fix: complete all P2 audit findings — dead code, NPE guard, hygiene

P2-1: Guard SessionId NPE with safe-call in SessionsReducer
P2-2: Remove 16 dead event classes + reducer branches; replace with live orchestration events in tests
P2-3: Standardize ChatInput divergences — guard CancelSession, single-arg ProtocolError
P2-4: Remove dead TuiToolRecord.diff and ToolDisplayStatus.REQUESTED
P2-5: Remove dead streamLive from SessionEventBridge
P2-6: Extract SessionsReducerContext data class for 6+ param method
P2-7: Replace StageId("none") sentinel with TypeId.NONE
P2-9: Add TypeId.random() factory on all type-alias IDs
P2-10: Add KDoc on schemaVersion documenting reserved-for-migration
P2-8: Verified RouterReducer string-template already correct (TypeId value class toString)

apps/server/src/main/kotlin/com/correx/apps/server/bridge/SessionEventBridge.kt

@@ -244,12 +244,4 @@ class SessionEventBridge(
         return orderedIds.mapNotNull { byInvocation[it] }
     }
 
-    suspend fun streamLive(sessionId: SessionId) {
-        var sessionSequence = 0L
-        eventStore.subscribe(sessionId).collect { event ->
-            sessionSequence++
-            domainEventToServerMessage(event, artifactStore, sessionSequence = sessionSequence)
-                ?.let { send(it) }
-        }
-    }
 }

apps/server/src/main/kotlin/com/correx/apps/server/ws/GlobalStreamHandler.kt

@@ -88,11 +88,7 @@ class GlobalStreamHandler(private val module: ServerModule) {
                         }
                         .onFailure {
                             log.warn("decode error: {}", it.message)
-                            val error = ServerMessage.ProtocolError(
+                            val error = ServerMessage.ProtocolError("Unknown message: ${it.message}")
-                                message = "Unknown message: ${it.message}",
-                                sequence = null,
-                                sessionSequence = null,
-                            )
                             session.send(Frame.Text(ProtocolSerializer.encodeServerMessage(error)))
                         }
                 }
@@ -144,7 +140,10 @@ class GlobalStreamHandler(private val module: ServerModule) {
             is ClientMessage.Ping -> Unit
             is ClientMessage.StartSession -> handleStartSession(session, msg, sendFrame)
             is ClientMessage.StartChatSession -> handleStartChatSession(session, msg, sendFrame)
-            is ClientMessage.CancelSession -> module.orchestrator.cancel(msg.sessionId)
+            is ClientMessage.CancelSession -> {
+                runCatching { module.orchestrator.cancel(msg.sessionId) }
+                    .onFailure { log.error("cancel failed for session={}: {}", msg.sessionId.value, it.message, it) }
+            }
             is ClientMessage.ResumeSession -> session.send(encodeError("ResumeSession not supported"))
             is ClientMessage.ApprovalResponse -> handleApprovalResponse(msg, sendFrame)
             is ClientMessage.CreateGrant -> handleCreateGrant(msg, sendFrame)
@@ -159,11 +158,7 @@ class GlobalStreamHandler(private val module: ServerModule) {
                     ))
                 }.onFailure {
                     log.error("routerFacade.onUserInput failed: {}", it.message)
-                    sendFrame(ServerMessage.ProtocolError(
+                    sendFrame(ServerMessage.ProtocolError("Router error: ${it.message}"))
-                        message = "Router error: ${it.message}",
-                        sequence = null,
-                        sessionSequence = null,
-                    ))
                 }
             }
         }
@@ -176,34 +171,16 @@ class GlobalStreamHandler(private val module: ServerModule) {
         val scopeSessionId = module.approvalCoordinator.lookupSession(msg.requestId)
         if (scopeSessionId == null) {
             log.warn("handleApprovalResponse: no session found for requestId={}", msg.requestId.value)
-            sendFrame(
+            sendFrame(ServerMessage.ProtocolError("Unknown approval request"))
-                ServerMessage.ProtocolError(
-                    message = "Unknown approval request",
-                    sequence = null,
-                    sessionSequence = null,
-                ),
-            )
             return
         }
         module.approvalCoordinator.handleResponse(msg, scopeSessionId)?.let { sendFrame(it) }
     }
 
-    private fun errorResponse(message: String) = ServerMessage.ProtocolError(
+    private fun errorResponse(message: String) = ServerMessage.ProtocolError(message)
-        message = message,
-        sequence = null,
-        sessionSequence = null,
-    )
 
     private fun encodeError(message: String): Frame.Text =
-        Frame.Text(
+        Frame.Text(ProtocolSerializer.encodeServerMessage(ServerMessage.ProtocolError(message)))
-            ProtocolSerializer.encodeServerMessage(
-                ServerMessage.ProtocolError(
-                    message = message,
-                    sequence = null,
-                    sessionSequence = null,
-                ),
-            ),
-        )
 
     private suspend fun handleCreateGrant(
         msg: ClientMessage.CreateGrant,

apps/server/src/test/kotlin/com/correx/apps/server/bridge/DomainEventMapperTest.kt

@@ -10,7 +10,7 @@ import com.correx.core.events.events.InferenceCompletedEvent
 import com.correx.core.events.events.InferenceStartedEvent
 import com.correx.core.events.events.InferenceTimeoutEvent
 import com.correx.core.events.events.OrchestrationPausedEvent
-import com.correx.core.events.events.SessionStartedEvent
+import com.correx.core.events.events.SteeringNoteAddedEvent
 import com.correx.core.events.events.StageCompletedEvent
 import com.correx.core.events.events.StageFailedEvent
 import com.correx.core.events.events.StoredEvent
@@ -371,7 +371,7 @@ class DomainEventMapperTest {
 
     @Test
     fun `unmapped event returns null`(): Unit = runTest {
-        val event = storedEvent(SessionStartedEvent(sessionId = sessionId))
+        val event = storedEvent(SteeringNoteAddedEvent(sessionId = sessionId, content = "test"))
         val result = domainEventToServerMessage(event, noopStore, sessionSequence = 0L)
         assertNull(result)
     }
@@ -392,12 +392,12 @@ class DomainEventMapperTest {
         val origLevel = logger.level
         logger.level = Level.DEBUG
         try {
-            val event = storedEvent(SessionStartedEvent(sessionId = sessionId))
+            val event = storedEvent(SteeringNoteAddedEvent(sessionId = sessionId, content = "test"))
             val result = domainEventToServerMessage(event, noopStore, sessionSequence = 0L)
             assertNull(result)
             assertEquals(1, appender.events.size)
             assertEquals(Level.DEBUG, appender.events[0].level)
-            assertTrue(appender.events[0].message.formattedMessage.contains("SessionStartedEvent"))
+            assertTrue(appender.events[0].message.formattedMessage.contains("SteeringNoteAddedEvent"))
         } finally {
             logger.removeAppender(appender)
             appender.stop()

apps/server/src/test/kotlin/com/correx/apps/server/bridge/SessionEventBridgeTest.kt

@@ -25,10 +25,8 @@ import com.correx.core.kernel.orchestration.OrchestrationRepository
 import com.correx.core.tools.contract.Tool
 import com.correx.core.tools.registry.ToolRegistry
 import com.correx.core.sessions.projections.replay.EventReplayer
-import kotlinx.coroutines.channels.Channel
 import kotlinx.coroutines.flow.Flow
 import kotlinx.coroutines.flow.flow
-import kotlinx.coroutines.launch
 import kotlinx.coroutines.test.runTest
 import kotlinx.datetime.Instant
 import org.junit.jupiter.api.Assertions.assertEquals
@@ -186,36 +184,6 @@ class SessionEventBridgeTest {
         assertEquals(ServerMessage.SnapshotComplete, sent[1])
     }
 
-    @Test
-    fun `streamLive sends mapped messages from live flow`() = runTest {
-        val events = listOf(
-            storedEvent(WorkflowStartedEvent(sessionId, workflowId, stageId), seq = 1L),
-            storedEvent(WorkflowCompletedEvent(sessionId, stageId, 1), seq = 2L),
-        )
-        val liveFlow: Flow<StoredEvent> = flow { events.forEach { emit(it) } }
-        val store = fakeEventStore(liveFlow = liveFlow)
-        val sent = mutableListOf<ServerMessage>()
-        val bridge = SessionEventBridge(
-            store,
-            noopArtifactStore,
-            activeOrchestrationRepository(),
-            noopWorkflowRegistry,
-            noopToolRegistry,
-        ) { sent.add(it) }
-
-        bridge.streamLive(sessionId)
-
-        assertEquals(2, sent.size)
-        assertEquals(
-            ServerMessage.SessionStarted(sessionId, workflowId, 1L, 1L),
-            sent[0],
-        )
-        assertEquals(
-            ServerMessage.SessionCompleted(sessionId, 2L, 2L),
-            sent[1],
-        )
-    }
-
     @Test
     fun `replaySnapshot with no sessions emits only SnapshotComplete`() = runTest {
         val store = fakeEventStore(allEventsList = emptyList())
@@ -266,29 +234,4 @@ class SessionEventBridgeTest {
         assertEquals(3L, snapshot.lastSessionSequence)
     }
 
-    @Test
-    fun `streamLive cancellation stops collection`() = runTest {
-        val channel = Channel<StoredEvent>(Channel.UNLIMITED)
-        val liveFlow: Flow<StoredEvent> = flow {
-            for (event in channel) emit(event)
-        }
-        val store = fakeEventStore(liveFlow = liveFlow)
-        val sent = mutableListOf<ServerMessage>()
-        val bridge = SessionEventBridge(
-            store,
-            noopArtifactStore,
-            activeOrchestrationRepository(),
-            noopWorkflowRegistry,
-            noopToolRegistry,
-        ) { sent.add(it) }
-
-        channel.send(storedEvent(WorkflowStartedEvent(sessionId, workflowId, stageId), seq = 1L))
-
-        val job = launch { bridge.streamLive(sessionId) }
-        channel.send(storedEvent(WorkflowCompletedEvent(sessionId, stageId, 1), seq = 2L))
-        channel.close()
-        job.join()
-
-        assertEquals(2, sent.size)
-    }
 }

apps/tui/src/main/kotlin/com/correx/apps/tui/components/EventHistoryStrip.kt

@@ -1,6 +1,5 @@
 package com.correx.apps.tui.components
 
-import com.correx.apps.tui.state.ToolDisplayStatus
 import com.correx.apps.tui.state.TuiState
 import dev.tamboui.style.Style
 import dev.tamboui.text.Line

apps/tui/src/main/kotlin/com/correx/apps/tui/reducer/RootReducer.kt

@@ -62,12 +62,14 @@ object RootReducer {
 
         log.debug("sessions state before reducers={}", state.sessions)
         val (sessions, se) = SessionsReducer.reduce(
-            sessions = afterInput.sessions,
+            SessionsReducerContext(
-            displayState = afterInput.displayState,
+                sessions = afterInput.sessions,
-            inputMode = prevInputMode,
+                displayState = afterInput.displayState,
-            inputText = prevInputBuffer,
+                inputMode = prevInputMode,
-            action = action,
+                inputText = prevInputBuffer,
-            clock = clock,
+                action = action,
+                clock = clock,
+            ),
         )
         log.debug("connection state before reducers={}", state.connection)
         val (connection, ce) = ConnectionReducer.reduce(afterInput.connection, action)

apps/tui/src/main/kotlin/com/correx/apps/tui/reducer/SessionsReducer.kt

@@ -22,40 +22,42 @@ import java.time.format.DateTimeFormatter
 
 private val log = LoggerFactory.getLogger(SessionsReducer::class.simpleName)
 
+data class SessionsReducerContext(
+    val sessions: SessionsState,
+    val displayState: DisplayState,
+    val inputMode: InputMode,
+    val inputText: String,
+    val action: Action,
+    val clock: () -> Long = System::currentTimeMillis,
+)
+
 object SessionsReducer {
     private val timeFormatter = DateTimeFormatter.ofPattern("HH:mm:ss").withZone(ZoneOffset.UTC)
 
-    fun reduce(
+    fun reduce(ctx: SessionsReducerContext): Pair<SessionsState, List<Effect>> = when (ctx.action) {
-        sessions: SessionsState,
-        displayState: DisplayState,
-        inputMode: InputMode,
-        inputText: String,
-        action: Action,
-        clock: () -> Long = System::currentTimeMillis,
-    ): Pair<SessionsState, List<Effect>> = when (action) {
         is Action.NavigateUp -> when {
-            inputMode == InputMode.FILTER -> navigateUp(sessions) to emptyList()
+            ctx.inputMode == InputMode.FILTER -> navigateUp(ctx.sessions) to emptyList()
-            displayState == DisplayState.IDLE -> navigateUp(sessions) to emptyList()
+            ctx.displayState == DisplayState.IDLE -> navigateUp(ctx.sessions) to emptyList()
-            displayState == DisplayState.IN_SESSION -> sessions to emptyList()
+            ctx.displayState == DisplayState.IN_SESSION -> ctx.sessions to emptyList()
-            else -> sessions to emptyList()
+            else -> ctx.sessions to emptyList()
         }
 
         is Action.NavigateDown -> when {
-            inputMode == InputMode.FILTER -> navigateDown(sessions) to emptyList()
+            ctx.inputMode == InputMode.FILTER -> navigateDown(ctx.sessions) to emptyList()
-            displayState == DisplayState.IDLE -> navigateDown(sessions) to emptyList()
+            ctx.displayState == DisplayState.IDLE -> navigateDown(ctx.sessions) to emptyList()
-            displayState == DisplayState.IN_SESSION -> sessions to emptyList()
+            ctx.displayState == DisplayState.IN_SESSION -> ctx.sessions to emptyList()
-            else -> sessions to emptyList()
+            else -> ctx.sessions to emptyList()
         }
 
         is Action.SubmitInput -> when {
-            inputMode == InputMode.FILTER -> sessions.copy(filter = inputText) to emptyList()
+            ctx.inputMode == InputMode.FILTER -> ctx.sessions.copy(filter = ctx.inputText) to emptyList()
-            displayState == DisplayState.IDLE -> {
+            ctx.displayState == DisplayState.IDLE -> {
-                val text = inputText.trim()
+                val text = ctx.inputText.trim()
-                val wfIndex = sessions.selectedWorkflowIndex
+                val wfIndex = ctx.sessions.selectedWorkflowIndex
                 when {
-                    wfIndex in sessions.workflows.indices -> {
+                    wfIndex in ctx.sessions.workflows.indices -> {
-                        val wf = sessions.workflows[wfIndex]
+                        val wf = ctx.sessions.workflows[wfIndex]
-                        sessions.copy(selectedWorkflowIndex = -1) to listOf(
+                        ctx.sessions.copy(selectedWorkflowIndex = -1) to listOf(
                             Effect.SendWs(ClientMessage.StartSession(workflowId = wf.workflowId, config = null)),
                         )
                     }
@@ -67,56 +69,56 @@ object SessionsReducer {
                             status = "STARTING",
                             workflowId = "chat",
                             name = "chat",
-                            lastEventAt = clock(),
+                            lastEventAt = ctx.clock(),
                         )
-                        sessions.copy(
+                        ctx.sessions.copy(
-                            sessions = sessions.sessions + optimistic,
+                            sessions = ctx.sessions.sessions + optimistic,
                             selectedId = sessionId.value,
                         ) to listOf(
                             Effect.SendWs(ClientMessage.StartChatSession(sessionId = sessionId, text = text)),
                         )
                     }
 
-                    else -> sessions to emptyList()
+                    else -> ctx.sessions to emptyList()
                 }
             }
 
-            displayState == DisplayState.IN_SESSION -> {
+            ctx.displayState == DisplayState.IN_SESSION -> ctx.sessions.selectedId?.let { sid ->
-                sessions to listOf(
+                ctx.sessions to listOf(
                     Effect.SendWs(
                         ClientMessage.ChatInput(
-                            sessionId = SessionId(sessions.selectedId!!),
+                            sessionId = SessionId(sid),
-                            text = inputText,
+                            text = ctx.inputText,
                             mode = ChatMode.CHAT,
                         ),
                     ),
                 )
-            }
+            } ?: (ctx.sessions to emptyList())
 
-            else -> sessions to emptyList()
+            else -> ctx.sessions to emptyList()
         }
 
-        is Action.CancelInput -> if (inputMode == InputMode.FILTER) {
+        is Action.CancelInput -> if (ctx.inputMode == InputMode.FILTER) {
-            sessions.copy(filter = "") to emptyList()
+            ctx.sessions.copy(filter = "") to emptyList()
         } else {
-            sessions to emptyList()
+            ctx.sessions to emptyList()
         }
 
         is Action.CancelSelectedSession -> {
-            val id = sessions.selectedId
+            val id = ctx.sessions.selectedId
             if (id != null) {
-                sessions to listOf(Effect.SendWs(ClientMessage.CancelSession(sessionId = SessionId(id))))
+                ctx.sessions to listOf(Effect.SendWs(ClientMessage.CancelSession(sessionId = SessionId(id))))
             } else {
-                sessions to emptyList()
+                ctx.sessions to emptyList()
             }
         }
 
-        is Action.ToggleWorkflows -> sessions.copy(
+        is Action.ToggleWorkflows -> ctx.sessions.copy(
-            workflowsVisible = !sessions.workflowsVisible,
+            workflowsVisible = !ctx.sessions.workflowsVisible,
         ) to emptyList()
 
-        is Action.ServerEventReceived -> applyServerMessage(sessions, action.message, clock)
+        is Action.ServerEventReceived -> applyServerMessage(ctx.sessions, ctx.action.message, ctx.clock)
-        else -> sessions to emptyList()
+        else -> ctx.sessions to emptyList()
     }
 
     private fun filteredSessions(sessions: SessionsState): List<SessionSummary> =
@@ -311,7 +313,6 @@ object SessionsReducer {
                 tier = tool.tier,
                 status = displayStatus,
                 argsPreview = null,
-                diff = tool.diff,
             )
         }
         val summary = SessionSummary(
@@ -409,7 +410,7 @@ object SessionsReducer {
                 if (s.id == msg.sessionId.value) {
                     val updatedTools = s.tools.map { t ->
                         if (t.name == msg.toolName && t.status == ToolDisplayStatus.STARTED) {
-                            t.copy(status = ToolDisplayStatus.COMPLETED, diff = msg.diff)
+                            t.copy(status = ToolDisplayStatus.COMPLETED)
                         } else {
                             t
                         }

apps/tui/src/main/kotlin/com/correx/apps/tui/state/TuiState.kt

@@ -5,7 +5,7 @@ import com.correx.apps.server.protocol.ServerMessage
 
 enum class InputMode { ROUTER, FILTER }
 
-enum class ToolDisplayStatus { REQUESTED, STARTED, COMPLETED, FAILED, REJECTED }
+enum class ToolDisplayStatus { STARTED, COMPLETED, FAILED, REJECTED }
 
 enum class ProviderType { LOCAL, REMOTE }
 
@@ -14,7 +14,6 @@ data class TuiToolRecord(
     val tier: Int,
     val status: ToolDisplayStatus,
     val argsPreview: String?,
-    val diff: String? = null,
 )
 
 data class TuiEventEntry(

apps/tui/src/test/kotlin/com/correx/apps/tui/reducer/SessionsReducerTest.kt

@@ -41,7 +41,16 @@ class SessionsReducerTest {
         inputMode: InputMode = InputMode.ROUTER,
         inputText: String = "",
         action: Action,
-    ) = SessionsReducer.reduce(sessions, displayState, inputMode, inputText, action, fixedClock)
+    ) = SessionsReducer.reduce(
+        SessionsReducerContext(
+            sessions = sessions,
+            displayState = displayState,
+            inputMode = inputMode,
+            inputText = inputText,
+            action = action,
+            clock = fixedClock,
+        ),
+    )
 
     @Test
     fun `NavigateUp wraps from top to bottom`() {

core/artifacts/src/main/kotlin/com/correx/core/artifacts/ArtifactReducer.kt

@@ -1,11 +1,7 @@
 package com.correx.core.artifacts
 
 import com.correx.core.artifacts.model.ArtifactRelationship
-import com.correx.core.events.events.ArtifactArchivedEvent
 import com.correx.core.events.events.ArtifactCreatedEvent
-import com.correx.core.events.events.ArtifactRejectedEvent
-import com.correx.core.events.events.ArtifactRelationshipAddedEvent
-import com.correx.core.events.events.ArtifactSupersededEvent
 import com.correx.core.events.events.ArtifactValidatedEvent
 import com.correx.core.events.events.ArtifactValidatingEvent
 import com.correx.core.events.events.StoredEvent
@@ -25,23 +21,6 @@ class DefaultArtifactReducer : ArtifactReducer {
                 transition(state, ArtifactLifecyclePhase.VALIDATING, ArtifactLifecyclePhase.CREATED)
             is ArtifactValidatedEvent ->
                 transition(state, ArtifactLifecyclePhase.VALIDATED, ArtifactLifecyclePhase.VALIDATING)
-            is ArtifactRejectedEvent ->
-                transition(state, ArtifactLifecyclePhase.REJECTED, ArtifactLifecyclePhase.VALIDATING)
-            is ArtifactSupersededEvent ->
-                transition(state, ArtifactLifecyclePhase.SUPERSEDED, ArtifactLifecyclePhase.VALIDATED)
-            is ArtifactArchivedEvent ->
-                transitionFromAny(
-                    state,
-                    ArtifactLifecyclePhase.ARCHIVED,
-                    ArtifactLifecyclePhase.VALIDATED,
-                    ArtifactLifecyclePhase.REJECTED,
-                )
-            is ArtifactRelationshipAddedEvent -> {
-                val rel = ArtifactRelationship(p.sourceId, p.targetId, p.relationshipType)
-                Result.success(
-                    state.copy(lineage = state.lineage.copy(relationships = state.lineage.relationships + rel))
-                )
-            }
             else -> Result.success(state)
         }
 
@@ -59,19 +38,4 @@ class DefaultArtifactReducer : ArtifactReducer {
                 )
             )
         }
-
-    private fun transitionFromAny(
-        state: ArtifactState,
-        to: ArtifactLifecyclePhase,
-        vararg validFrom: ArtifactLifecyclePhase,
-    ): Result<ArtifactState> =
-        if (state.phase in validFrom) {
-            Result.success(state.copy(phase = to))
-        } else {
-            Result.failure(
-                IllegalStateException(
-                    "Invalid artifact transition: ${state.phase} → $to (expected one of ${validFrom.toList()})"
-                )
-            )
-        }
 }

core/context/src/main/kotlin/com/correx/core/context/DefaultContextReducer.kt

@@ -1,23 +1,8 @@
 package com.correx.core.context
 
 import com.correx.core.context.state.ContextState
-import com.correx.core.events.events.ContextBuildingFailedEvent
-import com.correx.core.events.events.ContextBuildingInterruptedEvent
-import com.correx.core.events.events.ContextBuildingStartedEvent
-import com.correx.core.events.events.ContextPackBuiltEvent
 import com.correx.core.events.events.StoredEvent
 
 class DefaultContextReducer : ContextReducer {
-    override fun reduce(state: ContextState, event: StoredEvent): ContextState =
+    override fun reduce(state: ContextState, event: StoredEvent): ContextState = state
-        when (val p = event.payload) {
-            is ContextBuildingStartedEvent -> state.copy(buildingInProgress = true, interrupted = false)
-            is ContextPackBuiltEvent -> state.copy(
-                buildingInProgress = false,
-                interrupted = false,
-                builtPackIds = state.builtPackIds + p.contextPackId,
-            )
-            is ContextBuildingFailedEvent -> state.copy(buildingInProgress = false, interrupted = false)
-            is ContextBuildingInterruptedEvent -> state.copy(buildingInProgress = false, interrupted = true)
-            else -> state
-        }
 }

core/events/src/main/kotlin/com/correx/core/events/events/ArtifactEvents.kt

@@ -1,7 +1,6 @@
 package com.correx.core.events.events
 
 import com.correx.core.events.types.ArtifactId
-import com.correx.core.events.types.ArtifactRelationshipType
 import com.correx.core.events.types.SessionId
 import com.correx.core.events.types.StageId
 import kotlinx.serialization.SerialName
@@ -23,33 +22,6 @@ data class ArtifactValidatedEvent(
     val stageId: StageId,
 ) : EventPayload
 
-@Serializable
-@SerialName("ArtifactSuperseded")
-data class ArtifactSupersededEvent(
-    val artifactId: ArtifactId,
-    val supersededById: ArtifactId,
-    val sessionId: SessionId,
-    val stageId: StageId,
-) : EventPayload
-
-@Serializable
-@SerialName("ArtifactRelationshipAdded")
-data class ArtifactRelationshipAddedEvent(
-    val sourceId: ArtifactId,
-    val targetId: ArtifactId,
-    val relationshipType: ArtifactRelationshipType,
-    val sessionId: SessionId,
-) : EventPayload
-
-@Serializable
-@SerialName("ArtifactRejected")
-data class ArtifactRejectedEvent(
-    val artifactId: ArtifactId,
-    val sessionId: SessionId,
-    val stageId: StageId,
-    val reason: String,
-) : EventPayload
-
 @Serializable
 @SerialName("ArtifactCreated")
 data class ArtifactCreatedEvent(
@@ -58,11 +30,3 @@ data class ArtifactCreatedEvent(
     val stageId: StageId,
     val schemaVersion: Int,
 ) : EventPayload
-
-@Serializable
-@SerialName("ArtifactArchived")
-data class ArtifactArchivedEvent(
-    val artifactId: ArtifactId,
-    val sessionId: SessionId,
-    val stageId: StageId,
-) : EventPayload

core/events/src/main/kotlin/com/correx/core/events/events/ContextEvents.kt

@@ -1,62 +1,10 @@
 package com.correx.core.events.events
 
-import com.correx.core.events.types.ContextPackId
 import com.correx.core.events.types.SessionId
 import com.correx.core.events.types.StageId
 import kotlinx.serialization.SerialName
 import kotlinx.serialization.Serializable
 
-@Serializable
-@SerialName("LayerTruncated")
-data class LayerTruncatedEvent(
-    val contextPackId: ContextPackId,
-    val layer: String,
-    val entriesDropped: Int,
-    val reason: String,
-) : EventPayload
-
-@Serializable
-@SerialName("ContextBuildingStarted")
-data class ContextBuildingStartedEvent(
-    val sessionId: SessionId,
-    val stageId: StageId,
-) : EventPayload
-
-@Serializable
-@SerialName("ContextBuildingFailed")
-data class ContextBuildingFailedEvent(
-    val sessionId: SessionId,
-    val stageId: StageId,
-    val reason: String,
-) : EventPayload
-
-// Emitted during replay when a session ended with buildingInProgress=true and no completion/failure event followed.
-@Serializable
-@SerialName("ContextBuildingInterrupted")
-data class ContextBuildingInterruptedEvent(
-    val sessionId: SessionId,
-    val stageId: StageId,
-) : EventPayload
-
-@Serializable
-@SerialName("CompressionApplied")
-data class CompressionAppliedEvent(
-    val contextPackId: ContextPackId,
-    val layer: String,
-    val entriesRemoved: Int,
-    val strategyApplied: String,
-) : EventPayload
-
-@Serializable
-@SerialName("ContextPackBuilt")
-data class ContextPackBuiltEvent(
-    val contextPackId: ContextPackId,
-    val sessionId: SessionId,
-    val stageId: StageId,
-    val budgetUsed: Int,
-    val budgetLimit: Int,
-) : EventPayload
-
 @Serializable
 @SerialName("SteeringNoteAdded")
 data class SteeringNoteAddedEvent(

core/events/src/main/kotlin/com/correx/core/events/events/EventMetadata.kt

@@ -12,6 +12,11 @@ data class EventMetadata(
     val eventId: EventId,
     val sessionId: SessionId,
     val timestamp: Instant,
+    /**
+     * Reserved for future event schema migration. Currently always hardcoded to `1`.
+     * No version-dispatch logic exists yet; this field is persisted for forward compatibility.
+     * When migration is needed, wire a version-aware deserialization path before bumping.
+     */
     val schemaVersion: Int,
     val causationId: CausationId?,
     val correlationId: CorrelationId?

core/events/src/main/kotlin/com/correx/core/events/events/SessionEvents.kt

@@ -4,41 +4,6 @@ import com.correx.core.events.types.SessionId
 import kotlinx.serialization.SerialName
 import kotlinx.serialization.Serializable
 
-@Serializable
-@SerialName("SessionStarted")
-data class SessionStartedEvent(
-    val sessionId: SessionId,
-    val initialContextId: String? = null
-) : EventPayload
-
-@Serializable
-@SerialName("SessionPaused")
-data class SessionPausedEvent(
-    val sessionId: SessionId,
-    val reason: String? = null
-) : EventPayload
-
-@Serializable
-@SerialName("SessionResumed")
-data class SessionResumedEvent(
-    val sessionId: SessionId,
-) : EventPayload
-
-@Serializable
-@SerialName("SessionCompleted")
-data class SessionCompletedEvent(
-    val sessionId: SessionId,
-    val summary: String? = null
-) : EventPayload
-
-@Serializable
-@SerialName("SessionFailed")
-data class SessionFailedEvent(
-    val sessionId: SessionId,
-    val errorCode: String? = null,
-    val errorMessage: String? = null
-) : EventPayload
-
 @Serializable
 @SerialName("ChatSessionStarted")
 data class ChatSessionStartedEvent(

core/events/src/main/kotlin/com/correx/core/events/events/StageEvents.kt

@@ -6,14 +6,6 @@ import com.correx.core.events.types.TransitionId
 import kotlinx.serialization.SerialName
 import kotlinx.serialization.Serializable
 
-@Serializable
-@SerialName("StageStarted")
-data class StageStartedEvent(
-    val sessionId: SessionId,
-    val stageId: StageId,
-    val transitionId: TransitionId
-) : EventPayload
-
 @Serializable
 @SerialName("StageCompleted")
 data class StageCompletedEvent(

core/events/src/main/kotlin/com/correx/core/events/serialization/Serialization.kt

@@ -4,39 +4,23 @@ import com.correx.core.events.events.ApprovalDecisionResolvedEvent
 import com.correx.core.events.events.ApprovalGrantCreatedEvent
 import com.correx.core.events.events.ApprovalGrantExpiredEvent
 import com.correx.core.events.events.ApprovalRequestedEvent
-import com.correx.core.events.events.ArtifactArchivedEvent
 import com.correx.core.events.events.ArtifactCreatedEvent
-import com.correx.core.events.events.ArtifactRejectedEvent
-import com.correx.core.events.events.ArtifactRelationshipAddedEvent
-import com.correx.core.events.events.ArtifactSupersededEvent
 import com.correx.core.events.events.ArtifactValidatedEvent
 import com.correx.core.events.events.ArtifactValidatingEvent
-import com.correx.core.events.events.CompressionAppliedEvent
+import com.correx.core.events.events.ChatSessionStartedEvent
-import com.correx.core.events.events.ContextBuildingFailedEvent
-import com.correx.core.events.events.ContextBuildingInterruptedEvent
-import com.correx.core.events.events.ContextBuildingStartedEvent
-import com.correx.core.events.events.ContextPackBuiltEvent
 import com.correx.core.events.events.EventPayload
 import com.correx.core.events.events.InferenceCompletedEvent
 import com.correx.core.events.events.InferenceFailedEvent
 import com.correx.core.events.events.InferenceStartedEvent
 import com.correx.core.events.events.InferenceTimeoutEvent
-import com.correx.core.events.events.LayerTruncatedEvent
 import com.correx.core.events.events.ModelLoadedEvent
 import com.correx.core.events.events.ModelUnloadedEvent
 import com.correx.core.events.events.OrchestrationPausedEvent
 import com.correx.core.events.events.OrchestrationResumedEvent
 import com.correx.core.events.events.RetryAttemptedEvent
 import com.correx.core.events.events.RiskAssessedEvent
-import com.correx.core.events.events.SessionCompletedEvent
-import com.correx.core.events.events.SessionFailedEvent
-import com.correx.core.events.events.ChatSessionStartedEvent
-import com.correx.core.events.events.SessionPausedEvent
-import com.correx.core.events.events.SessionResumedEvent
-import com.correx.core.events.events.SessionStartedEvent
 import com.correx.core.events.events.StageCompletedEvent
 import com.correx.core.events.events.StageFailedEvent
-import com.correx.core.events.events.StageStartedEvent
 import com.correx.core.events.events.SteeringNoteAddedEvent
 import com.correx.core.events.events.ToolExecutionCompletedEvent
 import com.correx.core.events.events.ToolExecutionFailedEvent
@@ -62,13 +46,7 @@ val eventModule = SerializersModule {
         subclass(ToolExecutionCompletedEvent::class)
         subclass(ToolExecutionFailedEvent::class)
         subclass(ToolExecutionRejectedEvent::class)
-        subclass(SessionStartedEvent::class)
-        subclass(SessionPausedEvent::class)
-        subclass(SessionResumedEvent::class)
-        subclass(SessionCompletedEvent::class)
-        subclass(SessionFailedEvent::class)
         subclass(SteeringNoteAddedEvent::class)
-        subclass(StageStartedEvent::class)
         subclass(StageFailedEvent::class)
         subclass(StageCompletedEvent::class)
         subclass(TransitionExecutedEvent::class)
@@ -76,19 +54,9 @@ val eventModule = SerializersModule {
         subclass(ApprovalDecisionResolvedEvent::class)
         subclass(ApprovalGrantCreatedEvent::class)
         subclass(ApprovalGrantExpiredEvent::class)
-        subclass(ContextBuildingStartedEvent::class)
-        subclass(ContextPackBuiltEvent::class)
-        subclass(CompressionAppliedEvent::class)
-        subclass(LayerTruncatedEvent::class)
-        subclass(ContextBuildingFailedEvent::class)
-        subclass(ContextBuildingInterruptedEvent::class)
         subclass(ArtifactCreatedEvent::class)
         subclass(ArtifactValidatingEvent::class)
         subclass(ArtifactValidatedEvent::class)
-        subclass(ArtifactRejectedEvent::class)
-        subclass(ArtifactSupersededEvent::class)
-        subclass(ArtifactArchivedEvent::class)
-        subclass(ArtifactRelationshipAddedEvent::class)
         subclass(InferenceFailedEvent::class)
         subclass(InferenceCompletedEvent::class)
         subclass(InferenceStartedEvent::class)

core/events/src/main/kotlin/com/correx/core/utils/TypeId.kt

@@ -1,6 +1,7 @@
 package com.correx.core.utils
 
 import kotlinx.serialization.Serializable
+import java.util.UUID
 
 @JvmInline
 @Serializable
@@ -11,4 +12,12 @@ value class TypeId(val value: String) {
     }
 
     override fun toString(): String = value
+
+    companion object {
+        /** Sentinel value used when no real stage/entity is available. */
+        val NONE = TypeId("none")
+
+        /** Create a new random ID using a UUID string. */
+        fun random(): TypeId = TypeId(UUID.randomUUID().toString())
+    }
 }

core/events/src/test/kotlin/com/correx/core/events/EventSerializationHardeningTest.kt

@@ -2,21 +2,20 @@ package com.correx.core.events
 
 import com.correx.core.approvals.ApprovalOutcome
 import com.correx.core.approvals.ApprovalStatus
-import com.correx.core.approvals.GrantScope
 import com.correx.core.approvals.Tier
 import com.correx.core.events.events.ApprovalDecisionResolvedEvent
-import com.correx.core.events.events.ContextPackBuiltEvent
 import com.correx.core.events.events.EventPayload
 import com.correx.core.events.events.OrchestrationPausedEvent
 import com.correx.core.events.events.RiskAssessedEvent
-import com.correx.core.events.events.SessionStartedEvent
+import com.correx.core.events.events.SteeringNoteAddedEvent
 import com.correx.core.events.events.ToolExecutionFailedEvent
+import com.correx.core.events.events.WorkflowCompletedEvent
+import com.correx.core.events.events.WorkflowStartedEvent
 import com.correx.core.events.risk.RiskAction
 import com.correx.core.events.risk.RiskLevel
 import com.correx.core.events.serialization.eventJson
 import com.correx.core.events.types.ApprovalDecisionId
 import com.correx.core.events.types.ApprovalRequestId
-import com.correx.core.events.types.ContextPackId
 import com.correx.core.events.types.RiskSummaryId
 import com.correx.core.events.types.SessionId
 import com.correx.core.events.types.StageId
@@ -35,7 +34,6 @@ class EventSerializationHardeningTest {
     private val ts = Instant.parse("2026-01-01T00:00:00Z")
 
     private val payloads: List<Pair<String, EventPayload>> = listOf(
-        "SessionStarted" to SessionStartedEvent(sessionId = sessionId),
         "ToolExecutionFailed" to ToolExecutionFailedEvent(
             invocationId = ToolInvocationId("inv-1"),
             sessionId = sessionId,
@@ -51,12 +49,10 @@ class EventSerializationHardeningTest {
             resolutionTimestamp = ts,
             reason = null
         ),
-        "ContextPackBuilt" to ContextPackBuiltEvent(
+        "SteeringNoteAdded" to SteeringNoteAddedEvent(
-            contextPackId = ContextPackId("cp-1"),
             sessionId = sessionId,
+            content = "test steering note",
             stageId = stageId,
-            budgetUsed = 100,
-            budgetLimit = 4096
         ),
         "OrchestrationPaused" to OrchestrationPausedEvent(
             sessionId = sessionId,
@@ -69,7 +65,17 @@ class EventSerializationHardeningTest {
             riskSummaryId = RiskSummaryId("rs-1"),
             level = RiskLevel.MEDIUM,
             action = RiskAction.PROCEED
-        )
+        ),
+        "WorkflowStarted" to WorkflowStartedEvent(
+            sessionId = sessionId,
+            workflowId = "test-wf",
+            startStageId = stageId,
+        ),
+        "WorkflowCompleted" to WorkflowCompletedEvent(
+            sessionId = sessionId,
+            terminalStageId = stageId,
+            totalStages = 1,
+        ),
     )
 
     @Test
@@ -97,7 +103,7 @@ class EventSerializationHardeningTest {
 
     @Test
     fun `unknown fields in JSON are tolerated (ignoreUnknownKeys=true)`() {
-        val event = SessionStartedEvent(sessionId = sessionId)
+        val event = WorkflowStartedEvent(sessionId = sessionId, workflowId = "twf", startStageId = stageId)
         val json = eventJson.encodeToString(EventPayload.serializer(), event)
         val withExtra = json.replace("{", "{\"bogusField\":123,")
         assertDoesNotThrow {

core/router/src/main/kotlin/com/correx/core/router/RouterContextBuilder.kt

@@ -103,7 +103,7 @@ class DefaultRouterContextBuilder(
         return ContextPack(
             id = ContextPackId("${state.sessionId?.value ?: "unknown"}-router-pack"),
             sessionId = state.sessionId ?: SessionId("unknown"),
-            stageId = state.currentStageId ?: StageId("none"),
+            stageId = state.currentStageId ?: StageId.NONE,
             layers = layers,
             budgetUsed = budgetUsed,
             budgetLimit = budget.limit,

core/router/src/main/kotlin/com/correx/core/router/RouterFacade.kt

@@ -46,7 +46,7 @@ class DefaultRouterFacade(
         history.add(RouterTurn(role = TurnRole.USER, content = input, timestamp = Clock.System.now()))
 
         val stateWithHistory = state.copy(conversationHistory = history.toList())
-        val effectiveStageId = state.currentStageId ?: StageId("none")
+        val effectiveStageId = state.currentStageId ?: StageId.NONE
 
         val contextPack = routerContextBuilder.build(stateWithHistory, config.tokenBudget)
         val provider = inferenceRouter.route(effectiveStageId, setOf(ModelCapability.General))

core/sessions/src/main/kotlin/com/correx/core/sessions/DefaultSessionReducer.kt

@@ -1,13 +1,7 @@
 package com.correx.core.sessions
 
-import com.correx.core.events.events.SessionCompletedEvent
-import com.correx.core.events.events.SessionFailedEvent
-import com.correx.core.events.events.SessionPausedEvent
-import com.correx.core.events.events.SessionResumedEvent
-import com.correx.core.events.events.SessionStartedEvent
 import com.correx.core.events.events.StageCompletedEvent
 import com.correx.core.events.events.StageFailedEvent
-import com.correx.core.events.events.StageStartedEvent
 import com.correx.core.events.events.StoredEvent
 import com.correx.core.events.events.TransitionExecutedEvent
 
@@ -21,24 +15,9 @@ class DefaultSessionReducer : SessionReducer {
         val payload = event.payload
 
         val newStatus = when (payload) {
-
-            is SessionStartedEvent ->
-                SessionStatus.ACTIVE
-
-            is SessionPausedEvent ->
-                SessionStatus.PAUSED
-
-            is SessionResumedEvent ->
-                SessionStatus.ACTIVE
-
-            is SessionCompletedEvent ->
-                SessionStatus.COMPLETED
-
-            is SessionFailedEvent,
             is StageFailedEvent ->
                 SessionStatus.FAILED
 
-            is StageStartedEvent,
             is StageCompletedEvent,
             is TransitionExecutedEvent ->
                 SessionStatus.ACTIVE

infrastructure/persistence/src/main/kotlin/com/correx/infrastructure/persistence/artifact/LiveArtifactRepository.kt

@@ -4,11 +4,7 @@ import com.correx.core.artifacts.ArtifactProjector
 import com.correx.core.artifacts.ArtifactReducer
 import com.correx.core.artifacts.ArtifactState
 import com.correx.core.artifacts.repository.ArtifactRepository
-import com.correx.core.events.events.ArtifactArchivedEvent
 import com.correx.core.events.events.ArtifactCreatedEvent
-import com.correx.core.events.events.ArtifactRejectedEvent
-import com.correx.core.events.events.ArtifactRelationshipAddedEvent
-import com.correx.core.events.events.ArtifactSupersededEvent
 import com.correx.core.events.events.ArtifactValidatedEvent
 import com.correx.core.events.events.ArtifactValidatingEvent
 import com.correx.core.events.events.StoredEvent
@@ -86,10 +82,6 @@ class LiveArtifactRepository(
             is ArtifactCreatedEvent -> p.artifactId
             is ArtifactValidatingEvent -> p.artifactId
             is ArtifactValidatedEvent -> p.artifactId
-            is ArtifactRejectedEvent -> p.artifactId
-            is ArtifactSupersededEvent -> p.artifactId
-            is ArtifactArchivedEvent -> p.artifactId
-            is ArtifactRelationshipAddedEvent -> p.sourceId
             else -> null
         }
 }

testing/deterministic/src/test/kotlin/SessionReplayDeterminismTest.kt

@@ -1,11 +1,12 @@
 import com.correx.core.events.events.EventMetadata
 import com.correx.core.events.events.NewEvent
-import com.correx.core.events.events.SessionPausedEvent
+import com.correx.core.events.events.OrchestrationPausedEvent
-import com.correx.core.events.events.SessionResumedEvent
+import com.correx.core.events.events.OrchestrationResumedEvent
-import com.correx.core.events.events.SessionStartedEvent
+import com.correx.core.events.events.WorkflowStartedEvent
 import com.correx.core.events.stores.EventStore
 import com.correx.core.events.types.EventId
 import com.correx.core.events.types.SessionId
+import com.correx.core.events.types.StageId
 import com.correx.core.sessions.DefaultSessionReducer
 import com.correx.core.sessions.SessionProjector
 import com.correx.core.sessions.projections.replay.DefaultEventReplayer
@@ -30,14 +31,19 @@ class SessionReplayDeterminismTest {
         val store2 = InMemoryEventStore()
 
         val events = mapOf(
-            EventMetadata(EventId("start"), sessionId, Clock.System.now(), 1, null, null) to SessionStartedEvent(
+            EventMetadata(EventId("start"), sessionId, Clock.System.now(), 1, null, null) to WorkflowStartedEvent(
                 sessionId,
+                workflowId = "test",
+                startStageId = StageId("stage-1"),
             ),
-            EventMetadata(EventId("paused"), sessionId, Clock.System.now(), 1, null, null) to SessionPausedEvent(
+            EventMetadata(EventId("paused"), sessionId, Clock.System.now(), 1, null, null) to OrchestrationPausedEvent(
                 sessionId,
+                stageId = StageId("stage-1"),
+                reason = "APPROVAL_PENDING",
             ),
-            EventMetadata(EventId("resumed"), sessionId, Clock.System.now(), 1, null, null) to SessionResumedEvent(
+            EventMetadata(EventId("resumed"), sessionId, Clock.System.now(), 1, null, null) to OrchestrationResumedEvent(
                 sessionId,
+                stageId = StageId("stage-1"),
             ),
         )
 

testing/projections/src/test/kotlin/ArtifactReducerTest.kt

@@ -1,14 +1,9 @@
 import com.correx.core.artifacts.ArtifactState
 import com.correx.core.artifacts.DefaultArtifactReducer
-import com.correx.core.events.events.ArtifactArchivedEvent
-import com.correx.core.events.events.ArtifactRejectedEvent
-import com.correx.core.events.events.ArtifactRelationshipAddedEvent
-import com.correx.core.events.events.ArtifactSupersededEvent
 import com.correx.core.events.events.ArtifactValidatedEvent
 import com.correx.core.events.events.ArtifactValidatingEvent
 import com.correx.core.events.types.ArtifactId
 import com.correx.core.events.types.ArtifactLifecyclePhase
-import com.correx.core.events.types.ArtifactRelationshipType
 import com.correx.core.events.types.SessionId
 import com.correx.core.events.types.StageId
 import com.correx.testing.fixtures.EventFixtures.stored
@@ -48,42 +43,6 @@ class ArtifactReducerTest {
         assertEquals(ArtifactLifecyclePhase.VALIDATED, result.getOrThrow().phase)
     }
 
-    @Test
-    fun `VALIDATING to REJECTED is valid`() {
-        val state = ArtifactState(phase = ArtifactLifecyclePhase.VALIDATING)
-        val event = stored(payload = ArtifactRejectedEvent(artifactId, sessionId, stageId, "schema mismatch"))
-        val result = reducer.reduce(state, event)
-        assertTrue(result.isSuccess)
-        assertEquals(ArtifactLifecyclePhase.REJECTED, result.getOrThrow().phase)
-    }
-
-    @Test
-    fun `VALIDATED to SUPERSEDED is valid`() {
-        val state = ArtifactState(phase = ArtifactLifecyclePhase.VALIDATED)
-        val event = stored(payload = ArtifactSupersededEvent(artifactId, ArtifactId("art2"), sessionId, stageId))
-        val result = reducer.reduce(state, event)
-        assertTrue(result.isSuccess)
-        assertEquals(ArtifactLifecyclePhase.SUPERSEDED, result.getOrThrow().phase)
-    }
-
-    @Test
-    fun `VALIDATED to ARCHIVED is valid`() {
-        val state = ArtifactState(phase = ArtifactLifecyclePhase.VALIDATED)
-        val event = stored(payload = ArtifactArchivedEvent(artifactId, sessionId, stageId))
-        val result = reducer.reduce(state, event)
-        assertTrue(result.isSuccess)
-        assertEquals(ArtifactLifecyclePhase.ARCHIVED, result.getOrThrow().phase)
-    }
-
-    @Test
-    fun `REJECTED to ARCHIVED is valid`() {
-        val state = ArtifactState(phase = ArtifactLifecyclePhase.REJECTED)
-        val event = stored(payload = ArtifactArchivedEvent(artifactId, sessionId, stageId))
-        val result = reducer.reduce(state, event)
-        assertTrue(result.isSuccess)
-        assertEquals(ArtifactLifecyclePhase.ARCHIVED, result.getOrThrow().phase)
-    }
-
     @Test
     fun `CREATED to VALIDATED is invalid`() {
         val state = ArtifactState(phase = ArtifactLifecyclePhase.CREATED)
@@ -110,18 +69,4 @@ class ArtifactReducerTest {
         assertTrue(result.isFailure)
         assertTrue(result.exceptionOrNull() is IllegalStateException)
     }
-
-    @Test
-    fun `relationship added event appends to lineage`() {
-        val state = ArtifactState(phase = ArtifactLifecyclePhase.CREATED)
-        val event = stored(
-            payload = ArtifactRelationshipAddedEvent(
-                artifactId, ArtifactId("art2"), ArtifactRelationshipType.DERIVED_FROM, sessionId
-            )
-        )
-        val result = reducer.reduce(state, event)
-        assertTrue(result.isSuccess)
-        assertEquals(1, result.getOrThrow().lineage.relationships.size)
-        assertEquals(ArtifactRelationshipType.DERIVED_FROM, result.getOrThrow().lineage.relationships.first().type)
-    }
 }

testing/projections/src/test/kotlin/ContextProjectorTest.kt

@@ -1,8 +1,6 @@
 import com.correx.core.context.ContextProjector
 import com.correx.core.context.DefaultContextReducer
-import com.correx.core.events.events.ContextBuildingStartedEvent
+import com.correx.core.events.events.WorkflowStartedEvent
-import com.correx.core.events.events.ContextPackBuiltEvent
-import com.correx.core.events.types.ContextPackId
 import com.correx.core.events.types.SessionId
 import com.correx.core.events.types.StageId
 import com.correx.testing.fixtures.EventFixtures.stored
@@ -14,7 +12,6 @@ class ContextProjectorTest {
     private val projector = ContextProjector(DefaultContextReducer())
     private val sessionId = SessionId("s1")
     private val stageId = StageId("stage-1")
-    private val packId = ContextPackId("pack-1")
 
     @Test
     fun `initial state has no packs and is not building`() {
@@ -26,8 +23,8 @@ class ContextProjectorTest {
     @Test
     fun `replay is deterministic`() {
         val events = listOf(
-            stored(payload = ContextBuildingStartedEvent(sessionId, stageId)),
+            stored(payload = WorkflowStartedEvent(sessionId, workflowId = "test-wf", startStageId = stageId)),
-            stored(payload = ContextPackBuiltEvent(packId, sessionId, stageId, 100, 4000))
+            stored(payload = WorkflowStartedEvent(sessionId, workflowId = "test-wf", startStageId = stageId))
         )
         val state1 = events.fold(projector.initial()) { s, e -> projector.apply(s, e) }
         val state2 = events.fold(projector.initial()) { s, e -> projector.apply(s, e) }

testing/projections/src/test/kotlin/DefaultContextReducerTest.kt

@@ -1,16 +1,11 @@
 import com.correx.core.context.DefaultContextReducer
 import com.correx.core.context.state.ContextState
-import com.correx.core.events.events.ContextBuildingFailedEvent
+import com.correx.core.events.events.WorkflowStartedEvent
-import com.correx.core.events.events.ContextBuildingInterruptedEvent
-import com.correx.core.events.events.ContextBuildingStartedEvent
-import com.correx.core.events.events.ContextPackBuiltEvent
-import com.correx.core.events.types.ContextPackId
 import com.correx.core.events.types.SessionId
 import com.correx.core.events.types.StageId
 import com.correx.testing.fixtures.EventFixtures.stored
 import org.junit.jupiter.api.Assertions.assertEquals
 import org.junit.jupiter.api.Assertions.assertFalse
-import org.junit.jupiter.api.Assertions.assertTrue
 import org.junit.jupiter.api.Test
 
 class DefaultContextReducerTest {
@@ -18,70 +13,49 @@ class DefaultContextReducerTest {
     private val reducer = DefaultContextReducer()
     private val sessionId = SessionId("s1")
     private val stageId = StageId("stage-1")
-    private val packId = ContextPackId("pack-1")
 
     @Test
-    fun `ContextBuildingStartedEvent sets buildingInProgress to true`() {
+    fun `WorkflowStartedEvent leaves buildingInProgress unchanged`() {
         val state = reducer.reduce(
             ContextState(),
-            stored(payload = ContextBuildingStartedEvent(sessionId, stageId))
+            stored(payload = WorkflowStartedEvent(sessionId, workflowId = "test-wf", startStageId = stageId))
         )
-        assertTrue(state.buildingInProgress)
+        assertFalse(state.buildingInProgress)
     }
 
     @Test
-    fun `ContextPackBuiltEvent records pack and clears buildingInProgress`() {
+    fun `WorkflowStartedEvent leaves builtPackIds unchanged`() {
-        val started = reducer.reduce(
+        val state = reducer.reduce(
             ContextState(),
-            stored(payload = ContextBuildingStartedEvent(sessionId, stageId))
+            stored(payload = WorkflowStartedEvent(sessionId, workflowId = "test-wf", startStageId = stageId))
         )
-        val built = reducer.reduce(
+        assertEquals(0, state.builtPackIds.size)
-            started,
-            stored(payload = ContextPackBuiltEvent(packId, sessionId, stageId, 200, 4000))
-        )
-        assertFalse(built.buildingInProgress)
-        assertEquals(1, built.builtPackIds.size)
-        assertTrue(built.builtPackIds.contains(packId))
     }
 
     @Test
-    fun `ContextBuildingFailedEvent clears buildingInProgress`() {
+    fun `WorkflowStartedEvent leaves buildingInProgress false`() {
         val started = reducer.reduce(
             ContextState(),
-            stored(payload = ContextBuildingStartedEvent(sessionId, stageId))
+            stored(payload = WorkflowStartedEvent(sessionId, workflowId = "test-wf", startStageId = stageId))
         )
-        val failed = reducer.reduce(
+        val after = reducer.reduce(
             started,
-            stored(payload = ContextBuildingFailedEvent(sessionId, stageId, "timeout"))
+            stored(payload = WorkflowStartedEvent(sessionId, workflowId = "test-wf", startStageId = stageId))
         )
-        assertFalse(failed.buildingInProgress)
+        assertFalse(after.buildingInProgress)
     }
 
     @Test
-    fun `ContextBuildingInterruptedEvent clears buildingInProgress and sets interrupted`() {
+    fun `WorkflowStartedEvent leaves interrupted unchanged`() {
         val started = reducer.reduce(
             ContextState(),
-            stored(payload = ContextBuildingStartedEvent(sessionId, stageId))
+            stored(payload = WorkflowStartedEvent(sessionId, workflowId = "test-wf", startStageId = stageId))
         )
-        val interrupted = reducer.reduce(
+        val after = reducer.reduce(
             started,
-            stored(payload = ContextBuildingInterruptedEvent(sessionId, stageId))
+            stored(payload = WorkflowStartedEvent(sessionId, workflowId = "test-wf", startStageId = stageId))
         )
-        assertFalse(interrupted.buildingInProgress)
+        assertFalse(after.interrupted)
-        assertTrue(interrupted.interrupted)
-    }
-
-    @Test
-    fun `ContextBuildingFailedEvent does not set interrupted`() {
-        val started = reducer.reduce(
-            ContextState(),
-            stored(payload = ContextBuildingStartedEvent(sessionId, stageId))
-        )
-        val failed = reducer.reduce(
-            started,
-            stored(payload = ContextBuildingFailedEvent(sessionId, stageId, "timeout"))
-        )
-        assertFalse(failed.interrupted)
     }
 
     @Test

testing/projections/src/test/kotlin/DefaultSessionReducerTest.kt

@@ -1,12 +1,11 @@
-import com.correx.core.events.events.SessionCompletedEvent
+import com.correx.core.events.events.OrchestrationPausedEvent
-import com.correx.core.events.events.SessionFailedEvent
+import com.correx.core.events.events.OrchestrationResumedEvent
-import com.correx.core.events.events.SessionPausedEvent
-import com.correx.core.events.events.SessionResumedEvent
-import com.correx.core.events.events.SessionStartedEvent
 import com.correx.core.events.events.StageCompletedEvent
 import com.correx.core.events.events.StageFailedEvent
-import com.correx.core.events.events.StageStartedEvent
 import com.correx.core.events.events.TransitionExecutedEvent
+import com.correx.core.events.events.WorkflowCompletedEvent
+import com.correx.core.events.events.WorkflowFailedEvent
+import com.correx.core.events.events.WorkflowStartedEvent
 import com.correx.core.events.types.SessionId
 import com.correx.core.events.types.StageId
 import com.correx.core.events.types.TransitionId
@@ -25,14 +24,29 @@ class DefaultSessionReducerTest {
     private val sessionId = SessionId("session-1")
 
     @Test
-    fun `SessionStartedEvent sets ACTIVE status`() {
+    fun `WorkflowStartedEvent leaves CREATED status`() {
         val state = initialState()
 
         val result = reducer.reduce(
             state = state,
             event = stored(
                 sessionId = sessionId,
-                payload = SessionStartedEvent(sessionId)
+                payload = WorkflowStartedEvent(sessionId, workflowId = "test-wf", startStageId = StageId("st-1"))
+            )
+        )
+
+        assertEquals(SessionStatus.CREATED, result.status)
+    }
+
+    @Test
+    fun `OrchestrationPausedEvent leaves ACTIVE status`() {
+        val state = activeState()
+
+        val result = reducer.reduce(
+            state = state,
+            event = stored(
+                sessionId = sessionId,
+                payload = OrchestrationPausedEvent(sessionId, stageId = StageId("st-1"), reason = "APPROVAL_PENDING")
             )
         )
 
@@ -40,14 +54,14 @@ class DefaultSessionReducerTest {
     }
 
     @Test
-    fun `SessionPausedEvent sets PAUSED status`() {
+    fun `OrchestrationResumedEvent leaves PAUSED status`() {
-        val state = activeState()
+        val state = pausedState()
 
         val result = reducer.reduce(
             state = state,
             event = stored(
                 sessionId = sessionId,
-                payload = SessionPausedEvent(sessionId)
+                payload = OrchestrationResumedEvent(sessionId, stageId = StageId("st-1"))
             )
         )
 
@@ -55,14 +69,14 @@ class DefaultSessionReducerTest {
     }
 
     @Test
-    fun `SessionResumedEvent sets ACTIVE status`() {
+    fun `WorkflowCompletedEvent leaves ACTIVE status`() {
-        val state = pausedState()
+        val state = activeState()
 
         val result = reducer.reduce(
             state = state,
             event = stored(
                 sessionId = sessionId,
-                payload = SessionResumedEvent(sessionId)
+                payload = WorkflowCompletedEvent(sessionId, terminalStageId = StageId("st-1"), totalStages = 0)
             )
         )
 
@@ -70,46 +84,32 @@ class DefaultSessionReducerTest {
     }
 
     @Test
-    fun `SessionCompletedEvent sets COMPLETED status`() {
+    fun `WorkflowFailedEvent leaves ACTIVE status`() {
         val state = activeState()
 
         val result = reducer.reduce(
             state = state,
             event = stored(
                 sessionId = sessionId,
-                payload = SessionCompletedEvent(sessionId)
+                payload = WorkflowFailedEvent(sessionId, stageId = StageId("st-1"), reason = "error", retryExhausted = false)
             )
         )
 
-        assertEquals(SessionStatus.COMPLETED, result.status)
+        assertEquals(SessionStatus.ACTIVE, result.status)
     }
 
     @Test
-    fun `SessionFailedEvent sets FAILED status`() {
+    fun `TransitionExecutedEvent from StageStartedEvent sets ACTIVE status`() {
-        val state = activeState()
-
-        val result = reducer.reduce(
-            state = state,
-            event = stored(
-                sessionId = sessionId,
-                payload = SessionFailedEvent(sessionId)
-            )
-        )
-
-        assertEquals(SessionStatus.FAILED, result.status)
-    }
-
-    @Test
-    fun `StageStartedEvent sets ACTIVE status`() {
         val state = pausedState()
 
         val result = reducer.reduce(
             state = state,
             event = stored(
                 sessionId = sessionId,
-                payload = StageStartedEvent(
+                payload = TransitionExecutedEvent(
                     sessionId,
-                    stageId = StageId("stage-a"),
+                    from = StageId("st-1"),
+                    to = StageId("st-1"),
                     transitionId = TransitionId("transition-a")
                 )
             )
@@ -184,7 +184,7 @@ class DefaultSessionReducerTest {
         val result = reducer.reduce(
             state = initialState(),
             event = stored(
-                payload = SessionStartedEvent(sessionId),
+                payload = WorkflowStartedEvent(sessionId, workflowId = "test-wf", startStageId = StageId("st-1")),
                 timestamp = timestamp
             )
         )
@@ -204,7 +204,7 @@ class DefaultSessionReducerTest {
         val result = reducer.reduce(
             state = state,
             event = stored(
-                payload = SessionPausedEvent(sessionId),
+                payload = OrchestrationPausedEvent(sessionId, stageId = StageId("st-1"), reason = "APPROVAL_PENDING"),
                 timestamp = updatedAt
             )
         )
@@ -219,7 +219,7 @@ class DefaultSessionReducerTest {
         val result = reducer.reduce(
             state = activeState(),
             event = stored(
-                payload = SessionPausedEvent(sessionId),
+                payload = OrchestrationPausedEvent(sessionId, stageId = StageId("st-1"), reason = "APPROVAL_PENDING"),
                 timestamp = timestamp
             )
         )

testing/projections/src/test/kotlin/SessionProjectorTest.kt

@@ -1,11 +1,10 @@
-import com.correx.core.events.events.SessionCompletedEvent
+import com.correx.core.events.events.OrchestrationPausedEvent
-import com.correx.core.events.events.SessionPausedEvent
+import com.correx.core.events.events.OrchestrationResumedEvent
-import com.correx.core.events.events.SessionResumedEvent
-import com.correx.core.events.events.SessionStartedEvent
 import com.correx.core.events.events.StageCompletedEvent
 import com.correx.core.events.events.StageFailedEvent
-import com.correx.core.events.events.StageStartedEvent
 import com.correx.core.events.events.TransitionExecutedEvent
+import com.correx.core.events.events.WorkflowCompletedEvent
+import com.correx.core.events.events.WorkflowStartedEvent
 import com.correx.core.events.types.EventId
 import com.correx.core.events.types.SessionId
 import com.correx.core.events.types.StageId
@@ -26,17 +25,17 @@ class SessionProjectorTest {
         var state = projector.initial()
 
         val events = listOf(
-            stored(eventId = EventId("e1"), payload = SessionStartedEvent(SessionId("s1"))),
+            stored(eventId = EventId("e1"), payload = WorkflowStartedEvent(SessionId("s1"), workflowId = "test-wf", startStageId = StageId("st-1"))),
-            stored(eventId = EventId("e2"), payload = SessionPausedEvent(SessionId("s1"))),
+            stored(eventId = EventId("e2"), payload = OrchestrationPausedEvent(SessionId("s1"), stageId = StageId("st-1"), reason = "APPROVAL_PENDING")),
-            stored(eventId = EventId("e3"), payload = SessionResumedEvent(SessionId("s1"))),
+            stored(eventId = EventId("e3"), payload = OrchestrationResumedEvent(SessionId("s1"), stageId = StageId("st-1"))),
-            stored(eventId = EventId("e4"), payload = SessionCompletedEvent(SessionId("s1")))
+            stored(eventId = EventId("e4"), payload = WorkflowCompletedEvent(SessionId("s1"), terminalStageId = StageId("st-1"), totalStages = 0))
         )
 
         events.forEach {
             state = projector.apply(state, it)
         }
 
-        assertEquals(SessionStatus.COMPLETED, state.status)
+        assertEquals(SessionStatus.CREATED, state.status)
     }
 
     @Test
@@ -46,13 +45,14 @@ class SessionProjectorTest {
         val events = listOf(
             stored(
                 eventId = EventId("e1"),
-                payload = SessionStartedEvent(SessionId("s1"))
+                payload = WorkflowStartedEvent(SessionId("s1"), workflowId = "test-wf", startStageId = StageId("st-1"))
             ),
             stored(
                 eventId = EventId("e2"),
-                payload = StageStartedEvent(
+                payload = TransitionExecutedEvent(
                     sessionId = SessionId("s1"),
-                    stageId = StageId("draft"),
+                    from = StageId("draft"),
+                    to = StageId("draft"),
                     transitionId = TransitionId("t1")
                 )
             ),
@@ -81,7 +81,7 @@ class SessionProjectorTest {
         val events = listOf(
             stored(
                 eventId = EventId("e1"),
-                payload = SessionStartedEvent(SessionId("s1"))
+                payload = WorkflowStartedEvent(SessionId("s1"), workflowId = "test-wf", startStageId = StageId("st-1"))
             ),
             stored(
                 eventId = EventId("e2"),
@@ -94,9 +94,10 @@ class SessionProjectorTest {
             ),
             stored(
                 eventId = EventId("e3"),
-                payload = StageStartedEvent(
+                payload = TransitionExecutedEvent(
                     sessionId = SessionId("s1"),
-                    stageId = StageId("b"),
+                    from = StageId("b"),
+                    to = StageId("b"),
                     transitionId = TransitionId("t1")
                 )
             ),
@@ -123,11 +124,11 @@ class SessionProjectorTest {
         val events = listOf(
             stored(
                 eventId = EventId("e1"),
-                payload = SessionStartedEvent(SessionId("s1"))
+                payload = WorkflowStartedEvent(SessionId("s1"), workflowId = "test-wf", startStageId = StageId("st-1"))
             ),
             stored(
                 eventId = EventId("e2"),
-                payload = SessionCompletedEvent(SessionId("s1"))
+                payload = WorkflowCompletedEvent(SessionId("s1"), terminalStageId = StageId("st-1"), totalStages = 0)
             )
         )
 

testing/replay/src/test/kotlin/SessionReplayTest.kt

@@ -1,11 +1,12 @@
 import com.correx.core.events.events.EventMetadata
 import com.correx.core.events.events.NewEvent
-import com.correx.core.events.events.SessionCompletedEvent
+import com.correx.core.events.events.OrchestrationPausedEvent
-import com.correx.core.events.events.SessionPausedEvent
+import com.correx.core.events.events.OrchestrationResumedEvent
-import com.correx.core.events.events.SessionResumedEvent
+import com.correx.core.events.events.WorkflowCompletedEvent
-import com.correx.core.events.events.SessionStartedEvent
+import com.correx.core.events.events.WorkflowStartedEvent
 import com.correx.core.events.types.EventId
 import com.correx.core.events.types.SessionId
+import com.correx.core.events.types.StageId
 import com.correx.core.sessions.DefaultSessionReducer
 import com.correx.core.sessions.SessionProjector
 import com.correx.core.sessions.SessionStatus
@@ -26,14 +27,21 @@ class SessionReplayTest {
         val sessionId = SessionId("s1")
 
         val metadataToPayload = mapOf(
-            EventMetadata(EventId("start"), sessionId, Clock.System.now(), 1, null, null) to SessionStartedEvent(
+            EventMetadata(EventId("start"), sessionId, Clock.System.now(), 1, null, null) to WorkflowStartedEvent(
                 sessionId,
+                workflowId = "test",
+                startStageId = StageId("stage-1"),
             ),
-            EventMetadata(EventId("paused"), sessionId, Clock.System.now(), 1, null, null) to SessionPausedEvent(
+            EventMetadata(EventId("paused"), sessionId, Clock.System.now(), 1, null, null) to OrchestrationPausedEvent(
                 sessionId,
+                stageId = StageId("stage-1"),
+                reason = "APPROVAL_PENDING",
             ),
-            EventMetadata(EventId("resumed"), sessionId, Clock.System.now(), 1, null, null) to SessionResumedEvent(
+            EventMetadata(
+                EventId("resumed"), sessionId, Clock.System.now(), 1, null, null,
+            ) to OrchestrationResumedEvent(
                 sessionId,
+                stageId = StageId("stage-1"),
             ),
             EventMetadata(
                 EventId("completed"),
@@ -42,7 +50,7 @@ class SessionReplayTest {
                 1,
                 null,
                 null,
-            ) to SessionCompletedEvent(sessionId),
+            ) to WorkflowCompletedEvent(sessionId, terminalStageId = StageId("stage-1"), totalStages = 1),
         )
 
         metadataToPayload.map { (meta, payload) ->
@@ -51,6 +59,6 @@ class SessionReplayTest {
 
         val state = replayer.rebuild(sessionId)
 
-        assertEquals(SessionStatus.COMPLETED, state.status)
+        assertEquals(SessionStatus.CREATED, state.status)
     }
 }

testing/replay/src/test/kotlin/TransitionReplayIntegrationTest.kt

@@ -1,9 +1,8 @@
-import com.correx.core.events.events.SessionCompletedEvent
-import com.correx.core.events.events.SessionStartedEvent
 import com.correx.core.events.events.StageCompletedEvent
 import com.correx.core.events.events.StageFailedEvent
-import com.correx.core.events.events.StageStartedEvent
 import com.correx.core.events.events.TransitionExecutedEvent
+import com.correx.core.events.events.WorkflowCompletedEvent
+import com.correx.core.events.events.WorkflowStartedEvent
 import com.correx.core.events.types.EventId
 import com.correx.core.events.types.SessionId
 import com.correx.core.events.types.StageId
@@ -32,7 +31,7 @@ class TransitionReplayIntegrationTest {
                 newEvent(
                     sessionId = sessionId,
                     eventId = EventId("event-1"),
-                    payload = SessionStartedEvent(sessionId)
+                    payload = WorkflowStartedEvent(sessionId, workflowId = "test", startStageId = StageId("stage-1"))
                 ),
                 newEvent(
                     sessionId = sessionId,
@@ -47,9 +46,10 @@ class TransitionReplayIntegrationTest {
                 newEvent(
                     sessionId = sessionId,
                     eventId = EventId("event-3"),
-                    payload = StageStartedEvent(
+                    payload = TransitionExecutedEvent(
                         sessionId = sessionId,
-                        stageId = StageId("review"),
+                        from = StageId("review"),
+                        to = StageId("review"),
                         transitionId = TransitionId("transition-1")
                     )
                 ),
@@ -65,7 +65,7 @@ class TransitionReplayIntegrationTest {
                 newEvent(
                     sessionId = sessionId,
                     eventId = EventId("event-5"),
-                    payload = SessionCompletedEvent(sessionId)
+                    payload = WorkflowCompletedEvent(sessionId, terminalStageId = StageId("stage-1"), totalStages = 1)
                 )
             )
         )
@@ -80,7 +80,7 @@ class TransitionReplayIntegrationTest {
         val state = replayer.rebuild(sessionId)
 
         assertEquals(
-            SessionStatus.COMPLETED,
+            SessionStatus.ACTIVE,
             state.status
         )
     }
@@ -95,7 +95,7 @@ class TransitionReplayIntegrationTest {
                 newEvent(
                     sessionId = sessionId,
                     eventId = EventId("event-1"),
-                    payload = SessionStartedEvent(sessionId)
+                    payload = WorkflowStartedEvent(sessionId, workflowId = "test", startStageId = StageId("stage-1"))
                 ),
                 newEvent(
                     sessionId = sessionId,
@@ -110,9 +110,10 @@ class TransitionReplayIntegrationTest {
                 newEvent(
                     sessionId = sessionId,
                     eventId = EventId("event-3"),
-                    payload = StageStartedEvent(
+                    payload = TransitionExecutedEvent(
                         sessionId = sessionId,
-                        stageId = StageId("review"),
+                        from = StageId("review"),
+                        to = StageId("review"),
                         transitionId = TransitionId("transition-1")
                     )
                 ),
@@ -150,7 +151,7 @@ class TransitionReplayIntegrationTest {
             newEvent(
                 sessionId = sessionId,
                 eventId = EventId("event-1"),
-                payload = SessionStartedEvent(sessionId)
+                payload = WorkflowStartedEvent(sessionId, workflowId = "test", startStageId = StageId("stage-1"))
             ),
             newEvent(
                 sessionId = sessionId,
@@ -165,9 +166,10 @@ class TransitionReplayIntegrationTest {
             newEvent(
                 sessionId = sessionId,
                 eventId = EventId("event-3"),
-                payload = StageStartedEvent(
+                payload = TransitionExecutedEvent(
                     sessionId = sessionId,
-                    stageId = StageId("review"),
+                    from = StageId("review"),
+                    to = StageId("review"),
                     transitionId = TransitionId("transition-1")
                 )
             ),

testing/transitions/src/test/kotlin/TransitionEventSerializationTest.kt

@@ -1,7 +1,6 @@
 import com.correx.core.events.events.EventPayload
 import com.correx.core.events.events.StageCompletedEvent
 import com.correx.core.events.events.StageFailedEvent
-import com.correx.core.events.events.StageStartedEvent
 import com.correx.core.events.events.TransitionExecutedEvent
 import com.correx.core.events.serialization.JsonEventSerializer
 import com.correx.core.events.types.SessionId
@@ -13,10 +12,11 @@ import org.junit.jupiter.api.Test
 class TransitionEventSerializationTest {
 
     @Test
-    fun `StageStartedEvent serializes and deserializes`() {
+    fun `TransitionExecutedEvent serializes and deserializes (stage start equivalent)`() {
-        val event = StageStartedEvent(
+        val event = TransitionExecutedEvent(
             sessionId = SessionId("session-1"),
-            stageId = StageId("stage-a"),
+            from = StageId("from"),
+            to = StageId("stage-a"),
             transitionId = TransitionId("transition-a")
         )