Upstream sync: Port Commands, Elicitation, Session Capabilities, and getSessionMetadata (27 commits)

[Copilot]

Ports 27 upstream commits from github/copilot-sdk (up to f7fd757). Updates .lastmerge accordingly.

Before the change?

• No support for slash commands in sessions
• No elicitation (UI dialog) API
• No session capability reporting
• No per-session metadata lookup by ID
• Permission events resolved by a pre-hook were still dispatched to the client-side handler
• SessionUiApi Javadoc used ?. (not valid Java syntax) in the prose description
• README listed "GitHub Copilot 1.0.17" instead of "GitHub Copilot CLI 1.0.17"

After the change?

Slash Commands — Register /command handlers invoked from the CLI TUI:

new SessionConfig()
    .setCommands(List.of(
        new CommandDefinition()
            .setName("deploy")
            .setDescription("Deploy the current branch")
            .setHandler(ctx -> { /* ... */ return CompletableFuture.completedFuture(null); })
    ))

• command.execute events dispatched to registered handlers; responds via session.commands.handlePendingCommand
• commandName null-checked before ConcurrentHashMap lookup to prevent NullPointerException
• Wire: commands sent as CommandWireDefinition list in create/resume requests

Elicitation (UI Dialogs) — Two directions:

• Incoming: onElicitationRequest handler receives elicitation requests from server/MCP tools; requestElicitation=true advertises support
• Outgoing: session.getUi().confirm() / .select() / .input() / .elicitation() for proactive dialogs when host supports it

Session Capabilities — session.getCapabilities() populated from create/resume response and updated via capabilities.changed events:

var caps = session.getCapabilities();
if (caps.getUi() != null && Boolean.TRUE.equals(caps.getUi().getElicitation())) {
    boolean ok = session.getUi().confirm("Proceed?").get();
}

getSessionMetadata(sessionId) — O(1) session lookup by ID on CopilotClient (vs. scanning all sessions with listSessions()).

resolvedByHook fix — Permission events already resolved by a pre-hook now short-circuit before invoking the client-side permission handler.

Javadoc / docs fixes — SessionUiApi prose now uses valid Java null-check syntax instead of ?.; README updated to say "GitHub Copilot CLI 1.0.17".

New Types

• json/: CommandDefinition, CommandContext, CommandHandler, CommandWireDefinition, ElicitationContext, ElicitationResult, ElicitationSchema, ElicitationParams, ElicitationResultAction, ElicitationHandler, InputOptions, SessionCapabilities, SessionUiCapabilities, SessionUiApi, GetSessionMetadataResponse
• events/: CommandExecuteEvent, ElicitationRequestedEvent, CapabilitiesChangedEvent

Pull request checklist

• Tests for the changes have been added (for bug fixes / features)
• Docs have been reviewed and added / updated if needed (for bug fixes / features)
• mvn spotless:apply has been run to format the code
• mvn clean verify passes locally

Does this introduce a breaking change?

• Yes
• No

---

[Copilot]

Pull request overview

Ports upstream changes to add slash commands, elicitation (UI dialogs), session capability reporting/updates, and efficient per-session metadata lookup.

Changes:

• Add command registration and command.execute event handling, including wire-format support in create/resume requests.
• Add elicitation support (incoming handler + outgoing session.getUi() API) and session capabilities populated from create/resume + capabilities.changed.
• Add CopilotClient.getSessionMetadata(sessionId) plus tests and documentation updates (including required CLI version bump).

Show a summary per file

File	Description
src/test/java/com/github/copilot/sdk/ElicitationTest.java	Adds unit tests for elicitation DTOs, cloning behavior, and request flags.
src/test/java/com/github/copilot/sdk/CopilotSessionTest.java	Adds snapshot test for getSessionMetadata(sessionId) behavior.
src/test/java/com/github/copilot/sdk/CommandsTest.java	Adds unit tests for command DTOs, cloning behavior, and wire serialization.
src/site/markdown/index.md	Updates documented minimum Copilot CLI version.
src/site/markdown/advanced.md	Documents slash commands, elicitation, capabilities, and session-metadata-by-id.
src/main/java/com/github/copilot/sdk/SessionRequestBuilder.java	Includes commands + requestElicitation in create/resume requests; registers handlers on session.
src/main/java/com/github/copilot/sdk/json/SessionUiCapabilities.java	Introduces UI capability flag model (elicitation).
src/main/java/com/github/copilot/sdk/json/SessionUiApi.java	Introduces UI API surface for elicitation convenience methods.
src/main/java/com/github/copilot/sdk/json/SessionConfig.java	Adds commands + elicitation handler to session config (+ clone support).
src/main/java/com/github/copilot/sdk/json/SessionCapabilities.java	Adds capabilities container DTO.
src/main/java/com/github/copilot/sdk/json/ResumeSessionResponse.java	Extends resume response to include capabilities.
src/main/java/com/github/copilot/sdk/json/ResumeSessionRequest.java	Extends resume request to include commands + requestElicitation.
src/main/java/com/github/copilot/sdk/json/ResumeSessionConfig.java	Adds commands + elicitation handler to resume config (+ clone support).
src/main/java/com/github/copilot/sdk/json/InputOptions.java	Adds options DTO for ui.input(...).
src/main/java/com/github/copilot/sdk/json/GetSessionMetadataResponse.java	Adds RPC response wrapper for metadata-by-id call.
src/main/java/com/github/copilot/sdk/json/ElicitationSchema.java	Adds JSON-schema DTO used for elicitation dialogs.
src/main/java/com/github/copilot/sdk/json/ElicitationResultAction.java	Adds action enum for elicitation results.
src/main/java/com/github/copilot/sdk/json/ElicitationResult.java	Adds elicitation result DTO.
src/main/java/com/github/copilot/sdk/json/ElicitationParams.java	Adds outgoing elicitation request params DTO.
src/main/java/com/github/copilot/sdk/json/ElicitationHandler.java	Adds functional interface for incoming elicitation handling.
src/main/java/com/github/copilot/sdk/json/ElicitationContext.java	Adds context DTO for incoming elicitation requests.
src/main/java/com/github/copilot/sdk/json/CreateSessionResponse.java	Extends create response to include capabilities.
src/main/java/com/github/copilot/sdk/json/CreateSessionRequest.java	Extends create request to include commands + requestElicitation.
src/main/java/com/github/copilot/sdk/json/CommandWireDefinition.java	Adds wire DTO for command definitions sent over RPC.
src/main/java/com/github/copilot/sdk/json/CommandHandler.java	Adds functional interface for slash command handling.
src/main/java/com/github/copilot/sdk/json/CommandDefinition.java	Adds command definition DTO (name/description/handler).
src/main/java/com/github/copilot/sdk/json/CommandContext.java	Adds context DTO passed to command handlers.
src/main/java/com/github/copilot/sdk/events/SessionEventParser.java	Registers new event types (command.execute, elicitation.requested, capabilities.changed).
src/main/java/com/github/copilot/sdk/events/PermissionRequestedEvent.java	Adds resolvedByHook field to support short-circuit behavior.
src/main/java/com/github/copilot/sdk/events/ElicitationRequestedEvent.java	Adds event type for incoming elicitation requests.
src/main/java/com/github/copilot/sdk/events/CommandExecuteEvent.java	Adds event type for slash command execution requests.
src/main/java/com/github/copilot/sdk/events/CapabilitiesChangedEvent.java	Adds event type for capability updates.
src/main/java/com/github/copilot/sdk/events/AbstractSessionEvent.java	Updates sealed hierarchy to include new event classes.
src/main/java/com/github/copilot/sdk/CopilotSession.java	Implements command execution + elicitation handling, UI API, and capabilities updates.
src/main/java/com/github/copilot/sdk/CopilotClient.java	Populates session capabilities and adds getSessionMetadata(sessionId) RPC.
README.md	Updates documented minimum Copilot version.
.lastmerge	Advances upstream sync marker to f7fd757.

Copilot's findings

Comments suppressed due to low confidence (3)

src/main/java/com/github/copilot/sdk/CopilotSession.java:979

• handleElicitationRequestAsync assumes the elicitation handler completes with a non-null ElicitationResult. If a user handler returns CompletableFuture.completedFuture(null), result.getAction()/getContent() will throw a NullPointerException and no response will be sent. Treat a null result as CANCEL (and send a cancel response) to make the API more robust.

                handler.handle(context).thenAccept(result -> {
                    try {
                        String actionStr = result.getAction() != null
                                ? result.getAction().getValue()
                                : ElicitationResultAction.CANCEL.getValue();
                        Map<String, Object> resultMap = result.getContent() != null
                                ? Map.of("action", actionStr, "content", result.getContent())
                                : Map.of("action", actionStr);

src/main/java/com/github/copilot/sdk/CopilotSession.java:1043

• SessionUiApiImpl.elicitation dereferences params and params.getRequestedSchema() without validation. Passing null params (or a params object with null requestedSchema) will currently fail with a NullPointerException. Consider validating inputs and throwing an IllegalArgumentException with a clear message (e.g., require non-null params, message, and requestedSchema).

        public CompletableFuture<ElicitationResult> elicitation(ElicitationParams params) {
            assertElicitation();
            var schema = new java.util.HashMap<String, Object>();
            schema.put("type", params.getRequestedSchema().getType());
            schema.put("properties", params.getRequestedSchema().getProperties());
            if (params.getRequestedSchema().getRequired() != null) {

src/main/java/com/github/copilot/sdk/CopilotSession.java:1029

• The IllegalStateException message mentions getUi()?.getElicitation(), but ?. is not valid Java syntax. This can confuse SDK users trying to follow the guidance. Update the message to use a Java-accurate check (e.g., caps.getUi() != null && Boolean.TRUE.equals(caps.getUi().getElicitation())).

        SessionCapabilities caps = capabilities;
        if (caps == null || caps.getUi() == null || !Boolean.TRUE.equals(caps.getUi().getElicitation())) {
            throw new IllegalStateException("Elicitation is not supported by the host. "
                    + "Check session.getCapabilities().getUi()?.getElicitation() before calling UI methods.");
        }

• Files reviewed: 37/37 changed files
• Comments generated: 3