Summary

• retry Telegram text/media/sticker sends once without message_thread_id when Telegram returns 400: Bad Request: message thread not found
• keep existing behavior for other Telegram errors (no broad swallow/retry)
• clear stale persisted thread ids when updateLastRoute receives an explicit no-thread delivery context
• add changelog entry for [Bug]: Telegram message tool fails with "message thread not found" after Topics/Forum mode was toggled #11620

Why

The message tool could carry stale Telegram thread IDs after topic/forum toggles, causing proactive sends to fail with message thread not found.

Fixes #11620.

Testing

• pnpm check
• pnpm vitest src/telegram/send.returns-undefined-empty-input.test.ts src/config/sessions.test.ts

Greptile Overview

Greptile Summary

This PR hardens Telegram outbound sends against stale forum-topic thread IDs by retrying text/media/sticker sends once without message_thread_id when Telegram replies with 400: Bad Request: message thread not found. It also updates session routing persistence so an explicitly “no-thread” delivery context clears previously persisted thread IDs (instead of inheriting stale state), and adds a changelog entry for #11620.

Key touchpoints:

• src/telegram/send.ts wraps send attempts with a targeted threadless retry while preserving existing behavior for other Telegram errors.
• src/config/sessions/store.ts changes updateLastRoute merge behavior to optionally drop threadId from the fallback (existing session) route.
• Tests in src/telegram/send.returns-undefined-empty-input.test.ts and src/config/sessions.test.ts cover the new retry and clearing semantics.

Confidence Score: 3/5

• This PR is close to safe, but has at least one correctness edge case around clearing/stopping inheritance of thread IDs that may not work as intended.
• The Telegram retry change is narrow and well-tested, but updateLastRoute’s new “explicit no-thread clears stale threadId” logic depends on hasOwnProperty('threadId') on the raw deliveryContext, while normalization drops undefined threadId keys. Callers that indicate no-thread via threadId: undefined may not actually clear the persisted thread, undermining the main fix. There’s also a smaller robustness issue where the thread-not-found retry wrapper can be triggered even when message_thread_id is present-but-undefined, leading to redundant retries/logging.
• src/config/sessions/store.ts, src/telegram/send.ts