# Add Reaction — Slack

> Add an emoji reaction to a message. Accepts a channel ID (preferred — resolves instantly) or channel name (resolved by scanning up to 5 pages, ~5,000 channels, of the workspace's channel list — a name beyond that bound will not be found)…

- Key: `slack_v2-add-reaction`
- Type: Action (Write)
- Version: 0.0.8
- App: Slack (`slack_v2`) — https://pipedream.com/apps/slack-v2.md
- This page (HTML): https://pipedream.com/apps/slack-v2/actions/add-reaction
- Hints: open-world
- Source: https://github.com/PipedreamHQ/pipedream/blob/master/components/slack_v2/actions/add-reaction/add-reaction.mjs

## Description

Add an emoji reaction to a message. Accepts a channel ID (preferred — resolves instantly) or channel name (resolved by scanning up to 5 pages, ~5,000 channels, of the workspace's channel list — a name beyond that bound will not be found). Use **Get Channel History** or **Search** to find the message timestamp. Emoji name should be without colons (e.g. `thumbsup`, `fire`, `heart`). [See the documentation](https://api.slack.com/methods/reactions.add)

## Props

| Prop | Type | Required | Description |
|---|---|---|---|
| `channel` | `string` | Yes | Prefer a channel ID (e.g. C1234567890) — use List Channels to look it up; it resolves instantly. A channel NAME (e.g. general or #general) is also accepted, but resolving it scans up to 5 conversations.list pages (~5,000 channels), which is slow and, on large workspaces, can be rate-limited or fail with a ConfigurationError if the channel is beyond that bound — pass the ID whenever you have it. Depending on the action, this may also accept a user ID (opens a direct message) or a group DM ID — use Find User by Email / Find User by ID to resolve a user ID, or List Group Conversations for group DM IDs. |
| `timestamp` | `string` | Yes | The ts of the message to react to (e.g. 1234567890.123456). |
| `name` | `string` | Yes | The emoji name without colons (e.g. thumbsup, fire, heart). |

## Run it

**MCP**

```ts
import { Client } from "@modelcontextprotocol/sdk/client/index.js"
import { StreamableHTTPClientTransport } from "@modelcontextprotocol/sdk/client/streamableHttp.js"
import { PipedreamClient } from "@pipedream/sdk"

const pd = new PipedreamClient({
  projectId: process.env.PIPEDREAM_PROJECT_ID!,
  clientId: process.env.PIPEDREAM_CLIENT_ID!,
  clientSecret: process.env.PIPEDREAM_CLIENT_SECRET!,
  projectEnvironment: "production",
})

const accessToken = await pd.rawAccessToken

const transport = new StreamableHTTPClientTransport(
  new URL("https://remote.mcp.pipedream.net/v3"),
  {
    requestInit: {
      headers: {
        Authorization: `Bearer ${accessToken}`,
        "x-pd-project-id": process.env.PIPEDREAM_PROJECT_ID!,
        "x-pd-environment": "production",
        "x-pd-external-user-id": "{external_user_id}", // any stable ID for this user in your system
        "x-pd-app-slug": "slack_v2",
      },
    },
  },
)

const mcp = new Client({ name: "my-agent", version: "1.0.0" })
await mcp.connect(transport)

const { tools } = await mcp.listTools()

// listTools() hands your model this tool's input schema, so it can
// fill the arguments itself:
const result = await mcp.callTool({
  name: "slack_v2-add-reaction",
  arguments: {
    channel: "Channel",
    timestamp: "Message Timestamp",
  },
})
```

**TypeScript**

```ts
import { PipedreamClient } from "@pipedream/sdk"

const pd = new PipedreamClient({
  projectId: process.env.PIPEDREAM_PROJECT_ID!,
  clientId: process.env.PIPEDREAM_CLIENT_ID!,
  clientSecret: process.env.PIPEDREAM_CLIENT_SECRET!,
  projectEnvironment: "production",
})

const result = await pd.actions.run({
  id: "slack_v2-add-reaction",
  externalUserId: "{external_user_id}", // any stable ID for this user in your system
  configuredProps: {
    slack_v2: { authProvisionId: "apn_xxxxxxx" },
    channel: "Channel",
    timestamp: "Message Timestamp",
  },
})

console.log(result)
```

**cURL**

```bash
curl -X POST https://api.pipedream.com/v1/connect/{project_id}/actions/run \
  -H "Content-Type: application/json" \
  -H "X-PD-Environment: production" \
  -H "Authorization: Bearer {access_token}" \
  -d '{
    "external_user_id": "{external_user_id}",
    "id": "slack_v2-add-reaction",
    "configured_props": {
      "slack_v2": { "authProvisionId": "apn_xxxxxxx" },
      "channel": "Channel",
      "timestamp": "Message Timestamp"
    }
  }'
```

---

- App: https://pipedream.com/apps/slack-v2.md · All apps: https://pipedream.com/apps