Support reasoningEffort: max (#2228)

* feat: support reasoningEffort 'max' in SDK types and docs

* Fix Java formatting

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

---------

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

Author: 3 people

dotnet/README.md

@@ -123,7 +123,7 @@ Create a new conversation session.
 
 - `SessionId` - Custom session ID
 - `Model` - Model to use ("gpt-5", "claude-sonnet-4.5", etc.)
-- `ReasoningEffort` - Reasoning effort level for models that support it ("low", "medium", "high", "xhigh"). Use `ListModelsAsync()` to check which models support this option.
+- `ReasoningEffort` - Reasoning effort level for models that support it ("low", "medium", "high", "xhigh", "max"). Use `ListModelsAsync()` to check which models support this option.
 - `Tools` - Custom tool declarations exposed to the CLI. Declarations without an invocable `AIFunction` are left pending for manual resolution.
 - `SystemMessage` - System message customization
 - `AvailableTools` - List of tool names to allow

dotnet/src/Session.cs

@@ -1790,7 +1790,7 @@ public async Task AbortAsync(CancellationToken cancellationToken = default)
     /// The new model takes effect for the next message. Conversation history is preserved.
     /// </summary>
     /// <param name="model">Model ID to switch to (e.g., "gpt-5.4").</param>
-    /// <param name="reasoningEffort">Reasoning effort level (e.g., "low", "medium", "high", "xhigh").</param>
+    /// <param name="reasoningEffort">Reasoning effort level (e.g., "low", "medium", "high", "xhigh", "max").</param>
     /// <param name="modelCapabilities">Per-property overrides for model capabilities, deep-merged over runtime defaults.</param>
     /// <param name="cancellationToken">Optional cancellation token.</param>
     /// <example>

dotnet/src/Types.cs

@@ -3110,7 +3110,7 @@ protected SessionConfigBase(SessionConfigBase? other)
 
     /// <summary>
     /// Reasoning effort level for models that support it.
-    /// Valid values: "low", "medium", "high", "xhigh".
+    /// Valid values: "low", "medium", "high", "xhigh", "max".
     /// Only applies to models where capabilities.supports.reasoningEffort is true.
     /// </summary>
     public string? ReasoningEffort { get; set; }

go/README.md

@@ -210,7 +210,7 @@ Event types: `SessionLifecycleCreated`, `SessionLifecycleDeleted`, `SessionLifec
 **SessionConfig:**
 
 - `Model` (string): Model to use ("gpt-5", "claude-sonnet-4.5", etc.). **Required when using custom provider.**
-- `ReasoningEffort` (string): Reasoning effort level for models that support it ("low", "medium", "high", "xhigh"). Use `ListModels()` to check which models support this option.
+- `ReasoningEffort` (string): Reasoning effort level for models that support it ("low", "medium", "high", "xhigh", "max"). Use `ListModels()` to check which models support this option.
 - `SessionID` (string): Custom session ID
 - `Tools` ([]Tool): Custom tools exposed to the CLI
 - `SystemMessage` (\*SystemMessageConfig): System message configuration. Supports three modes:

go/session.go

@@ -1769,7 +1769,7 @@ func (s *Session) Abort(ctx context.Context) error {
 
 // SetModelOptions configures optional parameters for SetModel.
 type SetModelOptions struct {
-	// ReasoningEffort sets the reasoning effort level for the new model (e.g., "low", "medium", "high", "xhigh").
+	// ReasoningEffort sets the reasoning effort level for the new model (e.g., "low", "medium", "high", "xhigh", "max").
 	ReasoningEffort *string
 	// ReasoningSummary sets the reasoning summary mode for the new model.
 	// Use ReasoningSummaryNone to suppress summary output regardless of whether reasoning is enabled.

go/types.go

@@ -1163,7 +1163,7 @@ type SessionConfig struct {
 	// Model to use for this session
 	Model string
 	// ReasoningEffort level for models that support it.
-	// Valid values: "low", "medium", "high", "xhigh"
+	// Valid values: "low", "medium", "high", "xhigh", "max"
 	// Only applies to models where capabilities.supports.reasoningEffort is true.
 	ReasoningEffort string
 	// ReasoningSummary mode for models that support configurable reasoning summaries.
@@ -1721,7 +1721,7 @@ type ResumeSessionConfig struct {
 	// Only non-nil fields are applied over the runtime-resolved capabilities.
 	ModelCapabilities *rpc.ModelCapabilitiesOverride
 	// ReasoningEffort level for models that support it.
-	// Valid values: "low", "medium", "high", "xhigh"
+	// Valid values: "low", "medium", "high", "xhigh", "max"
 	ReasoningEffort string
 	// ReasoningSummary mode for models that support configurable reasoning summaries.
 	// Use ReasoningSummaryNone to suppress summary output regardless of whether reasoning is enabled.

java/src/main/java/com/github/copilot/CopilotSession.java

@@ -1972,7 +1972,8 @@ public CompletableFuture<Void> abort() {
      *            the model ID to switch to (e.g., {@code "gpt-5.4"})
      * @param reasoningEffort
      *            reasoning effort level (e.g., {@code "low"}, {@code "medium"},
-     *            {@code "high"}, {@code "xhigh"}); {@code null} to use default
+     *            {@code "high"}, {@code "xhigh"}, {@code "max"}); {@code null} to
+     *            use default
      * @return a future that completes when the model switch is acknowledged
      * @throws IllegalStateException
      *             if this session has been terminated
@@ -2003,7 +2004,8 @@ public CompletableFuture<Void> setModel(String model, String reasoningEffort) {
      *            the model ID to switch to (e.g., {@code "gpt-5.4"})
      * @param reasoningEffort
      *            reasoning effort level (e.g., {@code "low"}, {@code "medium"},
-     *            {@code "high"}, {@code "xhigh"}); {@code null} to use default
+     *            {@code "high"}, {@code "xhigh"}, {@code "max"}); {@code null} to
+     *            use default
      * @param modelCapabilities
      *            per-property overrides for model capabilities; {@code null} to use
      *            runtime defaults

java/src/main/java/com/github/copilot/rpc/ResumeSessionConfig.java

@@ -685,7 +685,8 @@ public ResumeSessionConfig clearManageScheduleEnabled() {
     /**
      * Gets the reasoning effort level.
      *
-     * @return the reasoning effort level ("low", "medium", "high", or "xhigh")
+     * @return the reasoning effort level ("low", "medium", "high", "xhigh", or
+     *         "max")
      */
     public String getReasoningEffort() {
         return reasoningEffort;
@@ -694,7 +695,7 @@ public String getReasoningEffort() {
     /**
      * Sets the reasoning effort level for models that support it.
      * <p>
-     * Valid values: "low", "medium", "high", "xhigh".
+     * Valid values: "low", "medium", "high", "xhigh", "max".
      *
      * @param reasoningEffort
      *            the reasoning effort level

java/src/main/java/com/github/copilot/rpc/SessionConfig.java

@@ -180,7 +180,8 @@ public SessionConfig setModel(String model) {
     /**
      * Gets the reasoning effort level.
      *
-     * @return the reasoning effort level ("low", "medium", "high", or "xhigh")
+     * @return the reasoning effort level ("low", "medium", "high", "xhigh", or
+     *         "max")
      */
     public String getReasoningEffort() {
         return reasoningEffort;
@@ -189,8 +190,8 @@ public String getReasoningEffort() {
     /**
      * Sets the reasoning effort level for models that support it.
      * <p>
-     * Valid values: "low", "medium", "high", "xhigh". Only applies to models where
-     * {@code capabilities.supports.reasoningEffort} is true.
+     * Valid values: "low", "medium", "high", "xhigh", "max". Only applies to models
+     * where {@code capabilities.supports.reasoningEffort} is true.
      *
      * @param reasoningEffort
      *            the reasoning effort level

nodejs/README.md

@@ -131,7 +131,7 @@ Create a new conversation session.
 
 - `sessionId?: string` - Custom session ID.
 - `model?: string` - Model to use ("gpt-5", "claude-sonnet-4.5", etc.). **Required when using custom provider.**
-- `reasoningEffort?: "low" | "medium" | "high" | "xhigh"` - Reasoning effort level for models that support it. Use `listModels()` to check which models support this option.
+- `reasoningEffort?: "low" | "medium" | "high" | "xhigh" | "max"` - Reasoning effort level for models that support it. Use `listModels()` to check which models support this option.
 - `tools?: Tool[]` - Custom tools exposed to the CLI. Tools without `handler` are declaration-only and must be resolved via pending tool-call RPCs.
 - `systemMessage?: SystemMessageConfig` - System message customization (see below)
 - `infiniteSessions?: InfiniteSessionConfig` - Configure automatic context compaction (see below)