[Node] Add Commands and UI Elicitation Support to SDK (#906)

* [Node] Add Commands and UI Elicitation Support to SDK

* CCR feedback and CI fixes

* Fix prettier

Author: MRayermannMSFT

nodejs/README.md

@@ -279,6 +279,20 @@ Get all events/messages from this session.
 
 Disconnect the session and free resources. Session data on disk is preserved for later resumption.
 
+##### `capabilities: SessionCapabilities`
+
+Host capabilities reported when the session was created or resumed. Use this to check feature support before calling capability-gated APIs.
+
+```typescript
+if (session.capabilities.ui?.elicitation) {
+    const ok = await session.ui.confirm("Deploy?");
+}
+```
+
+##### `ui: SessionUiApi`
+
+Interactive UI methods for showing dialogs to the user. Only available when the CLI host supports elicitation (`session.capabilities.ui?.elicitation === true`). See [UI Elicitation](#ui-elicitation) for full details.
+
 ##### `destroy(): Promise<void>` *(deprecated)*
 
 Deprecated — use `disconnect()` instead.
@@ -294,6 +308,8 @@ Sessions emit various events during processing:
 - `assistant.message_delta` - Streaming response chunk
 - `tool.execution_start` - Tool execution started
 - `tool.execution_complete` - Tool execution completed
+- `command.execute` - Command dispatch request (handled internally by the SDK)
+- `commands.changed` - Command registration changed
 - And more...
 
 See `SessionEvent` type in the source for full details.
@@ -455,6 +471,72 @@ defineTool("safe_lookup", {
 })
 ```
 
+### Commands
+
+Register slash commands so that users of the CLI's TUI can invoke custom actions via `/commandName`. Each command has a `name`, optional `description`, and a `handler` called when the user executes it.
+
+```ts
+const session = await client.createSession({
+    onPermissionRequest: approveAll,
+    commands: [
+        {
+            name: "deploy",
+            description: "Deploy the app to production",
+            handler: async ({ commandName, args }) => {
+                console.log(`Deploying with args: ${args}`);
+                // Do work here — any thrown error is reported back to the CLI
+            },
+        },
+    ],
+});
+```
+
+When the user types `/deploy staging` in the CLI, the SDK receives a `command.execute` event, routes it to your handler, and automatically responds to the CLI. If the handler throws, the error message is forwarded.
+
+Commands are sent to the CLI on both `createSession` and `resumeSession`, so you can update the command set when resuming.
+
+### UI Elicitation
+
+When the CLI is running with a TUI (not in headless mode), the SDK can request interactive form dialogs from the user. The `session.ui` object provides convenience methods built on a single generic `elicitation` RPC.
+
+> **Capability check:** Elicitation is only available when the host advertises support. Always check `session.capabilities.ui?.elicitation` before calling UI methods.
+
+```ts
+const session = await client.createSession({ onPermissionRequest: approveAll });
+
+if (session.capabilities.ui?.elicitation) {
+    // Confirm dialog — returns boolean
+    const ok = await session.ui.confirm("Deploy to production?");
+
+    // Selection dialog — returns selected value or null
+    const env = await session.ui.select("Pick environment", ["production", "staging", "dev"]);
+
+    // Text input — returns string or null
+    const name = await session.ui.input("Project name:", {
+        title: "Name",
+        minLength: 1,
+        maxLength: 50,
+    });
+
+    // Generic elicitation with full schema control
+    const result = await session.ui.elicitation({
+        message: "Configure deployment",
+        requestedSchema: {
+            type: "object",
+            properties: {
+                region: { type: "string", enum: ["us-east", "eu-west"] },
+                dryRun: { type: "boolean", default: true },
+            },
+            required: ["region"],
+        },
+    });
+    // result.action: "accept" | "decline" | "cancel"
+    // result.content: { region: "us-east", dryRun: true } (when accepted)
+}
+```
+
+All UI methods throw if elicitation is not supported by the host.
+
 ### System Message Customization
 
 Control the system prompt using `systemMessage` in session config:

nodejs/package-lock.json

@@ -56,7 +56,7 @@
   "author": "GitHub",
   "license": "MIT",
   "dependencies": {
-    "@github/copilot": "^1.0.10",
+    "@github/copilot": "^1.0.11-1",
     "vscode-jsonrpc": "^8.2.1",
     "zod": "^4.3.6"
   },

nodejs/package.json

@@ -639,6 +639,7 @@ export class CopilotClient {
             this.onGetTraceContext
         );
         session.registerTools(config.tools);
+        session.registerCommands(config.commands);
         session.registerPermissionHandler(config.onPermissionRequest);
         if (config.onUserInputRequest) {
             session.registerUserInputHandler(config.onUserInputRequest);
@@ -674,6 +675,10 @@ export class CopilotClient {
                     overridesBuiltInTool: tool.overridesBuiltInTool,
                     skipPermission: tool.skipPermission,
                 })),
+                commands: config.commands?.map((cmd) => ({
+                    name: cmd.name,
+                    description: cmd.description,
+                })),
                 systemMessage: wireSystemMessage,
                 availableTools: config.availableTools,
                 excludedTools: config.excludedTools,
@@ -693,11 +698,13 @@ export class CopilotClient {
                 infiniteSessions: config.infiniteSessions,
             });
 
-            const { workspacePath } = response as {
+            const { workspacePath, capabilities } = response as {
                 sessionId: string;
                 workspacePath?: string;
+                capabilities?: { ui?: { elicitation?: boolean } };
             };
             session["_workspacePath"] = workspacePath;
+            session.setCapabilities(capabilities);
         } catch (e) {
             this.sessions.delete(sessionId);
             throw e;
@@ -754,6 +761,7 @@ export class CopilotClient {
             this.onGetTraceContext
         );
         session.registerTools(config.tools);
+        session.registerCommands(config.commands);
         session.registerPermissionHandler(config.onPermissionRequest);
         if (config.onUserInputRequest) {
             session.registerUserInputHandler(config.onUserInputRequest);
@@ -792,6 +800,10 @@ export class CopilotClient {
                     overridesBuiltInTool: tool.overridesBuiltInTool,
                     skipPermission: tool.skipPermission,
                 })),
+                commands: config.commands?.map((cmd) => ({
+                    name: cmd.name,
+                    description: cmd.description,
+                })),
                 provider: config.provider,
                 requestPermission: true,
                 requestUserInput: !!config.onUserInputRequest,
@@ -809,11 +821,13 @@ export class CopilotClient {
                 disableResume: config.disableResume,
             });
 
-            const { workspacePath } = response as {
+            const { workspacePath, capabilities } = response as {
                 sessionId: string;
                 workspacePath?: string;
+                capabilities?: { ui?: { elicitation?: boolean } };
             };
             session["_workspacePath"] = workspacePath;
+            session.setCapabilities(capabilities);
         } catch (e) {
             this.sessions.delete(sessionId);
             throw e;

nodejs/src/client.ts

@@ -12,13 +12,22 @@ export { CopilotClient } from "./client.js";
 export { CopilotSession, type AssistantMessageEvent } from "./session.js";
 export { defineTool, approveAll, SYSTEM_PROMPT_SECTIONS } from "./types.js";
 export type {
+    CommandContext,
+    CommandDefinition,
+    CommandHandler,
     ConnectionState,
     CopilotClientOptions,
     CustomAgentConfig,
+    ElicitationFieldValue,
+    ElicitationParams,
+    ElicitationResult,
+    ElicitationSchema,
+    ElicitationSchemaField,
     ForegroundSessionInfo,
     GetAuthStatusResponse,
     GetStatusResponse,
     InfiniteSessionConfig,
+    InputOptions,
     MCPLocalServerConfig,
     MCPRemoteServerConfig,
     MCPServerConfig,
@@ -34,6 +43,7 @@ export type {
     SectionOverride,
     SectionOverrideAction,
     SectionTransformFn,
+    SessionCapabilities,
     SessionConfig,
     SessionEvent,
     SessionEventHandler,
@@ -45,6 +55,7 @@ export type {
     SessionContext,
     SessionListFilter,
     SessionMetadata,
+    SessionUiApi,
     SystemMessageAppendConfig,
     SystemMessageConfig,
     SystemMessageCustomizeConfig,