Add MCP server support: events and session management methods by Copilot · Pull Request #29 · github/copilot-sdk-java

Copilot · 2026-03-25T13:57:43Z

Resolves #17

Before the change?

No session.mcp_servers_loaded / session.mcp_server_status_changed events — these were deserialized as UnknownSessionEvent
No way to programmatically list, enable, disable, or reload MCP servers through an active session

After the change?

New event types (parity with upstream .NET/Node.js SDK):

SessionMcpServersLoadedEvent — fired when all configured MCP servers finish initializing
SessionMcpServerStatusChangedEvent — fired when a server's connection state transitions

New DTO:

McpServerInfo — captures name, status (connected | failed | pending | disabled | not_configured), source, and error

New CopilotSession methods:

listMcpServers() → session.mcp.list
enableMcpServer(String serverName) → session.mcp.enable
disableMcpServer(String serverName) → session.mcp.disable
reloadMcpServers() → session.mcp.reload

// Subscribe to MCP lifecycle events
session.on(SessionMcpServersLoadedEvent.class, evt -> {
    evt.getData().getServers().forEach(s ->
        System.out.println(s.getName() + ": " + s.getStatus()));
});
session.on(SessionMcpServerStatusChangedEvent.class, evt ->
    System.out.println(evt.getData().getServerName() + " → " + evt.getData().getStatus()));

// Manage servers at runtime
List<McpServerInfo> servers = session.listMcpServers().get();
session.disableMcpServer("github").get();
session.enableMcpServer("github").get();
session.reloadMcpServers().get();

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

✨ Let Copilot coding agent set things up for you — coding agent works faster and does higher quality work when set up for your repo.

Co-authored-by: brunoborges <129743+brunoborges@users.noreply.github.com> Agent-Logs-Url: https://github.com/github/copilot-sdk-java/sessions/4f9a9fb9-2883-4dd6-843d-2e4a25ddd7e0

Copilot

Pull request overview

Adds MCP (Model Context Protocol) server lifecycle support to the Java SDK, bringing it closer to upstream parity by exposing MCP-related session events and runtime management APIs on CopilotSession.

Changes:

Added new session event types for MCP server initialization and status transitions, and registered them in the event parser/sealed hierarchy.
Introduced McpServerInfo DTO for MCP server listing/status reporting.
Added CopilotSession APIs to list/enable/disable/reload MCP servers, plus termination-guard tests and event parsing tests.

Reviewed changes

Copilot reviewed 9 out of 9 changed files in this pull request and generated 4 comments.

Show a summary per file

File	Description
src/main/java/com/github/copilot/sdk/CopilotSession.java	Adds MCP server management RPC wrappers (`session.mcp.*`).
src/main/java/com/github/copilot/sdk/events/AbstractSessionEvent.java	Extends sealed permits list to include new MCP events.
src/main/java/com/github/copilot/sdk/events/SessionEventParser.java	Registers new MCP event types for polymorphic parsing.
src/main/java/com/github/copilot/sdk/events/SessionMcpServersLoadedEvent.java	New event type for MCP servers loaded.
src/main/java/com/github/copilot/sdk/events/SessionMcpServerStatusChangedEvent.java	New event type for MCP server status changes.
src/main/java/com/github/copilot/sdk/events/package-info.java	Documents MCP server events in events package overview.
src/main/java/com/github/copilot/sdk/json/McpServerInfo.java	New DTO describing MCP server name/status/source/error.
src/test/java/com/github/copilot/sdk/SessionEventParserTest.java	Adds parsing tests for the new MCP session events.
src/test/java/com/github/copilot/sdk/ClosedSessionGuardTest.java	Adds termination-guard tests for new MCP session APIs.

Copilot · 2026-03-25T15:21:24Z

src/main/java/com/github/copilot/sdk/json/McpServerInfo.java

+ * {@link com.github.copilot.sdk.events.SessionMcpServersLoadedEvent} and
+ * {@link com.github.copilot.sdk.events.SessionMcpServerStatusChangedEvent}.
+ *
+ * @since 1.0.0


The Javadoc says McpServerInfo is carried in SessionMcpServerStatusChangedEvent, but that event’s payload only includes serverName + status (no McpServerInfo). Please update the Javadoc to avoid misleading API docs. Also consider updating the @since tag to the version that actually introduces this DTO (it’s newly added in this PR).

Suggested change

* {@link com.github.copilot.sdk.events.SessionMcpServersLoadedEvent} and

* {@link com.github.copilot.sdk.events.SessionMcpServerStatusChangedEvent}.

*

* @since 1.0.0

* {@link com.github.copilot.sdk.events.SessionMcpServersLoadedEvent}.

* <p>

* Related:

* {@link com.github.copilot.sdk.events.SessionMcpServerStatusChangedEvent}

* reports status changes using the server name and status fields, rather than

* this DTO.

Copilot · 2026-03-25T15:21:24Z

src/main/java/com/github/copilot/sdk/events/SessionMcpServersLoadedEvent.java

+    public static class SessionMcpServersLoadedData {
+
+        @JsonProperty("servers")
+        private List<McpServerInfo> servers;
+
+        /**
+         * Gets the list of MCP server status summaries.
+         *
+         * @return the servers list
+         */
+        public List<McpServerInfo> getServers() {
+            return servers;
+        }
+
+        /**
+         * Sets the list of MCP server status summaries.
+         *
+         * @param servers
+         *            the servers list
+         */
+        public void setServers(List<McpServerInfo> servers) {
+            this.servers = servers;
+        }


All other event types in this package model their data payload as a record (e.g., SessionTaskCompleteEvent) for immutability and consistency with the rest of the event API. Consider changing SessionMcpServersLoadedData from a mutable class with setters to a record to match the established pattern.

Suggested change

public static class SessionMcpServersLoadedData {

@JsonProperty("servers")

private List<McpServerInfo> servers;

/**

* Gets the list of MCP server status summaries.

*

* @return the servers list

*/

public List<McpServerInfo> getServers() {

return servers;

}

/**

* Sets the list of MCP server status summaries.

*

* @param servers

* the servers list

*/

public void setServers(List<McpServerInfo> servers) {

this.servers = servers;

}

public static record SessionMcpServersLoadedData(

@JsonProperty("servers") List<McpServerInfo> servers) {

Copilot · 2026-03-25T15:21:24Z

src/main/java/com/github/copilot/sdk/events/SessionMcpServerStatusChangedEvent.java

+    public static class SessionMcpServerStatusChangedData {
+
+        @JsonProperty("serverName")
+        private String serverName;
+
+        @JsonProperty("status")
+        private String status;
+
+        /**
+         * Gets the name of the MCP server whose status changed.
+         *
+         * @return the server name
+         */
+        public String getServerName() {
+            return serverName;
+        }
+
+        /**
+         * Sets the server name.
+         *
+         * @param serverName
+         *            the server name
+         */
+        public void setServerName(String serverName) {
+            this.serverName = serverName;
+        }
+
+        /**
+         * Gets the new connection status.
+         * <p>
+         * Possible values: {@code "connected"}, {@code "failed"}, {@code "pending"},
+         * {@code "disabled"}, {@code "not_configured"}.
+         *
+         * @return the status string
+         */
+        public String getStatus() {
+            return status;
+        }
+
+        /**
+         * Sets the new connection status.
+         *
+         * @param status
+         *            the status string
+         */
+        public void setStatus(String status) {
+            this.status = status;
+        }


This event’s data payload is implemented as a mutable inner class with setters, but the rest of the events package consistently uses record payloads for data. Switching SessionMcpServerStatusChangedData to a record would improve consistency and reduce mutability in the public event model.

Suggested change

public static class SessionMcpServerStatusChangedData {

@JsonProperty("serverName")

private String serverName;

@JsonProperty("status")

private String status;

/**

* Gets the name of the MCP server whose status changed.

*

* @return the server name

*/

public String getServerName() {

return serverName;

}

/**

* Sets the server name.

*

* @param serverName

* the server name

*/

public void setServerName(String serverName) {

this.serverName = serverName;

}

/**

* Gets the new connection status.

* <p>

* Possible values: {@code "connected"}, {@code "failed"}, {@code "pending"},

* {@code "disabled"}, {@code "not_configured"}.

*

* @return the status string

*/

public String getStatus() {

return status;

}

/**

* Sets the new connection status.

*

* @param status

* the status string

*/

public void setStatus(String status) {

this.status = status;

}

public static record SessionMcpServerStatusChangedData(

@JsonProperty("serverName") String serverName,

@JsonProperty("status") String status) {

Copilot · 2026-03-25T15:21:25Z

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

+    /**
+     * Lists the MCP servers configured for this session, including their connection
+     * status.
+     *
+     * @return a future that resolves with the list of MCP server info objects
+     * @throws IllegalStateException
+     *             if this session has been terminated
+     * @since 1.0.0
+     */
+    public CompletableFuture<List<McpServerInfo>> listMcpServers() {
+        ensureNotTerminated();
+        return rpc.invoke("session.mcp.list", Map.of("sessionId", sessionId), McpListResponse.class)
+                .thenApply(response -> response.servers() != null
+                        ? Collections.unmodifiableList(response.servers())
+                        : Collections.emptyList());
+    }
+
+    /**
+     * Enables a previously disabled MCP server in this session.
+     *
+     * @param serverName
+     *            the name of the MCP server to enable (the key used in the
+     *            {@link com.github.copilot.sdk.json.SessionConfig#setMcpServers(java.util.Map)}
+     *            map)
+     * @return a future that completes when the server has been enabled
+     * @throws IllegalStateException
+     *             if this session has been terminated
+     * @since 1.0.0
+     */
+    public CompletableFuture<Void> enableMcpServer(String serverName) {
+        ensureNotTerminated();
+        return rpc.invoke("session.mcp.enable", Map.of("sessionId", sessionId, "serverName", serverName), Void.class);
+    }
+
+    /**
+     * Disables an MCP server in this session without removing its configuration.
+     * <p>
+     * A disabled server can be re-enabled later via
+     * {@link #enableMcpServer(String)}.
+     *
+     * @param serverName
+     *            the name of the MCP server to disable
+     * @return a future that completes when the server has been disabled
+     * @throws IllegalStateException
+     *             if this session has been terminated
+     * @since 1.0.0
+     */
+    public CompletableFuture<Void> disableMcpServer(String serverName) {
+        ensureNotTerminated();
+        return rpc.invoke("session.mcp.disable", Map.of("sessionId", sessionId, "serverName", serverName), Void.class);
+    }
+
+    /**
+     * Reloads all MCP servers in this session.
+     * <p>
+     * This disconnects and reconnects all configured MCP servers, which can be
+     * useful to pick up configuration changes or recover from failed connections.
+     *
+     * @return a future that completes when the reload is initiated
+     * @throws IllegalStateException
+     *             if this session has been terminated
+     * @since 1.0.0
+     */


These newly added public methods are annotated @since 1.0.0, but they’re being introduced now and appear next to APIs marked @since 1.0.11/1.2.0. Please align the @since values with the version that actually introduces the MCP server management API to keep generated Javadocs accurate.

QuinnBast · 2026-03-25T20:08:23Z

See this comment. This is great so far, but I'm not sure it solves the issue. Not sure if the AI can follow comment links so here is the full text:

Does this MR actually get the copilot agent to correctly load the user's MCPs? It adds support to the SDK that lets the user view and query current MCP status, but it doesn't change how the agent is created.

I think the issue here is that the agent that the SDK creates when it creates new sessions, for whatever reason, doesn't know how to find the user's mcp.json file. I have mine at ~/.copilot/mcp-config.json, and this works for the copilot CLI, but if I talk to copilot through the SDK it can't use any of the MCP tools. So I think there's a bigger issue at play here with how Copilot sessions are being created through the SDK.

edburns · 2026-03-25T20:48:46Z

See #17 (comment) for Close explanation.

Initial plan

20c551c

Copilot AI assigned Copilot and brunoborges Mar 25, 2026

Copilot started work on behalf of brunoborges March 25, 2026 13:57 View session

Copilot AI linked an issue Mar 25, 2026 that may be closed by this pull request

[FEAT]: Support MCP servers #17

Closed

1 task

Add MCP server events and session management methods

b08b5d4

Co-authored-by: brunoborges <129743+brunoborges@users.noreply.github.com> Agent-Logs-Url: https://github.com/github/copilot-sdk-java/sessions/4f9a9fb9-2883-4dd6-843d-2e4a25ddd7e0

Copilot AI changed the title ~~[WIP] Add support for MCP servers in Java SDK~~ Add MCP server support: events and session management methods Mar 25, 2026

Copilot AI requested a review from brunoborges March 25, 2026 14:17

Copilot finished work on behalf of brunoborges March 25, 2026 14:17

brunoborges marked this pull request as ready for review March 25, 2026 15:16

brunoborges requested review from Copilot and edburns March 25, 2026 15:16

Copilot started reviewing on behalf of brunoborges March 25, 2026 15:17 View session

Copilot AI reviewed Mar 25, 2026

View reviewed changes

edburns mentioned this pull request Mar 25, 2026

[FEAT]: Support MCP servers #17

Closed

1 task

edburns closed this Mar 25, 2026

Provide feedback

Saved searches

Use saved searches to filter your results more quickly

Add MCP server support: events and session management methods#29

Add MCP server support: events and session management methods#29
Copilot wants to merge 2 commits intomainfrom
copilot/add-support-for-mcp-servers

Copilot AI commented Mar 25, 2026 •

edited

Loading

Uh oh!

Copilot AI left a comment

Uh oh!

Copilot AI Mar 25, 2026

Uh oh!

Copilot AI Mar 25, 2026

Uh oh!

Copilot AI Mar 25, 2026

Uh oh!

Copilot AI Mar 25, 2026

Uh oh!

QuinnBast commented Mar 25, 2026

Uh oh!

edburns commented Mar 25, 2026

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

5 participants

Conversation

Copilot AI commented Mar 25, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Before the change?

After the change?

Pull request checklist

Does this introduce a breaking change?

Uh oh!

Copilot AI left a comment

Choose a reason for hiding this comment

Pull request overview

Reviewed changes

Uh oh!

Copilot AI Mar 25, 2026

Choose a reason for hiding this comment

Uh oh!

Copilot AI Mar 25, 2026

Choose a reason for hiding this comment

Uh oh!

Copilot AI Mar 25, 2026

Choose a reason for hiding this comment

Uh oh!

Copilot AI Mar 25, 2026

Choose a reason for hiding this comment

Uh oh!

QuinnBast commented Mar 25, 2026

Uh oh!

edburns commented Mar 25, 2026

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

5 participants

Copilot AI commented Mar 25, 2026 •

edited

Loading