feat(cli): enable skill activation via slash commands

- Register agent skills as dynamic slash commands using SkillCommandLoader
- Allow client-initiated tool calls to skip user confirmation if policy is ASK_USER
- Support follow-up prompt in skill slash commands via postSubmitPrompt
- Add tests for SkillCommandLoader and policy bypass

packages/cli/src/ui/commands/types.ts

@@ -182,6 +182,7 @@ export enum CommandKind {
   EXTENSION_FILE = 'extension-file',
   MCP_PROMPT = 'mcp-prompt',
   AGENT = 'agent',
+  SKILL = 'skill',
 }
 
 // The standardized contract for any command in the system.

packages/cli/src/ui/hooks/slashCommandProcessor.ts

@@ -52,6 +52,7 @@ import { CommandService } from '../../services/CommandService.js';
 import { BuiltinCommandLoader } from '../../services/BuiltinCommandLoader.js';
 import { FileCommandLoader } from '../../services/FileCommandLoader.js';
 import { McpPromptLoader } from '../../services/McpPromptLoader.js';
+import { SkillCommandLoader } from '../../services/SkillCommandLoader.js';
 import { parseSlashCommand } from '../../utils/commands.js';
 import {
   type ExtensionUpdateAction,
@@ -324,6 +325,7 @@ export const useSlashCommandProcessor = (
     (async () => {
       const commandService = await CommandService.create(
         [
+          new SkillCommandLoader(config),
           new McpPromptLoader(config),
           new BuiltinCommandLoader(config),
           new FileCommandLoader(config),
@@ -445,6 +447,7 @@ export const useSlashCommandProcessor = (
                     type: 'schedule_tool',
                     toolName: result.toolName,
                     toolArgs: result.toolArgs,
+                    postSubmitPrompt: result.postSubmitPrompt,
                   };
                 case 'message':
                   addItem(

packages/cli/src/ui/hooks/useGeminiStream.ts

@@ -747,7 +747,8 @@ export const useGeminiStream = (
           if (slashCommandResult) {
             switch (slashCommandResult.type) {
               case 'schedule_tool': {
-                const { toolName, toolArgs } = slashCommandResult;
+                const { toolName, toolArgs, postSubmitPrompt } =
+                  slashCommandResult;
                 const toolCallRequest: ToolCallRequestInfo = {
                   callId: `${toolName}-${Date.now()}-${Math.random().toString(16).slice(2)}`,
                   name: toolName,
@@ -756,6 +757,15 @@ export const useGeminiStream = (
                   prompt_id,
                 };
                 await scheduleToolCalls([toolCallRequest], abortSignal);
+
+                if (postSubmitPrompt) {
+                  localQueryToSendToGemini = postSubmitPrompt;
+                  return {
+                    queryToSend: localQueryToSendToGemini,
+                    shouldProceed: true,
+                  };
+                }
+
                 return { queryToSend: null, shouldProceed: false };
               }
               case 'submit_prompt': {

packages/cli/src/ui/types.ts

@@ -481,6 +481,7 @@ export type SlashCommandProcessorResult =
       type: 'schedule_tool';
       toolName: string;
       toolArgs: Record<string, unknown>;
+      postSubmitPrompt?: PartListUnion;
     }
   | {
       type: 'handled'; // Indicates the command was processed and no further action is needed.