refresh_credentials · Slack MCP Server MCP: Risk & Policy

WHAT IT DOES

What refresh_credentials does on Slack MCP Server

AI agents invoke refresh_credentials to trigger actions in Slack MCP Server. What it does depends on the arguments the agent supplies, and its effects often reach beyond the immediate call — builds kicked off, notifications sent, workflows started.

WHY IT NEEDS A POLICY

Why refresh_credentials needs a policy

While the server is described as 'read-only,' this particular tool performs an active operation that triggers external authentication state changes. Refreshing credentials is an Execute action because it causes the authentication system to perform an operation (token regeneration/validation), not merely retrieve data.

From the tool's definition Tool name 'refresh_credentials' combined with description 'Manually trigger a refresh of Slack user credentials (token and cookie)' indicates execution of an external authentication operation.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

refresh_credentials Rate-limited

refresh_credentials stays usable, but rate-capped — a runaway agent can't fire it dozens of times a minute. Everything else on the server is denied unless you say otherwise.

View as policy code

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "refresh_credentials": {
      "limits": [
        {
          "counter": "refresh_credentials_rate",
          "window": "minute",
          "max": 10,
          "scope": "grant"
        }
      ]
    }
  }
}

RATE-LIMIT THIS TOOL →

Instant setup, no code required.

PolicyLayer is an MCP gateway: every tool call is checked against your rule before it reaches Slack MCP Server, so you can run agents against it safely.

FAQ

Questions about refresh_credentials

What does the refresh_credentials tool do? +

Manually trigger a refresh of Slack user credentials (token and cookie). It is categorised as a Execute tool in the Slack MCP Server MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.

How do I enforce a policy on refresh_credentials? +

Register the Slack MCP Server MCP server in PolicyLayer and add a rule for refresh_credentials: allow, deny, rate-limit, or require approval. Point your MCP client at the PolicyLayer proxy URL and the rule is enforced on every call, before it reaches Slack MCP Server. Nothing to install.

What risk level is refresh_credentials? +

refresh_credentials is a Execute tool with high risk. Execute tools should be rate-limited and have argument validation enabled.

Can I rate-limit refresh_credentials? +

Yes. Add a rate_limit block to the refresh_credentials rule in your PolicyLayer 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 refresh_credentials completely? +

Set action: deny in the PolicyLayer policy for refresh_credentials. 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 refresh_credentials? +

refresh_credentials is provided by the Slack MCP Server MCP server (mynghn/slack-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.