fix: execute directives in background flows, reject partial send-file targeting

Two fixes from PR review:

1. sendToAgent() now parses and executes directives from agent responses.
   Previously, directives were only executed in processMessage() (foreground),
   so <send-message> and targeted <send-file> never fired from heartbeats,
   cron, or webhook contexts. Targeted directives resolve their own adapter;
   non-targeted directives use source context from the trigger if available.

2. send-file with only one of channel/chat (partial targeting) is now
   rejected with a warning instead of silently falling back to the
   triggering chat, which could send to an unintended destination.

Written by Cameron ◯ Letta Code

"Be conservative in what you send, be liberal in what you accept."
-- Jon Postel

src/core/bot.ts

@@ -363,6 +363,13 @@ export class LettaBot implements AgentSession {
       }
 
       if (directive.type === 'send-file') {
+        // Reject partial targeting: both channel and chat must be set together.
+        // Without this guard, a missing field silently falls back to the triggering chat.
+        if ((directive.channel && !directive.chat) || (!directive.channel && directive.chat)) {
+          log.warn(`Directive send-file skipped: cross-channel targeting requires both channel and chat (got channel=${directive.channel || 'missing'}, chat=${directive.chat || 'missing'})`);
+          continue;
+        }
+
         // Resolve target adapter: use cross-channel targeting if both channel and chat are set,
         // otherwise fall back to the adapter/chatId that triggered this response.
         const targetAdapter = (directive.channel && directive.chat)
@@ -1908,11 +1915,29 @@ export class LettaBot implements AgentSession {
             continue;
           }
 
+          // Parse and execute directives from the response.
+          // Targeted directives (send-message, cross-channel send-file) work in any context.
+          // Non-targeted directives work when source adapter context is available.
+          let executedDirectives = false;
+          if (response.trim()) {
+            const parsed = parseDirectives(response);
+            if (parsed.directives.length > 0) {
+              const sourceAdapter = (context?.sourceChannel ? this.channels.get(context.sourceChannel) : undefined)
+                ?? this.channels.values().next().value;
+              if (sourceAdapter) {
+                executedDirectives = await this.executeDirectives(
+                  parsed.directives, sourceAdapter, context?.sourceChatId ?? '',
+                );
+              }
+              response = parsed.cleanText;
+            }
+          }
+
           if (isSilent && response.trim()) {
-            if (usedMessageCli) {
-              log.info(`Silent mode: agent used lettabot-message CLI, collected ${response.length} chars (not delivered)`);
+            if (usedMessageCli || executedDirectives) {
+              log.info(`Silent mode: agent delivered via ${[usedMessageCli && 'CLI', executedDirectives && 'directives'].filter(Boolean).join(' + ')}, remaining text (${response.length} chars) not delivered`);
             } else {
-              log.warn(`Silent mode: agent produced ${response.length} chars but did NOT use lettabot-message CLI — response discarded. If this keeps happening, the agent's model may not be following silent mode instructions.`);
+              log.warn(`Silent mode: agent produced ${response.length} chars but did NOT use lettabot-message CLI or directives — response discarded. If this keeps happening, the agent's model may not be following silent mode instructions.`);
             }
           }
           return response;

src/core/directives.test.ts

@@ -306,6 +306,24 @@ describe('parseDirectives', () => {
       { type: 'send-file', path: 'report.pdf', caption: 'Report' },
     ]);
   });
+
+  it('parses send-file with only channel (no chat) -- stores partial targeting', () => {
+    const result = parseDirectives(
+      '<actions><send-file path="report.pdf" channel="whatsapp" /></actions>',
+    );
+    expect(result.directives).toEqual([
+      { type: 'send-file', path: 'report.pdf', channel: 'whatsapp' },
+    ]);
+  });
+
+  it('parses send-file with only chat (no channel) -- stores partial targeting', () => {
+    const result = parseDirectives(
+      '<actions><send-file path="report.pdf" chat="123" /></actions>',
+    );
+    expect(result.directives).toEqual([
+      { type: 'send-file', path: 'report.pdf', chat: '123' },
+    ]);
+  });
 });
 
 describe('stripActionsBlock', () => {