fix(kiro): improve direct session cache reuse

Reshape Kiro direct requests so resumed client sessions reuse Kiro's cache-affinity fields instead of starting unrelated CodeWhisperer conversations. - keep conversationState.conversationId stable when the client sends an explicit session id (x-session-id, session_id, conversation_id, Claude Code session metadata) - add a stable conversationState.agentContinuationId per Kiro session - send conversationState.agentTaskType: "vibe" and agentMode: "vibe", matching the normal Kiro CLI/KAS chat path - move Kiro thinking instructions into Kiro-compatible systemPrompt / additionalModelRequestFields instead of generic top-level thinking - keep volatile timestamp context out of the top-level systemPrompt; it remains only in user content fallback - suppress additionalModelRequestFields for legacy 4.5-era Claude/Kiro models that reject it, while defaulting future Claude/Kiro model ids to supported - preserve Kiro meteringEvent credit usage internally for accounting without leaking provider-specific fields into OpenAI-compatible usage - prevent unrelated headerless Kiro requests from sharing one connection-wide continuation - cap/evict continuation sessions so long-running processes do not grow the continuation map unbounded - treat generated headerless Kiro sessions as one-shot so they do not evict real explicit-session continuations - keep credit-only Kiro metering valid for internal persistence when token metrics are unavailable
2026-07-16 15:13:28 +07:00
parent 70e8dc4974
commit 9c58ba645e
10 changed files with 786 additions and 90 deletions
--- a/open-sse/config/kiroConstants.js
+++ b/open-sse/config/kiroConstants.js
@@ -131,6 +131,50 @@ export function resolveKiroThinkingBudget(body, headers, model) {
  return null;
 }

+export function extractKiroEffortLevel(body) {
+  const effort =
+    body?.output_config?.effort ??
+    body?.reasoning_effort ??
+    (typeof body?.reasoning === "object" ? body.reasoning?.effort : null);
+  if (typeof effort !== "string") return null;
+  const normalized = effort.toLowerCase();
+  if (normalized === "none" || normalized === "off" || normalized === "disabled") return null;
+  if (normalized === "xhigh" || normalized === "max") return "high";
+  if (["low", "medium", "high"].includes(normalized)) return normalized;
+  return null;
+}
+
+export function buildKiroAdditionalModelRequestFields(body) {
+  const effort = extractKiroEffortLevel(body);
+  if (!effort) return undefined;
+  // Mirrors Kiro CLI/KAS buildEffortRequestFields("output_config").
+  return {
+    thinking: { type: "adaptive", display: "summarized" },
+    output_config: { effort },
+  };
+}
+
+export function supportsKiroAdditionalModelRequestFields(model) {
+  if (typeof model !== "string") return false;
+  const normalized = model.toLowerCase().replace(/-/g, ".");
+  if (!normalized.includes("claude")) return false;
+  const match = normalized.match(/(?:^|[/.])claude(?:[/.][a-z]+)*[/.](\d+)(?:[/.](\d+))?(?:[/.]|$)/);
+  if (!match) return false;
+  const [, majorText, minorText] = match;
+  const major = Number(majorText);
+  const minor = minorText === undefined ? null : Number(minorText);
+  const dateSuffixMinor = minor !== null && minor >= 1000;
+  // Kiro rejected additionalModelRequestFields on legacy 4.5 models in live smoke.
+  // Default future Claude/Kiro models to supported so new model releases do not
+  // need a code allowlist update.
+  return !(major < 4 || (major === 4 && (minor === null || minor <= 5 || dateSuffixMinor)));
+}
+
+export function buildKiroAdditionalModelRequestFieldsForModel(body, model) {
+  if (!supportsKiroAdditionalModelRequestFields(model)) return undefined;
+  return buildKiroAdditionalModelRequestFields(body);
+}
+
 /**
 * Detect whether an inbound request is asking for reasoning / thinking output.
 * Thin wrapper over resolveKiroThinkingBudget (single source of truth).
--- a/open-sse/translator/index.js
+++ b/open-sse/translator/index.js
@@ -103,8 +103,16 @@ export function translateRequest(sourceFormat, targetFormat, model, body, stream
    }
  }

-  // Normalize thinking to the target provider-native format (config-driven, capability-aware)
-  applyThinking(targetFormat, model, result, provider, thinkingIntent);
+  // Normalize thinking to the target provider-native format (config-driven, capability-aware).
+  // Kiro's GenerateAssistantResponse request does not accept the generic top-level
+  // `thinking` field; its translators map thinking intent to KAS-compatible
+  // systemPrompt/additionalModelRequestFields instead.
+  const kiroThinkingMappedByTranslator =
+    targetFormat === FORMATS.KIRO &&
+    (sourceFormat === FORMATS.OPENAI || sourceFormat === FORMATS.CLAUDE);
+  if (!kiroThinkingMappedByTranslator) {
+    applyThinking(targetFormat, model, result, provider, thinkingIntent);
+  }

  // Always normalize to clean OpenAI format when target is OpenAI
  // This handles hybrid requests (e.g., OpenAI messages + Claude tools)
--- a/open-sse/translator/request/claude-to-kiro.js
+++ b/open-sse/translator/request/claude-to-kiro.js
@@ -24,13 +24,15 @@
 */
 import { register } from "../index.js";
 import { FORMATS } from "../formats.js";
-import { v4 as uuidv4 } from "uuid";
+import { applyKiroSessionReplay } from "../../utils/kiroSessionReplay.js";
+import { resolveContinuationId, resolveSessionIdentity } from "../../utils/sessionManager.js";
 import {
  resolveKiroModel,
  resolveKiroThinkingBudget,
  buildThinkingSystemPrefix,
  KIRO_AGENTIC_SYSTEM_PROMPT,
  resolveDefaultProfileArn,
+  buildKiroAdditionalModelRequestFieldsForModel,
 } from "../../config/kiroConstants.js";
 import { DEFAULT_IMAGE_MIME } from "../schema/index.js";
 import { ROLE, CLAUDE_BLOCK } from "../schema/index.js";
@@ -363,6 +365,18 @@ function reconcileOrphanedToolResults(history, currentMessage) {
  }
 }

+function extractClaudeSystemText(system) {
+  if (!system) return "";
+  if (typeof system === "string") return system;
+  if (Array.isArray(system)) {
+    return system.map((s) => {
+      if (typeof s === "string") return s;
+      return s?.text || "";
+    }).filter(Boolean).join("\n");
+  }
+  return "";
+}
+
 /**
 * Build a Kiro payload directly from a Claude Messages API request body.
 */
@@ -402,62 +416,75 @@ export function claudeToKiroRequest(model, body, stream, credentials) {
    ? (credentials?.providerSpecificData?.profileArn || "")
    : (credentials?.providerSpecificData?.profileArn || resolveDefaultProfileArn(authMethod));

-  let finalContent = currentMessage?.userInputMessage?.content || "";
-
-  // System prompt: pass via native systemInstruction field (Kiro/Q API supports it)
-  // and also prepend as <instructions> in user content as fallback for upstreams
-  // that don't support the native field.
-  let systemInstruction = undefined;
-  if (body.system) {
-    let systemText = "";
-    if (typeof body.system === "string") {
-      systemText = body.system;
-    } else if (Array.isArray(body.system)) {
-      systemText = body.system.map((s) => s.text || "").join("\n");
-    }
-    if (systemText) {
-      systemInstruction = systemText;
-      finalContent = `<instructions>\n${systemText}\n</instructions>\n\n${finalContent}`;
-    }
-  }
-
-  // Prefix order: thinking_mode tag, timestamp marker, then agentic prompt.
+  // Kiro CLI/KAS sends system prompt as top-level `systemPrompt`. Keep a
+  // content fallback too because the CodeWhisperer surface does not always
+  // enforce top-level systemPrompt for direct calls.
  const timestamp = new Date().toISOString();
-  const prefixParts = [];
-  if (thinkingBudget !== null) prefixParts.push(buildThinkingSystemPrefix(thinkingBudget));
-  prefixParts.push(`[Context: Current time is ${timestamp}]`);
-  if (agentic) prefixParts.push(KIRO_AGENTIC_SYSTEM_PROMPT);
-  finalContent = `${prefixParts.join("\n\n")}\n\n${finalContent}`;
+  const systemPromptParts = [];
+  if (thinkingBudget !== null) systemPromptParts.push(buildThinkingSystemPrefix(thinkingBudget));
+  if (agentic) systemPromptParts.push(KIRO_AGENTIC_SYSTEM_PROMPT);
+  const systemInstruction = extractClaudeSystemText(body.system);
+  if (systemInstruction) systemPromptParts.push(systemInstruction);
+  const systemPrompt = systemPromptParts.filter(Boolean).join("\n\n");
+  const currentTimeContext = `[Context: Current time is ${timestamp}]`;
+  const contentPrefix = [systemPrompt, currentTimeContext].filter(Boolean).join("\n\n");

+  const sessionIdentity = resolveSessionIdentity({
+    headers: credentials?.rawHeaders,
+    body,
+    connectionId: credentials?.connectionId,
+    scope: "kiro",
+  });
+  const conversationId = sessionIdentity.sessionId;
+  const continuationId = resolveContinuationId({
+    sessionId: conversationId,
+    connectionId: credentials?.connectionId,
+    scope: "kiro",
+    ephemeral: sessionIdentity.ephemeral,
+  });
+  const replay = applyKiroSessionReplay({
+    conversationId,
+    connectionId: credentials?.connectionId,
+    modelId: upstreamModel,
+    systemPrompt,
+    contentPrefix,
+    currentContentPrefix: currentTimeContext,
+    history,
+    currentMessage,
+  });
+  const replayCurrent = replay.currentMessage?.userInputMessage || {};
  const userInputMessage = {
-    content: finalContent,
+    content: replayCurrent.content || "",
    modelId: upstreamModel,
    origin: "AI_EDITOR",
-    ...(currentMessage?.userInputMessage?.userInputMessageContext && {
-      userInputMessageContext:
-        currentMessage.userInputMessage.userInputMessageContext,
+    ...(replayCurrent.userInputMessageContext && {
+      userInputMessageContext: replayCurrent.userInputMessageContext,
    }),
-    ...(currentMessage?.userInputMessage?.images && {
-      images: currentMessage.userInputMessage.images,
+    ...(replayCurrent.images && {
+      images: replayCurrent.images,
    }),
  };

-  if (systemInstruction) {
-    userInputMessage.systemInstruction = systemInstruction;
-  }
-
  const payload = {
    conversationState: {
      chatTriggerType: "MANUAL",
-      conversationId: uuidv4(),
+      conversationId,
+      agentContinuationId: continuationId,
+      agentTaskType: "vibe",
      currentMessage: {
        userInputMessage,
      },
-      history,
+      history: replay.history,
    },
+    agentMode: "vibe",
  };

  if (profileArn) payload.profileArn = profileArn;
+  if (systemPrompt) payload.systemPrompt = systemPrompt;
+  const additionalModelRequestFields = buildKiroAdditionalModelRequestFieldsForModel(body, upstreamModel);
+  if (additionalModelRequestFields) {
+    payload.additionalModelRequestFields = additionalModelRequestFields;
+  }

  if (maxTokens || temperature !== undefined || topP !== undefined) {
    payload.inferenceConfig = {};
--- a/open-sse/translator/request/openai-to-kiro.js
+++ b/open-sse/translator/request/openai-to-kiro.js
@@ -5,13 +5,15 @@
 import { register } from "../index.js";
 import { FORMATS } from "../formats.js";
 import { v4 as uuidv4 } from "uuid";
-import { resolveSessionId } from "../../utils/sessionManager.js";
+import { applyKiroSessionReplay } from "../../utils/kiroSessionReplay.js";
+import { resolveContinuationId, resolveSessionIdentity } from "../../utils/sessionManager.js";
 import {
  resolveKiroModel,
  resolveKiroThinkingBudget,
  buildThinkingSystemPrefix,
  KIRO_AGENTIC_SYSTEM_PROMPT,
-  resolveDefaultProfileArn
+  resolveDefaultProfileArn,
+  buildKiroAdditionalModelRequestFieldsForModel
 } from "../../config/kiroConstants.js";
 import { parseDataUri } from "../concerns/image.js";
 import { DEFAULT_IMAGE_MIME } from "../schema/index.js";
@@ -546,47 +548,74 @@ export function openaiToKiroRequest(model, body, stream, credentials) {
    ? (credentials?.providerSpecificData?.profileArn || "")
    : (credentials?.providerSpecificData?.profileArn || resolveDefaultProfileArn(authMethod));

-  let finalContent = currentMessage?.userInputMessage?.content || "";
-
  const timestamp = new Date().toISOString();

-  // Build the system-prompt prefix that goes ABOVE the user message body.
-  // Order: thinking_mode tag first (so Kiro sees it before any user text),
-  // then context/timestamp marker, then optional agentic chunked-write prompt.
-  const prefixParts = [];
+  // Kiro CLI/KAS sends these as top-level systemPrompt. Keep a content fallback
+  // too because the CodeWhisperer surface does not always enforce top-level
+  // systemPrompt for direct calls.
+  const systemPromptParts = [];
  if (thinkingBudget !== null) {
-    prefixParts.push(buildThinkingSystemPrefix(thinkingBudget));
+    systemPromptParts.push(buildThinkingSystemPrefix(thinkingBudget));
  }
-  prefixParts.push(`[Context: Current time is ${timestamp}]`);
  if (agentic) {
-    prefixParts.push(KIRO_AGENTIC_SYSTEM_PROMPT);
+    systemPromptParts.push(KIRO_AGENTIC_SYSTEM_PROMPT);
  }
-  finalContent = `${prefixParts.join("\n\n")}\n\n${finalContent}`;
+  const systemPrompt = systemPromptParts.filter(Boolean).join("\n\n");
+  const currentTimeContext = `[Context: Current time is ${timestamp}]`;
+  const contentPrefix = [systemPrompt, currentTimeContext].filter(Boolean).join("\n\n");
+
+  const sessionIdentity = resolveSessionIdentity({ headers: credentials?.rawHeaders, body, connectionId: credentials?.connectionId, scope: "kiro" });
+  const conversationId = sessionIdentity.sessionId;
+  const continuationId = resolveContinuationId({
+    sessionId: conversationId,
+    connectionId: credentials?.connectionId,
+    scope: "kiro",
+    ephemeral: sessionIdentity.ephemeral,
+  });
+  const replay = applyKiroSessionReplay({
+    conversationId,
+    connectionId: credentials?.connectionId,
+    modelId: upstreamModel,
+    systemPrompt,
+    contentPrefix,
+    currentContentPrefix: currentTimeContext,
+    history,
+    currentMessage,
+  });
+  const replayCurrent = replay.currentMessage?.userInputMessage || {};

  const payload = {
    conversationState: {
      chatTriggerType: "MANUAL",
-      conversationId: resolveSessionId({ headers: credentials?.rawHeaders, body, connectionId: credentials?.connectionId, scope: "kiro" }),
+      conversationId,
+      agentContinuationId: continuationId,
+      agentTaskType: "vibe",
      currentMessage: {
        userInputMessage: {
-          content: finalContent,
+          content: replayCurrent.content || "",
          modelId: upstreamModel,
          origin: "AI_EDITOR",
-          ...(currentMessage?.userInputMessage?.images?.length > 0 && {
-            images: currentMessage.userInputMessage.images
+          ...(replayCurrent.images?.length > 0 && {
+            images: replayCurrent.images
          }),
-          ...(currentMessage?.userInputMessage?.userInputMessageContext && {
-            userInputMessageContext: currentMessage.userInputMessage.userInputMessageContext
+          ...(replayCurrent.userInputMessageContext && {
+            userInputMessageContext: replayCurrent.userInputMessageContext
          })
        }
      },
-      history: history
-    }
+      history: replay.history
+    },
+    agentMode: "vibe",
  };

  if (profileArn) {
    payload.profileArn = profileArn;
  }
+  if (systemPrompt) payload.systemPrompt = systemPrompt;
+  const additionalModelRequestFields = buildKiroAdditionalModelRequestFieldsForModel(body, upstreamModel);
+  if (additionalModelRequestFields) {
+    payload.additionalModelRequestFields = additionalModelRequestFields;
+  }

  if (maxTokens || temperature !== undefined || topP !== undefined) {
    payload.inferenceConfig = {};
--- a/open-sse/utils/kiroSessionReplay.js
+++ b/open-sse/utils/kiroSessionReplay.js
@@ -0,0 +1,125 @@
+import { MEMORY_CONFIG } from "../config/runtimeConfig.js";
+
+const sessionStartStore = new Map();
+const MAX_SESSION_STARTS = 5000;
+
+function clone(value) {
+  return value == null ? value : JSON.parse(JSON.stringify(value));
+}
+
+function sessionKey(connectionId, conversationId) {
+  return `${connectionId || ""}:${conversationId || ""}`;
+}
+
+function ensureUserMessageModelId(message, modelId) {
+  if (message?.userInputMessage && !message.userInputMessage.modelId && modelId) {
+    message.userInputMessage.modelId = modelId;
+  }
+  return message;
+}
+
+function ensureHistoryModelIds(history, modelId) {
+  for (const item of history || []) {
+    ensureUserMessageModelId(item, modelId);
+  }
+  return history;
+}
+
+function prefixUserMessage(message, contentPrefix, modelId) {
+  const out = clone(message) || { userInputMessage: { content: "" } };
+  if (!out.userInputMessage) out.userInputMessage = { content: "" };
+  ensureUserMessageModelId(out, modelId);
+  if (contentPrefix) {
+    const content = out.userInputMessage.content || "";
+    out.userInputMessage.content = content
+      ? `${contentPrefix}\n\n${content}`
+      : contentPrefix;
+  }
+  return out;
+}
+
+function findFirstUserIndex(history) {
+  return history.findIndex((item) => item?.userInputMessage);
+}
+
+function rememberSessionStart(key, entry) {
+  if (sessionStartStore.size >= MAX_SESSION_STARTS) {
+    sessionStartStore.delete(sessionStartStore.keys().next().value);
+  }
+  sessionStartStore.set(key, { ...entry, lastUsed: Date.now() });
+}
+
+/**
+ * Preserve Kiro cacheability by freezing the first user message (`msg0`) for a
+ * session, replaying that exact message as the first history user on later
+ * turns, and injecting volatile current-time context only into the current turn.
+ */
+export function applyKiroSessionReplay({
+  conversationId,
+  connectionId,
+  modelId,
+  systemPrompt = "",
+  contentPrefix = "",
+  currentContentPrefix = "",
+  history = [],
+  currentMessage,
+} = {}) {
+  const key = sessionKey(connectionId, conversationId);
+  const existing = conversationId ? sessionStartStore.get(key) : null;
+  const baseHistory = clone(history) || [];
+  const baseCurrent = clone(currentMessage) || { userInputMessage: { content: "" } };
+
+  if (existing && existing.modelId === modelId && existing.systemPrompt === systemPrompt) {
+    existing.lastUsed = Date.now();
+    const firstUserIndex = findFirstUserIndex(baseHistory);
+    const sessionStart = ensureUserMessageModelId(clone(existing.sessionStart), modelId);
+    if (firstUserIndex >= 0) {
+      baseHistory[firstUserIndex] = sessionStart;
+    } else {
+      baseHistory.unshift(sessionStart);
+    }
+    return {
+      history: ensureHistoryModelIds(baseHistory, modelId),
+      currentMessage: prefixUserMessage(baseCurrent, currentContentPrefix, modelId),
+      replayed: true,
+    };
+  }
+
+  const firstUserIndex = findFirstUserIndex(baseHistory);
+  let sessionStart;
+  let nextCurrent = ensureUserMessageModelId(baseCurrent, modelId);
+  if (firstUserIndex >= 0) {
+    sessionStart = prefixUserMessage(baseHistory[firstUserIndex], contentPrefix, modelId);
+    baseHistory[firstUserIndex] = clone(sessionStart);
+    nextCurrent = prefixUserMessage(baseCurrent, currentContentPrefix, modelId);
+  } else {
+    sessionStart = prefixUserMessage(baseCurrent, contentPrefix, modelId);
+    nextCurrent = clone(sessionStart);
+  }
+
+  if (conversationId) {
+    rememberSessionStart(key, {
+      sessionStart: clone(sessionStart),
+      modelId,
+      systemPrompt,
+    });
+  }
+
+  return {
+    history: ensureHistoryModelIds(baseHistory, modelId),
+    currentMessage: nextCurrent,
+    replayed: false,
+  };
+}
+
+export function clearKiroSessionReplayStore() {
+  sessionStartStore.clear();
+}
+
+const cleanup = setInterval(() => {
+  const now = Date.now();
+  for (const [key, entry] of sessionStartStore) {
+    if (now - entry.lastUsed > MEMORY_CONFIG.sessionTtlMs) sessionStartStore.delete(key);
+  }
+}, MEMORY_CONFIG.sessionCleanupIntervalMs);
+if (cleanup.unref) cleanup.unref();
--- a/open-sse/utils/sessionManager.js
+++ b/open-sse/utils/sessionManager.js
@@ -13,6 +13,7 @@ import { MEMORY_CONFIG } from "../config/runtimeConfig.js";

 // Runtime storage: Key = connectionId, Value = { sessionId, lastUsed }
 const runtimeSessionStore = new Map();
+const continuationStore = new Map();

 // Periodically evict entries that haven't been used within TTL
 const cleanupInterval = setInterval(() => {
@@ -80,6 +81,7 @@ export function generateBinaryStyleId() {
 export function clearSessionStore() {
    runtimeSessionStore.clear();
    assistantSessionStore.clear();
+    continuationStore.clear();
 }

 // Conversation-stable session store: Key = hash(scope+assistant text), Value = { sessionId, lastUsed }
@@ -87,9 +89,10 @@ const assistantSessionStore = new Map();
 const ASSISTANT_MIN_LEN = 50;
 const ASSISTANT_CAP_LEN = 50;
 const MAX_ASSISTANT_SESSIONS = 5000;
+const MAX_CONTINUATION_SESSIONS = 5000;

 // Client headers/body fields that carry an upstream session id (priority order)
-const SESSION_HEADER_KEYS = ["x-session-id", "session-id", "session_id", "x-amp-thread-id", "x-client-request-id"];
+const SESSION_HEADER_KEYS = ["x-session-id", "session-id", "session_id", "x-amp-thread-id"];
 const CLAUDE_CODE_SESSION_RE = /_session_([a-f0-9-]+)$/;

 function sha16(text) {
@@ -131,7 +134,7 @@ function extractAntigravitySession(body) {
    return m ? normalizeSessionId(m[1]) : null;
 }

-function extractClientSessionId(headers, body) {
+function extractClientSessionId(headers, body, scope = "") {
    const claude = extractClaudeCodeSession(body?.metadata?.user_id);
    if (claude) return `claude:${claude}`;
    const antigravity = extractAntigravitySession(body);
@@ -140,18 +143,25 @@ function extractClientSessionId(headers, body) {
        const v = headerValue(headers, key);
        if (v) return v;
    }
+    const requestId = scope === "kiro" ? null : headerValue(headers, "x-client-request-id");
+    if (requestId) return requestId;
    const fromBody =
        normalizeSessionId(body?.prompt_cache_key) ||
        normalizeSessionId(body?.session_id) ||
        normalizeSessionId(body?.conversation_id) ||
-        normalizeSessionId(body?.metadata?.user_id);
+        (scope === "kiro" ? null : normalizeSessionId(body?.metadata?.user_id));
    return fromBody || null;
 }

+function requestMessages(body) {
+    if (Array.isArray(body?.messages)) return body.messages;
+    if (Array.isArray(body?.input)) return body.input;
+    return [];
+}
+
 // Accumulate assistant text from OpenAI/Responses-style input/messages (cap-limited)
 function accumulateAssistantText(body) {
-    const items = Array.isArray(body?.input) ? body.input
-        : Array.isArray(body?.messages) ? body.messages : null;
+    const items = requestMessages(body);
    if (!items) return "";
    let text = "";
    for (const item of items) {
@@ -193,16 +203,39 @@ function assistantTextSessionId(scope, body) {
 * @param {string} [opts.connectionId] - Connection identifier (fallback scope)
 * @param {string} [opts.workspaceId] - Provider workspace id (account-wide fallback)
 * @param {string} [opts.scope] - Provider scope to isolate cache keys across providers
- * @returns {string} A stable session id
+ * @returns {{sessionId: string, ephemeral: boolean}} A session id plus whether it is one-shot
 */
-export function resolveSessionId({ headers, body, connectionId, workspaceId, scope = "" } = {}) {
-    const client = extractClientSessionId(headers, body);
-    if (client) return client;
-    const fromAssistant = assistantTextSessionId(`${scope}:${connectionId || ""}`, body);
-    if (fromAssistant) return fromAssistant;
+export function resolveSessionIdentity({ headers, body, connectionId, workspaceId, scope = "" } = {}) {
+    const client = extractClientSessionId(headers, body, scope);
+    if (client) return { sessionId: client, ephemeral: false };
+    const fromAssistant = scope === "kiro" ? null : assistantTextSessionId(`${scope}:${connectionId || ""}`, body);
+    if (fromAssistant) return { sessionId: fromAssistant, ephemeral: false };
    const ws = normalizeSessionId(workspaceId);
-    if (ws) return ws;
-    return deriveSessionId(connectionId);
+    if (ws) return { sessionId: ws, ephemeral: false };
+    if (scope === "kiro") return { sessionId: generateBinaryStyleId(), ephemeral: true };
+    return { sessionId: deriveSessionId(connectionId), ephemeral: false };
+}
+
+export function resolveSessionId(opts = {}) {
+    return resolveSessionIdentity(opts).sessionId;
+}
+
+export function resolveContinuationId({ sessionId, connectionId, scope = "", ephemeral = false } = {}) {
+    if (ephemeral) return crypto.randomUUID();
+    const key = `${scope}:${connectionId || ""}:${sessionId || ""}`;
+    const existing = continuationStore.get(key);
+    if (existing) {
+        existing.lastUsed = Date.now();
+        continuationStore.delete(key);
+        continuationStore.set(key, existing);
+        return existing.continuationId;
+    }
+    const continuationId = crypto.randomUUID();
+    if (continuationStore.size >= MAX_CONTINUATION_SESSIONS) {
+        continuationStore.delete(continuationStore.keys().next().value);
+    }
+    continuationStore.set(key, { continuationId, lastUsed: Date.now() });
+    return continuationId;
 }

 // Capture session id from request body + credentials (envelope still intact here)
@@ -227,5 +260,8 @@ const assistantCleanup = setInterval(() => {
    for (const [key, entry] of assistantSessionStore) {
        if (now - entry.lastUsed > MEMORY_CONFIG.sessionTtlMs) assistantSessionStore.delete(key);
    }
+    for (const [key, entry] of continuationStore) {
+        if (now - entry.lastUsed > MEMORY_CONFIG.sessionTtlMs) continuationStore.delete(key);
+    }
 }, MEMORY_CONFIG.sessionCleanupIntervalMs);
 if (assistantCleanup.unref) assistantCleanup.unref();