Problem

Cron jobs targeting Telegram forum topics (e.g. delivery.to = "-1003885638534:topic:562") silently fail to deliver their output to the user.

Root Cause

For text-only cron output, the delivery path goes through the subagent announce flow (runSubagentAnnounceFlow → sendSubagentAnnounceDirectly), which triggers a full agent turn in the target session. The receiving agent is given the option to respond with ANNOUNCE_SKIP (or NO_REPLY), and it frequently does — silently dropping the cron output.

Forum topic sessions are especially prone to this because:

1. The announce arrives via an internal webchat-like channel context (channel=webchat in logs)
2. The target agent sees the ANNOUNCE_SKIP option in the announce prompt and decides to stay silent
3. The cron output never reaches the Telegram topic

Reproduction

1. Create a cron job with delivery.mode = "announce" targeting a Telegram forum topic:

   {
     "delivery": {
       "mode": "announce",
       "channel": "telegram",
       "to": "-1003885638534:topic:562"
     }
   }

2. The cron runs successfully, generates text output
3. parseTelegramTarget correctly extracts chatId and messageThreadId ✓
4. resolveDeliveryTarget correctly sets threadId: 562 and threadIdExplicit: true ✓
5. resolveCronAnnounceSessionKey correctly resolves to the forum topic session ✓
6. But sendSubagentAnnounceDirectly triggers an agent turn where the agent responds ANNOUNCE_SKIP
7. Gateway logs: [agent:nested] session=...topic:562 channel=webchat ANNOUNCE_SKIP
8. User sees nothing in the Telegram topic

Fix

When resolvedDelivery.threadId is present (indicating a forum topic or thread target), use the direct outbound delivery path (deliverOutboundPayloads) — the same path already used for structured payloads (media, etc.). This bypasses the intermediary agent turn entirely and sends the text straight to the Telegram API with the correct message_thread_id.

// Before: only structured payloads got direct delivery
if (deliveryPayloadHasStructuredContent) {

// After: forum topics also get direct delivery
const useDirectDelivery = deliveryPayloadHasStructuredContent || resolvedDelivery.threadId != null;
if (useDirectDelivery) {

Changes

• src/cron/isolated-agent/run.ts: Added useDirectDelivery condition that includes threadId presence
• New test file: isolated-agent.direct-delivery-forum-topics.test.ts — verifies direct delivery for forum topics and confirm announce flow still used for non-threaded targets
• Updated existing test: Changed "passes resolved threadId into shared subagent announce flow" to expect direct delivery behavior

Test Results

All 219 cron tests pass (36 test files).

Greptile Summary

This PR fixes a bug where cron job outputs targeting Telegram forum topics (or other threaded channels) were silently failing to deliver. The root cause was that text-only cron output went through the subagent announce flow, which triggered an agent turn in the target session. The receiving agent would often respond with ANNOUNCE_SKIP or NO_REPLY, silently dropping the cron output.

The fix introduces a useDirectDelivery flag that triggers direct delivery (bypassing the announce flow) when either:

• The payload contains structured content (media, channel data) - existing behavior
• The delivery target has a threadId (forum topics, Discord threads, Slack threads) - new behavior

This ensures forum topic deliveries go straight to the channel API with the correct message_thread_id, avoiding the intermediary agent turn entirely.

Changes:

• Modified src/cron/isolated-agent/run.ts:667-668 to check for threadId presence in addition to structured content
• Added comprehensive test coverage for both forum topic direct delivery and non-threaded announce flow preservation
• Updated existing test to reflect new behavior when threadId is present

Confidence Score: 5/5

• This PR is safe to merge with minimal risk
• The fix is well-targeted and addresses a specific, well-documented bug. The change uses the correct null-safety check (!= null) to handle both null and undefined while preserving valid falsy values like 0. The implementation properly passes threadId through the existing deliverOutboundPayloads path, which already handles threading for multiple channels (Telegram, Discord, Slack). Test coverage is comprehensive, including both the new forum topic scenario and verification that non-threaded targets still use the announce flow. All 219 cron tests pass.
• No files require special attention

_{Last reviewed commit: 28c5faf}

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