fix: stabilize embedded runner transport and channel state

src/agents/pi-embedded-runner/compact.ts

@@ -799,10 +799,13 @@ export async function compactEmbeddedPiSessionDirect(
         effectiveModel,
         agentDir,
       );
-      resolveAgentTransportOverride({
+      const agentTransportOverride = resolveAgentTransportOverride({
         settingsManager,
         effectiveExtraParams,
       });
+      if (agentTransportOverride && session.agent.transport !== agentTransportOverride) {
+        session.agent.setTransport(agentTransportOverride);
+      }
 
       try {
         const prior = await sanitizeSessionHistory({

src/agents/pi-embedded-runner/run/attempt.ts

@@ -981,6 +981,7 @@ export async function runEmbeddedAttempt(
           `embedded agent transport override: ${activeSession.agent.transport} -> ${agentTransportOverride} ` +
             `(${params.provider}/${params.modelId})`,
         );
+        activeSession.agent.setTransport(agentTransportOverride);
       }
 
       const cacheObservabilityEnabled = Boolean(cacheTrace) || log.isEnabled("debug");

src/gateway/server-channels.ts

@@ -78,6 +78,7 @@ function applyDescribedAccountFields(
   described: ChannelAccountSnapshot | undefined,
 ) {
   if (!described) {
+    next.configured ??= true;
     return next;
   }
   if (typeof described.configured === "boolean") {