# Add Slack reaction

Canonical URL: https://docs.fuse.init.inc/integrations/slack/actions/reactions.add

Add a reaction to a Slack message.

Action ID: `reactions.add`
Provider: Slack (`slack`)
Contract version: 1

## Risk and exposure

- Risk: Write
- Idempotency: Safe — Safe to retry without coordination; repeats do not create additional side effects.
- Availability: Default
- Exposure: REST, SDK, MCP
- MCP hints: readOnly=false, destructive=false, idempotent=true, openWorld=true

## Required scopes

- `reactions:write`

## Input schema fields

- `channel_id`
- `timestamp`
- `name`

## Output schema fields

None.

Provider overview: https://docs.fuse.init.inc/integrations/slack
Actions index: https://docs.fuse.init.inc/integrations/slack/actions
Exact canonical JSON contract: https://docs.fuse.init.inc/api/catalog/v1/providers/slack/actions/reactions.add
Deployment-effective discovery: https://api.fuse.init.inc/v1/tenants/%7Btenant_id%7D/providers/slack/actions