fix: expose AgentRun prompt assembly trace details

internal/cloud/code-agent-agentrun-adapter.ts

@@ -1021,7 +1021,15 @@ function mapAgentRunEvent(event, mapping = {}) {
   };
   if (event.type === "backend_status") {
     const phase = String(payload.phase ?? "status");
-    return { ...base, type: "backend", status: "running", label: `agentrun:backend:${phase}`, message: textPayload(payload, phase), waitingFor: waitingForForPhase(phase) };
+    return {
+      ...base,
+      type: "backend",
+      status: "running",
+      label: `agentrun:backend:${phase}`,
+      message: textPayload(payload, phase),
+      waitingFor: waitingForForPhase(phase),
+      details: agentRunBackendStatusDetails(phase, payload)
+    };
   }
   if (event.type === "assistant_message") {
     const terminal = payload.replyAuthority === true || payload.final === true;
@@ -1072,6 +1080,56 @@ function mapAgentRunEvent(event, mapping = {}) {
   return { ...base, type: "backend", status: "running", label: `agentrun:event:${String(event.type ?? "unknown")}`, message: textPayload(payload, "AgentRun event") };
 }
 
+function agentRunBackendStatusDetails(phase, payload = {}) {
+  if (phase === "initial-prompt-assembly") {
+    return compactObject({
+      initialPromptInjected: payload.initialPromptInjected === true,
+      reason: firstNonEmpty(payload.reason),
+      initialPrompt: agentRunResourceSummary(payload.initialPrompt),
+      valuesPrinted: false
+    });
+  }
+  if (phase === "resource-bundle-materialized") {
+    return compactObject({
+      kind: firstNonEmpty(payload.kind),
+      commitId: firstNonEmpty(payload.commitId),
+      toolAliases: agentRunResourceSummary(payload.toolAliases),
+      promptRefs: agentRunResourceSummary(payload.promptRefs),
+      skillRefs: agentRunResourceSummary(payload.skillRefs),
+      initialPrompt: agentRunResourceSummary(payload.initialPrompt),
+      valuesPrinted: false
+    });
+  }
+  return undefined;
+}
+
+function agentRunResourceSummary(value) {
+  if (!value || typeof value !== "object" || Array.isArray(value)) return undefined;
+  return compactObject({
+    available: typeof value.available === "boolean" ? value.available : undefined,
+    count: Number.isInteger(value.count) ? value.count : undefined,
+    bytes: Number.isInteger(value.bytes) ? value.bytes : undefined,
+    sha256: firstNonEmpty(value.sha256),
+    promptRefCount: Number.isInteger(value.promptRefCount) ? value.promptRefCount : undefined,
+    skillRefCount: Number.isInteger(value.skillRefCount) ? value.skillRefCount : undefined,
+    names: Array.isArray(value.names) ? value.names.map((item) => firstNonEmpty(item)).filter(Boolean).slice(0, 20) : undefined,
+    requiredMissing: Array.isArray(value.requiredMissing) ? value.requiredMissing.map((item) => firstNonEmpty(item)).filter(Boolean).slice(0, 20) : undefined,
+    valuesPrinted: false
+  });
+}
+
+function compactObject(value) {
+  if (!value || typeof value !== "object" || Array.isArray(value)) return undefined;
+  const result = {};
+  for (const [key, item] of Object.entries(value)) {
+    if (item === undefined || item === null) continue;
+    if (Array.isArray(item) && item.length === 0) continue;
+    if (typeof item === "object" && !Array.isArray(item) && Object.keys(item).length === 0) continue;
+    result[key] = item;
+  }
+  return Object.keys(result).length > 0 ? result : undefined;
+}
+
 function agentRunCommandExecutionEvent(base, payload = {}) {
   const item = payload.item && typeof payload.item === "object" ? payload.item : null;
   const payloadToolType = firstNonEmpty(payload.toolName, payload.type, payload.name);