feat: add sendFile support to Signal channel adapter (#407)

src/channels/signal.test.ts

@@ -0,0 +1,89 @@
+import { describe, it, expect, vi } from 'vitest';
+import { SignalAdapter } from './signal.js';
+
+describe('SignalAdapter sendFile', () => {
+  function createAdapter(phone = '+15555555555') {
+    return new SignalAdapter({ phoneNumber: phone });
+  }
+
+  it('sends attachment to a direct message recipient', async () => {
+    const adapter = createAdapter();
+    const rpcSpy = vi.spyOn(adapter as any, 'rpcRequest').mockResolvedValue({ timestamp: 12345 });
+
+    const result = await adapter.sendFile({
+      chatId: '+12223334444',
+      filePath: '/tmp/voice.ogg',
+    });
+
+    expect(rpcSpy).toHaveBeenCalledWith('send', {
+      attachment: ['/tmp/voice.ogg'],
+      account: '+15555555555',
+      recipient: ['+12223334444'],
+    });
+    expect(result.messageId).toBe('12345');
+  });
+
+  it('sends attachment to a group', async () => {
+    const adapter = createAdapter();
+    const rpcSpy = vi.spyOn(adapter as any, 'rpcRequest').mockResolvedValue({ timestamp: 99 });
+
+    await adapter.sendFile({
+      chatId: 'group:abc123',
+      filePath: '/tmp/photo.png',
+      kind: 'image',
+    });
+
+    expect(rpcSpy).toHaveBeenCalledWith('send', {
+      attachment: ['/tmp/photo.png'],
+      account: '+15555555555',
+      groupId: 'abc123',
+    });
+  });
+
+  it('includes caption as message text', async () => {
+    const adapter = createAdapter();
+    const rpcSpy = vi.spyOn(adapter as any, 'rpcRequest').mockResolvedValue({ timestamp: 1 });
+
+    await adapter.sendFile({
+      chatId: '+12223334444',
+      filePath: '/tmp/report.pdf',
+      caption: 'Here is the report',
+    });
+
+    expect(rpcSpy).toHaveBeenCalledWith('send', {
+      attachment: ['/tmp/report.pdf'],
+      message: 'Here is the report',
+      account: '+15555555555',
+      recipient: ['+12223334444'],
+    });
+  });
+
+  it('sends to own number for note-to-self', async () => {
+    const adapter = createAdapter('+19998887777');
+    const rpcSpy = vi.spyOn(adapter as any, 'rpcRequest').mockResolvedValue({ timestamp: 42 });
+
+    await adapter.sendFile({
+      chatId: 'note-to-self',
+      filePath: '/tmp/memo.ogg',
+      kind: 'audio',
+    });
+
+    expect(rpcSpy).toHaveBeenCalledWith('send', {
+      attachment: ['/tmp/memo.ogg'],
+      account: '+19998887777',
+      recipient: ['+19998887777'],
+    });
+  });
+
+  it('returns unknown when no timestamp in response', async () => {
+    const adapter = createAdapter();
+    vi.spyOn(adapter as any, 'rpcRequest').mockResolvedValue({});
+
+    const result = await adapter.sendFile({
+      chatId: '+12223334444',
+      filePath: '/tmp/file.txt',
+    });
+
+    expect(result.messageId).toBe('unknown');
+  });
+});

src/channels/signal.ts

@@ -6,7 +6,7 @@
  */
 
 import type { ChannelAdapter } from './types.js';
-import type { InboundAttachment, InboundMessage, OutboundMessage } from '../core/types.js';
+import type { InboundAttachment, InboundMessage, OutboundFile, OutboundMessage } from '../core/types.js';
 import { applySignalGroupGating } from './signal/group-gating.js';
 import type { DmPolicy } from '../pairing/types.js';
 import {
@@ -305,6 +305,36 @@ This code expires in 1 hour.`;
     };
   }
   
+  async sendFile(file: OutboundFile): Promise<{ messageId: string }> {
+    const params: Record<string, unknown> = {
+      attachment: [file.filePath],
+    };
+
+    // Include caption as the message text
+    if (file.caption) {
+      params.message = file.caption;
+    }
+
+    if (this.config.phoneNumber) {
+      params.account = this.config.phoneNumber;
+    }
+
+    const target = file.chatId === 'note-to-self' ? this.config.phoneNumber : file.chatId;
+
+    if (target.startsWith('group:')) {
+      params.groupId = target.slice('group:'.length);
+    } else {
+      params.recipient = [target];
+    }
+
+    const result = await this.rpcRequest<{ timestamp?: number }>('send', params);
+    const timestamp = result?.timestamp;
+
+    return {
+      messageId: timestamp ? String(timestamp) : 'unknown',
+    };
+  }
+
   getDmPolicy(): string {
     return this.config.dmPolicy || 'pairing';
   }

src/config/types.ts

@@ -529,7 +529,7 @@ export function normalizeAgents(config: LettaBotConfig): AgentConfig[] {
     ];
     for (const [name, raw, included] of channelCredentials) {
       if (raw && (raw as Record<string, unknown>).enabled !== false && !included) {
-        console.warn(`[Config] Channel '${name}' is in ${sourcePath} but missing required credentials -- skipping. Check your lettabot.yaml or environment variables.`);
+        log.warn(`Channel '${name}' is in ${sourcePath} but missing required credentials -- skipping. Check your lettabot.yaml or environment variables.`);
       }
     }
 

src/core/bot.ts

@@ -1065,7 +1065,11 @@ export class LettaBot implements AgentSession {
       let oldestKey: string | null = null;
       let oldestTime = Infinity;
       for (const [k, ts] of this.sessionLastUsed) {
-        if (k !== key && ts < oldestTime && this.sessions.has(k)) {
+        if (k === key) continue;
+        if (!this.sessions.has(k)) continue;
+        // Never evict an active/in-flight key (can close a live stream).
+        if (this.processingKeys.has(k) || this.sessionCreationLocks.has(k)) continue;
+        if (ts < oldestTime) {
           oldestKey = k;
           oldestTime = ts;
         }
@@ -1078,6 +1082,9 @@ export class LettaBot implements AgentSession {
         this.sessionLastUsed.delete(oldestKey);
         this.sessionGenerations.delete(oldestKey);
         this.sessionCreationLocks.delete(oldestKey);
+      } else {
+        // All existing sessions are active; allow temporary overflow.
+        log.debug(`LRU session eviction skipped: all ${this.sessions.size} sessions are active/in-flight`);
       }
     }
 
@@ -1137,9 +1144,10 @@ export class LettaBot implements AgentSession {
     this.store.refresh();
     if (!this.store.agentId && !this.store.conversationId) return;
     try {
-      // In shared mode, warm the single session. In per-channel mode, warm nothing
+      const mode = this.config.conversationMode || 'shared';
-      // (sessions are created on first message per channel).
+      // In shared mode, warm the single session. In per-channel/per-chat modes,
-      if (this.config.conversationMode !== 'per-channel') {
+      // warm nothing (sessions are created on first message per key).
+      if (mode === 'shared') {
         await this.ensureSessionForKey('shared');
       }
     } catch (err) {

src/core/sdk-session-contract.test.ts

@@ -262,6 +262,20 @@ describe('SDK session contract', () => {
     expect(vi.mocked(createSession)).toHaveBeenCalledTimes(1);
   });
 
+  it('does not pre-warm a shared session in per-chat mode', async () => {
+    const bot = new LettaBot({
+      workingDir: join(dataDir, 'working'),
+      allowedTools: [],
+      conversationMode: 'per-chat',
+    });
+    bot.setAgentId('agent-contract-test');
+
+    await bot.warmSession();
+
+    expect(vi.mocked(createSession)).not.toHaveBeenCalled();
+    expect(vi.mocked(resumeSession)).not.toHaveBeenCalled();
+  });
+
   it('passes memfs: true to createSession when config sets memfs true', async () => {
     const mockSession = {
       initialize: vi.fn(async () => undefined),
@@ -378,6 +392,52 @@ describe('SDK session contract', () => {
     expect(processSpy).toHaveBeenCalledWith('slack');
   });
 
+  it('LRU eviction in per-chat mode does not close active keys', async () => {
+    const createdSession = {
+      initialize: vi.fn(async () => undefined),
+      send: vi.fn(async (_message: unknown) => undefined),
+      stream: vi.fn(() =>
+        (async function* () {
+          yield { type: 'result', success: true };
+        })()
+      ),
+      close: vi.fn(() => undefined),
+      agentId: 'agent-contract-test',
+      conversationId: 'conv-new',
+    };
+    vi.mocked(createSession).mockReturnValue(createdSession as never);
+
+    const activeSession = {
+      close: vi.fn(() => undefined),
+    };
+    const idleSession = {
+      close: vi.fn(() => undefined),
+    };
+
+    const bot = new LettaBot({
+      workingDir: join(dataDir, 'working'),
+      allowedTools: [],
+      conversationMode: 'per-chat',
+      maxSessions: 2,
+    });
+    bot.setAgentId('agent-contract-test');
+
+    const botInternal = bot as any;
+    botInternal.sessions.set('telegram:active', activeSession);
+    botInternal.sessions.set('telegram:idle', idleSession);
+    botInternal.sessionLastUsed.set('telegram:active', 1);
+    botInternal.sessionLastUsed.set('telegram:idle', 2);
+    botInternal.processingKeys.add('telegram:active');
+
+    await botInternal._createSessionForKey('telegram:new', true, 0);
+
+    expect(activeSession.close).not.toHaveBeenCalled();
+    expect(idleSession.close).toHaveBeenCalledTimes(1);
+    expect(botInternal.sessions.has('telegram:active')).toBe(true);
+    expect(botInternal.sessions.has('telegram:idle')).toBe(false);
+    expect(botInternal.sessions.has('telegram:new')).toBe(true);
+  });
+
   it('enriches opaque error via stream error event in sendToAgent', async () => {
     const mockSession = {
       initialize: vi.fn(async () => undefined),