AIX: Reattach: preserve the creation time and don't overwrite handle on reattach

src/common/stores/chat/chat.message.ts

@@ -132,8 +132,10 @@ export type DMessageGenerator = ({
   },
   upstreamHandle?:
     // unified `runId` across variants - vendor-specific id lives behind it; `uht` is consulted only for dispatch routing
-    | { uht: 'vnd.oai.responses', runId: string /* OpenAI `response.id` */, expiresAt: number | null /* null = never expires */ }
-    | { uht: 'vnd.gem.interactions', runId: string /* Gemini `interaction.id` */, expiresAt: number | null },
+    // createdAt/expiresAt: server-clock (ms) at the FIRST observation for this runId - preserved across reattaches
+    // (reassembler ignores re-emissions for the same runId so retention is measured from creation, not last reattach)
+    | { uht: 'vnd.oai.responses', runId: string /* OpenAI `response.id` */, createdAt: number | null, expiresAt: number | null /* null = never expires */ }
+    | { uht: 'vnd.gem.interactions', runId: string /* Gemini `interaction.id` */, createdAt: number | null, expiresAt: number | null },
   tokenStopReason?:
     | 'client-abort'                  // if the generator stopped due to a client abort signal
     | 'filter'                        // (inline filter message injected) if the generator stopped due to a filter

src/modules/aix/client/ContentReassembler.ts

@@ -1052,10 +1052,17 @@ export class ContentReassembler {
   private onResponseHandle({ handle }: Extract<AixWire_Particles.ChatGenerateOp, { cg: 'set-upstream-handle' }>): void {
     // validate the handle
     const knownUht = handle?.uht === 'vnd.oai.responses' || handle?.uht === 'vnd.gem.interactions';
-    if (!knownUht || !handle?.runId || handle.expiresAt === undefined) {
+    if (!knownUht || !handle?.runId || handle.createdAt === undefined || handle.expiresAt === undefined) {
       this._appendReassemblyDevError(`Invalid response handle received: ${JSON.stringify(handle)}`);
       return;
     }
+
+    // Preserve earliest-observed timestamps for a given runId: on reattach the server emits fresh server-clock
+    // values but the original createdAt is the truth we want to keep (so retention is measured from creation, not reattach).
+    const existing = this.S.generator.upstreamHandle;
+    if (existing && existing.runId === handle.runId && existing.createdAt !== null && handle.createdAt !== null && existing.createdAt <= handle.createdAt)
+      return; // no-op: existing handle already carries the earliest createdAt for this runId
+
     // type check point for AixWire_Particles.ChatControlOp('set-upstream-handle') -> DUpstreamResponseHandle
     this.S.generator = { ...this.S.generator, upstreamHandle: handle };
   }

src/modules/aix/server/api/aix.wiretypes.ts

@@ -540,6 +540,9 @@ export namespace AixWire_API {
    *  - vnd.oai.responses: OpenAI Responses API - GET /v1/responses/{id}
    *  - vnd.gem.interactions: Gemini Interactions API for background agents - GET-poll /v1beta/interactions/{id}
    */
+  // Wire input for reattach: server only consumes `runId` (+ `startingAfter` for OpenAI). Timestamps live
+  // on the persisted `DMessageGenerator.upstreamHandle` (client concerns) and on the `set-upstream-handle`
+  // particle (server-to-client transport), but don't need to travel back in the reattach request.
   export const ResumeHandle_schema = z.discriminatedUnion('uht', [
     z.object({
       uht: z.literal('vnd.oai.responses'),
@@ -683,7 +686,7 @@ export namespace AixWire_Particles {
     | { cg: 'set-metrics', metrics: CGSelectMetrics }
     | { cg: 'set-model', name: string }
     | { cg: 'set-provider-infra', label: string }
-    | { cg: 'set-upstream-handle', handle: { uht: 'vnd.oai.responses' | 'vnd.gem.interactions', runId: string, expiresAt: number | null } }
+    | { cg: 'set-upstream-handle', handle: { uht: 'vnd.oai.responses' | 'vnd.gem.interactions', runId: string, createdAt: number | null, expiresAt: number | null } }
     | { cg: '_debugDispatchRequest', security: 'dev-env', dispatchRequest: { url: string, headers: string, body: string, bodySize: number } } // may generalize this in the future
     | { cg: '_debugProfiler', measurements: Record<string, number | string>[] };
 

src/modules/aix/server/dispatch/chatGenerate/ChatGenerateTransmitter.ts

@@ -522,6 +522,9 @@ export class ChatGenerateTransmitter implements IParticleTransmitter {
     if (SERVER_DEBUG_WIRE)
       console.log('|response-handle|', type, handle);
     // NOTE: if needed, we could store the handle locally for server-side resumability, but we just implement client-side (correction, manual) for now
+    // createdAt/expiresAt are server-clock at emit time; on reattach the server has no knowledge of the original create,
+    // so it emits fresh values. The client reassembler preserves the earliest values for a given runId.
+    const now = Date.now();
     const expireDays = type === 'vnd.gem.interactions'
       ? 1 // Gemini Interactions: 1d free / 55d paid - use the conservative lower bound
       : 30; // OpenAI Responses: default 30 days
@@ -530,7 +533,8 @@ export class ChatGenerateTransmitter implements IParticleTransmitter {
       handle: {
         uht: type,
         runId: handle,
-        expiresAt: Date.now() + expireDays * 24 * 3600 * 1000,
+        createdAt: now,
+        expiresAt: now + expireDays * 24 * 3600 * 1000,
       },
     });
     // send it right away, in case the connection closes soon