When Slack native streaming (`chat.startStream`/`stopStream`) is enabled,
`disableBlockStreaming` was set to `false`, which activated the app-level
block streaming pipeline. This pipeline intercepted agent output, sent it
via block replies, then dropped the final payloads that would have flowed
through `deliverWithStreaming` to the Slack streaming API — resulting in
zero replies delivered.
Set `disableBlockStreaming: true` when native streaming is active so the
final reply flows through the Slack streaming API path as intended.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
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