fix(FN-3886): resolve peer agent names in mail and notifications

- Resolve participant display names in AgentDetailView mail tab for peer agents
- Update MailboxModal labeling to use readable agent names instead of raw IDs
- Propagate resolved agent names through notification service, notifier, and provider payloads
- Add and update dashboard/engine tests plus a changeset for @runfusion/fusion

Fusion-Task-Id: FN-3886

packages/engine/src/notification/notification-service.ts

@@ -21,6 +21,8 @@ export interface NotificationServiceOptions {
   ntfyBaseUrl?: string;
   /** Optional message store for mailbox message notifications */
   messageStore?: NotificationMessageStore;
+  /** Resolve human-readable name for an agent ID used in message notifications */
+  agentNameResolver?: (agentId: string) => Promise<string | null> | string | null;
 }
 
 interface NotificationServiceStore {
@@ -267,6 +269,9 @@ export class NotificationService {
 
     const taskId = typeof message.metadata?.taskId === "string" ? message.metadata.taskId : undefined;
 
+    const fromName = await this.resolveAgentName(message.fromType, message.fromId, "from");
+    const toName = await this.resolveAgentName(message.toType, message.toId, "to");
+
     this.maybeNotify(message.id, eventType, {
       taskId,
       taskTitle: undefined,
@@ -275,8 +280,10 @@ export class NotificationService {
         messageId: message.id,
         fromId: message.fromId,
         fromType: message.fromType,
+        ...(fromName ? { fromName } : {}),
         toId: message.toId,
         toType: message.toType,
+        ...(toName ? { toName } : {}),
         type: message.type,
         replyToMessageId: message.metadata?.replyTo?.messageId,
         preview,
@@ -288,6 +295,33 @@ export class NotificationService {
     );
   }
 
+  private async resolveAgentName(
+    participantType: Message["fromType"],
+    participantId: string,
+    direction: "from" | "to",
+  ): Promise<string | null> {
+    if (participantType !== "agent") {
+      return null;
+    }
+
+    const resolver = this.options.agentNameResolver;
+    if (!resolver) {
+      return null;
+    }
+
+    try {
+      const resolved = await resolver(participantId);
+      const trimmed = typeof resolved === "string" ? resolved.trim() : "";
+      return trimmed.length > 0 ? trimmed : null;
+    } catch (error) {
+      const message = error instanceof Error ? error.message : String(error);
+      schedulerLog.log(
+        `NotificationService.handleMessageSent failed to resolve ${direction} agent name agentId=${participantId} error=${message}`,
+      );
+      return null;
+    }
+  }
+
   private setNotificationsEnabledFromSettings(settings: Settings): void {
     this.notificationsEnabled = Boolean(
       (settings.ntfyEnabled && settings.ntfyTopic) ||

packages/engine/src/notification/ntfy-provider.ts

@@ -51,6 +51,20 @@ const SUPPORTED_EVENTS = new Set<SupportedNtfyEvent>([
   "message:agent-to-agent",
 ]);
 
+export function resolveParticipantLabel(
+  metadata: NotificationPayload["metadata"] | undefined,
+  kind: "from" | "to",
+): string {
+  const nameKey = kind === "from" ? "fromName" : "toName";
+  const idKey = kind === "from" ? "fromId" : "toId";
+  const name = typeof metadata?.[nameKey] === "string" ? metadata[nameKey].trim() : "";
+  if (name.length > 0) {
+    return name;
+  }
+  const id = typeof metadata?.[idKey] === "string" ? metadata[idKey].trim() : "";
+  return id.length > 0 ? id : kind === "from" ? "agent" : "recipient";
+}
+
 export class NtfyNotificationProvider implements NotificationProvider {
   private config?: NtfyProviderConfig;
   private abortController: AbortController | null = null;
@@ -113,8 +127,8 @@ export class NtfyNotificationProvider implements NotificationProvider {
 
     const identifier = formatTaskIdentifier(taskLike);
     const messageId = typeof payload.metadata?.messageId === "string" ? payload.metadata.messageId : undefined;
-    const senderLabel = typeof payload.metadata?.fromId === "string" ? payload.metadata.fromId : "agent";
-    const recipientLabel = typeof payload.metadata?.toId === "string" ? payload.metadata.toId : "recipient";
+    const senderLabel = resolveParticipantLabel(payload.metadata, "from");
+    const recipientLabel = resolveParticipantLabel(payload.metadata, "to");
     const preview = typeof payload.metadata?.preview === "string"
       ? payload.metadata.preview
       : "(no preview)";

packages/engine/src/notification/webhook-provider.ts

@@ -20,6 +20,20 @@ export interface WebhookProviderConfig {
   projectId?: string;
 }
 
+function resolveParticipantLabel(
+  metadata: NotificationPayload["metadata"] | undefined,
+  kind: "from" | "to",
+): string {
+  const nameKey = kind === "from" ? "fromName" : "toName";
+  const idKey = kind === "from" ? "fromId" : "toId";
+  const name = typeof metadata?.[nameKey] === "string" ? metadata[nameKey].trim() : "";
+  if (name.length > 0) {
+    return name;
+  }
+  const id = typeof metadata?.[idKey] === "string" ? metadata[idKey].trim() : "";
+  return id.length > 0 ? id : kind === "from" ? "agent" : "recipient";
+}
+
 export class WebhookNotificationProvider implements NotificationProvider {
   private config: WebhookProviderConfig | null = null;
   private abortController: AbortController | null = null;
@@ -142,6 +156,17 @@ export class WebhookNotificationProvider implements NotificationProvider {
         return "Pipeline gridlocked";
       case "fallback-used":
         return `Fusion recovered by switching from ${String(payload.metadata?.primaryModel ?? "primary model")} to ${String(payload.metadata?.fallbackModel ?? "fallback model")} (${String(payload.metadata?.triggerPoint ?? "unknown trigger")})`;
+      case "message:agent-to-user": {
+        const from = resolveParticipantLabel(payload.metadata, "from");
+        const preview = typeof payload.metadata?.preview === "string" ? payload.metadata.preview : "(no preview)";
+        return `From: ${from} → You: ${preview}`;
+      }
+      case "message:agent-to-agent": {
+        const from = resolveParticipantLabel(payload.metadata, "from");
+        const to = resolveParticipantLabel(payload.metadata, "to");
+        const preview = typeof payload.metadata?.preview === "string" ? payload.metadata.preview : "(no preview)";
+        return `From: ${from} → To: ${to}: ${preview}`;
+      }
       default:
         return `Event "${event}" for task ${identifier}`;
     }
@@ -172,6 +197,9 @@ export class WebhookNotificationProvider implements NotificationProvider {
 
     const messageId = typeof payload.metadata?.messageId === "string" ? payload.metadata.messageId : undefined;
 
+    const fromLabel = resolveParticipantLabel(payload.metadata, "from");
+    const toLabel = resolveParticipantLabel(payload.metadata, "to");
+
     return {
       event: payload.event,
       timestamp: new Date().toISOString(),
@@ -179,7 +207,15 @@ export class WebhookNotificationProvider implements NotificationProvider {
         id: payload.taskId,
         title: payload.taskTitle,
       },
-      metadata: payload.metadata,
+      metadata: {
+        ...payload.metadata,
+        ...(payload.event === "message:agent-to-user" || payload.event === "message:agent-to-agent"
+          ? {
+            fromName: typeof payload.metadata?.fromName === "string" ? payload.metadata.fromName : fromLabel,
+            toName: typeof payload.metadata?.toName === "string" ? payload.metadata.toName : toLabel,
+          }
+          : {}),
+      },
       clickUrl: buildNtfyClickUrl({
         dashboardHost: this.config.dashboardHost,
         projectId: this.config.projectId,