Slack Chat OS plugin for Paperclip. Turns Slack into a bidirectional agent command center - notifications, approvals, multi-agent threads, voice-to-task pipelines, custom workflow commands, and proactive agent suggestions.

Built on the Paperclip plugin SDK and the domain event bridge (PR #909).

Multiple Paperclip users asked for notifications on the same day the plugin system shipped (2026-03-14):

"is there a way to have codex/claude check paperclip to see when tasks are done without me prompting it?" - @Choose Liberty, Discord #dev

"basically to have it 'let me know when its done'" - @Choose Liberty, Discord #dev

"can claude code check paperclip to see when tasks are done" - @Nascozz, Discord #dev

@dotta (maintainer) responded: "we're also adding issue-changed hooks for plugins so when that lands someone could [make notifications]." The event bridge (PR #909) shipped that same day. @dotta also asked for "someone to make a plugin that's a totally separate package" to validate the DX. @Ryze said "Really excited by the plugins. I had developed a custom plugin bridge that I will now deprecate and migrate over to the new supported plugin system."

This is that plugin.

Notifications (rich Block Kit formatting)

• Issue created - Title, description snippet, status, priority, assignee, project fields, and a "View Issue" button
• Issue done - Completion confirmation with status fields and view button
• Approval requested - Interactive Approve, Reject, and View buttons. Click to act without leaving Slack.
• Agent error - Error message in a code block with warning indicator
• Agent online - Connection confirmation with check mark
• Budget threshold - Alerts at 80%, 90%, and 100% budget usage (deduped per threshold)
• Onboarding milestone - Celebrates an agent's first successful run

Interactive approvals

• Approve/reject buttons on every approval notification
• Clicking a button calls the Paperclip API and updates the Slack message inline
• Identifies which Slack user acted (logged as slack:{user_id})

HITL escalation

• Agents that get stuck can escalate to a dedicated Slack channel with full conversation context
• Rich Block Kit formatting with conversation history, agent reasoning, and confidence score
• "Use Suggested Reply" button when the agent has a best-guess response
• "Reply to Customer", "Override Agent", and "Dismiss" buttons
• Configurable timeout (default 15 min) with automatic default action (defer, close, retry)
• Customer messages queued during escalation and delivered with the human's response
• Exposes escalate_to_human tool for agents

Per-type channel routing

• Route approvals, errors, and pipeline events to separate Slack channels
• Falls back to the default channel when a per-type channel isn't configured
• Per-company overrides still take priority

Daily digest

• Scheduled job (9am daily) with real stats from the Paperclip API
• Tasks completed, tasks created, active agents, total cost, and top performer
• Cost data accumulated from cost_event.created events throughout the day

• Multiple agents per thread - Spawn up to maxAgentsPerThread (default 5) agents in a single Slack thread via /clip acp spawn <agent> [display_name]
• @mention routing - @mention an agent name to direct your message to a specific agent; falls back to reply-to context, then most recently active
• Agent handoff - handoff_to_agent tool lets one agent request a handoff to another with Approve/Reject buttons in-thread
• Discussion loops - discuss_with_agent tool starts a back-and-forth conversation between two agents with configurable max turns
• Human checkpoints - Discussion pauses every 5 turns with Continue/Stop buttons so humans stay in the loop
• Stale detection - Discussions auto-pause after 5 minutes of inactivity
• Output sequencing - When multiple agents are active, outputs are queued and delivered in order with agent name labels
• Session registry - Tracks active/closed sessions per thread with native SDK sessions (preferred) and ACP fallback
• /clip acp status - Show all active agents in the current thread
• /clip acp close [name] - Close a specific agent or the most recently active one

• Auto-detect media files - Audio (mp3, m4a, ogg, wav, webm, flac) and video (mp4, webm, quicktime) attachments in threads are automatically processed
• Whisper transcription - Audio files are sent to a whisper-transcriber agent for speech-to-text
• Brief Agent - Optional agent summarizes the transcription into an actionable brief
• Inline results - Transcription and brief run IDs posted back to the original thread
• process_media tool - Agents can programmatically trigger media processing with an optional briefAgentId
• Slack Events API - file_shared events trigger the pipeline automatically

• !command syntax - Type !deploy staging or !triage bug-123 in any thread to trigger registered workflows
• Multi-step workflows - Each command runs a sequence of steps: invoke_agent, post_message, create_issue, wait_approval
• Argument interpolation - Use $1, $2, or $args in step templates to pass user arguments
• register_command tool - Agents or admins can register new commands at runtime
• Step-level approval gates - wait_approval steps pause execution with Approve/Reject buttons
• Progress indicators - Each step posts status to the thread; failures show error details
• /clip commands - List all registered custom commands with descriptions and usage

• Event watches - register_watch tool sets up a trigger: when an event matching a pattern fires, an agent is invoked with a templated prompt
• Wildcard patterns - Match exact events (issue.created) or wildcards (agent.run.*)
• Prompt interpolation - Use ${event.payload.key} in watch prompts to inject event data
• Built-in sales templates - 5 pre-built watch templates: new-lead-follow-up, deal-stalled, high-value-issue, budget-warning, agent-error-diagnosis
• list_watch_templates tool - Browse available templates
• remove_watch tool - Remove watches by ID
• Scheduled check job - Watches are evaluated periodically against buffered events (last 100 per company)
• /clip watches - List all active watches with trigger counts

• /clip status - Show active agents and recent completions
• /clip agents - List all agents with status badges
• /clip issues [open|done] - List issues filtered by status
• /clip approve <id> - Approve a pending approval
• /clip acp spawn <agent> [display] - Add an agent to this thread
• /clip acp status - Show all agents in this thread
• /clip acp close [name] - Close a specific agent (or most recent)
• /clip commands - List registered custom commands
• /clip watches - List active event watches
• /clip help - Show this help message

npm install paperclip-plugin-slack

Or register with your Paperclip instance directly:

curl -X POST http://127.0.0.1:3100/api/plugins/install \
  -H "Content-Type: application/json" \
  -d '{"packageName":"paperclip-plugin-slack"}'

1. Create a Slack app at https://api.slack.com/apps
2. Add the chat:write bot scope
3. Enable Interactivity and point the Request URL to your Paperclip host's slack-interactivity webhook endpoint
4. Install the app to your workspace and copy the Bot OAuth Token
5. In Paperclip, go to Settings -> Secrets and create a new secret with your Bot OAuth Token. Copy the secret UUID.
6. Install the plugin and configure the secret UUID in the slackTokenRef field + your default channel ID

The plugin registers these tools that agents can call:

The slackTokenRef field now declares format: "secret-ref", which is required for Paperclip to collect and resolve secret references at activation time. Previously, the field was a plain string with no format annotation, causing plugin activation to fail with Invalid secret reference.

If you installed v2.0.0: you must re-configure the plugin. Go to Settings -> Secrets, create a secret with your Slack Bot OAuth Token, and paste the resulting secret UUID into the slackTokenRef field in the plugin configuration. Raw token strings are no longer accepted in this field.

pnpm install
pnpm typecheck
pnpm test
pnpm build

97 tests covering notifications, approvals, escalation, session registry, media pipeline, custom commands, proactive suggestions, Block Kit formatting, and slash commands.

Issues and PRs welcome at github.com/mvanhorn/paperclip-plugin-slack.

Auto-publishes to npm on push to main via OIDC trusted publishing.

@MatB57 - Escalation channel concept, "Chat OS" vision for turning chat plugins into bidirectional agent command centers, and the HITL suggested-reply flow.

MIT