feat(slack): per-message thread for top-level posts in per-thread sessions#2472
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feat(slack): per-message thread for top-level posts in per-thread sessions#2472luisfontes wants to merge 1 commit into
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…sions Implement ChannelAdapter.rewriteThreadIdForSession on the Slack adapter. Slack's chat-sdk adapter encodes top-level (un-threaded) messages with an empty thread_ts — for DMs this means every unsolicited message arrives with the same threadId, so a wiring with `session_mode=per-thread` degenerates to a single ever-growing session and outbound replies post as flat channel messages instead of in-thread (postMessage decodes thread_ts from the threadId, and an empty thread_ts means "post at top level"). The rewriter mints a per-message threadId by re-encoding the channel with the message's own ts as thread_ts. Each new top-level post becomes its own thread/session AND the reply posts in-thread because Slack auto-creates the thread on the first reply. In-thread events already carry a real thread_ts (decoded.threadTs is non-empty) so the rewrite no-ops. The router only consults this hook when the wiring's effective session_mode is per-thread (see ChannelAdapter.rewriteThreadIdForSession docs upstream of this branch). In shared / agent-shared mode the threadId doesn't gate the session, so the rewriter wouldn't help and isn't called. Note for review: depends on the host-side hook landing in main first (adapter interface + router integration). Once main is merged forward into channels, this PR rebases trivially. Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
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TL;DR
Before: a wiring with
session_mode=per-threadon a Slack DM collapses every top-level DM into one ever-growing session, and the bot's replies post as flat top-level messages.After: each top-level DM becomes its own session and the bot's reply posts in-thread.
(No change in
session_mode=shared. Depends on #2471.)Summary
Implements
ChannelAdapter.rewriteThreadIdForSessionon the Slack adapter. When a wiring is insession_mode=per-thread, top-level Slack posts (DMs and channel posts without a parent thread) each get their own thread/session instead of all collapsing under the same threadId. The reply posts in-thread.Why
Slack's
@chat-adapter/slackencodes top-level (un-threaded) messages withthread_ts="". For DMs that means every unsolicited message arrives with the same threadId — so a wiring withsession_mode=per-threadon a DM degenerates to a single ever-growing session, and outbound replies post as flat channel messages (becausepostMessagereadsthread_tsfrom the threadId and empty means "post at top level").The rewriter re-encodes the threadId with the message's own
tsasthread_ts. Each top-level post becomes its own thread/session AND Slack auto-creates the thread on first reply. In-thread events already carry a realthread_ts, sodecoded.threadTsis non-empty and the rewrite no-ops.Why no toggle
The router only consults this hook when the wiring's effective
session_modeisper-thread(see #2471 againstmain).shared/agent-sharedusers see no change. Operators who explicitly opt into per-thread DMs get the correct behavior without any new config flag.Depends on
main).channelsnext mergesmain, this PR rebases trivially. Verified locally by combining both patches: build + channel tests green.Files
src/channels/slack.ts— attachesbridge.rewriteThreadIdForSession.Test plan
session_mode=per-threadDM wiring: top-level DM sends create distinct sessions; bot replies post in-thread.session_mode=sharedDM wiring: no change from today's behavior (hook not consulted).🤖 Generated with Claude Code