feat: Add Thinking LSP protocol types and generateTitle request (Thinking Part2) (#156)

Adds the protocol surface for streaming model-thinking content from the language server:

- Thinking record + ThinkingTypeAdapter (tolerates the server's mixed wire shape for 	ext: string delta or array of fragments).
- ChatProgressValue.thinking field (with equals/hashCode/toString updates).
- thinking/generateTitle JSON request (GenerateThinkingTitleParams/Response, server interface, connection wrapper).
- Register ThinkingTypeAdapter.Factory in CopilotLauncherBuilder.

Author: ethanyhou

com.microsoft.copilot.eclipse.core/src/com/microsoft/copilot/eclipse/core/lsp/CopilotLanguageServer.java

@@ -32,6 +32,8 @@
 import com.microsoft.copilot.eclipse.core.lsp.protocol.CopilotModel;
 import com.microsoft.copilot.eclipse.core.lsp.protocol.CopilotStatusResult;
 import com.microsoft.copilot.eclipse.core.lsp.protocol.DidShowInlineEditParams;
+import com.microsoft.copilot.eclipse.core.lsp.protocol.GenerateThinkingTitleParams;
+import com.microsoft.copilot.eclipse.core.lsp.protocol.GenerateThinkingTitleResponse;
 import com.microsoft.copilot.eclipse.core.lsp.protocol.LanguageModelToolInformation;
 import com.microsoft.copilot.eclipse.core.lsp.protocol.NextEditSuggestionsParams;
 import com.microsoft.copilot.eclipse.core.lsp.protocol.NextEditSuggestionsResult;
@@ -195,6 +197,12 @@ public interface CopilotLanguageServer extends LanguageServer {
   @JsonRequest("git/commitGenerate")
   CompletableFuture<GenerateCommitMessageResult> generateCommitMessage(GenerateCommitMessageParams params);
 
+  /**
+   * Generate a short title summarizing a thinking block.
+   */
+  @JsonRequest("thinking/generateTitle")
+  CompletableFuture<GenerateThinkingTitleResponse> generateThinkingTitle(GenerateThinkingTitleParams params);
+
   /**
    * List BYOK models.
    */

com.microsoft.copilot.eclipse.core/src/com/microsoft/copilot/eclipse/core/lsp/CopilotLanguageServerConnection.java

@@ -50,6 +50,8 @@
 import com.microsoft.copilot.eclipse.core.lsp.protocol.CopilotStatusResult;
 import com.microsoft.copilot.eclipse.core.lsp.protocol.DidChangeCopilotWatchedFilesParams;
 import com.microsoft.copilot.eclipse.core.lsp.protocol.DidShowInlineEditParams;
+import com.microsoft.copilot.eclipse.core.lsp.protocol.GenerateThinkingTitleParams;
+import com.microsoft.copilot.eclipse.core.lsp.protocol.GenerateThinkingTitleResponse;
 import com.microsoft.copilot.eclipse.core.lsp.protocol.LanguageModelToolInformation;
 import com.microsoft.copilot.eclipse.core.lsp.protocol.NextEditSuggestionsParams;
 import com.microsoft.copilot.eclipse.core.lsp.protocol.NextEditSuggestionsResult;
@@ -526,6 +528,19 @@ public CompletableFuture<GenerateCommitMessageResult> generateCommitMessage(Gene
     });
   }
 
+  /**
+   * Generate a short title summarizing a thinking block.
+   */
+  public CompletableFuture<GenerateThinkingTitleResponse> generateThinkingTitle(
+      GenerateThinkingTitleParams params) {
+    Function<LanguageServer, CompletableFuture<GenerateThinkingTitleResponse>> fn =
+        server -> ((CopilotLanguageServer) server).generateThinkingTitle(params);
+    return this.languageServerWrapper.execute(fn).exceptionally(ex -> {
+      CopilotCore.LOGGER.error(ex);
+      return null;
+    });
+  }
+
   /**
    * List BYOK models.
    */

com.microsoft.copilot.eclipse.core/src/com/microsoft/copilot/eclipse/core/lsp/CopilotLauncherBuilder.java

@@ -8,6 +8,7 @@
 
 import com.microsoft.copilot.eclipse.core.lsp.protocol.ChatReferenceTypeAdapter;
 import com.microsoft.copilot.eclipse.core.lsp.protocol.ProgressParamsAdapter;
+import com.microsoft.copilot.eclipse.core.lsp.protocol.ThinkingTypeAdapter;
 
 /**
  * Builder for Copilot Language Server.
@@ -19,7 +20,8 @@ public class CopilotLauncherBuilder<T extends LanguageServer> extends Launcher.B
    */
   public CopilotLauncherBuilder() {
     this.configureGson(gsonBuilder -> gsonBuilder.registerTypeAdapterFactory(new ProgressParamsAdapter.Factory())
-        .registerTypeAdapterFactory(new ChatReferenceTypeAdapter.Factory()));
+        .registerTypeAdapterFactory(new ChatReferenceTypeAdapter.Factory())
+        .registerTypeAdapterFactory(new ThinkingTypeAdapter.Factory()));
   }
 
 }

com.microsoft.copilot.eclipse.core/src/com/microsoft/copilot/eclipse/core/lsp/protocol/ChatProgressValue.java

@@ -25,6 +25,7 @@ public class ChatProgressValue implements WorkDoneProgressNotification {
   private ChatReference[] references;
   private boolean hideText;
   private String[] notifications;
+  private Thinking thinking;
   private ChatStep[] steps;
   private String cancellationReason;
   private ConversationError error;
@@ -80,6 +81,10 @@ public String[] getNotifications() {
     return notifications;
   }
 
+  public Thinking getThinking() {
+    return thinking;
+  }
+
   public ChatStep[] getSteps() {
     return steps;
   }
@@ -140,6 +145,10 @@ public void setNotifications(String[] notifications) {
     this.notifications = notifications;
   }
 
+  public void setThinking(Thinking thinking) {
+    this.thinking = thinking;
+  }
+
   public void setSteps(ChatStep[] steps) {
     this.steps = steps;
   }
@@ -177,7 +186,7 @@ public int hashCode() {
     result = prime * result + Arrays.hashCode(references);
     result = prime * result + Arrays.hashCode(steps);
     result = prime * result + Objects.hash(editAgentRounds, cancellationReason, contextSize, conversationId, error,
-        hideText, kind, reply, title, turnId, parentTurnId, suggestedTitle);
+        hideText, kind, reply, thinking, title, turnId, parentTurnId, suggestedTitle);
     return result;
   }
 
@@ -199,7 +208,8 @@ public boolean equals(Object obj) {
         && Objects.equals(conversationId, other.conversationId) && Objects.equals(error, other.error)
         && hideText == other.hideText && kind == other.kind && Arrays.equals(notifications, other.notifications)
         && Arrays.equals(references, other.references) && Objects.equals(reply, other.reply)
-        && Arrays.equals(steps, other.steps) && Objects.equals(title, other.title)
+        && Arrays.equals(steps, other.steps) && Objects.equals(thinking, other.thinking)
+        && Objects.equals(title, other.title)
         && Objects.equals(turnId, other.turnId) && Objects.equals(parentTurnId, other.parentTurnId)
         && Objects.equals(suggestedTitle, other.suggestedTitle);
   }
@@ -217,6 +227,7 @@ public String toString() {
     builder.append("references", Arrays.toString(references));
     builder.append("hideText", hideText);
     builder.append("notifications", Arrays.toString(notifications));
+    builder.append("thinking", thinking);
     builder.append("steps", Arrays.toString(steps));
     builder.append("cancellationReason", cancellationReason);
     builder.append("error", error);

com.microsoft.copilot.eclipse.core/src/com/microsoft/copilot/eclipse/core/lsp/protocol/GenerateThinkingTitleParams.java

@@ -0,0 +1,16 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT license.
+
+package com.microsoft.copilot.eclipse.core.lsp.protocol;
+
+/**
+ * Parameters for the {@code thinking/generateTitle} request.
+ *
+ * <p>Either {@code thinkingContent} or {@code extractedTitles} should be provided depending on
+ * whether parsed section titles are available on the client side.
+ *
+ * @param thinkingContent the raw thinking content (used when no extracted titles are available)
+ * @param extractedTitles previously extracted section titles, may be {@code null}
+ */
+public record GenerateThinkingTitleParams(String thinkingContent, String[] extractedTitles) {
+}

com.microsoft.copilot.eclipse.core/src/com/microsoft/copilot/eclipse/core/lsp/protocol/GenerateThinkingTitleResponse.java

@@ -0,0 +1,12 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT license.
+
+package com.microsoft.copilot.eclipse.core.lsp.protocol;
+
+/**
+ * Response for the {@code thinking/generateTitle} request.
+ *
+ * @param title the title returned by the language server
+ */
+public record GenerateThinkingTitleResponse(String title) {
+}

com.microsoft.copilot.eclipse.core/src/com/microsoft/copilot/eclipse/core/lsp/protocol/Thinking.java

@@ -0,0 +1,15 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT license.
+
+package com.microsoft.copilot.eclipse.core.lsp.protocol;
+
+/**
+ * Wire-level "thinking" payload streamed from the language server inside ChatProgressValue. Each report carries a
+ * delta; callers accumulate the deltas across reports.
+ *
+ * @param id the (optional) identifier of the thinking block
+ * @param text the delta text for this report; callers should treat blank text as "no content"
+ * @param encrypted the (optional) encrypted form of the thinking content
+ */
+public record Thinking(String id, String text, String encrypted) {
+}

com.microsoft.copilot.eclipse.core/src/com/microsoft/copilot/eclipse/core/lsp/protocol/ThinkingTypeAdapter.java

@@ -0,0 +1,87 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT license.
+
+package com.microsoft.copilot.eclipse.core.lsp.protocol;
+
+import java.io.IOException;
+
+import com.google.gson.Gson;
+import com.google.gson.JsonArray;
+import com.google.gson.JsonElement;
+import com.google.gson.JsonNull;
+import com.google.gson.JsonObject;
+import com.google.gson.JsonPrimitive;
+import com.google.gson.TypeAdapter;
+import com.google.gson.TypeAdapterFactory;
+import com.google.gson.reflect.TypeToken;
+import com.google.gson.stream.JsonReader;
+import com.google.gson.stream.JsonWriter;
+
+/**
+ * TypeAdapter for {@link Thinking} that tolerates the server's mixed wire shape for
+ * {@code text}: it may be a string delta (e.g. {@code "text":"The"}) or an array
+ * (e.g. {@code "text":[]}) when the report carries only an encrypted payload, or a
+ * multi-fragment array of deltas. The array form is concatenated into a single string
+ * (or {@code null} when empty) so the rest of the UI treats the report as scalar.
+ */
+public class ThinkingTypeAdapter extends TypeAdapter<Thinking> {
+  private final TypeAdapter<Thinking> delegate;
+  private final TypeAdapter<JsonElement> elementAdapter;
+
+  /**
+   * Construct a new adapter that delegates to the given default adapter after the
+   * {@code text} field has been normalized.
+   *
+   * @param delegate the Gson-generated default adapter for {@link Thinking}
+   * @param elementAdapter the adapter used to read the JSON tree
+   */
+  public ThinkingTypeAdapter(TypeAdapter<Thinking> delegate, TypeAdapter<JsonElement> elementAdapter) {
+    this.delegate = delegate;
+    this.elementAdapter = elementAdapter;
+  }
+
+  /** TypeAdapterFactory for {@link Thinking}. */
+  public static final class Factory implements TypeAdapterFactory {
+    @SuppressWarnings("unchecked")
+    @Override
+    public <T> TypeAdapter<T> create(Gson gson, TypeToken<T> typeToken) {
+      if (typeToken.getRawType() != Thinking.class) {
+        return null;
+      }
+      TypeAdapter<Thinking> defaultAdapter = gson.getDelegateAdapter(this, TypeToken.get(Thinking.class));
+      TypeAdapter<JsonElement> elementAdapter = gson.getAdapter(JsonElement.class);
+      return (TypeAdapter<T>) new ThinkingTypeAdapter(defaultAdapter, elementAdapter);
+    }
+  }
+
+  @Override
+  public Thinking read(JsonReader in) throws IOException {
+    JsonElement element = elementAdapter.read(in);
+    if (element != null && element.isJsonObject()) {
+      JsonObject obj = element.getAsJsonObject();
+      JsonElement text = obj.get("text");
+      if (text != null && text.isJsonArray()) {
+        obj.add("text", flattenTextArray(text.getAsJsonArray()));
+      }
+    }
+    return delegate.fromJsonTree(element);
+  }
+
+  private static JsonElement flattenTextArray(JsonArray arr) {
+    StringBuilder sb = new StringBuilder();
+    for (JsonElement e : arr) {
+      if (!e.isJsonNull() && e.isJsonPrimitive()) {
+        JsonPrimitive prim = e.getAsJsonPrimitive();
+        if (prim.isString()) {
+          sb.append(prim.getAsString());
+        }
+      }
+    }
+    return sb.length() == 0 ? JsonNull.INSTANCE : new JsonPrimitive(sb.toString());
+  }
+
+  @Override
+  public void write(JsonWriter out, Thinking value) throws IOException {
+    delegate.write(out, value);
+  }
+}