Add parent/child thread delegation primitives

apps/server/integration/orchestrationEngine.integration.test.ts

@@ -128,6 +128,7 @@ const seedProjectAndThread = (harness: OrchestrationIntegrationHarness) =>
       commandId: CommandId.makeUnsafe("cmd-thread-create"),
       threadId: THREAD_ID,
       projectId: PROJECT_ID,
+      parentThreadId: null,
       title: "Integration Thread",
       modelSelection: {
         provider,
@@ -277,6 +278,7 @@ it.live.skipIf(!process.env.CODEX_BINARY_PATH)(
           commandId: CommandId.makeUnsafe("cmd-thread-create-real-codex"),
           threadId: THREAD_ID,
           projectId: PROJECT_ID,
+          parentThreadId: null,
           title: "Integration Thread",
           modelSelection: {
             provider: "codex",

apps/server/src/orchestration/Layers/CheckpointReactor.test.ts

@@ -304,6 +304,7 @@ describe("CheckpointReactor", () => {
         commandId: CommandId.makeUnsafe("cmd-thread-create"),
         threadId: ThreadId.makeUnsafe("thread-1"),
         projectId: asProjectId("project-1"),
+        parentThreadId: null,
         title: "Thread",
         modelSelection: {
           provider: "codex",

apps/server/src/orchestration/Layers/OrchestrationEngine.test.ts

@@ -115,6 +115,7 @@ describe("OrchestrationEngine", () => {
         {
           id: ThreadId.makeUnsafe("thread-bootstrap"),
           projectId: asProjectId("project-bootstrap"),
+          parentThreadId: null,
           title: "Bootstrap Thread",
           modelSelection: {
             provider: "codex" as const,
@@ -198,6 +199,7 @@ describe("OrchestrationEngine", () => {
         commandId: CommandId.makeUnsafe("cmd-thread-1-create"),
         threadId: ThreadId.makeUnsafe("thread-1"),
         projectId: asProjectId("project-1"),
+        parentThreadId: null,
         title: "Thread",
         modelSelection: {
           provider: "codex",
@@ -258,6 +260,7 @@ describe("OrchestrationEngine", () => {
         commandId: CommandId.makeUnsafe("cmd-thread-archive-create"),
         threadId: ThreadId.makeUnsafe("thread-archive"),
         projectId: asProjectId("project-archive"),
+        parentThreadId: null,
         title: "Archive me",
         modelSelection: {
           provider: "codex",
@@ -325,6 +328,7 @@ describe("OrchestrationEngine", () => {
         commandId: CommandId.makeUnsafe("cmd-thread-replay-create"),
         threadId: ThreadId.makeUnsafe("thread-replay"),
         projectId: asProjectId("project-replay"),
+        parentThreadId: null,
         title: "replay",
         modelSelection: {
           provider: "codex",
@@ -393,6 +397,7 @@ describe("OrchestrationEngine", () => {
           commandId: CommandId.makeUnsafe("cmd-stream-thread-create"),
           threadId: ThreadId.makeUnsafe("thread-stream"),
           projectId: asProjectId("project-stream"),
+          parentThreadId: null,
           title: "domain-stream",
           modelSelection: {
             provider: "codex",
@@ -445,6 +450,7 @@ describe("OrchestrationEngine", () => {
         commandId: CommandId.makeUnsafe("cmd-thread-ack-create"),
         threadId: ThreadId.makeUnsafe("thread-ack"),
         projectId: asProjectId("project-ack"),
+        parentThreadId: null,
         title: "Ack Thread",
         modelSelection: {
           provider: "codex",
@@ -482,6 +488,7 @@ describe("OrchestrationEngine", () => {
           commandId: CommandId.makeUnsafe("cmd-thread-missing-project"),
           threadId: ThreadId.makeUnsafe("thread-missing-project"),
           projectId: asProjectId("project-missing"),
+          parentThreadId: null,
           title: "Missing Project Thread",
           modelSelection: {
             provider: "codex",
@@ -533,6 +540,7 @@ describe("OrchestrationEngine", () => {
         commandId: CommandId.makeUnsafe("cmd-thread-turn-diff-create"),
         threadId: ThreadId.makeUnsafe("thread-turn-diff"),
         projectId: asProjectId("project-turn-diff"),
+        parentThreadId: null,
         title: "Turn diff thread",
         modelSelection: {
           provider: "codex",
@@ -653,6 +661,7 @@ describe("OrchestrationEngine", () => {
           commandId: CommandId.makeUnsafe("cmd-flaky-1"),
           threadId: ThreadId.makeUnsafe("thread-flaky-fail"),
           projectId: asProjectId("project-flaky"),
+          parentThreadId: null,
           title: "flaky-fail",
           modelSelection: {
             provider: "codex",
@@ -673,6 +682,7 @@ describe("OrchestrationEngine", () => {
         commandId: CommandId.makeUnsafe("cmd-flaky-2"),
         threadId: ThreadId.makeUnsafe("thread-flaky-ok"),
         projectId: asProjectId("project-flaky"),
+        parentThreadId: null,
         title: "flaky-ok",
         modelSelection: {
           provider: "codex",
@@ -745,6 +755,7 @@ describe("OrchestrationEngine", () => {
         commandId: CommandId.makeUnsafe("cmd-thread-atomic-create"),
         threadId: ThreadId.makeUnsafe("thread-atomic"),
         projectId: asProjectId("project-atomic"),
+        parentThreadId: null,
         title: "atomic",
         modelSelection: {
           provider: "codex",
@@ -887,6 +898,7 @@ describe("OrchestrationEngine", () => {
         commandId: CommandId.makeUnsafe("cmd-thread-sync-create"),
         threadId: ThreadId.makeUnsafe("thread-sync"),
         projectId: asProjectId("project-sync"),
+        parentThreadId: null,
         title: "sync-before",
         modelSelection: {
           provider: "codex",
@@ -973,6 +985,7 @@ describe("OrchestrationEngine", () => {
         commandId: CommandId.makeUnsafe("cmd-thread-duplicate-1"),
         threadId: ThreadId.makeUnsafe("thread-duplicate"),
         projectId: asProjectId("project-duplicate"),
+        parentThreadId: null,
         title: "duplicate",
         modelSelection: {
           provider: "codex",
@@ -993,6 +1006,7 @@ describe("OrchestrationEngine", () => {
           commandId: CommandId.makeUnsafe("cmd-thread-duplicate-2"),
           threadId: ThreadId.makeUnsafe("thread-duplicate"),
           projectId: asProjectId("project-duplicate"),
+          parentThreadId: null,
           title: "duplicate",
           modelSelection: {
             provider: "codex",

apps/server/src/orchestration/Layers/ProjectionPipeline.test.ts

@@ -89,6 +89,7 @@ it.layer(BaseTestLayer)("OrchestrationProjectionPipeline", (it) => {
         payload: {
           threadId: ThreadId.makeUnsafe("thread-1"),
           projectId: ProjectId.makeUnsafe("project-1"),
+          parentThreadId: ThreadId.makeUnsafe("thread-parent"),
           title: "Thread 1",
           modelSelection: {
             provider: "codex",
@@ -152,6 +153,17 @@ it.layer(BaseTestLayer)("OrchestrationProjectionPipeline", (it) => {
       `;
       assert.deepEqual(messageRows, [{ messageId: "message-1", text: "hello" }]);
 
+      const threadRows = yield* sql<{
+        readonly threadId: string;
+        readonly parentThreadId: string | null;
+      }>`
+        SELECT
+          thread_id AS "threadId",
+          parent_thread_id AS "parentThreadId"
+        FROM projection_threads
+      `;
+      assert.deepEqual(threadRows, [{ threadId: "thread-1", parentThreadId: "thread-parent" }]);
+
       const stateRows = yield* sql<{
         readonly projector: string;
         readonly lastAppliedSequence: number;

apps/server/src/orchestration/Layers/ProjectionPipeline.ts

@@ -440,6 +440,7 @@ const makeOrchestrationProjectionPipeline = Effect.fn("makeOrchestrationProjecti
           yield* projectionThreadRepository.upsert({
             threadId: event.payload.threadId,
             projectId: event.payload.projectId,
+            parentThreadId: event.payload.parentThreadId,
             title: event.payload.title,
             modelSelection: event.payload.modelSelection,
             runtimeMode: event.payload.runtimeMode,

apps/server/src/orchestration/Layers/ProjectionSnapshotQuery.test.ts

@@ -56,6 +56,7 @@ projectionSnapshotLayer("ProjectionSnapshotQuery", (it) => {
         INSERT INTO projection_threads (
           thread_id,
           project_id,
+          parent_thread_id,
           title,
           model_selection_json,
           branch,
@@ -68,6 +69,7 @@ projectionSnapshotLayer("ProjectionSnapshotQuery", (it) => {
         VALUES (
           'thread-1',
           'project-1',
+          'thread-parent',
           'Thread 1',
           '{"provider":"codex","model":"gpt-5-codex"}',
           NULL,
@@ -256,6 +258,7 @@ projectionSnapshotLayer("ProjectionSnapshotQuery", (it) => {
         {
           id: ThreadId.makeUnsafe("thread-1"),
           projectId: asProjectId("project-1"),
+          parentThreadId: ThreadId.makeUnsafe("thread-parent"),
           title: "Thread 1",
           modelSelection: {
             provider: "codex",

apps/server/src/orchestration/Layers/ProjectionSnapshotQuery.ts

@@ -191,6 +191,7 @@ const makeProjectionSnapshotQuery = Effect.gen(function* () {
         SELECT
           thread_id AS "threadId",
           project_id AS "projectId",
+          parent_thread_id AS "parentThreadId",
           title,
           model_selection_json AS "modelSelection",
           runtime_mode AS "runtimeMode",
@@ -666,6 +667,7 @@ const makeProjectionSnapshotQuery = Effect.gen(function* () {
           const threads: ReadonlyArray<OrchestrationThread> = threadRows.map((row) => ({
             id: row.threadId,
             projectId: row.projectId,
+            parentThreadId: row.parentThreadId,
             title: row.title,
             modelSelection: row.modelSelection,
             runtimeMode: row.runtimeMode,

apps/server/src/orchestration/Layers/ProviderCommandReactor.test.ts

@@ -259,6 +259,7 @@ describe("ProviderCommandReactor", () => {
         commandId: CommandId.makeUnsafe("cmd-thread-create"),
         threadId: ThreadId.makeUnsafe("thread-1"),
         projectId: asProjectId("project-1"),
+        parentThreadId: null,
         title: "Thread",
         modelSelection: modelSelection,
         interactionMode: DEFAULT_PROVIDER_INTERACTION_MODE,

apps/server/src/orchestration/Layers/ProviderRuntimeIngestion.test.ts

@@ -242,6 +242,7 @@ describe("ProviderRuntimeIngestion", () => {
         commandId: CommandId.makeUnsafe("cmd-thread-create"),
         threadId: ThreadId.makeUnsafe("thread-1"),
         projectId: asProjectId("project-1"),
+        parentThreadId: null,
         title: "Thread",
         modelSelection: {
           provider: "codex",
@@ -771,6 +772,7 @@ describe("ProviderRuntimeIngestion", () => {
         commandId: CommandId.makeUnsafe("cmd-thread-create-plan-source"),
         threadId: sourceThreadId,
         projectId: asProjectId("project-1"),
+        parentThreadId: null,
         title: "Plan Source",
         modelSelection: {
           provider: "codex",
@@ -806,6 +808,7 @@ describe("ProviderRuntimeIngestion", () => {
         commandId: CommandId.makeUnsafe("cmd-thread-create-plan-target"),
         threadId: targetThreadId,
         projectId: asProjectId("project-1"),
+        parentThreadId: null,
         title: "Plan Target",
         modelSelection: {
           provider: "codex",
@@ -958,6 +961,7 @@ describe("ProviderRuntimeIngestion", () => {
         commandId: CommandId.makeUnsafe("cmd-thread-create-plan-source-guarded"),
         threadId: sourceThreadId,
         projectId: asProjectId("project-1"),
+        parentThreadId: null,
         title: "Plan Source",
         modelSelection: {
           provider: "codex",
@@ -1111,6 +1115,7 @@ describe("ProviderRuntimeIngestion", () => {
         commandId: CommandId.makeUnsafe("cmd-thread-create-plan-source-unrelated"),
         threadId: sourceThreadId,
         projectId: asProjectId("project-1"),
+        parentThreadId: null,
         title: "Plan Source",
         modelSelection: {
           provider: "codex",
@@ -1146,6 +1151,7 @@ describe("ProviderRuntimeIngestion", () => {
         commandId: CommandId.makeUnsafe("cmd-thread-create-plan-target-unrelated"),
         threadId: targetThreadId,
         projectId: asProjectId("project-1"),
+        parentThreadId: null,
         title: "Plan Target",
         modelSelection: {
           provider: "codex",

apps/server/src/orchestration/commandInvariants.test.ts

@@ -55,6 +55,7 @@ const readModel: OrchestrationReadModel = {
     {
       id: ThreadId.makeUnsafe("thread-1"),
       projectId: ProjectId.makeUnsafe("project-a"),
+      parentThreadId: null,
       title: "Thread A",
       modelSelection: {
         provider: "codex",
@@ -78,6 +79,7 @@ const readModel: OrchestrationReadModel = {
     {
       id: ThreadId.makeUnsafe("thread-2"),
       projectId: ProjectId.makeUnsafe("project-b"),
+      parentThreadId: null,
       title: "Thread B",
       modelSelection: {
         provider: "codex",
@@ -157,6 +159,7 @@ describe("commandInvariants", () => {
           commandId: CommandId.makeUnsafe("cmd-2"),
           threadId: ThreadId.makeUnsafe("thread-3"),
           projectId: ProjectId.makeUnsafe("project-a"),
+          parentThreadId: null,
           title: "new",
           modelSelection: {
             provider: "codex",
@@ -181,6 +184,7 @@ describe("commandInvariants", () => {
             commandId: CommandId.makeUnsafe("cmd-3"),
             threadId: ThreadId.makeUnsafe("thread-1"),
             projectId: ProjectId.makeUnsafe("project-a"),
+            parentThreadId: null,
             title: "dup",
             modelSelection: {
               provider: "codex",

apps/server/src/orchestration/commandInvariants.ts

@@ -107,6 +107,25 @@ export function requireThreadArchived(input: {
   );
 }
 
+export function requireThreadNotDeleted(input: {
+  readonly readModel: OrchestrationReadModel;
+  readonly command: OrchestrationCommand;
+  readonly threadId: ThreadId;
+}): Effect.Effect<OrchestrationThread, OrchestrationCommandInvariantError> {
+  return requireThread(input).pipe(
+    Effect.flatMap((thread) =>
+      thread.deletedAt === null
+        ? Effect.succeed(thread)
+        : Effect.fail(
+            invariantError(
+              input.command.type,
+              `Thread '${input.threadId}' is deleted and cannot handle command '${input.command.type}'.`,
+            ),
+          ),
+    ),
+  );
+}
+
 export function requireThreadNotArchived(input: {
   readonly readModel: OrchestrationReadModel;
   readonly command: OrchestrationCommand;