MCP Tool Reference Medium Risk

slack_add_reaction

Add an emoji reaction to a message

Part of the Slack MCP server. Enforce policies on this tool with Intercept, the open-source MCP proxy.

modelcontextprotocol/server-slack Write

WHEN AI AGENTS USE THIS TOOL

AI agents use slack_add_reaction to create or modify resources in Slack. Write operations carry medium risk because an autonomous agent could trigger bulk unintended modifications. Rate limits prevent a single agent session from making hundreds of changes in rapid succession. Argument validation ensures the agent passes expected values.

WHY ENFORCE A POLICY ON SLACK_ADD_REACTION

Without a policy, an AI agent could call slack_add_reaction repeatedly, creating or modifying resources faster than any human could review. Intercept's rate limiting ensures write operations happen at a controlled pace, and argument validation catches malformed or unexpected inputs before they reach Slack.

RECOMMENDED POLICY

Write tools can modify data. A rate limit prevents runaway bulk operations from AI agents.

slack.yaml 
tools:
  slack_add_reaction:
    rules:
      - action: allow
        rate_limit:
          max: 30
          window: 60

See the full Slack policy for all 8 tools.

DETAILS

Tool Name

slack_add_reaction

Category

Write

MCP Server

Slack MCP Server

Risk Level

Medium

MORE SLACK TOOLS

slack_post_message Write
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slack_get_channel_history Read
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slack_get_thread_replies Read
Get all replies in a message thread
slack_get_user_profile Read
Get detailed profile information for a specific user
slack_get_users Read
Get list of workspace users with basic profile information
slack_list_channels Read
List public or pre-defined channels in the workspace
slack_reply_to_thread Other
Reply to a specific message thread

SIMILAR WRITE TOOLS ON OTHER SERVERS

create_table Airtable
Create a new table with fields
update_table Airtable
Update a table's name or description
create_field Airtable
Add a new field to a table
update_field Airtable
Modify an existing field
create_record Airtable
Add a new record
update_record Airtable
Modify an existing record

RELATED READING

FREQUENTLY ASKED QUESTIONS

What does the slack_add_reaction tool do?

Add an emoji reaction to a message. It is categorised as a Write tool in the Slack MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on slack_add_reaction?

Add a rule in your Intercept YAML policy under the tools section for slack_add_reaction. You can allow, deny, rate-limit, or validate arguments. Then run Intercept as a proxy in front of the Slack MCP server.

What risk level is slack_add_reaction?

slack_add_reaction is a Write tool with medium risk. Write tools should be rate-limited to prevent accidental bulk modifications.

Can I rate-limit slack_add_reaction?

Yes. Add a rate_limit block to the slack_add_reaction rule in your Intercept policy. For example, setting max: 10 and window: 60 limits the tool to 10 calls per minute. Rate limits are tracked per agent session and reset automatically.

How do I block slack_add_reaction completely?

Set action: deny in the Intercept policy for slack_add_reaction. The AI agent will receive a policy violation error and cannot call the tool. You can also include a reason field to explain why the tool is blocked.

What MCP server provides slack_add_reaction?

slack_add_reaction is provided by the Slack MCP server (modelcontextprotocol/server-slack). Intercept sits as a proxy in front of this server to enforce policies before tool calls reach the server.

ENFORCE POLICIES ON SLACK

Open source. One binary. Zero dependencies.

VIEW ON GITHUB Full Slack policy →