diff --git a/docs/README.instructions.md b/docs/README.instructions.md
index 1211113f4..f31a6e3d9 100644
--- a/docs/README.instructions.md
+++ b/docs/README.instructions.md
@@ -106,6 +106,7 @@ See [CONTRIBUTING.md](../CONTRIBUTING.md#adding-instructions) for guidelines on
| [GitHub Actions CI/CD Best Practices](../instructions/github-actions-ci-cd-best-practices.instructions.md)
[](https://aka.ms/awesome-copilot/install/instructions?url=vscode%3Achat-instructions%2Finstall%3Furl%3Dhttps%3A%2F%2Fraw.githubusercontent.com%2Fgithub%2Fawesome-copilot%2Fmain%2Finstructions%2Fgithub-actions-ci-cd-best-practices.instructions.md)
[](https://aka.ms/awesome-copilot/install/instructions?url=vscode-insiders%3Achat-instructions%2Finstall%3Furl%3Dhttps%3A%2F%2Fraw.githubusercontent.com%2Fgithub%2Fawesome-copilot%2Fmain%2Finstructions%2Fgithub-actions-ci-cd-best-practices.instructions.md) | Comprehensive guide for building robust, secure, and efficient CI/CD pipelines using GitHub Actions. Covers workflow structure, jobs, steps, environment variables, secret management, caching, matrix strategies, testing, and deployment strategies. |
| [GitHub Copilot SDK C# Instructions](../instructions/copilot-sdk-csharp.instructions.md)
[](https://aka.ms/awesome-copilot/install/instructions?url=vscode%3Achat-instructions%2Finstall%3Furl%3Dhttps%3A%2F%2Fraw.githubusercontent.com%2Fgithub%2Fawesome-copilot%2Fmain%2Finstructions%2Fcopilot-sdk-csharp.instructions.md)
[](https://aka.ms/awesome-copilot/install/instructions?url=vscode-insiders%3Achat-instructions%2Finstall%3Furl%3Dhttps%3A%2F%2Fraw.githubusercontent.com%2Fgithub%2Fawesome-copilot%2Fmain%2Finstructions%2Fcopilot-sdk-csharp.instructions.md) | This file provides guidance on building C# applications using GitHub Copilot SDK. |
| [GitHub Copilot SDK Go Instructions](../instructions/copilot-sdk-go.instructions.md)
[](https://aka.ms/awesome-copilot/install/instructions?url=vscode%3Achat-instructions%2Finstall%3Furl%3Dhttps%3A%2F%2Fraw.githubusercontent.com%2Fgithub%2Fawesome-copilot%2Fmain%2Finstructions%2Fcopilot-sdk-go.instructions.md)
[](https://aka.ms/awesome-copilot/install/instructions?url=vscode-insiders%3Achat-instructions%2Finstall%3Furl%3Dhttps%3A%2F%2Fraw.githubusercontent.com%2Fgithub%2Fawesome-copilot%2Fmain%2Finstructions%2Fcopilot-sdk-go.instructions.md) | This file provides guidance on building Go applications using GitHub Copilot SDK. |
+| [GitHub Copilot SDK Java Instructions](../instructions/copilot-sdk-java.instructions.md)
[](https://aka.ms/awesome-copilot/install/instructions?url=vscode%3Achat-instructions%2Finstall%3Furl%3Dhttps%3A%2F%2Fraw.githubusercontent.com%2Fgithub%2Fawesome-copilot%2Fmain%2Finstructions%2Fcopilot-sdk-java.instructions.md)
[](https://aka.ms/awesome-copilot/install/instructions?url=vscode-insiders%3Achat-instructions%2Finstall%3Furl%3Dhttps%3A%2F%2Fraw.githubusercontent.com%2Fgithub%2Fawesome-copilot%2Fmain%2Finstructions%2Fcopilot-sdk-java.instructions.md) | This file provides guidance on building Java applications using GitHub Copilot SDK for Java. |
| [GitHub Copilot SDK Node.js Instructions](../instructions/copilot-sdk-nodejs.instructions.md)
[](https://aka.ms/awesome-copilot/install/instructions?url=vscode%3Achat-instructions%2Finstall%3Furl%3Dhttps%3A%2F%2Fraw.githubusercontent.com%2Fgithub%2Fawesome-copilot%2Fmain%2Finstructions%2Fcopilot-sdk-nodejs.instructions.md)
[](https://aka.ms/awesome-copilot/install/instructions?url=vscode-insiders%3Achat-instructions%2Finstall%3Furl%3Dhttps%3A%2F%2Fraw.githubusercontent.com%2Fgithub%2Fawesome-copilot%2Fmain%2Finstructions%2Fcopilot-sdk-nodejs.instructions.md) | This file provides guidance on building Node.js/TypeScript applications using GitHub Copilot SDK. |
| [GitHub Copilot SDK Python Instructions](../instructions/copilot-sdk-python.instructions.md)
[](https://aka.ms/awesome-copilot/install/instructions?url=vscode%3Achat-instructions%2Finstall%3Furl%3Dhttps%3A%2F%2Fraw.githubusercontent.com%2Fgithub%2Fawesome-copilot%2Fmain%2Finstructions%2Fcopilot-sdk-python.instructions.md)
[](https://aka.ms/awesome-copilot/install/instructions?url=vscode-insiders%3Achat-instructions%2Finstall%3Furl%3Dhttps%3A%2F%2Fraw.githubusercontent.com%2Fgithub%2Fawesome-copilot%2Fmain%2Finstructions%2Fcopilot-sdk-python.instructions.md) | This file provides guidance on building Python applications using GitHub Copilot SDK. |
| [GitHub Flavored Markdown (GFM)](../instructions/markdown-gfm.instructions.md)
[](https://aka.ms/awesome-copilot/install/instructions?url=vscode%3Achat-instructions%2Finstall%3Furl%3Dhttps%3A%2F%2Fraw.githubusercontent.com%2Fgithub%2Fawesome-copilot%2Fmain%2Finstructions%2Fmarkdown-gfm.instructions.md)
[](https://aka.ms/awesome-copilot/install/instructions?url=vscode-insiders%3Achat-instructions%2Finstall%3Furl%3Dhttps%3A%2F%2Fraw.githubusercontent.com%2Fgithub%2Fawesome-copilot%2Fmain%2Finstructions%2Fmarkdown-gfm.instructions.md) | Markdown formatting for GitHub-flavored markdown (GFM) files |
diff --git a/instructions/copilot-sdk-java.instructions.md b/instructions/copilot-sdk-java.instructions.md
new file mode 100644
index 000000000..c4f604ed1
--- /dev/null
+++ b/instructions/copilot-sdk-java.instructions.md
@@ -0,0 +1,890 @@
+---
+applyTo: '**/*.java, **/pom.xml'
+description: 'This file provides guidance on building Java applications using GitHub Copilot SDK for Java.'
+name: 'GitHub Copilot SDK Java Instructions'
+---
+
+## Core Principles
+
+- The SDK is in public preview and may have breaking changes
+- Requires Java 17 or later for baseline SDK usage. Some examples use newer JDK features and therefore require JDK 21 or later (for example, virtual threads via `Executors.newVirtualThreadPerTaskExecutor()` and `switch` pattern matching). **Java 25 or later highly recommended**.
+- Requires GitHub Copilot CLI installed and in PATH
+- Uses `CompletableFuture` for all async operations
+- Implements `AutoCloseable` for resource cleanup (try-with-resources)
+- Getters on configuration classes return `Optional` (or `OptionalInt`/`OptionalDouble`) to distinguish "not set" from explicit values; setters accept raw types and return `this` for chaining. Use the `clear` methods to unset values if needed.
+
+## Installation
+
+### Maven
+
+```xml
+
+ com.github
+ copilot-sdk-java
+ ${copilot-sdk-java.version}
+
+```
+
+### Gradle
+
+```groovy
+implementation "com.github:copilot-sdk-java:${copilotSdkJavaVersion}"
+```
+
+## Client Initialization
+
+### Basic Client Setup
+
+```java
+try (var client = new CopilotClient()) {
+ client.start().get();
+ // Use client...
+}
+```
+
+### Virtual Threads (JDK 25+)
+
+Virtual threads were introduced in JDK 21, but significant performance bugs were not fixed until JDK 25, making JDK 25 the minimum recommended version for production use of virtual threads. On JDK 25+, use a virtual-thread executor for significantly better scalability. The SDK's async operations will run on virtual threads instead of the default `ForkJoinPool`:
+
+```java
+var options = new CopilotClientOptions()
+ .setExecutor(Executors.newVirtualThreadPerTaskExecutor());
+
+try (var client = new CopilotClient(options)) {
+ client.start().get();
+ // Use client...
+}
+```
+
+### Client Configuration Options
+
+When creating a CopilotClient, use `CopilotClientOptions`:
+
+- `cliPath` - Path to CLI executable (default: "copilot" from PATH)
+- `cliArgs` - Extra arguments prepended before SDK-managed flags
+- `cliUrl` - URL of existing CLI server (e.g., "localhost:8080"). When provided, client won't spawn a process
+- `port` - Server port (default: 0 for random, only when `useStdio` is false)
+- `useStdio` - Use stdio transport instead of TCP (default: true)
+- `logLevel` - Log level: "error", "warn", "info", "debug", "trace" (default: "info")
+- `autoStart` - Auto-start server on first request (default: true)
+- `autoRestart` - Auto-restart on crash (default: true)
+- `cwd` - Working directory for the CLI process
+- `environment` - Environment variables for the CLI process
+- `gitHubToken` - GitHub token for authentication
+- `useLoggedInUser` - Use logged-in `gh` CLI auth (default: true unless token provided)
+- `onListModels` - Custom model list handler for BYOK scenarios
+- `remote` - Enable Mission Control / cloud session integration (default: false)
+- `telemetry` - `TelemetryConfig` for OpenTelemetry export (since 1.2.0)
+- `sessionIdleTimeoutSeconds` - Idle timeout before session auto-closes (since 1.3.0)
+- `executor` - Custom `Executor` for async operations (default: ForkJoinPool)
+- `tcpConnectionToken` - Security token for TCP transport authentication
+
+```java
+var options = new CopilotClientOptions()
+ .setCliPath("/path/to/copilot")
+ .setLogLevel("debug")
+ .setAutoStart(true)
+ .setAutoRestart(true)
+ .setGitHubToken(System.getenv("GITHUB_TOKEN"));
+
+try (var client = new CopilotClient(options)) {
+ client.start().get();
+ // Use client...
+}
+```
+
+### Manual Server Control
+
+For explicit control:
+```java
+var client = new CopilotClient(new CopilotClientOptions().setAutoStart(false));
+client.start().get();
+// Use client...
+client.stop().get();
+```
+
+Use `forceStop()` when `stop()` takes too long.
+
+## Session Management
+
+### Creating Sessions
+
+Use `SessionConfig` for configuration. The permission handler is **required**:
+
+```java
+var session = client.createSession(new SessionConfig()
+ .setModel("gpt-5")
+ .setStreaming(true)
+ .setTools(List.of(...))
+ .setSystemMessage(new SystemMessageConfig()
+ .setMode(SystemMessageMode.APPEND)
+ .setContent("Custom instructions"))
+ .setAvailableTools(List.of("tool1", "tool2"))
+ .setExcludedTools(List.of("tool3"))
+ .setProvider(new ProviderConfig().setType("openai"))
+ .setOnPermissionRequest(PermissionHandler.APPROVE_ALL)
+).get();
+```
+
+### Session Config Options
+
+- `sessionId` - Custom session ID
+- `clientName` - Application name
+- `model` - Model name ("gpt-5", "claude-sonnet-4.5", etc.)
+- `reasoningEffort` - "low", "medium", "high", "xhigh"
+- `tools` - Custom tools exposed to the CLI
+- `systemMessage` - System message customization
+- `availableTools` - Allowlist of tool names
+- `excludedTools` - Blocklist of tool names
+- `provider` - Custom API provider configuration (BYOK)
+- `streaming` - Enable streaming response chunks (default: false)
+- `workingDirectory` - Session working directory
+- `mcpServers` - MCP server configurations
+- `customAgents` - Custom agent configurations
+- `agent` - Pre-select agent by name
+- `infiniteSessions` - Infinite sessions configuration
+- `skillDirectories` - Skill SKILL.md directories
+- `disabledSkills` - Skills to disable
+- `configDir` - Config directory path
+- `hooks` - Session lifecycle hooks
+- `onPermissionRequest` - **REQUIRED** permission handler
+- `onUserInputRequest` - User input handler
+- `onEvent` - Event handler registered before session creation
+
+All setters return `SessionConfig` for method chaining.
+
+### Resuming Sessions
+
+```java
+var session = client.resumeSession(sessionId, new ResumeSessionConfig()
+ .setOnPermissionRequest(PermissionHandler.APPROVE_ALL)
+).get();
+```
+
+### Session Operations
+
+- `session.getSessionId()` - Get session identifier
+- `session.send(prompt)` / `session.send(MessageOptions)` - Send message, returns `CompletableFuture` (the message ID, useful for correlation)
+- `session.sendAndWait(prompt)` / `session.sendAndWait(MessageOptions)` - Send and wait for response (60s timeout)
+- `session.sendAndWait(options, timeoutMs)` - Send and wait with custom timeout
+- `session.abort()` - Abort current processing
+- `session.getMessages()` - Get all events/messages
+- `session.setModel(modelId)` - Switch to a different model
+- `session.setModel(modelId, reasoningEffort)` - Switch model with reasoning effort ("low", "medium", "high", "xhigh")
+- `session.setModel(modelId, reasoningEffort, modelCapabilities)` - Switch model with `ModelCapabilitiesOverride` (since 1.3.0)
+- `session.log(message)` / `session.log(message, "warning", false)` / `session.log(message, "error", false)` - Log to session timeline with level `"info"`, `"warning"`, or `"error"`
+- `session.log(message, level, ephemeral, url)` - Log with a clickable URL link
+- `session.close()` - Clean up resources
+
+## Event Handling
+
+### Event Subscription Pattern
+
+Use `CompletableFuture` for waiting on session events:
+
+```java
+var done = new CompletableFuture();
+
+session.on(event -> {
+ if (event instanceof AssistantMessageEvent msg) {
+ System.out.println(msg.getData().content());
+ } else if (event instanceof SessionIdleEvent) {
+ done.complete(null);
+ }
+});
+
+session.send(new MessageOptions().setPrompt("Hello"));
+done.get();
+```
+
+### Type-Safe Event Handling
+
+Use the typed `on()` overload for compile-time safety:
+
+```java
+var done = new java.util.concurrent.CompletableFuture();
+
+session.on(AssistantMessageEvent.class, msg -> {
+ System.out.println(msg.getData().content());
+});
+
+session.on(SessionIdleEvent.class, idle -> {
+ done.complete(null);
+});
+```
+
+### Unsubscribing from Events
+
+The `on()` method returns a `Closeable`:
+
+```java
+var subscription = session.on(event -> { /* handler */ });
+// Later...
+subscription.close();
+```
+
+### Event Types
+
+Use pattern matching (Java 17+) for event handling:
+
+```java
+session.on(event -> {
+ if (event instanceof UserMessageEvent userMsg) {
+ // Handle user message
+ } else if (event instanceof AssistantMessageEvent assistantMsg) {
+ System.out.println(assistantMsg.getData().content());
+ } else if (event instanceof AssistantMessageDeltaEvent delta) {
+ System.out.print(delta.getData().deltaContent());
+ } else if (event instanceof ToolExecutionStartEvent toolStart) {
+ // Tool execution started
+ } else if (event instanceof ToolExecutionCompleteEvent toolComplete) {
+ // Tool execution completed
+ } else if (event instanceof SessionStartEvent start) {
+ // Session started
+ } else if (event instanceof SessionIdleEvent idle) {
+ // Session is idle (processing complete)
+ } else if (event instanceof SessionErrorEvent error) {
+ System.err.println("Error: " + error.getData().message());
+ }
+});
+```
+
+### Event Error Handling
+
+Control how errors in event handlers are handled:
+
+```java
+// Set a custom error handler
+session.setEventErrorHandler(ex -> {
+ logger.error("Event handler error", ex);
+});
+
+// Or set the error propagation policy
+session.setEventErrorPolicy(EventErrorPolicy.SUPPRESS_AND_LOG_ERRORS);
+```
+
+`EventErrorPolicy` values:
+- `PROPAGATE_AND_LOG_ERRORS` - Stop event dispatch on error (default)
+- `SUPPRESS_AND_LOG_ERRORS` - Continue dispatch, log the error
+
+## Streaming Responses
+
+### Enabling Streaming
+
+Set `streaming(true)` in SessionConfig:
+
+```java
+var session = client.createSession(new SessionConfig()
+ .setModel("gpt-5")
+ .setStreaming(true)
+ .setOnPermissionRequest(PermissionHandler.APPROVE_ALL)
+).get();
+```
+
+### Handling Streaming Events
+
+Handle both delta events (incremental) and final events:
+
+Requires Java 21+, but 25 preferred.
+
+```java
+var done = new CompletableFuture();
+
+session.on(event -> {
+ switch (event) {
+ case AssistantMessageDeltaEvent delta ->
+ // Incremental text chunk
+ System.out.print(delta.getData().deltaContent());
+ case AssistantReasoningDeltaEvent reasoningDelta ->
+ // Incremental reasoning chunk (model-dependent)
+ System.out.print(reasoningDelta.getData().deltaContent());
+ case AssistantMessageEvent msg ->
+ // Final complete message
+ System.out.println("\n--- Final ---\n" + msg.getData().content());
+ case AssistantReasoningEvent reasoning ->
+ // Final reasoning content
+ System.out.println("--- Reasoning ---\n" + reasoning.getData().content());
+ case SessionIdleEvent idle ->
+ done.complete(null);
+ default -> { }
+ }
+});
+
+session.send(new MessageOptions().setPrompt("Tell me a story"));
+done.get();
+```
+
+Note: Final events (`AssistantMessageEvent`, `AssistantReasoningEvent`) are ALWAYS sent regardless of streaming setting.
+
+## Custom Tools
+
+### Defining Tools
+
+Use `ToolDefinition.create()` with JSON Schema parameters and a `ToolHandler`:
+
+```java
+var tool = ToolDefinition.create(
+ "get_weather",
+ "Get weather for a location",
+ Map.of(
+ "type", "object",
+ "properties", Map.of(
+ "location", Map.of("type", "string", "description", "City name")
+ ),
+ "required", List.of("location")
+ ),
+ invocation -> {
+ String location = (String) invocation.getArguments().get("location");
+ return CompletableFuture.completedFuture("Sunny in " + location);
+ }
+);
+
+var session = client.createSession(new SessionConfig()
+ .setModel("gpt-5")
+ .setTools(List.of(tool))
+ .setOnPermissionRequest(PermissionHandler.APPROVE_ALL)
+).get();
+```
+
+### Type-Safe Tool Arguments
+
+Use `getArgumentsAs()` for deserialization into a typed record or class:
+
+```java
+record WeatherArgs(String location, String unit) {}
+
+var tool = ToolDefinition.create(
+ "get_weather",
+ "Get weather for a location",
+ Map.of(
+ "type", "object",
+ "properties", Map.of(
+ "location", Map.of("type", "string"),
+ "unit", Map.of("type", "string", "enum", List.of("celsius", "fahrenheit"))
+ ),
+ "required", List.of("location")
+ ),
+ invocation -> {
+ var args = invocation.getArgumentsAs(WeatherArgs.class);
+ return CompletableFuture.completedFuture(
+ Map.of("temp", 72, "unit", args.unit(), "location", args.location())
+ );
+ }
+);
+```
+
+### Overriding Built-In Tools
+
+```java
+var override = ToolDefinition.createOverride(
+ "built_in_tool_name",
+ "Custom description",
+ Map.of("type", "object", "properties", Map.of(...)),
+ invocation -> CompletableFuture.completedFuture("custom result")
+);
+```
+
+### Skipping Permission Checks (since 1.2.0)
+
+Use `createSkipPermission()` to define a tool that bypasses the CLI's permission request flow:
+
+```java
+var tool = ToolDefinition.createSkipPermission(
+ "safe_read_only_tool",
+ "A tool that needs no permission confirmation",
+ Map.of("type", "object", "properties", Map.of(...)),
+ invocation -> CompletableFuture.completedFuture("result")
+);
+```
+
+### Tool Return Types
+
+- Return any JSON-serializable value (String, Map, List, record, POJO)
+- The SDK automatically serializes the return value and sends it back to the CLI
+
+### Tool Execution Flow
+
+When Copilot invokes a tool, the client automatically:
+1. Deserializes the arguments
+2. Runs your handler function
+3. Serializes the return value
+4. Responds to the CLI
+
+## Permission Handling
+
+### Required Permission Handler
+
+A permission handler is **mandatory** when creating or resuming sessions:
+
+```java
+// Approve all requests (for development/testing)
+new SessionConfig()
+ .setOnPermissionRequest(PermissionHandler.APPROVE_ALL)
+
+// Custom permission logic
+new SessionConfig()
+ .setOnPermissionRequest((request, invocation) -> {
+ if ("dangerous-action".equals(request.getKind())) {
+ return CompletableFuture.completedFuture(
+ new PermissionRequestResult().setKind(PermissionRequestResultKind.DENIED)
+ );
+ }
+ return CompletableFuture.completedFuture(
+ new PermissionRequestResult().setKind(PermissionRequestResultKind.APPROVED)
+ );
+ })
+```
+
+## User Input Handling
+
+Handle user input requests from the agent:
+
+```java
+new SessionConfig()
+ .setOnUserInputRequest((request, invocation) -> {
+ System.out.println("Agent asks: " + request.getQuestion());
+ String answer = scanner.nextLine();
+ return CompletableFuture.completedFuture(
+ new UserInputResponse()
+ .setAnswer(answer)
+ .setWasFreeform(true)
+ );
+ })
+```
+
+## System Message Customization
+
+### Append Mode (Default - Preserves Guardrails)
+
+```java
+var session = client.createSession(new SessionConfig()
+ .setModel("gpt-5")
+ .setSystemMessage(new SystemMessageConfig()
+ .setMode(SystemMessageMode.APPEND)
+ .setContent("""
+
+ - Always check for security vulnerabilities
+ - Suggest performance improvements when applicable
+
+ """))
+ .setOnPermissionRequest(PermissionHandler.APPROVE_ALL)
+).get();
+```
+
+### Replace Mode (Full Control - Removes Guardrails)
+
+```java
+var session = client.createSession(new SessionConfig()
+ .setModel("gpt-5")
+ .setSystemMessage(new SystemMessageConfig()
+ .setMode(SystemMessageMode.REPLACE)
+ .setContent("You are a helpful assistant."))
+ .setOnPermissionRequest(PermissionHandler.APPROVE_ALL)
+).get();
+```
+
+## File Attachments
+
+Attach files to messages using `Attachment`:
+
+```java
+session.send(new MessageOptions()
+ .setPrompt("Analyze this file")
+ .setAttachments(List.of(
+ new Attachment("file", "/path/to/file.java", "My File")
+ ))
+);
+```
+
+## Message Delivery Modes
+
+Use the `mode` property in `MessageOptions`:
+
+- `"enqueue"` - Queue message for processing (default)
+- `"immediate"` - Process message immediately
+
+```java
+session.send(new MessageOptions()
+ .setPrompt("...")
+ .setMode("enqueue")
+);
+```
+
+## Convenience: Send and Wait
+
+Use `sendAndWait()` to send a message and block until the assistant responds:
+
+```java
+// With default 60-second timeout
+AssistantMessageEvent response = session.sendAndWait("What is 2+2?").get();
+System.out.println(response.getData().content());
+
+// With custom timeout
+AssistantMessageEvent response = session.sendAndWait(
+ new MessageOptions().setPrompt("Write a long story"),
+ 120_000 // 120 seconds
+).get();
+```
+
+## Multiple Sessions
+
+Sessions are independent and can run concurrently:
+
+```java
+var session1 = client.createSession(new SessionConfig()
+ .setModel("gpt-5")
+ .setOnPermissionRequest(PermissionHandler.APPROVE_ALL)
+).get();
+
+var session2 = client.createSession(new SessionConfig()
+ .setModel("claude-sonnet-4.5")
+ .setOnPermissionRequest(PermissionHandler.APPROVE_ALL)
+).get();
+
+session1.send(new MessageOptions().setPrompt("Hello from session 1"));
+session2.send(new MessageOptions().setPrompt("Hello from session 2"));
+```
+
+## Bring Your Own Key (BYOK)
+
+Use custom API providers via `ProviderConfig`:
+
+```java
+// OpenAI
+var session = client.createSession(new SessionConfig()
+ .setProvider(new ProviderConfig()
+ .setType("openai")
+ .setBaseUrl("https://api.openai.com/v1")
+ .setApiKey("sk-..."))
+ .setOnPermissionRequest(PermissionHandler.APPROVE_ALL)
+).get();
+
+// Azure OpenAI
+var session = client.createSession(new SessionConfig()
+ .setProvider(new ProviderConfig()
+ .setType("azure")
+ .setAzure(new AzureOptions()
+ .setEndpoint("https://my-resource.openai.azure.com")
+ .setDeployment("gpt-4"))
+ .setBearerToken("..."))
+ .setOnPermissionRequest(PermissionHandler.APPROVE_ALL)
+).get();
+```
+
+## Session Lifecycle Management
+
+### Listing Sessions
+
+```java
+var sessions = client.listSessions().get();
+for (var metadata : sessions) {
+ System.out.println("Session: " + metadata.getSessionId());
+}
+```
+
+### Filtering Sessions
+
+Use `SessionListFilter` to narrow results by working directory, git root, repository, or branch:
+
+```java
+var filter = new SessionListFilter()
+ .setRepository("owner/repo")
+ .setBranch("main");
+
+var sessions = client.listSessions(filter).get();
+```
+
+### Deleting Sessions
+
+```java
+client.deleteSession(sessionId).get();
+```
+
+### Checking Connection State
+
+```java
+var state = client.getState();
+```
+
+### Lifecycle Event Subscription
+
+```java
+AutoCloseable subscription = client.onLifecycle(event -> {
+ System.out.println("Lifecycle event: " + event);
+});
+// Later...
+subscription.close();
+```
+
+### Filtered Lifecycle Events
+
+Subscribe to specific lifecycle event types:
+
+```java
+AutoCloseable subscription = client.onLifecycle("session.created", event -> {
+ System.out.println("New session created");
+});
+```
+
+## Error Handling
+
+### Standard Exception Handling
+
+```java
+try {
+ var session = client.createSession(new SessionConfig()
+ .setOnPermissionRequest(PermissionHandler.APPROVE_ALL)
+ ).get();
+ session.sendAndWait("Hello").get();
+} catch (ExecutionException ex) {
+ Throwable cause = ex.getCause();
+ System.err.println("Error: " + cause.getMessage());
+} catch (Exception ex) {
+ System.err.println("Error: " + ex.getMessage());
+}
+```
+
+### Session Error Events
+
+Monitor `SessionErrorEvent` for runtime errors:
+
+```java
+session.on(SessionErrorEvent.class, error -> {
+ System.err.println("Session Error: " + error.getData().message());
+});
+```
+
+## Connectivity Testing
+
+Use `ping()` to verify server connectivity:
+
+```java
+var response = client.ping("test message").get();
+```
+
+## Status and Authentication
+
+```java
+// Get CLI version and protocol info
+var status = client.getStatus().get();
+
+// Check authentication status
+var authStatus = client.getAuthStatus().get();
+
+// List available models
+var models = client.listModels().get();
+```
+
+## Resource Cleanup
+
+### Automatic Cleanup with try-with-resources
+
+ALWAYS use try-with-resources for automatic disposal:
+
+```java
+try (var client = new CopilotClient()) {
+ client.start().get();
+ try (var session = client.createSession(new SessionConfig()
+ .setOnPermissionRequest(PermissionHandler.APPROVE_ALL)).get()) {
+ // Use session...
+ }
+}
+// Resources automatically cleaned up
+```
+
+### Manual Cleanup
+
+If not using try-with-resources:
+
+```java
+var client = new CopilotClient();
+try {
+ client.start().get();
+ // Use client...
+} finally {
+ client.stop().get();
+}
+```
+
+## Best Practices
+
+1. **Always use try-with-resources** for `CopilotClient` and `CopilotSession`
+2. **Always provide a permission handler** - it is required for `createSession` and `resumeSession`
+3. **Use `CompletableFuture`** properly - call `.get()` to block, or chain with `.thenApply()`/`.thenCompose()`
+4. **Use `sendAndWait()`** for simple request-response patterns instead of manual event handling
+5. **Handle `SessionErrorEvent`** for robust error handling
+6. **Use pattern matching** (switch with sealed types) for event handling
+7. **Enable streaming** for better UX in interactive scenarios
+8. **Close event subscriptions** (`Closeable`) when no longer needed
+9. **Use `SystemMessageMode.APPEND`** to preserve safety guardrails
+10. **Provide descriptive tool names and descriptions** for better model understanding
+11. **Handle both delta and final events** when streaming is enabled
+12. **Use `getArgumentsAs()`** for type-safe tool argument deserialization
+
+## Common Patterns
+
+### Simple Query-Response
+
+```java
+try (var client = new CopilotClient()) {
+ client.start().get();
+
+ try (var session = client.createSession(new SessionConfig()
+ .setModel("gpt-5")
+ .setOnPermissionRequest(PermissionHandler.APPROVE_ALL)).get()) {
+
+ var response = session.sendAndWait("What is 2+2?").get();
+ System.out.println(response.getData().content());
+ }
+}
+```
+
+### Event-Driven Conversation
+
+```java
+try (var client = new CopilotClient()) {
+ client.start().get();
+
+ try (var session = client.createSession(new SessionConfig()
+ .setModel("gpt-5")
+ .setOnPermissionRequest(PermissionHandler.APPROVE_ALL)).get()) {
+
+ var done = new CompletableFuture();
+
+ session.on(AssistantMessageEvent.class, msg ->
+ System.out.println(msg.getData().content()));
+
+ session.on(SessionIdleEvent.class, idle ->
+ done.complete(null));
+
+ session.send(new MessageOptions().setPrompt("What is 2+2?"));
+ done.get();
+ }
+}
+```
+
+### Multi-Turn Conversation
+
+```java
+try (var session = client.createSession(new SessionConfig()
+ .setModel("gpt-5")
+ .setOnPermissionRequest(PermissionHandler.APPROVE_ALL)).get()) {
+
+ var response1 = session.sendAndWait("What is the capital of France?").get();
+ System.out.println(response1.getData().content());
+
+ var response2 = session.sendAndWait("What is its population?").get();
+ System.out.println(response2.getData().content());
+}
+```
+
+### Tool with Complex Return Type
+
+```java
+record UserInfo(String id, String name, String email, String role) {}
+
+var tool = ToolDefinition.create(
+ "get_user",
+ "Retrieve user information",
+ Map.of(
+ "type", "object",
+ "properties", Map.of(
+ "userId", Map.of("type", "string", "description", "User ID")
+ ),
+ "required", List.of("userId")
+ ),
+ invocation -> {
+ String userId = (String) invocation.getArguments().get("userId");
+ return CompletableFuture.completedFuture(
+ new UserInfo(userId, "John Doe", "john@example.com", "Developer")
+ );
+ }
+);
+```
+
+### Session Hooks
+
+```java
+var session = client.createSession(new SessionConfig()
+ .setModel("gpt-5")
+ .setOnPermissionRequest(PermissionHandler.APPROVE_ALL)
+ .setHooks(new SessionHooks()
+ .setOnPreToolUse((input, invocation) -> {
+ System.out.println("About to execute tool: " + input.getToolName());
+ // Use static factory methods on PreToolUseHookOutput:
+ // PreToolUseHookOutput.allow()
+ // PreToolUseHookOutput.deny()
+ // PreToolUseHookOutput.deny("reason")
+ // PreToolUseHookOutput.ask()
+ return CompletableFuture.completedFuture(PreToolUseHookOutput.allow());
+ })
+ .setOnPostToolUse((output, invocation) -> {
+ System.out.println("Tool execution complete: " + output);
+ return CompletableFuture.completedFuture(null);
+ })
+ .setOnUserPromptSubmitted((prompt, invocation) -> {
+ // Intercept user prompts before processing
+ return CompletableFuture.completedFuture(null);
+ })
+ .setOnSessionStart((event, invocation) -> {
+ return CompletableFuture.completedFuture(null);
+ })
+ .setOnSessionEnd((event, invocation) -> {
+ return CompletableFuture.completedFuture(null);
+ }))
+).get();
+```
+
+## MCP Server Configuration
+
+Configure Model Context Protocol servers via `SessionConfig.setMcpServers()`:
+
+### Stdio-Based MCP Server
+
+```java
+var mcpServers = Map.of(
+ "my-server", new McpStdioServerConfig()
+ .setCommand("node")
+ .setArgs(List.of("path/to/server.js"))
+);
+
+var session = client.createSession(new SessionConfig()
+ .setModel("gpt-5")
+ .setMcpServers(mcpServers)
+ .setOnPermissionRequest(PermissionHandler.APPROVE_ALL)
+).get();
+```
+
+### HTTP/SSE MCP Server
+
+```java
+var mcpServers = Map.of(
+ "remote-server", new McpHttpServerConfig()
+ .setUrl("https://my-mcp-server.example.com/sse")
+);
+
+var session = client.createSession(new SessionConfig()
+ .setModel("gpt-5")
+ .setMcpServers(mcpServers)
+ .setOnPermissionRequest(PermissionHandler.APPROVE_ALL)
+).get();
+```
+
+## Model Capabilities Override (since 1.3.0)
+
+Override model capabilities for BYOK or custom providers:
+
+```java
+var capabilities = new ModelCapabilitiesOverride()
+ .setSupports(new ModelCapabilitiesOverride.Supports()
+ .setVision(true)
+ .setReasoningEffort(true))
+ .setLimits(new ModelCapabilitiesOverride.Limits()
+ .setMaxPromptTokens(128000));
+
+var session = client.createSession(new SessionConfig()
+ .setModel("custom-model")
+ .setModelCapabilities(capabilities)
+ .setOnPermissionRequest(PermissionHandler.APPROVE_ALL)
+).get();
+```