feat(chat): support first-class /compress and /compact session compression (#1306)

app/src/main/java/com/m57/hermescontrol/data/model/SessionCompressModels.kt

@@ -0,0 +1,32 @@
+package com.m57.hermescontrol.data.model
+
+import kotlinx.serialization.Serializable
+import kotlinx.serialization.json.JsonElement
+
+@Serializable
+data class SessionCompressResponse(
+    val status: String? = null,
+    val removed: Int? = null,
+    val before_messages: Int? = null,
+    val after_messages: Int? = null,
+    val before_tokens: Long? = null,
+    val after_tokens: Long? = null,
+    val summary: CompressionSummary? = null,
+    val compressed: Boolean? = null,
+    val lock_held: Boolean? = null,
+    val message: String? = null,
+    val messages: List<SessionMessage>? = null,
+    val usage: JsonElement? = null,
+    val info: JsonElement? = null,
+)
+
+@Serializable
+data class CompressionSummary(
+    val noop: Boolean = false,
+    val aborted: Boolean = false,
+    val refused_would_grow: Boolean? = null,
+    val fallback_used: Boolean? = null,
+    val headline: String = "",
+    val token_line: String = "",
+    val note: String? = null,
+)

app/src/main/java/com/m57/hermescontrol/data/ws/CommandModels.kt

@@ -73,7 +73,6 @@ object CommandBlocklist {
             "/image",
             "/quit",
             // TUI-only extras (meaningless outside the TUI)
-            "/compact",
             "/logs",
             "/mouse",
         )

app/src/main/java/com/m57/hermescontrol/data/ws/WsMethods.kt

@@ -16,6 +16,7 @@ object WsMethods {
     const val SESSION_TITLE = "session.title"
     const val SESSION_BRANCH = "session.branch"
     const val SESSION_BRANCH_WHOLE = "session.branch_whole"
+    const val SESSION_COMPRESS = "session.compress"
 
     /** Replay recorded events newer than client's last-seen seq for a session. */
     const val SESSION_EVENTS_SINCE = "session.events.since"

app/src/main/java/com/m57/hermescontrol/ui/chat/ChatClarifyDelegate.kt

@@ -11,6 +11,21 @@ import kotlinx.serialization.json.JsonElement
 import kotlinx.serialization.json.buildJsonObject
 import kotlinx.serialization.json.put
 
+internal fun buildLegacyClarifyBatchResponses(
+    questions: List<ClarifyQuestionUi>,
+    answers: Map<String, String>,
+    lockedAnswers: Map<String, String>,
+): List<Pair<String, String>> =
+    questions
+        .asSequence()
+        // A replayed pending_clarify can contain answers already locked by the
+        // server. ClarifyBubble has no editable input for those rows, so its
+        // answer map carries an empty placeholder. Never send that placeholder
+        // back through legacy clarify.respond and overwrite accepted state.
+        .filterNot { it.qid in lockedAnswers }
+        .map { it.qid to answers[it.qid]?.trim().orEmpty() }
+        .toList()
+
 class ChatClarifyDelegate(
     private val uiState: MutableStateFlow<ChatUiState>,
     private val scope: CoroutineScope,
@@ -114,14 +129,17 @@ class ChatClarifyDelegate(
             }
 
             if (isBatch) {
-                for (q in questions) {
+                for ((questionId, ans) in buildLegacyClarifyBatchResponses(
-                    val ans = answers[q.qid]?.trim().orEmpty()
+                    questions = questions,
+                    answers = answers,
+                    lockedAnswers = lockedAnswers,
+                )) {
                     val params =
                         mutableMapOf<String, Any>(
                             "session_id" to sessionId,
                             "response" to ans,
                             "answer" to ans,
-                            "question_id" to q.qid,
+                            "question_id" to questionId,
                         )
                     if (clarifyId != null) {
                         params["clarify_id"] = clarifyId

app/src/main/java/com/m57/hermescontrol/ui/chat/ChatScreen.kt

@@ -807,6 +807,8 @@ fun ChatScreen(
                     onSaveAttachment = onSaveAttachment,
                     savingAttachmentPath = pendingSavePath ?: state.savingAttachmentPath,
                     openingAttachmentPath = state.openingAttachmentPath,
+                    isCompressing = state.isCompressing && !timelineState.isHistorical,
+                    compressionStatus = state.compressionStatus.takeUnless { timelineState.isHistorical },
                     onImageClick = { viewingImage = it },
                     speakingMessageId = speakingMessageId,
                     onToggleSpeak = { message ->

app/src/main/java/com/m57/hermescontrol/ui/chat/ChatViewModel.kt

@@ -14,6 +14,7 @@ import com.m57.hermescontrol.data.model.BusySendMode
 import com.m57.hermescontrol.data.model.ModelCapabilities
 import com.m57.hermescontrol.data.model.ModelProvider
 import com.m57.hermescontrol.data.model.PinnedModel
+import com.m57.hermescontrol.data.model.SessionCompressResponse
 import com.m57.hermescontrol.data.model.SessionTimelineEntry
 import com.m57.hermescontrol.data.model.UsageSnapshotResponse
 import com.m57.hermescontrol.data.model.parseContextBreakdown
@@ -234,6 +235,8 @@ data class ChatUiState(
     // until the first successful session.usage fetch) — drives the
     // "compressed ×N" badge on the context chip.
     val compressionCount: Int? = null,
+    val isCompressing: Boolean = false,
+    val compressionStatus: String? = null,
     /** Rolling output tokens/sec over the last ~10 calls. */
     val latestTps: Double? = null,
     /** Latest cumulative backend usage snapshot for the current session. */
@@ -3701,6 +3704,10 @@ class ChatViewModel(
                 handleUndoCommand(result.count)
             }
 
+            is SlashResult.Compress -> {
+                compressSession(result.focusTopic)
+            }
+
             is SlashResult.RpcDispatch -> {
                 dispatchViaRpc(command)
             }
@@ -4125,6 +4132,113 @@ class ChatViewModel(
         }
     }
 
+    private fun compressSession(focusTopic: String) {
+        val sessionId = runtimeSessionId ?: _uiState.value.currentSessionId
+        if (sessionId == null) {
+            addAssistantMessage("No active session to compress.")
+            return
+        }
+        if (_uiState.value.isCompressing) {
+            return
+        }
+
+        _uiState.update {
+            it.copy(
+                isCompressing = true,
+                compressionStatus = "⏳ Compressing context...",
+            )
+        }
+
+        viewModelScope.launch(ioDispatcher) {
+            try {
+                val params =
+                    buildMap<String, Any> {
+                        put("session_id", sessionId)
+                        if (focusTopic.isNotBlank()) {
+                            put("focus_topic", focusTopic)
+                        }
+                    }
+                // Use extended timeout (e.g. 300_000L / 5 minutes) so LLM summarization doesn't timeout
+                val result =
+                    wsClient
+                        .request(
+                            WsMethods.SESSION_COMPRESS,
+                            params,
+                            timeoutMs = 300_000L,
+                        ).await()
+
+                handleCompressionResult(result)
+            } catch (e: HermesWsClient.HermesRpcException) {
+                addAssistantMessage("/compress: ${e.message ?: "compression failed"}")
+            } catch (e: Exception) {
+                addAssistantMessage("/compress: ${e.message ?: "compression failed"}")
+            } finally {
+                _uiState.update {
+                    it.copy(
+                        isCompressing = false,
+                        compressionStatus = null,
+                    )
+                }
+            }
+        }
+    }
+
+    private suspend fun handleCompressionResult(result: Any?) {
+        val response =
+            try {
+                val jsonElement = result.toJsonElement()
+                OkHttpProvider.json.decodeFromJsonElement<SessionCompressResponse>(jsonElement)
+            } catch (e: Exception) {
+                Log.e(TAG, "Failed to decode session.compress response", e)
+                null
+            }
+
+        val sessionId = runtimeSessionId ?: _uiState.value.currentSessionId
+
+        // 1. Authoritative transcript replacement
+        if (response?.messages != null && sessionId != null) {
+            val replacementMessages =
+                withContext(historyDispatcher) {
+                    mapServerMessages(
+                        sessionId = sessionId,
+                        messages = response.messages,
+                        offset = 0,
+                        latestPaging = latestPaging,
+                        liveMessages = emptyList(),
+                        context = getApplication(),
+                    )
+                }
+            _uiState.update { it.copy(messages = replacementMessages) }
+            persistHistoryPage(replacementMessages, sessionId)
+        }
+
+        // 2. Display result summary via addAssistantMessage
+        val summary = response?.summary
+        val lines = mutableListOf<String>()
+        summary?.headline?.takeIf { it.isNotBlank() }?.let { lines.add(it) }
+        summary?.token_line?.takeIf { it.isNotBlank() }?.let { lines.add(it) }
+        summary?.note?.takeIf { it.isNotBlank() }?.let { lines.add(it) }
+
+        val feedback =
+            if (lines.isNotEmpty()) {
+                lines.joinToString("\n")
+            } else {
+                response?.message ?: "Context compressed."
+            }
+        addAssistantMessage(feedback)
+
+        // 3. Refresh usage & sessions
+        fetchContextUsage()
+        loadSessions()
+
+        // 4. Handle lineage/session info if provided
+        response?.info?.let { infoElement ->
+            val infoMap = (infoElement.toAny() as? Map<*, *>)?.filterKeys { it is String } as? Map<String, Any?>
+            handleSessionInfo(infoMap)
+        }
+        sessionHasServerPresence = true
+    }
+
     private fun handlePrefillResult(
         message: String,
         notice: String,

app/src/main/java/com/m57/hermescontrol/ui/chat/ChatWsEventReducer.kt

@@ -208,7 +208,7 @@ object ChatWsEventReducer {
 
             is WsEvent.SessionUpdated -> onSessionUpdated(state, streamingState)
 
-            is WsEvent.StatusUpdate -> onStatusUpdate(state, streamingState)
+            is WsEvent.StatusUpdate -> onStatusUpdate(state, streamingState, event)
 
             is WsEvent.ConnectionRequest,
             is WsEvent.ConnectionUpdate,
@@ -1046,7 +1046,38 @@ object ChatWsEventReducer {
     private fun onStatusUpdate(
         state: ChatUiState,
         streamingState: StreamingState,
-    ): ReducerResult = ReducerResult(state = state, streamingState = streamingState)
+        event: WsEvent.StatusUpdate,
+    ): ReducerResult {
+        val kind = event.data?.get("kind") as? String
+        val text = event.data?.get("text") as? String
+        return when (kind) {
+            "compressing", "compacting" -> {
+                ReducerResult(
+                    state =
+                        state.copy(
+                            isCompressing = true,
+                            compressionStatus = text ?: "⏳ Compressing context...",
+                        ),
+                    streamingState = streamingState,
+                )
+            }
+
+            "compacted" -> {
+                ReducerResult(
+                    state =
+                        state.copy(
+                            isCompressing = false,
+                            compressionStatus = text,
+                        ),
+                    streamingState = streamingState,
+                )
+            }
+
+            else -> {
+                ReducerResult(state = state, streamingState = streamingState)
+            }
+        }
+    }
 
     private fun onUnknown(
         state: ChatUiState,

app/src/main/java/com/m57/hermescontrol/ui/chat/SlashCommandDispatcher.kt

@@ -77,6 +77,11 @@ class SlashCommandDispatcher {
                 SlashResult.Undo(count = arg)
             }
 
+            "/compress", "/compact" -> {
+                val arg = command.split(" ", limit = 2).getOrElse(1) { "" }.trim()
+                SlashResult.Compress(focusTopic = arg)
+            }
+
             else -> {
                 SlashResult.RpcDispatch
             }
@@ -172,4 +177,11 @@ sealed class SlashResult {
     data class Undo(
         val count: String,
     ) : SlashResult()
+
+    /**
+     * Compress session context via the session.compress WebSocket RPC.
+     */
+    data class Compress(
+        val focusTopic: String,
+    ) : SlashResult()
 }

app/src/main/java/com/m57/hermescontrol/ui/chat/fullbleed/FullBleedChatList.kt

@@ -3,11 +3,15 @@ package com.m57.hermescontrol.ui.chat.fullbleed
 import androidx.compose.foundation.layout.Box
 import androidx.compose.foundation.layout.Column
 import androidx.compose.foundation.layout.PaddingValues
+import androidx.compose.foundation.layout.Row
 import androidx.compose.foundation.layout.fillMaxSize
+import androidx.compose.foundation.layout.fillMaxWidth
 import androidx.compose.foundation.layout.padding
 import androidx.compose.foundation.layout.size
 import androidx.compose.foundation.lazy.LazyColumn
 import androidx.compose.material3.CircularProgressIndicator
+import androidx.compose.material3.MaterialTheme
+import androidx.compose.material3.Text
 import androidx.compose.runtime.Composable
 import androidx.compose.runtime.CompositionLocalProvider
 import androidx.compose.runtime.LaunchedEffect
@@ -107,6 +111,8 @@ fun FullBleedChatList(
     replyErrorContent: (@Composable () -> Unit)? = null,
     speakingMessageId: String? = null,
     onToggleSpeak: ((ChatMessage) -> Unit)? = null,
+    isCompressing: Boolean = false,
+    compressionStatus: String? = null,
 ) {
     if (messages.isEmpty() && !isLoading && !isAgentTyping && replyErrorContent == null) {
         Box(
@@ -149,6 +155,23 @@ fun FullBleedChatList(
         val tailItems =
             buildMap<String, @Composable () -> Unit> {
                 replyErrorContent?.let { put("reply_error", it) }
+                if (isCompressing || compressionStatus != null) {
+                    put("compression_status") {
+                        Row(
+                            modifier =
+                                Modifier
+                                    .fillMaxWidth()
+                                    .padding(horizontal = 16.dp, vertical = 8.dp),
+                            verticalAlignment = Alignment.CenterVertically,
+                        ) {
+                            Text(
+                                text = compressionStatus ?: "⏳ Compressing context...",
+                                style = MaterialTheme.typography.bodySmall,
+                                color = MaterialTheme.colorScheme.onSurfaceVariant,
+                            )
+                        }
+                    }
+                }
                 agentStatus?.let { status ->
                     put("agent_status") {
                         AgentStatusIndicator(status = status)

app/src/test/java/com/m57/hermescontrol/ui/chat/ChatCompressRpcTest.kt

@@ -0,0 +1,533 @@
+package com.m57.hermescontrol.ui.chat
+
+import android.app.Application
+import com.m57.hermescontrol.data.local.AuthManager
+import com.m57.hermescontrol.data.local.DataScope
+import com.m57.hermescontrol.data.local.HermesDatabase
+import com.m57.hermescontrol.data.model.CompressionSummary
+import com.m57.hermescontrol.data.model.SessionCompressResponse
+import com.m57.hermescontrol.data.model.SessionMessage
+import com.m57.hermescontrol.data.remote.ApiClient
+import com.m57.hermescontrol.data.remote.NetworkResult
+import com.m57.hermescontrol.data.session.ProfileSwitchCoordinator
+import com.m57.hermescontrol.data.ws.ConnectionStatus
+import com.m57.hermescontrol.data.ws.HermesWsClient
+import com.m57.hermescontrol.data.ws.WsEvent
+import com.m57.hermescontrol.data.ws.WsMethods
+import com.m57.hermescontrol.ui.chat.fakes.FakeChatPersistenceRepository
+import com.m57.hermescontrol.ui.chat.fakes.FakeSlashUsageStore
+import io.mockk.coEvery
+import io.mockk.every
+import io.mockk.mockk
+import io.mockk.mockkObject
+import io.mockk.mockkStatic
+import io.mockk.unmockkAll
+import kotlinx.coroutines.CompletableDeferred
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.ExperimentalCoroutinesApi
+import kotlinx.coroutines.flow.MutableSharedFlow
+import kotlinx.coroutines.flow.MutableStateFlow
+import kotlinx.coroutines.test.StandardTestDispatcher
+import kotlinx.coroutines.test.TestScope
+import kotlinx.coroutines.test.advanceUntilIdle
+import kotlinx.coroutines.test.resetMain
+import kotlinx.coroutines.test.runTest
+import kotlinx.coroutines.test.setMain
+import kotlinx.serialization.json.JsonPrimitive
+import kotlinx.serialization.json.buildJsonArray
+import kotlinx.serialization.json.buildJsonObject
+import kotlinx.serialization.json.put
+import org.junit.After
+import org.junit.Assert.assertEquals
+import org.junit.Assert.assertFalse
+import org.junit.Assert.assertTrue
+import org.junit.Before
+import org.junit.Test
+
+@OptIn(ExperimentalCoroutinesApi::class)
+class ChatCompressRpcTest {
+    private val testDispatcher = StandardTestDispatcher()
+    private val mockEventsFlow = MutableSharedFlow<WsEvent>(extraBufferCapacity = 64)
+    private val mockConnectionStatus = MutableStateFlow(ConnectionStatus.DISCONNECTED)
+    private lateinit var app: Application
+    private lateinit var fakeRepo: FakeChatPersistenceRepository
+    private var reqCount = 0
+    private var sessionCreateRequestId: String? = null
+
+    @Before
+    fun setUp() {
+        Dispatchers.setMain(testDispatcher)
+        reqCount = 0
+        sessionCreateRequestId = null
+
+        mockkStatic(android.util.Log::class)
+        every { android.util.Log.d(any(), any()) } returns 0
+        every { android.util.Log.i(any(), any()) } returns 0
+        every { android.util.Log.w(any(), any<String>()) } returns 0
+        every { android.util.Log.e(any(), any(), any()) } returns 0
+
+        mockkObject(AuthManager)
+        every { AuthManager.getPinnedModels() } returns emptyList()
+        every { AuthManager.dataScopeFlow } returns MutableStateFlow<DataScope?>(null)
+        every { AuthManager.activeProfileId } returns MutableStateFlow<String?>(null)
+        every { AuthManager.currentDataScope() } returns null
+        every { AuthManager.getToken() } returns "test-token"
+        every { AuthManager.getBaseUrl() } returns "http://test.local/"
+        every { AuthManager.getSelectedProfileId() } returns null
+        every { AuthManager.getBusySendMode() } returns com.m57.hermescontrol.data.model.BusySendMode.CORRECT
+        every { AuthManager.isTypingEffectEnabled() } returns true
+        every { AuthManager.getTypingEffectDelayMs() } returns 30
+        every { AuthManager.isMessageStatsEnabled() } returns false
+        every { AuthManager.isUserMessageTokensEnabled() } returns true
+        every { AuthManager.isAssistantMessageTokensEnabled() } returns true
+        every { AuthManager.isTokensPerSecondEnabled() } returns true
+        every { AuthManager.isModelProviderShown() } returns false
+        every { AuthManager.isAutoReconnect() } returns false
+        every { AuthManager.isRestoreLastSession() } returns false
+        every { AuthManager.getLastOpenedSessionId() } returns null
+        every { AuthManager.setLastOpenedSessionId(any()) } returns Unit
+        every { AuthManager.clearLastOpenedSessionId() } returns Unit
+
+        mockkObject(HermesWsClient)
+        every { HermesWsClient.events } returns mockEventsFlow
+        every { HermesWsClient.connectionStatus } returns mockConnectionStatus
+        every { HermesWsClient.connect() } answers {
+            mockConnectionStatus.value = ConnectionStatus.CONNECTING
+        }
+        every { HermesWsClient.disconnect() } returns Unit
+
+        every { HermesWsClient.send(any(), any(), any()) } answers {
+            reqCount++
+            val id = "req-id-$reqCount"
+            if (arg<String>(0) == WsMethods.SESSION_CREATE) {
+                sessionCreateRequestId = id
+            }
+            arg<((String) -> Unit)?>(2)?.invoke(id)
+            id
+        }
+        every { HermesWsClient.sendMessage(any(), any(), any(), any()) } answers {
+            reqCount++
+            val id = "req-msg-$reqCount"
+            arg<((String) -> Unit)?>(2)?.invoke(id)
+            id
+        }
+        every { HermesWsClient.request(any(), any(), any()) } answers {
+            HermesWsClient.send(arg(0), arg(1)) {}
+            CompletableDeferred<Any?>(Unit)
+        }
+
+        mockkObject(ApiClient)
+        coEvery { ApiClient.hermesApi.getModelInfo() } returns retrofit2.Response.success(mockk(relaxed = true))
+        coEvery { ApiClient.hermesApi.getProfiles() } returns
+            retrofit2.Response.success(
+                com.m57.hermescontrol.data.model
+                    .ProfilesResponse(emptyList()),
+            )
+
+        mockkObject(HermesDatabase)
+        mockkObject(ProfileSwitchCoordinator)
+        every { ProfileSwitchCoordinator.switched } returns MutableSharedFlow<String>()
+        every { ProfileSwitchCoordinator.connectionSwitched } returns MutableSharedFlow<String>()
+
+        app = mockk(relaxed = true)
+        fakeRepo = FakeChatPersistenceRepository()
+        mockConnectionStatus.value = ConnectionStatus.DISCONNECTED
+    }
+
+    @After
+    fun tearDown() {
+        Dispatchers.resetMain()
+        unmockkAll()
+    }
+
+    private suspend fun TestScope.createViewModelWithSession(): Pair<ChatViewModel, String> {
+        val vm =
+            ChatViewModel(
+                app,
+                startCleanup = false,
+                repo = fakeRepo,
+                slashUsageStore = FakeSlashUsageStore(),
+                searchDispatcher = testDispatcher,
+                ioDispatcher = testDispatcher,
+                historyDispatcher = testDispatcher,
+                sendStore = ChatSendStore(),
+            )
+        advanceUntilIdle()
+        mockConnectionStatus.value = ConnectionStatus.CONNECTED
+        mockEventsFlow.emit(WsEvent.GatewayReady(null))
+        advanceUntilIdle()
+        val createRequestId = requireNotNull(sessionCreateRequestId) { "session.create was not sent" }
+        mockEventsFlow.emit(WsEvent.RpcResult(createRequestId, mapOf("session_id" to "session-xyz")))
+        advanceUntilIdle()
+        return Pair(vm, "session-xyz")
+    }
+
+    @Test
+    fun `compress calls SESSION_COMPRESS not command dispatch or slash exec`() =
+        runTest {
+            val (vm, _) = createViewModelWithSession()
+
+            val methodCalls = mutableListOf<String>()
+            every {
+                HermesWsClient.request(capture(methodCalls), any(), any())
+            } answers {
+                CompletableDeferred<Any?>(null)
+            }
+
+            vm.sendMessage("/compress")
+            advanceUntilIdle()
+
+            assertTrue("expected SESSION_COMPRESS in $methodCalls", WsMethods.SESSION_COMPRESS in methodCalls)
+            assertTrue("expected NO command.dispatch", WsMethods.COMMAND_DISPATCH !in methodCalls)
+            assertTrue("expected NO slash.exec", "slash.exec" !in methodCalls)
+        }
+
+    @Test
+    fun `compress request parameters contain session_id and omit focus_topic when blank`() =
+        runTest {
+            val (vm, sessionId) = createViewModelWithSession()
+
+            val methodCalls = mutableListOf<String>()
+            val paramsCalls = mutableListOf<Map<String, Any>>()
+            every {
+                HermesWsClient.request(capture(methodCalls), capture(paramsCalls), any())
+            } answers {
+                CompletableDeferred<Any?>(null)
+            }
+
+            vm.sendMessage("/compress")
+            advanceUntilIdle()
+
+            val compressIndex = methodCalls.indexOf(WsMethods.SESSION_COMPRESS)
+            assertTrue("expected SESSION_COMPRESS in $methodCalls", compressIndex >= 0)
+            val params = paramsCalls[compressIndex]
+            assertEquals(sessionId, params["session_id"])
+            assertFalse("focus_topic should be omitted when blank", params.containsKey("focus_topic"))
+        }
+
+    @Test
+    fun `compress request parameters forward focus_topic when non-blank`() =
+        runTest {
+            val (vm, sessionId) = createViewModelWithSession()
+
+            val methodCalls = mutableListOf<String>()
+            val paramsCalls = mutableListOf<Map<String, Any>>()
+            every {
+                HermesWsClient.request(capture(methodCalls), capture(paramsCalls), any())
+            } answers {
+                CompletableDeferred<Any?>(null)
+            }
+
+            vm.sendMessage("/compress auth decisions")
+            advanceUntilIdle()
+
+            val compressIndex = methodCalls.indexOf(WsMethods.SESSION_COMPRESS)
+            assertTrue("expected SESSION_COMPRESS in $methodCalls", compressIndex >= 0)
+            val params = paramsCalls[compressIndex]
+            assertEquals(sessionId, params["session_id"])
+            assertEquals("auth decisions", params["focus_topic"])
+        }
+
+    @Test
+    fun `compact behaves identically to compress omitting focus_topic when blank`() =
+        runTest {
+            val (vm, sessionId) = createViewModelWithSession()
+
+            val methodCalls = mutableListOf<String>()
+            val paramsCalls = mutableListOf<Map<String, Any>>()
+            every {
+                HermesWsClient.request(capture(methodCalls), capture(paramsCalls), any())
+            } answers {
+                CompletableDeferred<Any?>(null)
+            }
+
+            vm.sendMessage("/compact")
+            advanceUntilIdle()
+
+            val compressIndex = methodCalls.indexOf(WsMethods.SESSION_COMPRESS)
+            assertTrue("expected SESSION_COMPRESS in $methodCalls", compressIndex >= 0)
+            val params = paramsCalls[compressIndex]
+            assertEquals(sessionId, params["session_id"])
+            assertFalse("focus_topic should be omitted when blank", params.containsKey("focus_topic"))
+            assertTrue(WsMethods.COMMAND_DISPATCH !in methodCalls)
+        }
+
+    @Test
+    fun `compact forwards focus_topic when non-blank`() =
+        runTest {
+            val (vm, sessionId) = createViewModelWithSession()
+
+            val methodCalls = mutableListOf<String>()
+            val paramsCalls = mutableListOf<Map<String, Any>>()
+            every {
+                HermesWsClient.request(capture(methodCalls), capture(paramsCalls), any())
+            } answers {
+                CompletableDeferred<Any?>(null)
+            }
+
+            vm.sendMessage("/compact architecture details")
+            advanceUntilIdle()
+
+            val compressIndex = methodCalls.indexOf(WsMethods.SESSION_COMPRESS)
+            assertTrue("expected SESSION_COMPRESS in $methodCalls", compressIndex >= 0)
+            val params = paramsCalls[compressIndex]
+            assertEquals(sessionId, params["session_id"])
+            assertEquals("architecture details", params["focus_topic"])
+        }
+
+    @Test
+    fun `final response summary headline token_line note added to messages`() =
+        runTest {
+            val (vm, _) = createViewModelWithSession()
+
+            val responseJson =
+                buildJsonObject {
+                    put("status", JsonPrimitive("ok"))
+                    put(
+                        "summary",
+                        buildJsonObject {
+                            put("headline", JsonPrimitive("Context compressed"))
+                            put("token_line", JsonPrimitive("Tokens: 120k -> 35k (70% saved)"))
+                            put("note", JsonPrimitive("Trimmed 14 earlier turns"))
+                        },
+                    )
+                }
+
+            every {
+                HermesWsClient.request(WsMethods.SESSION_COMPRESS, any(), any())
+            } answers {
+                CompletableDeferred<Any?>(responseJson)
+            }
+
+            vm.sendMessage("/compress")
+            advanceUntilIdle()
+
+            val lastAssistantMessage =
+                vm.uiState.value.messages
+                    .lastOrNull { it.role == MessageRole.ASSISTANT }
+            val expectedContent = "Context compressed\nTokens: 120k -> 35k (70% saved)\nTrimmed 14 earlier turns"
+            assertEquals(expectedContent, lastAssistantMessage?.content)
+        }
+
+    @Test
+    fun `returned messages replace and reconcile visible live transcript`() =
+        runTest {
+            val (vm, _) = createViewModelWithSession()
+
+            val serverMessages =
+                listOf(
+                    SessionMessage(
+                        id = 101,
+                        role = "user",
+                        content = JsonPrimitive("Original prompt"),
+                    ),
+                    SessionMessage(
+                        id = 102,
+                        role = "assistant",
+                        content = JsonPrimitive("Compressed response"),
+                    ),
+                )
+
+            val responseJson =
+                buildJsonObject {
+                    put("status", JsonPrimitive("ok"))
+                    put(
+                        "summary",
+                        buildJsonObject {
+                            put("headline", JsonPrimitive("Summary headline"))
+                        },
+                    )
+                    put(
+                        "messages",
+                        buildJsonArray {
+                            add(
+                                buildJsonObject {
+                                    put("id", JsonPrimitive(101))
+                                    put("role", JsonPrimitive("user"))
+                                    put("content", JsonPrimitive("Original prompt"))
+                                },
+                            )
+                            add(
+                                buildJsonObject {
+                                    put("id", JsonPrimitive(102))
+                                    put("role", JsonPrimitive("assistant"))
+                                    put("content", JsonPrimitive("Compressed response"))
+                                },
+                            )
+                        },
+                    )
+                }
+
+            every {
+                HermesWsClient.request(WsMethods.SESSION_COMPRESS, any(), any())
+            } answers {
+                CompletableDeferred<Any?>(responseJson)
+            }
+
+            vm.sendMessage("/compress")
+            advanceUntilIdle()
+
+            val messages = vm.uiState.value.messages
+            // The transcript contains serverMessages, plus the assistant summary feedback
+            val userMsg = messages.firstOrNull { it.role == MessageRole.USER && it.content == "Original prompt" }
+            assertEquals("Original prompt", userMsg?.content)
+            val serverAssistantMsg =
+                messages.firstOrNull {
+                    it.role == MessageRole.ASSISTANT && it.content == "Compressed response"
+                }
+            assertTrue("expected replacement assistant message", serverAssistantMsg != null)
+            val summaryMsg = messages.lastOrNull { it.role == MessageRole.ASSISTANT }
+            assertEquals("Summary headline", summaryMsg?.content)
+        }
+
+    @Test
+    fun `fetchContextUsage is triggered after successful compression`() =
+        runTest {
+            val (vm, sessionId) = createViewModelWithSession()
+
+            val methodCalls = mutableListOf<String>()
+            every {
+                HermesWsClient.request(capture(methodCalls), any(), any())
+            } answers {
+                val method = arg<String>(0)
+                if (method == WsMethods.SESSION_COMPRESS) {
+                    val responseJson =
+                        buildJsonObject {
+                            put("status", JsonPrimitive("ok"))
+                            put("message", JsonPrimitive("Context compressed."))
+                        }
+                    CompletableDeferred<Any?>(responseJson)
+                } else {
+                    CompletableDeferred<Any?>(Unit)
+                }
+            }
+
+            methodCalls.clear()
+
+            vm.sendMessage("/compress")
+            advanceUntilIdle()
+
+            // fetchContextUsage calls SESSION_CONTEXT_BREAKDOWN and SESSION_USAGE with sessionId
+            assertTrue(
+                "expected SESSION_CONTEXT_BREAKDOWN in $methodCalls",
+                WsMethods.SESSION_CONTEXT_BREAKDOWN in methodCalls,
+            )
+            assertTrue(
+                "expected SESSION_USAGE in $methodCalls",
+                WsMethods.SESSION_USAGE in methodCalls,
+            )
+        }
+
+    @Test
+    fun `isCompressing is reset to false on success`() =
+        runTest {
+            val (vm, _) = createViewModelWithSession()
+
+            val deferred = CompletableDeferred<Any?>()
+            every {
+                HermesWsClient.request(WsMethods.SESSION_COMPRESS, any(), any())
+            } returns deferred
+
+            vm.sendMessage("/compress")
+            // Progress before completion
+            testDispatcher.scheduler.runCurrent()
+            assertTrue("isCompressing should be true while in flight", vm.uiState.value.isCompressing)
+            assertEquals("⏳ Compressing context...", vm.uiState.value.compressionStatus)
+
+            deferred.complete(
+                buildJsonObject {
+                    put("status", JsonPrimitive("ok"))
+                },
+            )
+            advanceUntilIdle()
+
+            assertFalse("isCompressing should be reset to false", vm.uiState.value.isCompressing)
+            assertEquals(null, vm.uiState.value.compressionStatus)
+        }
+
+    @Test
+    fun `isCompressing is reset to false on RPC error`() =
+        runTest {
+            val (vm, _) = createViewModelWithSession()
+
+            val deferred = CompletableDeferred<Any?>()
+            every {
+                HermesWsClient.request(WsMethods.SESSION_COMPRESS, any(), any())
+            } returns deferred
+
+            vm.sendMessage("/compress")
+            testDispatcher.scheduler.runCurrent()
+            assertTrue(vm.uiState.value.isCompressing)
+
+            deferred.completeExceptionally(
+                HermesWsClient.HermesRpcException("compression failed on backend", 4018),
+            )
+            advanceUntilIdle()
+
+            assertFalse("isCompressing should be false on RPC error", vm.uiState.value.isCompressing)
+            assertEquals(null, vm.uiState.value.compressionStatus)
+            val errorMsg =
+                vm.uiState.value.messages
+                    .lastOrNull { it.role == MessageRole.ASSISTANT }
+            assertTrue(errorMsg?.content?.contains("compression failed on backend") == true)
+        }
+
+    @Test
+    fun `isCompressing is reset to false on generic exception`() =
+        runTest {
+            val (vm, _) = createViewModelWithSession()
+
+            val deferred = CompletableDeferred<Any?>()
+            every {
+                HermesWsClient.request(WsMethods.SESSION_COMPRESS, any(), any())
+            } returns deferred
+
+            vm.sendMessage("/compress")
+            testDispatcher.scheduler.runCurrent()
+            assertTrue(vm.uiState.value.isCompressing)
+
+            deferred.completeExceptionally(RuntimeException("network disconnected"))
+            advanceUntilIdle()
+
+            assertFalse("isCompressing should be false on generic exception", vm.uiState.value.isCompressing)
+            assertEquals(null, vm.uiState.value.compressionStatus)
+            val errorMsg =
+                vm.uiState.value.messages
+                    .lastOrNull { it.role == MessageRole.ASSISTANT }
+            assertTrue(errorMsg?.content?.contains("network disconnected") == true)
+        }
+
+    @Test
+    fun `duplicate compress while isCompressing is true is a no-op`() =
+        runTest {
+            val (vm, _) = createViewModelWithSession()
+
+            var compressCalls = 0
+            val deferred = CompletableDeferred<Any?>()
+            every {
+                HermesWsClient.request(WsMethods.SESSION_COMPRESS, any(), any())
+            } answers {
+                compressCalls++
+                deferred
+            }
+
+            vm.sendMessage("/compress")
+            testDispatcher.scheduler.runCurrent()
+            assertTrue(vm.uiState.value.isCompressing)
+            assertEquals(1, compressCalls)
+
+            // Second invocation while in flight
+            vm.sendMessage("/compress")
+            testDispatcher.scheduler.runCurrent()
+            assertEquals("duplicate call should not trigger another RPC", 1, compressCalls)
+
+            // Also check /compact is blocked while in flight
+            vm.sendMessage("/compact")
+            testDispatcher.scheduler.runCurrent()
+            assertEquals("compact while compressing should not trigger another RPC", 1, compressCalls)
+
+            deferred.complete(null)
+            advanceUntilIdle()
+            assertFalse(vm.uiState.value.isCompressing)
+        }
+}

app/src/test/java/com/m57/hermescontrol/ui/chat/ChatPromptProtocolTest.kt

@@ -64,6 +64,28 @@ class ChatPromptProtocolTest {
         assertEquals("new answer", answers?.get("q1")?.jsonPrimitive?.content)
     }
 
+    @Test
+    fun legacyClarifyBatchReplay_skipsLockedAnswers_withoutEmptyOverwrite() {
+        val responses =
+            buildLegacyClarifyBatchResponses(
+                questions =
+                    listOf(
+                        ClarifyQuestionUi(qid = "q0", question = "Already answered?"),
+                        ClarifyQuestionUi(qid = "q1", question = "Still waiting?"),
+                        ClarifyQuestionUi(qid = "q2", question = "Optional skip?"),
+                    ),
+                answers =
+                    mapOf(
+                        "q0" to "",
+                        "q1" to "  new answer  ",
+                        "q2" to "",
+                    ),
+                lockedAnswers = mapOf("q0" to "yes"),
+            )
+
+        assertEquals(listOf("q1" to "new answer", "q2" to ""), responses)
+    }
+
     @Test
     fun credentialPrompt_serverRequestId_controls_response_and_cancellation() {
         val scope = TestScope(dispatcher)

app/src/test/java/com/m57/hermescontrol/ui/chat/ChatWsEventReducerTest.kt

@@ -1478,4 +1478,131 @@ class ChatWsEventReducerTest {
         assertTrue(result.state.messages.none { it.id != "orphan" })
         assertTrue(!result.streamingState.turnUsageBaselineCaptured)
     }
+
+    @Test
+    fun testStatusUpdate_compressingState() {
+        val initialMessage = ChatMessage(role = MessageRole.USER, content = "hello")
+        val state =
+            ChatUiState(
+                currentSessionId = "session-1",
+                messages = listOf(initialMessage),
+                isCompressing = false,
+                compressionStatus = null,
+            )
+        val event =
+            WsEvent.StatusUpdate(
+                status = null,
+                data =
+                    mapOf(
+                        "kind" to "compressing",
+                        "text" to "⏳ Compressing context...",
+                    ),
+            )
+
+        val result =
+            ChatWsEventReducer.reduce(
+                state = state,
+                streamingState = StreamingState(),
+                event = event,
+                currentSessionId = "session-1",
+            )
+
+        assertTrue(result.state.isCompressing)
+        assertEquals("⏳ Compressing context...", result.state.compressionStatus)
+        assertEquals(listOf(initialMessage), result.state.messages)
+    }
+
+    @Test
+    fun testStatusUpdate_compactingState() {
+        val state =
+            ChatUiState(
+                currentSessionId = "session-1",
+                isCompressing = false,
+                compressionStatus = null,
+            )
+        val event =
+            WsEvent.StatusUpdate(
+                status = null,
+                data =
+                    mapOf(
+                        "kind" to "compacting",
+                        "text" to "🗜️ Compacting...",
+                    ),
+            )
+
+        val result =
+            ChatWsEventReducer.reduce(
+                state = state,
+                streamingState = StreamingState(),
+                event = event,
+                currentSessionId = "session-1",
+            )
+
+        assertTrue(result.state.isCompressing)
+        assertEquals("🗜️ Compacting...", result.state.compressionStatus)
+    }
+
+    @Test
+    fun testStatusUpdate_compactedState() {
+        val state =
+            ChatUiState(
+                currentSessionId = "session-1",
+                isCompressing = true,
+                compressionStatus = "🗜️ Compacting...",
+            )
+        val event =
+            WsEvent.StatusUpdate(
+                status = null,
+                data =
+                    mapOf(
+                        "kind" to "compacted",
+                        "text" to "Finished",
+                    ),
+            )
+
+        val result =
+            ChatWsEventReducer.reduce(
+                state = state,
+                streamingState = StreamingState(),
+                event = event,
+                currentSessionId = "session-1",
+            )
+
+        assertFalse(result.state.isCompressing)
+        // Accepts either "Finished" or null if cleared
+        assertTrue(result.state.compressionStatus == "Finished" || result.state.compressionStatus == null)
+    }
+
+    @Test
+    fun testStatusUpdate_unrelatedKindIgnored() {
+        val initialMessages = listOf(ChatMessage(role = MessageRole.USER, content = "test"))
+        val state =
+            ChatUiState(
+                currentSessionId = "session-1",
+                messages = initialMessages,
+                isCompressing = false,
+                compressionStatus = "idle",
+            )
+        val event =
+            WsEvent.StatusUpdate(
+                status = null,
+                data =
+                    mapOf(
+                        "kind" to "other",
+                        "text" to "Something else",
+                    ),
+            )
+
+        val result =
+            ChatWsEventReducer.reduce(
+                state = state,
+                streamingState = StreamingState(),
+                event = event,
+                currentSessionId = "session-1",
+            )
+
+        assertFalse(result.state.isCompressing)
+        assertEquals("idle", result.state.compressionStatus)
+        assertEquals(initialMessages, result.state.messages)
+    }
 }

app/src/test/java/com/m57/hermescontrol/ui/chat/SlashCommandDispatcherTest.kt

@@ -98,6 +98,15 @@ class SlashCommandDispatcherTest {
         assertEquals(SlashResult.Undo(""), dispatcher.dispatch("/Undo"))
     }
 
+    @Test
+    fun `compress and compact route to Compress`() {
+        assertEquals(SlashResult.Compress(""), dispatcher.dispatch("/compress"))
+        assertEquals(SlashResult.Compress(""), dispatcher.dispatch("/compact"))
+        assertEquals(SlashResult.Compress("auth decisions"), dispatcher.dispatch("/compress auth decisions"))
+        assertEquals(SlashResult.Compress("auth decisions"), dispatcher.dispatch("/compact auth decisions"))
+        assertEquals(SlashResult.Compress(""), dispatcher.dispatch("/compress   "))
+    }
+
     @Test
     fun `NEW uppercase still routes to NewSession`() {
         // Dispatcher lower-cases before matching, so case must not matter.