Rich inline cards for tool results via Chat Output Renderer API

package.json

@@ -31,6 +31,9 @@
   ],
   "license": "MIT",
   "main": "./dist/extension.js",
+  "enabledApiProposals": [
+    "chatOutputRenderer"
+  ],
   "engines": {
     "vscode": "^1.104.0"
   },
@@ -321,6 +324,20 @@
         }
       }
     ],
+    "chatOutputRenderers": [
+      {
+        "viewType": "seamless-agent.askUserResult",
+        "mimeTypes": [
+          "application/vnd.seamless-agent.ask-user-result"
+        ]
+      },
+      {
+        "viewType": "seamless-agent.planReviewResult",
+        "mimeTypes": [
+          "application/vnd.seamless-agent.plan-review-result"
+        ]
+      }
+    ],
     "commands": [
       {
         "command": "seamless-agent.cancelPendingPlans",

package.nls.json

@@ -113,6 +113,22 @@
   "batch.deleteSelected": "Delete Selected",
   "batch.selectedCount": "{0} selected",
   "confirm.deleteSelected": "Are you sure you want to delete {0} selected items?",
+  "renderer.userResponse": "User Response",
+  "renderer.defaultAgentName": "Agent",
+  "renderer.userDismissed": "User dismissed this prompt",
+  "renderer.clickToExpand": "(click to expand)",
+  "renderer.userResponded": "User responded:",
+  "renderer.attachments": "Attachments:",
+  "renderer.renderErrorAskUser": "Unable to render ask_user result",
+  "renderer.renderErrorPlanReview": "Unable to render plan review result",
+  "renderer.error": "Error",
+  "renderer.planReview": "Plan Review",
+  "renderer.walkthrough": "Walkthrough",
+  "renderer.review": "Review",
+  "renderer.status": "Status:",
+  "renderer.changesRequested": "Changes Requested",
+  "renderer.viewPlan": "View Plan",
+  "renderer.revisionsRequired": "Revisions Required:",
   "console.orTypeYourOwn": "Or type your own response below",
   "response.selectedOptions": "Selected options:",
   "response.additionalResponse": "Additional response:"

package.nls.pt-br.json

@@ -113,6 +113,23 @@
   "batch.deleteSelected": "Excluir Selecionados",
   "batch.selectedCount": "{0} selecionados",
   "confirm.deleteSelected": "Tem certeza que deseja excluir {0} itens selecionados?",
+
+  "renderer.userResponse": "Resposta do Usuário",
+  "renderer.defaultAgentName": "Agente",
+  "renderer.userDismissed": "Usuário dispensou esta solicitação",
+  "renderer.clickToExpand": "(clique para expandir)",
+  "renderer.userResponded": "Usuário respondeu:",
+  "renderer.attachments": "Anexos:",
+  "renderer.renderErrorAskUser": "Não foi possível renderizar o resultado de ask_user",
+  "renderer.renderErrorPlanReview": "Não foi possível renderizar o resultado da revisão de plano",
+  "renderer.error": "Erro",
+  "renderer.planReview": "Revisão de Plano",
+  "renderer.walkthrough": "Passo a Passo",
+  "renderer.review": "Revisão",
+  "renderer.status": "Status:",
+  "renderer.changesRequested": "Alterações Solicitadas",
+  "renderer.viewPlan": "Ver Plano",
+  "renderer.revisionsRequired": "Revisões Necessárias:",
   "console.orTypeYourOwn": "Ou digite sua própria resposta abaixo",
   "response.selectedOptions": "Opções selecionadas:",
   "response.additionalResponse": "Resposta adicional:"

package.nls.pt.json

@@ -113,6 +113,22 @@
   "batch.deleteSelected": "Eliminar Selecionados",
   "batch.selectedCount": "{0} selecionados",
   "confirm.deleteSelected": "Tem a certeza que deseja eliminar {0} itens selecionados?",
+  "renderer.userResponse": "Resposta do Utilizador",
+  "renderer.defaultAgentName": "Agente",
+  "renderer.userDismissed": "Utilizador dispensou esta solicitação",
+  "renderer.clickToExpand": "(clique para expandir)",
+  "renderer.userResponded": "Utilizador respondeu:",
+  "renderer.attachments": "Anexos:",
+  "renderer.renderErrorAskUser": "Não foi possível renderizar o resultado de ask_user",
+  "renderer.renderErrorPlanReview": "Não foi possível renderizar o resultado da revisão de plano",
+  "renderer.error": "Erro",
+  "renderer.planReview": "Revisão de Plano",
+  "renderer.walkthrough": "Passo a Passo",
+  "renderer.review": "Revisão",
+  "renderer.status": "Estado:",
+  "renderer.changesRequested": "Alterações Solicitadas",
+  "renderer.viewPlan": "Ver Plano",
+  "renderer.revisionsRequired": "Revisões Necessárias:",
   "console.orTypeYourOwn": "Ou escreva a sua própria resposta abaixo",
   "response.selectedOptions": "Opções selecionadas:",
   "response.additionalResponse": "Resposta adicional:"

src/extension.ts

@@ -3,6 +3,7 @@ import { registerNativeTools } from './tools';
 import { AgentInteractionProvider } from './webview/webviewProvider';
 import { initializeChatHistoryStorage, getChatHistoryStorage } from './storage/chatHistoryStorage';
 import { strings } from './localization';
+import { registerChatOutputRenderers } from './renderers';
 
 const PARTICIPANT_ID = 'seamless-agent.agent';
 
@@ -28,6 +29,9 @@ export function activate(context: vscode.ExtensionContext) {
     // Register the ask_user tool with the webview provider
     registerNativeTools(context, provider);
 
+    // Register chat output renderers for rich inline cards (proposed API, feature-gated)
+    registerChatOutputRenderers(context);
+
     // Register command to cancel pending plans
     const cancelPendingPlansCommand = vscode.commands.registerCommand('seamless-agent.cancelPendingPlans', async () => {
         const storage = getChatHistoryStorage();
@@ -146,10 +150,13 @@ Never finish a response without first calling the ask_user tool to verify with t
                         toolInvocationToken: request.toolInvocationToken
                     }, token);
 
-                    // Show tool result
-                    for (const resultPart of toolResult.content) {
-                        if (resultPart instanceof vscode.LanguageModelTextPart) {
-                            stream.markdown(`\n\n**User Response:** ${resultPart.value}\n\n`);
+                    // Show tool result — skip markdown when a renderer card handles the display
+                    const hasRendererCard = !!(toolResult as any).toolResultDetails2;
+                    if (!hasRendererCard) {
+                        for (const resultPart of toolResult.content) {
+                            if (resultPart instanceof vscode.LanguageModelTextPart) {
+                                stream.markdown(`\n\n**User Response:** ${resultPart.value}\n\n`);
+                            }
                         }
                     }
                 }

src/localization.ts

@@ -167,4 +167,22 @@ export const strings = {
 
     // Errors
     get noSuchInteraction() { return localize('error.noSuchInteraction'); },
+
+    // Renderer cards
+    get rendererUserResponse() { return localize('renderer.userResponse'); },
+    get rendererDefaultAgentName() { return localize('renderer.defaultAgentName'); },
+    get rendererUserDismissed() { return localize('renderer.userDismissed'); },
+    get rendererClickToExpand() { return localize('renderer.clickToExpand'); },
+    get rendererUserResponded() { return localize('renderer.userResponded'); },
+    get rendererAttachments() { return localize('renderer.attachments'); },
+    get rendererRenderErrorAskUser() { return localize('renderer.renderErrorAskUser'); },
+    get rendererRenderErrorPlanReview() { return localize('renderer.renderErrorPlanReview'); },
+    get rendererError() { return localize('renderer.error'); },
+    get rendererPlanReview() { return localize('renderer.planReview'); },
+    get rendererWalkthrough() { return localize('renderer.walkthrough'); },
+    get rendererReview() { return localize('renderer.review'); },
+    get rendererStatus() { return localize('renderer.status'); },
+    get rendererChangesRequested() { return localize('renderer.changesRequested'); },
+    get rendererViewPlan() { return localize('renderer.viewPlan'); },
+    get rendererRevisionsRequired() { return localize('renderer.revisionsRequired'); },
 };

src/proposed-api.d.ts

@@ -0,0 +1,59 @@
+/**
+ * Type declarations for the proposed `chatOutputRenderer` API.
+ * 
+ * These types extend the stable vscode API with proposed features that are
+ * gated behind `enabledApiProposals: ["chatOutputRenderer"]` in package.json.
+ * 
+ * Reference: https://github.com/microsoft/vscode-extension-samples/tree/main/chat-output-renderer-sample
+ * 
+ * TODO: Remove this file once the API is stabilized and types are included in @types/vscode.
+ */
+
+import * as vscode from 'vscode';
+
+declare module 'vscode' {
+
+    /**
+     * Extended tool result that supports attaching binary data for chat output renderers.
+     * The `toolResultDetails2` property provides MIME-typed binary data that VS Code
+     * matches against registered `chatOutputRenderers` to render inline webview cards.
+     */
+    interface ExtendedLanguageModelToolResult2 extends LanguageModelToolResult {
+        toolResultDetails2?: {
+            /** MIME type used to match a registered chatOutputRenderer */
+            mime: string;
+            /** Binary data (typically UTF-8 encoded JSON) passed to the renderer */
+            value: Uint8Array;
+        };
+    }
+
+    /**
+     * A webview container provided to chat output renderers for rendering inline content.
+     */
+    interface ChatOutputWebview {
+        readonly webview: Webview;
+    }
+
+    /**
+     * Renderer that creates inline webview widgets in the chat stream.
+     */
+    interface ChatOutputRenderer {
+        renderChatOutput(
+            data: { value: Uint8Array },
+            chatOutputWebview: ChatOutputWebview,
+            ctx: unknown,
+            token: CancellationToken
+        ): Promise<void> | void;
+    }
+
+    namespace chat {
+        /**
+         * Register a chat output renderer for a specific view type.
+         * The view type must match a `chatOutputRenderers` contribution in package.json.
+         */
+        function registerChatOutputRenderer(
+            viewType: string,
+            renderer: ChatOutputRenderer
+        ): Disposable;
+    }
+}