* fix(slack): use thread-level sessions for channels to prevent context mixing
All messages in a Slack channel share a single session, causing context from
different threads to mix together. When users have multiple conversations in
different threads of the same channel, the agent sees combined context from
all threads, leading to confused responses.
Session key was: `slack:channel:${channelId}` (no thread identifier)
1. **Thread-level session keys**: Each message in channels/groups now gets
its own session based on thread_ts:
- Thread replies: use the parent thread's ts
- New messages: use the message's own ts (becomes thread root)
- DMs: unchanged (no thread-level sessions needed)
New session key format: `slack:channel:${channelId}🧵${threadTs}`
2. **Increased thread cache TTL**: Changed from 60 seconds to 6 hours.
Users often pause conversations, and the short TTL caused unnecessary
API calls and thread resolution failures.
3. **Increased cache size**: Changed from 500 to 10,000 entries to support
busy workspaces with many active threads.
1. Create two threads in the same Slack channel
2. In Thread A: tell the bot your name is "Alice" and ask about "billing"
3. In Thread B: tell the bot your name is "Bob" and ask about "API"
4. Reply in Thread A and ask "what's my name?" - should say "Alice"
5. Check sessions: each thread should have a unique session key with 🧵 suffix
Fixes context bleed issues related to #758
* fix(slack): also update resolveSlackSystemEventSessionKey for thread-level sessions
The context.ts file has a separate function for resolving session keys for
system events (reactions, file uploads, etc.). This also needs to support
thread-level sessions to ensure all Slack events route to the correct
thread-specific session.
Added threadTs and messageTs parameters to resolveSlackSystemEventSessionKey
and updated the implementation to use thread-level keys for channels/groups.
* fix(slack): preserve DM thread sessions for thread replies
The previous change broke thread-level sessions for DMs that have threads.
DMs with parent_user_id should still get thread-level sessions.
- For channels/groups: always use thread-level sessions
- For DMs: use thread-level sessions only when isThreadReply is true
* fix(slack): use thread-level sessionKey for previousTimestamp
Fixes the bug where previousTimestamp was read from the base channel
session key (route.sessionKey) instead of the resolved thread-level
sessionKey. This caused the elapsed-time calculation in the inbound
envelope to always pull from the channel session rather than the
thread session.
Also adds regression tests for the thread-level session key behavior.
Co-authored-by: Tony Dehnke <tdehnke@gmail.com>
* fix(slack): narrow #10686 to surgical thread-session patch
* test(slack): satisfy context/account typing in thread-session tests
* docs(changelog): record surgical slack thread-session fix
---------
Co-authored-by: Pablo Carvalho <pablo@telnyx.com>
Co-authored-by: Tony Dehnke <tdehnke@gmail.com>
Co-authored-by: Tak Hoffman <781889+Takhoffman@users.noreply.github.com>
* feat(slack): add download-file action for on-demand file attachment access
Adds a new `download-file` message tool action that allows the agent to
download Slack file attachments by file ID on demand. This is a prerequisite
for accessing images posted in thread history, where file attachments are
not automatically resolved.
Changes:
- Add `files` field to `SlackMessageSummary` type so file IDs are
visible in message read results
- Add `downloadSlackFile()` to fetch a file by ID via `files.info`
and resolve it through the existing `resolveSlackMedia()` pipeline
- Register `download-file` in `CHANNEL_MESSAGE_ACTION_NAMES`,
`MESSAGE_ACTION_TARGET_MODE`, and `listSlackMessageActions`
- Add `downloadFile` dispatch case in `handleSlackAction`
- Wire agent-facing `download-file` → internal `downloadFile` in
`handleSlackMessageAction`
Closes#24681
* style: fix formatting in slack-actions and actions
* test(slack): cover download-file action path
---------
Co-authored-by: Tak Hoffman <781889+Takhoffman@users.noreply.github.com>
* fix(slack): replace files.uploadV2 with 3-step upload flow
files.uploadV2 from @slack/web-api internally calls the deprecated
files.upload endpoint, which fails with missing_scope even when
files:write is correctly granted in the bot token scopes.
Replace with Slack's recommended 3-step upload flow:
1. files.getUploadURLExternal - get presigned URL + file_id
2. fetch(upload_url) - upload file content
3. files.completeUploadExternal - finalize & share to channel/thread
This preserves all existing behavior including thread replies via
thread_ts and caption via initial_comment.
* fix(slack): harden external upload flow and tests
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Co-authored-by: Tak Hoffman <781889+Takhoffman@users.noreply.github.com>
* fix(discord,slack): add SSRF policy for media downloads in proxy environments
Discord and Slack media downloads (attachments, stickers, forwarded
images) call fetchRemoteMedia without any ssrfPolicy. When running
behind a local transparent proxy (Clash, mihomo, Shadowrocket) in
fake-ip mode, DNS returns virtual IPs in the 198.18.0.0/15 range,
which the SSRF guard blocks.
Add per-channel SSRF policy constants—matching the pattern already
applied to Telegram on main—that allowlist known CDN hostnames and
set allowRfc2544BenchmarkRange: true.
Refs #25355, #25322
Co-authored-by: Cursor <cursoragent@cursor.com>
* chore(slack): keep raw-fetch allowlist line anchors stable
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Co-authored-by: Cursor <cursoragent@cursor.com>
Co-authored-by: Tak Hoffman <781889+Takhoffman@users.noreply.github.com>
* feat(slack): create thread sessions for auto-threaded DM messages
When replyToMode="all", every top-level message starts a new Slack thread.
Previously, only subsequent replies in that thread got an isolated session
(via 🧵<threadTs> suffix). The initial message fell back to the base
DM session, mixing context across unrelated conversations.
Now, when replyToMode="all" and a message is not already a thread reply,
the message's own ts is used as the threadId for session key resolution.
This gives the initial message AND all subsequent thread replies the same
isolated session.
This enables per-thread session isolation for Slack DMs — each new message
starts its own thread and session, keeping conversations separate.
* Slack: fix auto-thread session key mode check and add changelog
---------
Co-authored-by: Tak Hoffman <781889+Takhoffman@users.noreply.github.com>
* fix(slack): reject HTML responses when downloading media
Slack sometimes returns HTML login pages instead of binary media when
authentication fails or URLs expire. This change detects HTML responses
by checking content-type header and buffer content, then skips to the
next available file URL.
* fix: format import order and add braces to continue statement
* chore: format Slack media tests
* chore: apply formatter to Slack media tests
* fix(slack): merge auth-header forwarding and html media guard
---------
Co-authored-by: Tak Hoffman <781889+Takhoffman@users.noreply.github.com>
* fix(slack): use SLACK_USER_TOKEN when connecting to Slack (closes#26480)
* test(slack): fix account fixture typing for user token source
---------
Co-authored-by: Tak Hoffman <781889+Takhoffman@users.noreply.github.com>
* fix(slack): honor direct replyToMode when thread label exists
ThreadLabel is a session/conversation label, not a reliable indicator
of an actual Slack thread reply. Using it to force replyToMode="all"
overrides replyToModeByChatType.direct="off" in DMs.
Switch to MessageThreadId which indicates a real thread target is
available, preserving expected behavior: thread replies stay threaded,
normal DMs respect the configured mode.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
* Slack: add changelog for threading tool context fix
---------
Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>
Co-authored-by: Tak Hoffman <781889+Takhoffman@users.noreply.github.com>
* feat: detect stale Slack sockets and auto-restart
Slack Socket Mode connections can silently stop delivering events while
still appearing connected (health checks pass, WebSocket stays open).
This "half-dead socket" problem causes messages to go unanswered.
This commit adds two layers of protection:
1. **Event liveness tracking**: Every inbound Slack event (messages,
reactions, member joins/leaves, channel events, pins) now calls
`setStatus({ lastEventAt, lastInboundAt })` to update the channel
account snapshot with the timestamp of the last received event.
2. **Health monitor stale socket detection**: The channel health monitor
now checks `lastEventAt` against a configurable threshold (default
30 minutes). If a channel has been running longer than the threshold
and hasn't received any events in that window, it is flagged as
unhealthy and automatically restarted — the same way disconnected
or crashed channels are already handled.
The restart reason is logged as "stale-socket" for observability, and
the existing cooldown/rate-limit logic (3 restarts/hour max) prevents
restart storms.
* Slack: gate liveness tracking to accepted events
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Co-authored-by: Tak Hoffman <781889+Takhoffman@users.noreply.github.com>
