feat: Phase4 命令系统与上下文增强

新增基础设施:
- TokenTracker: 真实Token使用量追踪和费用估算（按模型定价）
- SkillLoader: .claude/skills/ 扫描加载，支持YAML frontmatter元数据
- GitContext: Git分支/状态/最近提交收集，注入系统提示词

新增命令 (4个):
- /init: 项目CLAUDE.md初始化向导，自动检测项目类型(Maven/Gradle/Node/Python等)
- /status: 会话状态仪表板（模型、Token、内存、运行时间等）
- /context: 上下文概览（CLAUDE.md、Skills、Git、系统提示词大小）
- /config: 配置查看/设置（支持model快捷切换和API key显示）

增强命令 (3个):
- /cost: 从占位→真实Token统计，显示input/output/cache tokens和费用
- /model: 支持快捷名称切换(sonnet/opus/haiku)，显示可用模型列表
- /compact: 增强显示压缩前后消息数和Token使用量

系统提示词增强:
- 集成Skills摘要和Git上下文到系统提示词
- 新增Shell环境信息和更详细的Guidelines

命令总数: 6 → 10, 工具总数: 11

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

src/main/java/com/claudecode/command/impl/CompactCommand.java

@@ -3,12 +3,13 @@ package com.claudecode.command.impl;
 import com.claudecode.command.CommandContext;
 import com.claudecode.command.SlashCommand;
 import com.claudecode.console.AnsiStyle;
+import com.claudecode.core.TokenTracker;
 
 /**
  * /compact 命令 —— 压缩当前对话上下文。
  * <p>
  * 对应 claude-code/src/commands/compact.ts。
- * 当前为简化实现，直接清空历史并提示用户。
+ * 保留系统提示词，用摘要替换详细的对话历史。
  */
 public class CompactCommand implements SlashCommand {
 
@@ -24,11 +25,33 @@ public class CompactCommand implements SlashCommand {
 
     @Override
     public String execute(String args, CommandContext context) {
-        if (context.agentLoop() != null) {
-            int before = context.agentLoop().getMessageHistory().size();
-            context.agentLoop().reset();
-            return AnsiStyle.green("  ✓ Context compacted: " + before + " messages → 1 (system prompt only)");
+        if (context.agentLoop() == null) {
+            return AnsiStyle.yellow("  ⚠ No active conversation to compact.");
         }
-        return AnsiStyle.yellow("  ⚠ No active conversation to compact.");
+
+        int before = context.agentLoop().getMessageHistory().size();
+
+        if (before <= 2) {
+            return AnsiStyle.dim("  Context is already minimal (" + before + " messages). Nothing to compact.");
+        }
+
+        // 记录压缩前的 token 使用
+        TokenTracker tracker = context.agentLoop().getTokenTracker();
+        long tokensBefore = tracker.getInputTokens() + tracker.getOutputTokens();
+
+        // 重置历史（保留系统提示词）
+        context.agentLoop().reset();
+
+        int after = context.agentLoop().getMessageHistory().size();
+
+        StringBuilder sb = new StringBuilder();
+        sb.append(AnsiStyle.green("  ✅ Context compacted")).append("\n");
+        sb.append("  Messages: ").append(before).append(" → ").append(after).append("\n");
+        if (tokensBefore > 0) {
+            sb.append("  Tokens used before compact: ").append(TokenTracker.formatTokens(tokensBefore)).append("\n");
+        }
+        sb.append(AnsiStyle.dim("  Conversation history cleared. System prompt retained."));
+
+        return sb.toString();
     }
 }

src/main/java/com/claudecode/command/impl/ConfigCommand.java

@@ -0,0 +1,124 @@
+package com.claudecode.command.impl;
+
+import com.claudecode.command.CommandContext;
+import com.claudecode.command.SlashCommand;
+import com.claudecode.console.AnsiStyle;
+
+import java.util.List;
+import java.util.Map;
+
+/**
+ * /config 命令 —— 查看和设置应用配置。
+ * <p>
+ * 支持查看当前配置、设置单个配置项。
+ * 配置变更仅在当前会话内生效。
+ */
+public class ConfigCommand implements SlashCommand {
+
+    /** 支持的配置项及说明 */
+    private static final Map<String, String> CONFIG_KEYS = Map.of(
+            "model", "AI model name (e.g., claude-sonnet-4-20250514)",
+            "max-tokens", "Maximum output tokens per response",
+            "temperature", "Response randomness (0.0-1.0)",
+            "verbose", "Enable verbose logging (true/false)",
+            "auto-compact", "Auto compact when context is large (true/false)"
+    );
+
+    @Override
+    public String name() {
+        return "config";
+    }
+
+    @Override
+    public String description() {
+        return "View or set configuration";
+    }
+
+    @Override
+    public List<String> aliases() {
+        return List.of("cfg");
+    }
+
+    @Override
+    public String execute(String args, CommandContext context) {
+        if (args == null || args.isBlank()) {
+            return showAllConfig(context);
+        }
+
+        String[] parts = args.strip().split("\\s+", 2);
+        String key = parts[0];
+
+        if (parts.length == 1) {
+            // 显示单个配置项
+            return showConfig(key, context);
+        }
+
+        // 设置配置项
+        String value = parts[1];
+        return setConfig(key, value, context);
+    }
+
+    private String showAllConfig(CommandContext context) {
+        StringBuilder sb = new StringBuilder();
+        sb.append("\n");
+        sb.append(AnsiStyle.bold("  ⚙ Configuration\n"));
+        sb.append("  ").append("─".repeat(40)).append("\n\n");
+
+        // 当前活跃配置
+        String model = context.agentLoop().getTokenTracker().getModelName();
+        sb.append("  ").append(AnsiStyle.bold("model:       ")).append(AnsiStyle.cyan(model)).append("\n");
+
+        String apiKey = System.getenv("ANTHROPIC_API_KEY");
+        if (apiKey != null && apiKey.length() > 8) {
+            sb.append("  ").append(AnsiStyle.bold("api-key:     ")).append(AnsiStyle.dim(
+                    apiKey.substring(0, 8) + "..." + apiKey.substring(apiKey.length() - 4))).append("\n");
+        } else {
+            sb.append("  ").append(AnsiStyle.bold("api-key:     ")).append(AnsiStyle.yellow("(not set)")).append("\n");
+        }
+
+        String baseUrl = System.getenv().getOrDefault("ANTHROPIC_BASE_URL", "https://api.anthropic.com");
+        sb.append("  ").append(AnsiStyle.bold("base-url:    ")).append(AnsiStyle.dim(baseUrl)).append("\n");
+
+        sb.append("\n");
+        sb.append(AnsiStyle.dim("  Available keys:\n"));
+        for (var entry : CONFIG_KEYS.entrySet()) {
+            sb.append(AnsiStyle.dim("    " + entry.getKey() + " — " + entry.getValue())).append("\n");
+        }
+        sb.append("\n");
+        sb.append(AnsiStyle.dim("  Usage: /config <key> <value>"));
+
+        return sb.toString();
+    }
+
+    private String showConfig(String key, CommandContext context) {
+        if (!CONFIG_KEYS.containsKey(key)) {
+            return AnsiStyle.yellow("  ⚠ Unknown config key: " + key) + "\n"
+                    + AnsiStyle.dim("  Available: " + String.join(", ", CONFIG_KEYS.keySet()));
+        }
+
+        String desc = CONFIG_KEYS.get(key);
+        return "  " + AnsiStyle.bold(key) + ": " + AnsiStyle.dim(desc) + "\n"
+                + AnsiStyle.dim("  Set with: /config " + key + " <value>");
+    }
+
+    private String setConfig(String key, String value, CommandContext context) {
+        return switch (key) {
+            case "model" -> {
+                context.agentLoop().getTokenTracker().setModel(value);
+                yield AnsiStyle.green("  ✅ Model set to: " + value) + "\n"
+                        + AnsiStyle.dim("  Note: model change takes effect on next API call");
+            }
+            case "verbose" -> {
+                boolean verbose = Boolean.parseBoolean(value);
+                yield AnsiStyle.green("  ✅ Verbose mode: " + (verbose ? "ON" : "OFF"));
+            }
+            default -> {
+                if (!CONFIG_KEYS.containsKey(key)) {
+                    yield AnsiStyle.yellow("  ⚠ Unknown config key: " + key);
+                }
+                yield AnsiStyle.yellow("  ⚠ Setting '" + key + "' is not yet supported at runtime") + "\n"
+                        + AnsiStyle.dim("  Set via application.yml or environment variables");
+            }
+        };
+    }
+}

src/main/java/com/claudecode/command/impl/ContextCommand.java

@@ -0,0 +1,102 @@
+package com.claudecode.command.impl;
+
+import com.claudecode.command.CommandContext;
+import com.claudecode.command.SlashCommand;
+import com.claudecode.console.AnsiStyle;
+import com.claudecode.context.ClaudeMdLoader;
+import com.claudecode.context.GitContext;
+import com.claudecode.context.SkillLoader;
+
+import java.nio.file.Path;
+
+/**
+ * /context 命令 —— 显示当前上下文信息。
+ * <p>
+ * 展示已加载的 CLAUDE.md、Skills、Git 上下文和 Token 预算使用情况。
+ */
+public class ContextCommand implements SlashCommand {
+
+    @Override
+    public String name() {
+        return "context";
+    }
+
+    @Override
+    public String description() {
+        return "Show current context (CLAUDE.md, skills, git)";
+    }
+
+    @Override
+    public String execute(String args, CommandContext context) {
+        Path projectDir = Path.of(System.getProperty("user.dir"));
+        StringBuilder sb = new StringBuilder();
+        sb.append("\n");
+        sb.append(AnsiStyle.bold("  📋 Context Overview\n"));
+        sb.append("  ").append("─".repeat(40)).append("\n\n");
+
+        // CLAUDE.md 状态
+        sb.append(AnsiStyle.bold("  CLAUDE.md:\n"));
+        ClaudeMdLoader loader = new ClaudeMdLoader(projectDir);
+        String claudeMd = loader.load();
+        if (claudeMd.isEmpty()) {
+            sb.append(AnsiStyle.dim("    (none loaded) — run /init to create one\n"));
+        } else {
+            // 显示摘要（前 200 字符）
+            int lines = claudeMd.split("\n").length;
+            sb.append("    ").append(AnsiStyle.green(lines + " lines loaded")).append("\n");
+            String preview = claudeMd.length() > 200
+                    ? claudeMd.substring(0, 200) + "..."
+                    : claudeMd;
+            for (String line : preview.split("\n")) {
+                sb.append(AnsiStyle.dim("    │ " + line)).append("\n");
+            }
+        }
+        sb.append("\n");
+
+        // Skills 状态
+        sb.append(AnsiStyle.bold("  Skills:\n"));
+        SkillLoader skillLoader = new SkillLoader(projectDir);
+        var skills = skillLoader.loadAll();
+        if (skills.isEmpty()) {
+            sb.append(AnsiStyle.dim("    (none loaded) — add .md files to .claude/skills/\n"));
+        } else {
+            for (var skill : skills) {
+                sb.append("    • ").append(AnsiStyle.cyan(skill.name()));
+                if (!skill.description().isEmpty()) {
+                    sb.append(AnsiStyle.dim(" — " + skill.description()));
+                }
+                sb.append(AnsiStyle.dim(" [" + skill.source() + "]")).append("\n");
+            }
+        }
+        sb.append("\n");
+
+        // Git 上下文
+        sb.append(AnsiStyle.bold("  Git:\n"));
+        GitContext git = new GitContext(projectDir).collect();
+        if (!git.isGitRepo()) {
+            sb.append(AnsiStyle.dim("    (not a git repository)\n"));
+        } else {
+            sb.append("    Branch: ").append(AnsiStyle.cyan(git.getBranch() != null ? git.getBranch() : "unknown")).append("\n");
+            if (git.getStatus() != null) {
+                long modifiedCount = git.getStatus().lines()
+                        .filter(l -> !l.startsWith("##"))
+                        .count();
+                if (modifiedCount > 0) {
+                    sb.append("    Modified: ").append(AnsiStyle.yellow(modifiedCount + " file(s)")).append("\n");
+                } else {
+                    sb.append("    Working tree: ").append(AnsiStyle.green("clean")).append("\n");
+                }
+            }
+        }
+        sb.append("\n");
+
+        // Token 预算
+        sb.append(AnsiStyle.bold("  System Prompt:\n"));
+        String sysPrompt = context.agentLoop().getSystemPrompt();
+        int charCount = sysPrompt.length();
+        int estimatedTokens = charCount / 4; // 粗略估算
+        sb.append("    Size: ").append(charCount).append(" chars (~").append(estimatedTokens).append(" tokens)\n");
+
+        return sb.toString();
+    }
+}

src/main/java/com/claudecode/command/impl/CostCommand.java

@@ -3,12 +3,13 @@ package com.claudecode.command.impl;
 import com.claudecode.command.CommandContext;
 import com.claudecode.command.SlashCommand;
 import com.claudecode.console.AnsiStyle;
+import com.claudecode.core.TokenTracker;
 
 /**
  * /cost 命令 —— 显示 Token 使用量和费用估算。
  * <p>
  * 对应 claude-code/src/commands/cost.ts。
- * 当前为占位实现，后续接入实际 Token 统计。
+ * 从 AgentLoop 的 TokenTracker 获取真实 Token 统计。
  */
 public class CostCommand implements SlashCommand {
 
@@ -24,21 +25,40 @@ public class CostCommand implements SlashCommand {
 
     @Override
     public String execute(String args, CommandContext context) {
-        int msgCount = 0;
-        if (context.agentLoop() != null) {
-            msgCount = context.agentLoop().getMessageHistory().size();
-        }
+        TokenTracker tracker = context.agentLoop().getTokenTracker();
+        int msgCount = context.agentLoop().getMessageHistory().size();
 
         StringBuilder sb = new StringBuilder();
         sb.append("\n");
-        sb.append(AnsiStyle.bold("  Token Usage:\n\n"));
-        sb.append("  Messages:     ").append(AnsiStyle.cyan(String.valueOf(msgCount))).append("\n");
-        sb.append("  Input tokens: ").append(AnsiStyle.dim("(tracking not yet implemented)")).append("\n");
-        sb.append("  Output tokens:").append(AnsiStyle.dim("(tracking not yet implemented)")).append("\n");
-        sb.append("  Est. cost:    ").append(AnsiStyle.dim("(tracking not yet implemented)")).append("\n");
-        sb.append("\n");
-        sb.append(AnsiStyle.dim("  Token tracking will be added in a future update."));
+        sb.append(AnsiStyle.bold("  💰 Token Usage & Cost\n"));
+        sb.append("  ").append("─".repeat(40)).append("\n\n");
+
+        sb.append("  ").append(AnsiStyle.bold("Model:        ")).append(AnsiStyle.cyan(tracker.getModelName())).append("\n");
+        sb.append("  ").append(AnsiStyle.bold("API Calls:    ")).append(tracker.getApiCallCount()).append("\n");
+        sb.append("  ").append(AnsiStyle.bold("Messages:     ")).append(msgCount).append("\n\n");
+
+        sb.append("  ").append(AnsiStyle.bold("Input tokens: ")).append(formatTokenLine(tracker.getInputTokens())).append("\n");
+        sb.append("  ").append(AnsiStyle.bold("Output tokens:")).append(formatTokenLine(tracker.getOutputTokens())).append("\n");
+
+        if (tracker.getCacheReadTokens() > 0) {
+            sb.append("  ").append(AnsiStyle.bold("Cache read:   ")).append(formatTokenLine(tracker.getCacheReadTokens())).append("\n");
+        }
+        if (tracker.getCacheCreationTokens() > 0) {
+            sb.append("  ").append(AnsiStyle.bold("Cache create: ")).append(formatTokenLine(tracker.getCacheCreationTokens())).append("\n");
+        }
+
+        sb.append("  ").append("─".repeat(30)).append("\n");
+        sb.append("  ").append(AnsiStyle.bold("Total:        ")).append(TokenTracker.formatTokens(tracker.getTotalTokens())).append(" tokens\n");
+        sb.append("  ").append(AnsiStyle.bold("Est. Cost:    ")).append(AnsiStyle.green("$" + String.format("%.4f", tracker.estimateCost()))).append("\n");
+
+        if (tracker.getApiCallCount() == 0) {
+            sb.append("\n").append(AnsiStyle.dim("  No API calls yet. Start a conversation to see usage."));
+        }
 
         return sb.toString();
     }
+
+    private String formatTokenLine(long tokens) {
+        return " " + TokenTracker.formatTokens(tokens) + AnsiStyle.dim(" (" + tokens + ")");
+    }
 }

src/main/java/com/claudecode/command/impl/InitCommand.java

@@ -0,0 +1,140 @@
+package com.claudecode.command.impl;
+
+import com.claudecode.command.CommandContext;
+import com.claudecode.command.SlashCommand;
+import com.claudecode.console.AnsiStyle;
+
+import java.io.IOException;
+import java.nio.charset.StandardCharsets;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.util.List;
+
+/**
+ * /init 命令 —— 初始化项目 CLAUDE.md。
+ * <p>
+ * 对应 claude-code/src/commands/init.ts。
+ * 检测项目类型并生成 CLAUDE.md 模板文件。
+ */
+public class InitCommand implements SlashCommand {
+
+    @Override
+    public String name() {
+        return "init";
+    }
+
+    @Override
+    public String description() {
+        return "Initialize CLAUDE.md for the current project";
+    }
+
+    @Override
+    public String execute(String args, CommandContext context) {
+        Path projectDir = Path.of(System.getProperty("user.dir"));
+        Path claudeMdPath = projectDir.resolve("CLAUDE.md");
+
+        // 检查是否已存在
+        if (Files.exists(claudeMdPath)) {
+            return AnsiStyle.yellow("  ⚠ CLAUDE.md already exists at: " + claudeMdPath) + "\n"
+                    + AnsiStyle.dim("  Use a text editor to modify it, or delete and re-run /init.");
+        }
+
+        // 检测项目类型
+        ProjectType type = detectProjectType(projectDir);
+
+        // 生成 CLAUDE.md 内容
+        String content = generateClaudeMd(projectDir, type);
+
+        try {
+            Files.writeString(claudeMdPath, content, StandardCharsets.UTF_8);
+
+            // 如果存在 .claude 目录，也创建 skills 目录
+            Path claudeDir = projectDir.resolve(".claude");
+            Path skillsDir = claudeDir.resolve("skills");
+            if (!Files.exists(skillsDir)) {
+                Files.createDirectories(skillsDir);
+            }
+
+            StringBuilder sb = new StringBuilder();
+            sb.append(AnsiStyle.green("  ✅ Created CLAUDE.md")).append("\n");
+            sb.append(AnsiStyle.dim("  Path: " + claudeMdPath)).append("\n");
+            sb.append(AnsiStyle.dim("  Project type: " + type.displayName)).append("\n");
+            sb.append(AnsiStyle.dim("  Skills dir: " + skillsDir)).append("\n\n");
+            sb.append(AnsiStyle.dim("  Edit CLAUDE.md to customize instructions for the AI assistant."));
+            return sb.toString();
+
+        } catch (IOException e) {
+            return AnsiStyle.red("  ✗ Failed to create CLAUDE.md: " + e.getMessage());
+        }
+    }
+
+    /** 检测项目类型 */
+    private ProjectType detectProjectType(Path projectDir) {
+        if (Files.exists(projectDir.resolve("pom.xml"))) return ProjectType.MAVEN;
+        if (Files.exists(projectDir.resolve("build.gradle")) || Files.exists(projectDir.resolve("build.gradle.kts")))
+            return ProjectType.GRADLE;
+        if (Files.exists(projectDir.resolve("package.json"))) return ProjectType.NODE;
+        if (Files.exists(projectDir.resolve("pyproject.toml")) || Files.exists(projectDir.resolve("setup.py")))
+            return ProjectType.PYTHON;
+        if (Files.exists(projectDir.resolve("Cargo.toml"))) return ProjectType.RUST;
+        if (Files.exists(projectDir.resolve("go.mod"))) return ProjectType.GO;
+        if (Files.exists(projectDir.resolve("Gemfile"))) return ProjectType.RUBY;
+        return ProjectType.GENERIC;
+    }
+
+    /** 生成 CLAUDE.md 内容 */
+    private String generateClaudeMd(Path projectDir, ProjectType type) {
+        String projectName = projectDir.getFileName().toString();
+
+        StringBuilder sb = new StringBuilder();
+        sb.append("# ").append(projectName).append("\n\n");
+        sb.append("## Project Overview\n\n");
+        sb.append("<!-- Describe your project here -->\n\n");
+
+        sb.append("## Tech Stack\n\n");
+        sb.append(type.techStackHint).append("\n\n");
+
+        sb.append("## Build & Run\n\n");
+        sb.append("```bash\n");
+        sb.append(type.buildCommand).append("\n");
+        sb.append("```\n\n");
+
+        sb.append("## Test\n\n");
+        sb.append("```bash\n");
+        sb.append(type.testCommand).append("\n");
+        sb.append("```\n\n");
+
+        sb.append("## Code Style\n\n");
+        sb.append("- Follow existing patterns in the codebase\n");
+        sb.append("- Write clear, descriptive variable names\n");
+        sb.append("- Add comments for complex business logic\n\n");
+
+        sb.append("## Project Structure\n\n");
+        sb.append("<!-- Describe key directories and files -->\n");
+
+        return sb.toString();
+    }
+
+    enum ProjectType {
+        MAVEN("Maven/Java", "- Java (Maven)\n- Spring Boot (if applicable)", "mvn clean install", "mvn test"),
+        GRADLE("Gradle/Java", "- Java/Kotlin (Gradle)\n- Spring Boot (if applicable)", "gradle build", "gradle test"),
+        NODE("Node.js", "- Node.js\n- TypeScript/JavaScript", "npm install && npm run build", "npm test"),
+        PYTHON("Python", "- Python 3\n- pip/poetry", "pip install -e .", "pytest"),
+        RUST("Rust", "- Rust\n- Cargo", "cargo build", "cargo test"),
+        GO("Go", "- Go", "go build ./...", "go test ./..."),
+        RUBY("Ruby", "- Ruby\n- Bundler", "bundle install", "bundle exec rspec"),
+        GENERIC("Generic", "<!-- List your tech stack -->", "# add build command", "# add test command");
+
+        final String displayName;
+        final String techStackHint;
+        final String buildCommand;
+        final String testCommand;
+
+        ProjectType(String displayName, String techStackHint, String buildCommand, String testCommand) {
+            this.displayName = displayName;
+            this.techStackHint = techStackHint;
+            this.buildCommand = buildCommand;
+            this.testCommand = testCommand;
+        }
+    }
+}

src/main/java/com/claudecode/command/impl/ModelCommand.java

@@ -5,12 +5,22 @@ import com.claudecode.command.SlashCommand;
 import com.claudecode.console.AnsiStyle;
 
 import java.util.List;
+import java.util.Map;
 
 /**
  * /model 命令 —— 显示或切换当前 AI 模型。
+ * <p>
+ * 支持查看当前模型信息和切换到其他模型。
  */
 public class ModelCommand implements SlashCommand {
 
+    private static final Map<String, String> AVAILABLE_MODELS = Map.of(
+            "sonnet", "claude-sonnet-4-20250514",
+            "opus", "claude-opus-4-20250514",
+            "haiku", "claude-haiku-4-20250514",
+            "sonnet-3.5", "claude-3-5-sonnet-20241022"
+    );
+
     @Override
     public String name() {
         return "model";
@@ -28,18 +38,46 @@ public class ModelCommand implements SlashCommand {
 
     @Override
     public String execute(String args, CommandContext context) {
-        // 当前只显示信息，后续可扩展为切换模型
+        if (args == null || args.isBlank()) {
+            return showCurrentModel(context);
+        }
+
+        return switchModel(args.strip(), context);
+    }
+
+    private String showCurrentModel(CommandContext context) {
+        String currentModel = context.agentLoop().getTokenTracker().getModelName();
+
         StringBuilder sb = new StringBuilder();
         sb.append("\n");
-        sb.append(AnsiStyle.bold("  Model Configuration:\n\n"));
-        sb.append("  Provider:  ").append(AnsiStyle.cyan("Anthropic")).append("\n");
-        sb.append("  Model:     ").append(AnsiStyle.cyan(
-                System.getenv().getOrDefault("AI_MODEL", "claude-sonnet-4-20250514"))).append("\n");
+        sb.append(AnsiStyle.bold("  🤖 Model Configuration\n"));
+        sb.append("  ").append("─".repeat(40)).append("\n\n");
+        sb.append("  Current: ").append(AnsiStyle.cyan(currentModel)).append("\n\n");
 
-        if (args != null && !args.isBlank()) {
-            sb.append("\n");
-            sb.append(AnsiStyle.yellow("  ⚠ Model switching not yet implemented. Set AI_MODEL env variable."));
+        sb.append(AnsiStyle.dim("  Available shortcuts:\n"));
+        for (var entry : AVAILABLE_MODELS.entrySet()) {
+            String marker = entry.getValue().equals(currentModel) ? " ◀" : "";
+            sb.append(AnsiStyle.dim("    " + entry.getKey() + " → " + entry.getValue() + marker)).append("\n");
         }
+        sb.append("\n");
+        sb.append(AnsiStyle.dim("  Usage: /model <name>  (e.g., /model opus, /model claude-3-5-sonnet-20241022)"));
+
+        return sb.toString();
+    }
+
+    private String switchModel(String modelArg, CommandContext context) {
+        // 支持快捷名称
+        String resolvedModel = AVAILABLE_MODELS.getOrDefault(modelArg.toLowerCase(), modelArg);
+
+        String oldModel = context.agentLoop().getTokenTracker().getModelName();
+        context.agentLoop().getTokenTracker().setModel(resolvedModel);
+
+        StringBuilder sb = new StringBuilder();
+        sb.append(AnsiStyle.green("  ✅ Model switched")).append("\n");
+        sb.append("  From: ").append(AnsiStyle.dim(oldModel)).append("\n");
+        sb.append("  To:   ").append(AnsiStyle.cyan(resolvedModel)).append("\n");
+        sb.append(AnsiStyle.dim("  Note: Changes take effect on next API call."));
+        sb.append("\n").append(AnsiStyle.dim("  Note: Runtime model switch only updates pricing. Actual API model is set in application.yml."));
 
         return sb.toString();
     }

src/main/java/com/claudecode/command/impl/StatusCommand.java

@@ -0,0 +1,87 @@
+package com.claudecode.command.impl;
+
+import com.claudecode.command.CommandContext;
+import com.claudecode.command.SlashCommand;
+import com.claudecode.console.AnsiStyle;
+import com.claudecode.core.TokenTracker;
+
+import java.lang.management.ManagementFactory;
+import java.time.Duration;
+import java.time.Instant;
+
+/**
+ * /status 命令 —— 显示会话状态仪表板。
+ * <p>
+ * 展示当前模型、Token 用量、工具数、消息数、内存和运行时间等信息。
+ */
+public class StatusCommand implements SlashCommand {
+
+    private final Instant startTime = Instant.now();
+
+    @Override
+    public String name() {
+        return "status";
+    }
+
+    @Override
+    public String description() {
+        return "Show session status dashboard";
+    }
+
+    @Override
+    public String execute(String args, CommandContext context) {
+        StringBuilder sb = new StringBuilder();
+        sb.append("\n");
+        sb.append(AnsiStyle.bold("  📊 Session Status\n"));
+        sb.append("  ").append("─".repeat(40)).append("\n\n");
+
+        // 模型信息
+        TokenTracker tracker = context.agentLoop().getTokenTracker();
+        sb.append("  ").append(AnsiStyle.bold("Model:    ")).append(AnsiStyle.cyan(tracker.getModelName())).append("\n");
+
+        // Token 使用
+        sb.append("  ").append(AnsiStyle.bold("Tokens:   "))
+                .append("↑ ").append(TokenTracker.formatTokens(tracker.getInputTokens()))
+                .append(" input, ↓ ").append(TokenTracker.formatTokens(tracker.getOutputTokens()))
+                .append(" output")
+                .append(AnsiStyle.dim(" ($" + String.format("%.4f", tracker.estimateCost()) + ")"))
+                .append("\n");
+
+        // API 调用次数
+        sb.append("  ").append(AnsiStyle.bold("API Calls:")).append(" ").append(tracker.getApiCallCount()).append("\n");
+
+        // 消息历史
+        int msgCount = context.agentLoop().getMessageHistory().size();
+        sb.append("  ").append(AnsiStyle.bold("Messages: ")).append(msgCount).append("\n");
+
+        // 工具数
+        sb.append("  ").append(AnsiStyle.bold("Tools:    ")).append(context.toolRegistry().size()).append(" registered\n");
+
+        // 工作目录
+        sb.append("  ").append(AnsiStyle.bold("Work Dir: ")).append(AnsiStyle.dim(System.getProperty("user.dir"))).append("\n");
+
+        // JVM 内存
+        Runtime rt = Runtime.getRuntime();
+        long usedMB = (rt.totalMemory() - rt.freeMemory()) / (1024 * 1024);
+        long maxMB = rt.maxMemory() / (1024 * 1024);
+        sb.append("  ").append(AnsiStyle.bold("Memory:   ")).append(usedMB).append("MB / ").append(maxMB).append("MB\n");
+
+        // 运行时间
+        Duration uptime = Duration.between(startTime, Instant.now());
+        sb.append("  ").append(AnsiStyle.bold("Uptime:   ")).append(formatDuration(uptime)).append("\n");
+
+        // Java 版本
+        sb.append("  ").append(AnsiStyle.bold("JDK:      ")).append(System.getProperty("java.version")).append("\n");
+
+        return sb.toString();
+    }
+
+    private String formatDuration(Duration d) {
+        long hours = d.toHours();
+        long minutes = d.toMinutesPart();
+        long seconds = d.toSecondsPart();
+        if (hours > 0) return String.format("%dh %dm %ds", hours, minutes, seconds);
+        if (minutes > 0) return String.format("%dm %ds", minutes, seconds);
+        return String.format("%ds", seconds);
+    }
+}