayToDisplayContent(resultDisplay);
   }
 
@@ -91,7 +94,7 @@ export function renderDisplayDiff(diff: DisplayDiff): string {
  * Useful for fallback displays or non-interactive environments.
  */
 export function displayContentToString(
-  display: DisplayContent | undefined,
+  display: DisplayContent | undefined | null,
 ): string | undefined {
   if (!display) {
     return undefined;

packages/core/src/agent/types.ts

@@ -4,6 +4,7 @@
  * SPDX-License-Identifier: Apache-2.0
  */
 
+import type { AnsiOutput } from '../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;
-  resultSummary?: string;
-  result?: DisplayContent;
+  /** 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 {