slack_reply_to_thread

Reply to a specific message thread in Slack

Single-target operation

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

// WHEN AI AGENTS USE THIS TOOL

AI agents call slack_reply_to_thread to retrieve information from Slack User MCP Server without modifying any data. This is common in research, monitoring, and reporting workflows where the agent needs context before taking action. Because read operations don't change state, they are generally safe to allow without restrictions -- but you may still want rate limits to control API costs.

// WHY ENFORCE A POLICY ON SLACK_REPLY_TO_THREAD

Even though slack_reply_to_thread only reads data, uncontrolled read access can leak sensitive information or rack up API costs. An agent caught in a retry loop could make thousands of calls per minute. A rate limit gives you a safety net without blocking legitimate use.

// RECOMMENDED POLICY

Read-only tools are safe to allow by default. No rate limit needed unless you want to control costs.

lars-hagen-slack-user-mcp.yaml

tools:
  slack_reply_to_thread:
    rules:
      - action: allow

See the full Slack User MCP Server policy for all 8 tools.

// DETAILS

Tool Name slack_reply_to_thread

Category Read

MCP Server Slack User MCP Server MCP Server

Risk Level Low

// MORE SLACK USER MCP SERVER TOOLS

Write slack_add_reaction Write slack_post_message Read slack_get_channel_history Read slack_get_thread_replies Read slack_get_user_profile Read slack_get_users Read slack_list_channels

// WHAT CAN GO WRONG

Agents calling read-class tools like slack_reply_to_thread have been implicated in these attack patterns. Read the full case and prevention policy for each:

Browse the full MCP Attack Database →

// OTHER READ TOOLS ACROSS MCP SERVERS

Other tools in the Read risk category across the catalogue. The same policy patterns (rate-limit, allow) apply to each.

Open Library MCP Server get_author_info Open Library MCP Server get_author_photo Open Library MCP Server get_authors_by_name Open Library MCP Server get_book_by_id Open Library MCP Server get_book_by_title Open Library MCP Server get_book_cover

// RELATED READING

// FAQ

What does the slack_reply_to_thread tool do? +

Reply to a specific message thread in Slack. It is categorised as a Read tool in the Slack User MCP Server MCP Server, which means it retrieves data without modifying state.

How do I enforce a policy on slack_reply_to_thread? +

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

What risk level is slack_reply_to_thread? +

slack_reply_to_thread is a Read tool with low risk. Read-only tools are generally safe to allow by default.

Can I rate-limit slack_reply_to_thread? +

Yes. Add a rate_limit block to the slack_reply_to_thread 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_reply_to_thread completely? +

Set action: deny in the Intercept policy for slack_reply_to_thread. 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_reply_to_thread? +

slack_reply_to_thread is provided by the Slack User MCP Server MCP server (lars-hagen/slack-user-mcp). Intercept sits as a proxy in front of this server to enforce policies before tool calls reach the server.

slack_reply_to_thread

Enforce policies on Slack User MCP Server