refactor(chat): route browser chat through one runtime (P3 Slice-Zero Task 5) (#1172)

Co-authored-by: shaggy <[email protected]>
2026-08-12 20:11:12 +00:00
parent 6a8ce66702
commit 216cd72226
33 changed files with 7209 additions and 672 deletions
@@ -0,0 +1,47 @@
+import type {
+  AttachConversation,
+  ConversationSnapshot,
+  DetachConversation,
+  HarnessConversationService,
+  HarnessEventEnvelope,
+  SendHarnessTurn,
+  TurnReceipt,
+} from '@mosaicstack/types';
+import type { ChatRuntime } from './chat-runtime.js';
+
+/**
+ * The `pi-rpc` chat runtime. It executes browser chat exclusively through the
+ * harness-neutral {@link HarnessConversationService} RPC boundary — it never
+ * touches the embedded `AgentService`/`ProviderService`/`RoutingEngineService`
+ * stack, and it forwards the caller's exact selection tuple and idempotency key
+ * without substitution.
+ *
+ * It owns no state and adds no policy: every method forwards the caller's exact
+ * argument to the injected {@link HarnessConversationService} and returns its
+ * result unchanged, so the requested selection tuple and idempotency key can
+ * never be substituted on the way through.
+ */
+export class HarnessChatRuntime implements ChatRuntime {
+  readonly kind = 'harness' as const;
+
+  constructor(private readonly conversations: HarnessConversationService) {}
+
+  attach(input: AttachConversation & { afterSequence?: number }): Promise<ConversationSnapshot> {
+    return this.conversations.attach(input);
+  }
+
+  detach(input: DetachConversation): Promise<void> {
+    return this.conversations.detach(input);
+  }
+
+  send(input: SendHarnessTurn & { idempotencyKey: string }): Promise<TurnReceipt> {
+    return this.conversations.send(input);
+  }
+
+  subscribeFrom(
+    conversationId: string,
+    afterSequence: number,
+  ): AsyncIterable<HarnessEventEnvelope> {
+    return this.conversations.subscribeFrom(conversationId, afterSequence);
+  }
+}