fix: align ldctx anonymous and multi-kind key with other SDKs (AIC-2695)

- Always expose ldctx.anonymous as true/false rather than only when true.
- Expose the canonical fully-qualified key at the top level of a multi-kind
  ldctx so {{ldctx.key}} resolves, matching the .NET (and other) SDKs.

Adds InterpolatorTest cases for both.

Co-authored-by: Cursor <cursoragent@cursor.com>

Author: ctawiah

lib/sdk/server-ai/src/main/java/com/launchdarkly/sdk/server/ai/internal/Interpolator.java

@@ -87,8 +87,9 @@ private String render(String template, Map<String, Object> variables) {
   /**
    * Encodes the evaluation context directly into the nested map structure exposed to templates as
    * {@code ldctx}, without round-tripping through JSON serialization. A single-kind context becomes
-   * a map of its attributes; a multi-kind context becomes {@code {"kind":"multi", <kind>: {...}}}
-   * with one nested map per individual context.
+   * a map of its attributes; a multi-kind context becomes
+   * {@code {"kind":"multi", "key":<fully-qualified key>, <kind>: {...}}} with one nested map per
+   * individual context.
    */
   private static Map<String, Object> contextToMap(LDContext context) {
     if (context == null || !context.isValid()) {
@@ -97,6 +98,9 @@ private static Map<String, Object> contextToMap(LDContext context) {
     if (context.isMultiple()) {
       Map<String, Object> map = new HashMap<>();
       map.put("kind", "multi");
+      // Expose the canonical multi-kind key at the top level (matching other SDKs) so
+      // {{ldctx.key}} resolves for multi-kind contexts.
+      map.put("key", context.getFullyQualifiedKey());
       int count = context.getIndividualContextCount();
       for (int i = 0; i < count; i++) {
         LDContext individual = context.getIndividualContext(i);
@@ -120,9 +124,8 @@ private static Map<String, Object> singleContextToMap(LDContext context, boolean
     if (context.getName() != null) {
       map.put("name", context.getName());
     }
-    if (context.isAnonymous()) {
-      map.put("anonymous", true);
-    }
+    // Always expose anonymous as true/false (matching other SDKs) rather than only when true.
+    map.put("anonymous", context.isAnonymous());
     // Custom attribute values can be arbitrary JSON; convert each LDValue to a plain Java value
     // (depth-capped) so nested objects/arrays remain addressable from templates.
     for (String attribute : context.getCustomAttributeNames()) {

lib/sdk/server-ai/src/test/java/com/launchdarkly/sdk/server/ai/internal/InterpolatorTest.java

@@ -96,6 +96,25 @@ public void multiKindNestedContextsOmitKind() {
         interpolator.interpolate("[{{ldctx.user.kind}}]", null, multi), is("[]"));
   }
 
+  @Test
+  public void anonymousIsAlwaysExposedAsBoolean() {
+    LDContext anon = LDContext.builder("k").anonymous(true).build();
+    assertThat(interpolator.interpolate("{{ldctx.anonymous}}", null, anon), is("true"));
+    // Matches other SDKs: anonymous is emitted even when false, rather than rendering empty.
+    LDContext named = LDContext.builder("k").build();
+    assertThat(interpolator.interpolate("{{ldctx.anonymous}}", null, named), is("false"));
+  }
+
+  @Test
+  public void multiKindExposesFullyQualifiedKeyAtTopLevel() {
+    LDContext multi = LDContext.createMulti(
+        LDContext.builder("user-key").build(),
+        LDContext.builder(com.launchdarkly.sdk.ContextKind.of("org"), "org-key").build());
+    // {{ldctx.key}} on a multi-kind context resolves to the canonical fully-qualified key.
+    assertThat(
+        interpolator.interpolate("{{ldctx.key}}", null, multi), is(multi.getFullyQualifiedKey()));
+  }
+
   @Test
   public void ldctxOverridesUserSuppliedValue() {
     Map<String, Object> userLdctx = new HashMap<>();