Fixes #756 (#763)

apps/gateway/src/agent/agent.service.ts

@@ -15,6 +15,7 @@ import {
   type ToolDefinition,
 } from '@mariozechner/pi-coding-agent';
 import type { Brain } from '@mosaicstack/brain';
+import type { ChannelAttachmentDto } from '@mosaicstack/types';
 import type { Memory, OperatorMemoryPlugin } from '@mosaicstack/memory';
 import { BRAIN } from '../brain/brain.tokens.js';
 import { MEMORY } from '../memory/memory.tokens.js';
@@ -43,6 +44,8 @@ export interface ConversationHistoryMessage {
   role: 'user' | 'assistant' | 'system';
   content: string;
   createdAt: Date;
+  /** Validated, URI-referenced channel attachments preserved on session resume. */
+  attachments?: readonly ChannelAttachmentDto[];
 }
 
 export interface AgentSessionOptions {
@@ -428,7 +431,7 @@ export class AgentService implements OnModuleDestroy {
     const formatMessage = (msg: ConversationHistoryMessage): string => {
       const roleLabel =
         msg.role === 'user' ? 'User' : msg.role === 'assistant' ? 'Assistant' : 'System';
-      return `**${roleLabel}:** ${msg.content}`;
+      return `**${roleLabel}:** ${msg.content}${this.attachmentContext(msg.attachments ?? [])}`;
     };
 
     const formatted = history.map((msg) => formatMessage(msg));
@@ -487,6 +490,21 @@ export class AgentService implements OnModuleDestroy {
     return result;
   }
 
+  private attachmentContext(attachments: readonly ChannelAttachmentDto[]): string {
+    if (attachments.length === 0) return '';
+    return `\n\n[Untrusted channel attachments]\n${attachments
+      .map((attachment: ChannelAttachmentDto): string =>
+        JSON.stringify({
+          id: attachment.id,
+          name: attachment.name,
+          mimeType: attachment.mimeType,
+          url: attachment.url,
+          ...(attachment.sizeBytes !== undefined ? { sizeBytes: attachment.sizeBytes } : {}),
+        }),
+      )
+      .join('\n')}`;
+  }
+
   private resolveModel(options?: AgentSessionOptions) {
     if (!options?.provider && !options?.modelId) {
       return this.providerService.getDefaultModel() ?? null;
@@ -673,7 +691,19 @@ export class AgentService implements OnModuleDestroy {
     session.channels.delete(channel);
   }
 
-  async prompt(sessionId: string, message: string, scope: ActorTenantScope): Promise<void> {
+  async prompt(sessionId: string, message: string, scope: ActorTenantScope): Promise<void>;
+  async prompt(
+    sessionId: string,
+    message: string,
+    scope: ActorTenantScope,
+    attachments: readonly ChannelAttachmentDto[] | undefined,
+  ): Promise<void>;
+  async prompt(
+    sessionId: string,
+    message: string,
+    scope: ActorTenantScope,
+    attachments: readonly ChannelAttachmentDto[] = [],
+  ): Promise<void> {
     const session = this.sessions.get(sessionId);
     if (!session) {
       throw new Error(`No agent session found: ${sessionId}`);
@@ -681,12 +711,16 @@ export class AgentService implements OnModuleDestroy {
     this.assertSessionScope(session, scope);
     session.promptCount += 1;
 
+    // Channel attachments are untrusted URI references. Preserve exact,
+    // authenticated metadata for the agent without treating it as authority.
+    const attachmentContext = this.attachmentContext(attachments);
+
     // Prepend session-scoped system override if present (renew TTL on each turn)
-    let effectiveMessage = message;
+    let effectiveMessage = `${message}${attachmentContext}`;
     if (this.systemOverride) {
       const override = await this.systemOverride.get(sessionId, scope);
       if (override) {
-        effectiveMessage = `[System Override]\n${override}\n\n${message}`;
+        effectiveMessage = `[System Override]\n${override}\n\n${effectiveMessage}`;
         await this.systemOverride.renew(sessionId, scope);
         this.logger.debug(`Applied system override for session ${sessionId}`);
       }