Remove autoRestart feature across all SDKs (#803)

* Remove autoRestart feature across all SDKs

The autoRestart option never worked correctly. This removes it from:
- Node.js: types, client options, reconnect logic
- Python: types, client options
- Go: types, client options, struct field
- .NET: types, clone copy, tests
- Docs: setup, troubleshooting, READMEs
- Agent config: docs-maintenance validation lists

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

* Mark client as disconnected on connection close/error

Instead of leaving onClose/onError as no-ops (which would leave the
client in a stale 'connected' state), transition to 'disconnected'
so callers fail fast or can re-start cleanly.

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

* Fix numbered list after removing auto-restart step

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

* Transition to disconnected state on unexpected process/connection death

All SDKs now properly transition their connection state to 'disconnected'
when the child process exits unexpectedly or the TCP connection drops:

- Node.js: onClose/onError handlers in attachConnectionHandlers()
- Go: onClose callback fired from readLoop() on unexpected exit
- Python: on_close callback fired from _read_loop() on unexpected exit
- .NET: rpc.Completion continuation sets _disconnected flag

Includes unit tests for all four SDKs verifying the state transition.

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

* Remove .NET disconnection test

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

* Re-add autoRestart as deprecated no-op to avoid source-breaking change

Mark the option as obsolete/deprecated in Go, .NET, and TypeScript so
existing consumers continue to compile without changes.

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

* Fix go fmt alignment in Client struct

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

* Fix Go onClose deadlock by running state update in goroutine

The onClose callback acquires startStopMux, but Stop/ForceStop already
hold that lock while waiting for readLoop to finish via wg.Wait().
Running the state update in a goroutine allows readLoop to complete,
breaking the circular wait.

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

---------

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

Author: SteveSandersonMS

.github/agents/docs-maintenance.agent.md

@@ -122,7 +122,6 @@ Every major SDK feature should be documented. Core features include:
 - Client initialization and configuration
 - Connection modes (stdio vs TCP)
 - Authentication options
-- Auto-start and auto-restart behavior
 
 **Session Management:**
 - Creating sessions
@@ -342,7 +341,7 @@ cat nodejs/src/types.ts | grep -A 10 "export interface ExportSessionOptions"
 ```
 
 **Must match:**
-- `CopilotClient` constructor options: `cliPath`, `cliUrl`, `useStdio`, `port`, `logLevel`, `autoStart`, `autoRestart`, `env`, `githubToken`, `useLoggedInUser`
+- `CopilotClient` constructor options: `cliPath`, `cliUrl`, `useStdio`, `port`, `logLevel`, `autoStart`, `env`, `githubToken`, `useLoggedInUser`
 - `createSession()` config: `model`, `tools`, `hooks`, `systemMessage`, `mcpServers`, `availableTools`, `excludedTools`, `streaming`, `reasoningEffort`, `provider`, `infiniteSessions`, `customAgents`, `workingDirectory`
 - `CopilotSession` methods: `send()`, `sendAndWait()`, `getMessages()`, `disconnect()`, `abort()`, `on()`, `once()`, `off()`
 - Hook names: `onPreToolUse`, `onPostToolUse`, `onUserPromptSubmitted`, `onSessionStart`, `onSessionEnd`, `onErrorOccurred`
@@ -360,7 +359,7 @@ cat python/copilot/types.py | grep -A 15 "class SessionHooks"
 ```
 
 **Must match (snake_case):**
-- `CopilotClient` options: `cli_path`, `cli_url`, `use_stdio`, `port`, `log_level`, `auto_start`, `auto_restart`, `env`, `github_token`, `use_logged_in_user`
+- `CopilotClient` options: `cli_path`, `cli_url`, `use_stdio`, `port`, `log_level`, `auto_start`, `env`, `github_token`, `use_logged_in_user`
 - `create_session()` config keys: `model`, `tools`, `hooks`, `system_message`, `mcp_servers`, `available_tools`, `excluded_tools`, `streaming`, `reasoning_effort`, `provider`, `infinite_sessions`, `custom_agents`, `working_directory`
 - `CopilotSession` methods: `send()`, `send_and_wait()`, `get_messages()`, `disconnect()`, `abort()`, `export_session()`
 - Hook names: `on_pre_tool_use`, `on_post_tool_use`, `on_user_prompt_submitted`, `on_session_start`, `on_session_end`, `on_error_occurred`
@@ -378,7 +377,7 @@ cat go/types.go | grep -A 15 "type SessionHooks struct"
 ```
 
 **Must match (PascalCase for exported):**
-- `ClientOptions` fields: `CLIPath`, `CLIUrl`, `UseStdio`, `Port`, `LogLevel`, `AutoStart`, `AutoRestart`, `Env`, `GithubToken`, `UseLoggedInUser`
+- `ClientOptions` fields: `CLIPath`, `CLIUrl`, `UseStdio`, `Port`, `LogLevel`, `AutoStart`, `Env`, `GithubToken`, `UseLoggedInUser`
 - `SessionConfig` fields: `Model`, `Tools`, `Hooks`, `SystemMessage`, `MCPServers`, `AvailableTools`, `ExcludedTools`, `Streaming`, `ReasoningEffort`, `Provider`, `InfiniteSessions`, `CustomAgents`, `WorkingDirectory`
 - `Session` methods: `Send()`, `SendAndWait()`, `GetMessages()`, `Disconnect()`, `Abort()`, `ExportSession()`
 - Hook fields: `OnPreToolUse`, `OnPostToolUse`, `OnUserPromptSubmitted`, `OnSessionStart`, `OnSessionEnd`, `OnErrorOccurred`
@@ -396,7 +395,7 @@ cat dotnet/src/Types.cs | grep -A 15 "public class SessionHooks"
 ```
 
 **Must match (PascalCase):**
-- `CopilotClientOptions` properties: `CliPath`, `CliUrl`, `UseStdio`, `Port`, `LogLevel`, `AutoStart`, `AutoRestart`, `Environment`, `GithubToken`, `UseLoggedInUser`
+- `CopilotClientOptions` properties: `CliPath`, `CliUrl`, `UseStdio`, `Port`, `LogLevel`, `AutoStart`, `Environment`, `GithubToken`, `UseLoggedInUser`
 - `SessionConfig` properties: `Model`, `Tools`, `Hooks`, `SystemMessage`, `McpServers`, `AvailableTools`, `ExcludedTools`, `Streaming`, `ReasoningEffort`, `Provider`, `InfiniteSessions`, `CustomAgents`, `WorkingDirectory`
 - `CopilotSession` methods: `SendAsync()`, `SendAndWaitAsync()`, `GetMessagesAsync()`, `DisposeAsync()`, `AbortAsync()`, `ExportSessionAsync()`
 - Hook properties: `OnPreToolUse`, `OnPostToolUse`, `OnUserPromptSubmitted`, `OnSessionStart`, `OnSessionEnd`, `OnErrorOccurred`

docs/setup/local-cli.md

@@ -171,9 +171,6 @@ const client = new CopilotClient({
 
     // Set working directory
     cwd: "/path/to/project",
-
-    // Auto-restart CLI if it crashes (default: true)
-    autoRestart: true,
 });
 ```
 

docs/troubleshooting/debugging.md

@@ -297,14 +297,7 @@ var client = new CopilotClient(new CopilotClientOptions
    copilot --server --stdio
    ```
 
-2. Enable auto-restart (enabled by default):
-   ```typescript
-   const client = new CopilotClient({
-     autoRestart: true,
-   });
-   ```
-
-3. Check for port conflicts if using TCP mode:
+2. Check for port conflicts if using TCP mode:
    ```typescript
    const client = new CopilotClient({
      useStdio: false,

dotnet/README.md

@@ -73,7 +73,6 @@ new CopilotClient(CopilotClientOptions? options = null)
 - `UseStdio` - Use stdio transport instead of TCP (default: true)
 - `LogLevel` - Log level (default: "info")
 - `AutoStart` - Auto-start server (default: true)
-- `AutoRestart` - Auto-restart on crash (default: true)
 - `Cwd` - Working directory for the CLI process
 - `Environment` - Environment variables to pass to the CLI process
 - `Logger` - `ILogger` instance for SDK logging

dotnet/src/Client.cs

@@ -66,6 +66,7 @@ public sealed partial class CopilotClient : IDisposable, IAsyncDisposable
     private readonly CopilotClientOptions _options;
     private readonly ILogger _logger;
     private Task<Connection>? _connectionTask;
+    private volatile bool _disconnected;
     private bool _disposed;
     private readonly int? _optionsPort;
     private readonly string? _optionsHost;
@@ -202,6 +203,7 @@ public Task StartAsync(CancellationToken cancellationToken = default)
         async Task<Connection> StartCoreAsync(CancellationToken ct)
         {
             _logger.LogDebug("Starting Copilot client");
+            _disconnected = false;
 
             Task<Connection> result;
 
@@ -593,6 +595,7 @@ public ConnectionState State
             if (_connectionTask == null) return ConnectionState.Disconnected;
             if (_connectionTask.IsFaulted) return ConnectionState.Error;
             if (!_connectionTask.IsCompleted) return ConnectionState.Connecting;
+            if (_disconnected) return ConnectionState.Disconnected;
             return ConnectionState.Connected;
         }
     }
@@ -1201,6 +1204,9 @@ private async Task<Connection> ConnectToServerAsync(Process? cliProcess, string?
         rpc.AddLocalRpcMethod("hooks.invoke", handler.OnHooksInvoke);
         rpc.StartListening();
 
+        // Transition state to Disconnected if the JSON-RPC connection drops
+        _ = rpc.Completion.ContinueWith(_ => _disconnected = true, TaskScheduler.Default);
+
         _rpc = new ServerRpc(rpc);
 
         return new Connection(rpc, cliProcess, tcpClient, networkStream, stderrBuffer);

dotnet/src/Types.cs

@@ -50,8 +50,10 @@ protected CopilotClientOptions(CopilotClientOptions? other)
     {
         if (other is null) return;
 
-        AutoRestart = other.AutoRestart;
         AutoStart = other.AutoStart;
+#pragma warning disable CS0618 // Obsolete member
+        AutoRestart = other.AutoRestart;
+#pragma warning restore CS0618
         CliArgs = (string[]?)other.CliArgs?.Clone();
         CliPath = other.CliPath;
         CliUrl = other.CliUrl;
@@ -99,9 +101,10 @@ protected CopilotClientOptions(CopilotClientOptions? other)
     /// </summary>
     public bool AutoStart { get; set; } = true;
     /// <summary>
-    /// Whether to automatically restart the CLI server if it exits unexpectedly.
+    /// Obsolete. This option has no effect.
     /// </summary>
-    public bool AutoRestart { get; set; } = true;
+    [Obsolete("AutoRestart has no effect and will be removed in a future release.")]
+    public bool AutoRestart { get; set; }
     /// <summary>
     /// Environment variables to pass to the CLI process.
     /// </summary>

dotnet/test/CloneTests.cs

@@ -22,7 +22,7 @@ public void CopilotClientOptions_Clone_CopiesAllProperties()
             CliUrl = "http://localhost:8080",
             LogLevel = "debug",
             AutoStart = false,
-            AutoRestart = false,
+
             Environment = new Dictionary<string, string> { ["KEY"] = "value" },
             GitHubToken = "ghp_test",
             UseLoggedInUser = false,
@@ -38,7 +38,7 @@ public void CopilotClientOptions_Clone_CopiesAllProperties()
         Assert.Equal(original.CliUrl, clone.CliUrl);
         Assert.Equal(original.LogLevel, clone.LogLevel);
         Assert.Equal(original.AutoStart, clone.AutoStart);
-        Assert.Equal(original.AutoRestart, clone.AutoRestart);
+
         Assert.Equal(original.Environment, clone.Environment);
         Assert.Equal(original.GitHubToken, clone.GitHubToken);
         Assert.Equal(original.UseLoggedInUser, clone.UseLoggedInUser);

go/README.md

@@ -138,7 +138,6 @@ Event types: `SessionLifecycleCreated`, `SessionLifecycleDeleted`, `SessionLifec
 - `UseStdio` (bool): Use stdio transport instead of TCP (default: true)
 - `LogLevel` (string): Log level (default: "info")
 - `AutoStart` (\*bool): Auto-start server on first use (default: true). Use `Bool(false)` to disable.
-- `AutoRestart` (\*bool): Auto-restart on crash (default: true). Use `Bool(false)` to disable.
 - `Env` ([]string): Environment variables for CLI process (default: inherits from current process)
 - `GitHubToken` (string): GitHub token for authentication. When provided, takes priority over other auth methods.
 - `UseLoggedInUser` (\*bool): Whether to use logged-in user for authentication (default: true, but false when `GitHubToken` is provided). Cannot be used with `CLIUrl`.
@@ -174,7 +173,7 @@ Event types: `SessionLifecycleCreated`, `SessionLifecycleDeleted`, `SessionLifec
 
 ### Helper Functions
 
-- `Bool(v bool) *bool` - Helper to create bool pointers for `AutoStart`/`AutoRestart` options
+- `Bool(v bool) *bool` - Helper to create bool pointers for `AutoStart` option
 
 ## Image Support
 

go/client.go

@@ -73,19 +73,19 @@ const noResultPermissionV2Error = "permission handlers cannot return 'no-result'
 //	}
 //	defer client.Stop()
 type Client struct {
-	options                   ClientOptions
-	process                   *exec.Cmd
-	client                    *jsonrpc2.Client
-	actualPort                int
-	actualHost                string
-	state                     ConnectionState
-	sessions                  map[string]*Session
-	sessionsMux               sync.Mutex
-	isExternalServer          bool
-	conn                      net.Conn // stores net.Conn for external TCP connections
-	useStdio                  bool     // resolved value from options
-	autoStart                 bool     // resolved value from options
-	autoRestart               bool     // resolved value from options
+	options          ClientOptions
+	process          *exec.Cmd
+	client           *jsonrpc2.Client
+	actualPort       int
+	actualHost       string
+	state            ConnectionState
+	sessions         map[string]*Session
+	sessionsMux      sync.Mutex
+	isExternalServer bool
+	conn             net.Conn // stores net.Conn for external TCP connections
+	useStdio         bool     // resolved value from options
+	autoStart        bool     // resolved value from options
+
 	modelsCache               []ModelInfo
 	modelsCacheMux            sync.Mutex
 	lifecycleHandlers         []SessionLifecycleHandler
@@ -134,7 +134,6 @@ func NewClient(options *ClientOptions) *Client {
 		isExternalServer: false,
 		useStdio:         true,
 		autoStart:        true, // default
-		autoRestart:      true, // default
 	}
 
 	if options != nil {
@@ -184,9 +183,6 @@ func NewClient(options *ClientOptions) *Client {
 		if options.AutoStart != nil {
 			client.autoStart = *options.AutoStart
 		}
-		if options.AutoRestart != nil {
-			client.autoRestart = *options.AutoRestart
-		}
 		if options.GitHubToken != "" {
 			opts.GitHubToken = options.GitHubToken
 		}
@@ -1233,6 +1229,15 @@ func (c *Client) startCLIServer(ctx context.Context) error {
 		// Create JSON-RPC client immediately
 		c.client = jsonrpc2.NewClient(stdin, stdout)
 		c.client.SetProcessDone(c.processDone, c.processErrorPtr)
+		c.client.SetOnClose(func() {
+			// Run in a goroutine to avoid deadlocking with Stop/ForceStop,
+			// which hold startStopMux while waiting for readLoop to finish.
+			go func() {
+				c.startStopMux.Lock()
+				defer c.startStopMux.Unlock()
+				c.state = StateDisconnected
+			}()
+		})
 		c.RPC = rpc.NewServerRpc(c.client)
 		c.setupNotificationHandler()
 		c.client.Start()
@@ -1348,6 +1353,13 @@ func (c *Client) connectViaTcp(ctx context.Context) error {
 	if c.processDone != nil {
 		c.client.SetProcessDone(c.processDone, c.processErrorPtr)
 	}
+	c.client.SetOnClose(func() {
+		go func() {
+			c.startStopMux.Lock()
+			defer c.startStopMux.Unlock()
+			c.state = StateDisconnected
+		}()
+	})
 	c.RPC = rpc.NewServerRpc(c.client)
 	c.setupNotificationHandler()
 	c.client.Start()

go/internal/jsonrpc2/jsonrpc2.go

@@ -61,6 +61,7 @@ type Client struct {
 	processDone     chan struct{} // closed when the underlying process exits
 	processError    error         // set before processDone is closed
 	processErrorMu  sync.RWMutex  // protects processError
+	onClose         func()        // called when the read loop exits unexpectedly
 }
 
 // NewClient creates a new JSON-RPC client
@@ -293,9 +294,22 @@ func (c *Client) sendMessage(message any) error {
 	return nil
 }
 
+// SetOnClose sets a callback invoked when the read loop exits unexpectedly
+// (e.g. the underlying connection or process was lost).
+func (c *Client) SetOnClose(fn func()) {
+	c.onClose = fn
+}
+
 // readLoop reads messages from stdout in a background goroutine
 func (c *Client) readLoop() {
 	defer c.wg.Done()
+	defer func() {
+		// If still running, the read loop exited unexpectedly (process died or
+		// connection dropped). Notify the caller so it can update its state.
+		if c.onClose != nil && c.running.Load() {
+			c.onClose()
+		}
+	}()
 
 	reader := bufio.NewReader(c.stdout)