Java SDK: sync reference implementation to ^1.0.52-1, add preMcpToolCall hook, fix PingResponse timestamp type (#1389)

## XL — Regenerated RPC types from `@github/copilot schema` update (288 files)

Upgrading the reference implementation version from `^1.0.49-1` to `^1.0.52-1`
required updating the `@github/copilot` npm package in `scripts/codegen/`, which
brought in schema changes. The Java code generator (`java.ts`) was updated to
handle these schema changes, and all generated types were regenerated.

- 222 new generated RPC types under `src/generated/java/` (new API surfaces:
  `SessionEventLogApi`, `SessionMetadataApi`, `SessionQueueApi`, `SessionTasksApi`,
  `SessionUiApi`, `SessionOptionsApi`, `SessionLspApi`, `SessionMcpApi`,
  `SessionScheduleApi`, permission `location/path/URL` config types, and more)
- 66 modified generated files (field type changes, new fields, new enum values)
- Updated `scripts/codegen/java.ts` to handle new schema patterns
- Updated `scripts/codegen/package.json` and `package-lock.json`

These are all machine-generated. Human review should focus on the `java.ts`
codegen script changes; the generated output can be spot-checked.

## M — Port `preMcpToolCall` hook (6 files)

New hook that fires before an MCP tool call is dispatched to an MCP server,
giving SDK consumers the ability to inspect or modify the call.

- New: `PreMcpToolCallHandler.java` (functional interface)
- New: `PreMcpToolCallHookInput.java` (input DTO with server name, tool name, arguments)
- New: `PreMcpToolCallHookOutput.java` (output DTO with allow/deny/modify)
- Modified: `SessionHooks.java` (added onPreMcpToolCall field, getter, setter, hasHooks check)
- Modified: `CopilotSession.java` (dispatch "preMcpToolCall" hook name to handler)
- New test: `PreMcpToolCallHookTest.java` (unit tests for the new hook)

## S — Fix `PingResponse` timestamp type (2 files)

The CLI server changed the ping response timestamp from a numeric epoch
(long) to an ISO 8601 string. Updated `PingResponse` record field from
`long timestamp` to `String timestamp`, and updated `CopilotClientTest`
accordingly.

## S — `SessionLogParams` constructor change (1 file)

`SessionLogParams` gained new nullable fields in the schema. Updated the
call site in `CopilotSession.log()` to pass the additional null parameters.

## S — Test maintenance (4 files)

- `McpAndAgentsTest`: new E2E test for MCP and agents scenario
- `PermissionsTest`: minor test adjustment
- `SessionEventDeserializationTest`: updated assertions to match new generated types
- `GeneratedRpcRecordsCoverageTest`: updated coverage list for new generated types

## S — Infra / metadata (3 files)

- `.lastmerge`: updated to `f4d22d70016c377881d86e4c77f8a3f93746ffae`
- `pom.xml`: ref-impl version property updated to `^1.0.52-1`
- `.github/workflows/copilot-setup-steps.yml`: bump gh-aw setup-cli to `v0.74.8`

Author: edburns

.github/workflows/copilot-setup-steps.yml

@@ -76,7 +76,7 @@ jobs:
 
       # Install gh-aw extension for advanced GitHub CLI features
       - name: Install gh-aw extension
-        uses: github/gh-aw/actions/setup-cli@4d44d0e89851a877f4ddc0cb6c0197e42b1016c5 # v0.73.0
+        uses: github/gh-aw/actions/setup-cli@0feed75a980b06f247abbbf80127f8eb2c19e2c5 # v0.74.8
         with:
           version: v0.74.4
 

java/.lastmerge

@@ -1 +1 @@
-f6c1adf8329ad4206e5ed2e8d12fb8082bc841a2
+f4d22d70016c377881d86e4c77f8a3f93746ffae

java/pom.xml

@@ -94,7 +94,7 @@
             reference-impl-sync workflow and deal with the subsequent
             PR.
         -->
-        <readonly-copilot-sdk-ref-impl-version-from-lastmerge-file-updated-by-reference-impl-sync>^1.0.49-1</readonly-copilot-sdk-ref-impl-version-from-lastmerge-file-updated-by-reference-impl-sync>
+        <readonly-copilot-sdk-ref-impl-version-from-lastmerge-file-updated-by-reference-impl-sync>^1.0.52-1</readonly-copilot-sdk-ref-impl-version-from-lastmerge-file-updated-by-reference-impl-sync>
 
     </properties>
 
@@ -321,7 +321,7 @@
                         CompactionTest) where snapshot matching can be sensitive
                         to non-deterministic compaction behaviour.
                         Revisit this once this issue is successfully resolved.
-                        https://github.com/github/copilot-sdk/issues/1227 
+                        https://github.com/github/copilot-sdk/issues/1227
                     -->
                     <rerunFailingTestsCount>2</rerunFailingTestsCount>
                     <systemPropertyVariables>

java/scripts/codegen/java.ts

@@ -37,9 +37,25 @@ function toJavaClassName(typeName: string): string {
     return typeName.split(/[._]/).map((p) => p.charAt(0).toUpperCase() + p.slice(1)).join("");
 }
 
+/** Java reserved keywords and Object method names that cannot be used as record component names. */
+const JAVA_RESERVED_IDENTIFIERS = new Set([
+    "abstract", "assert", "boolean", "break", "byte", "case", "catch", "char", "class", "const",
+    "continue", "default", "do", "double", "else", "enum", "extends", "final", "finally", "float",
+    "for", "goto", "if", "implements", "import", "instanceof", "int", "interface", "long", "native",
+    "new", "package", "private", "protected", "public", "return", "short", "static", "strictfp",
+    "super", "switch", "synchronized", "this", "throw", "throws", "transient", "try", "void",
+    "volatile", "while",
+    // Object methods that conflict with record component accessor names
+    "wait", "notify", "notifyAll", "getClass", "clone", "finalize", "toString", "hashCode", "equals",
+]);
+
 function toCamelCase(name: string): string {
     const pascal = toPascalCase(name);
-    return pascal.charAt(0).toLowerCase() + pascal.slice(1);
+    let result = pascal.charAt(0).toLowerCase() + pascal.slice(1);
+    if (JAVA_RESERVED_IDENTIFIERS.has(result)) {
+        result = result + "_";
+    }
+    return result;
 }
 
 function toEnumConstant(value: string): string {
@@ -102,6 +118,11 @@ interface JavaTypeResult {
 let currentDefinitions: Record<string, JSONSchema7> = {};
 const pendingStandaloneTypes = new Map<string, JSONSchema7>();
 
+// Cross-schema definitions: keyed by schema filename (e.g. "session-events.schema.json"),
+// value is the definitions map from that schema. Populated by generateRpcTypes so that
+// cross-schema $ref values like "session-events.schema.json#/definitions/Foo" can be resolved.
+const crossSchemaDefinitions = new Map<string, Record<string, JSONSchema7>>();
+
 /**
  * Resolve a $ref in a JSON Schema against the current definitions.
  * Returns the resolved schema, or the original if no $ref is present.
@@ -131,6 +152,28 @@ function schemaTypeToJava(
 
     // Resolve $ref first — register standalone types for generation
     if (schema.$ref) {
+        // Handle cross-schema $ref (e.g. "session-events.schema.json#/definitions/Foo")
+        const crossSchemaMatch = schema.$ref.match(/^([^#]+)#\/definitions\/(.+)$/);
+        if (crossSchemaMatch) {
+            const [, schemaFile, typeName] = crossSchemaMatch;
+            const externalDefs = crossSchemaDefinitions.get(schemaFile);
+            if (externalDefs) {
+                const resolved = externalDefs[typeName];
+                if (resolved) {
+                    // Save and swap currentDefinitions so recursive calls resolve against
+                    // the external schema's definitions.
+                    const savedDefs = currentDefinitions;
+                    currentDefinitions = externalDefs;
+                    const result = schemaTypeToJava(resolved, required, context, propName, nestedTypes);
+                    currentDefinitions = savedDefs;
+                    return result;
+                }
+            }
+            // Fallback: extract just the type name and warn
+            console.warn(`[codegen] Unresolved cross-schema $ref: ${schema.$ref}`);
+            return { javaType: typeName, imports };
+        }
+
         const name = schema.$ref.replace(/^#\/definitions\//, "");
         const resolved = currentDefinitions[name];
         if (resolved) {
@@ -883,6 +926,19 @@ async function generateRpcTypes(schemaPath: string): Promise<void> {
     // Set module-level definitions for $ref resolution
     currentDefinitions = (schema.definitions ?? {}) as Record<string, JSONSchema7>;
     pendingStandaloneTypes.clear();
+    crossSchemaDefinitions.clear();
+
+    // Load cross-schema definitions (session-events) so that cross-schema $ref values
+    // like "session-events.schema.json#/definitions/Foo" can be resolved.
+    try {
+        const sessionEventsSchemaPath = await getSessionEventsSchemaPath();
+        const sessionEventsContent = await fs.readFile(sessionEventsSchemaPath, "utf-8");
+        const sessionEventsSchema = JSON.parse(sessionEventsContent) as JSONSchema7;
+        crossSchemaDefinitions.set("session-events.schema.json",
+            (sessionEventsSchema.definitions ?? {}) as Record<string, JSONSchema7>);
+    } catch (e) {
+        console.warn(`[codegen] Could not load session-events schema for cross-ref resolution: ${e}`);
+    }
 
     const packageName = "com.github.copilot.sdk.generated.rpc";
     const packageDir = `src/generated/java/com/github/copilot/sdk/generated/rpc`;

java/scripts/codegen/package-lock.json

@@ -7,7 +7,7 @@
     "generate:java": "tsx java.ts"
   },
   "dependencies": {
-    "@github/copilot": "^1.0.49-1",
+    "@github/copilot": "^1.0.52-1",
     "json-schema": "^0.4.0",
     "tsx": "^4.20.6"
   }

java/scripts/codegen/package.json

@@ -53,7 +53,7 @@ public record AssistantMessageEventData(
         /** Generation phase for phased-output models (e.g., thinking vs. response phases) */
         @JsonProperty("phase") String phase,
         /** Actual output token count from the API response (completion_tokens), used for accurate token accounting */
-        @JsonProperty("outputTokens") Double outputTokens,
+        @JsonProperty("outputTokens") Long outputTokens,
         /** CAPI interaction ID for correlating this message with upstream telemetry */
         @JsonProperty("interactionId") String interactionId,
         /** GitHub request tracing ID (x-github-request-id header) for correlating with server-side logs */

java/src/generated/java/com/github/copilot/sdk/generated/AssistantMessageEvent.java

@@ -36,7 +36,7 @@ public final class AssistantStreamingDeltaEvent extends SessionEvent {
     @JsonInclude(JsonInclude.Include.NON_NULL)
     public record AssistantStreamingDeltaEventData(
         /** Cumulative total bytes received from the streaming response so far */
-        @JsonProperty("totalResponseSizeBytes") Double totalResponseSizeBytes
+        @JsonProperty("totalResponseSizeBytes") Long totalResponseSizeBytes
     ) {
     }
 }

java/src/generated/java/com/github/copilot/sdk/generated/AssistantStreamingDeltaEvent.java

@@ -22,11 +22,11 @@
 @JsonIgnoreProperties(ignoreUnknown = true)
 public record AssistantUsageCopilotUsageTokenDetail(
     /** Number of tokens in this billing batch */
-    @JsonProperty("batchSize") Double batchSize,
+    @JsonProperty("batchSize") Long batchSize,
     /** Cost per batch of tokens */
-    @JsonProperty("costPerBatch") Double costPerBatch,
+    @JsonProperty("costPerBatch") Long costPerBatch,
     /** Total token count for this entry */
-    @JsonProperty("tokenCount") Double tokenCount,
+    @JsonProperty("tokenCount") Long tokenCount,
     /** Token category (e.g., "input", "output") */
     @JsonProperty("tokenType") String tokenType
 ) {

java/src/generated/java/com/github/copilot/sdk/generated/AssistantUsageCopilotUsageTokenDetail.java

@@ -39,21 +39,21 @@ public record AssistantUsageEventData(
         /** Model identifier used for this API call */
         @JsonProperty("model") String model,
         /** Number of input tokens consumed */
-        @JsonProperty("inputTokens") Double inputTokens,
+        @JsonProperty("inputTokens") Long inputTokens,
         /** Number of output tokens produced */
-        @JsonProperty("outputTokens") Double outputTokens,
+        @JsonProperty("outputTokens") Long outputTokens,
         /** Number of tokens read from prompt cache */
-        @JsonProperty("cacheReadTokens") Double cacheReadTokens,
+        @JsonProperty("cacheReadTokens") Long cacheReadTokens,
         /** Number of tokens written to prompt cache */
-        @JsonProperty("cacheWriteTokens") Double cacheWriteTokens,
+        @JsonProperty("cacheWriteTokens") Long cacheWriteTokens,
         /** Number of output tokens used for reasoning (e.g., chain-of-thought) */
-        @JsonProperty("reasoningTokens") Double reasoningTokens,
+        @JsonProperty("reasoningTokens") Long reasoningTokens,
         /** Model multiplier cost for billing purposes */
         @JsonProperty("cost") Double cost,
         /** Duration of the API call in milliseconds */
-        @JsonProperty("duration") Double duration,
+        @JsonProperty("duration") Long duration,
         /** Time to first token in milliseconds. Only available for streaming requests */
-        @JsonProperty("ttftMs") Double ttftMs,
+        @JsonProperty("timeToFirstTokenMs") Long timeToFirstTokenMs,
         /** Average inter-token latency in milliseconds. Only available for streaming requests */
         @JsonProperty("interTokenLatencyMs") Double interTokenLatencyMs,
         /** What initiated this API call (e.g., "sub-agent", "mcp-sampling"); absent for user-initiated calls */