oauth_v2_access · Slack MCP: Risk & Policy

WHAT IT DOES

What oauth_v2_access does on Slack

AI agents invoke oauth_v2_access to trigger actions in Slack. 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 oauth_v2_access needs a policy

The OAuth v2 access endpoint in Slack is used to exchange an authorization code for an access token, effectively granting API access credentials. This is an external operation that triggers authentication flows and issues tokens.

From the tool's definition Tool name 'oauth_v2_access' on a Slack MCP server; description is empty and uninformative.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

oauth_v2_access Rate-limited

oauth_v2_access 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": {
    "oauth_v2_access": {
      "limits": [
        {
          "counter": "oauth_v2_access_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, so you can run agents against it safely.

FAQ

Questions about oauth_v2_access

What does the oauth_v2_access tool do? +

oauth_v2_access. It is categorised as a Execute tool in the Slack MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.

How do I enforce a policy on oauth_v2_access? +

Register the Slack MCP server in PolicyLayer and add a rule for oauth_v2_access: 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. Nothing to install.

What risk level is oauth_v2_access? +

oauth_v2_access is a Execute tool with high risk. Execute tools should be rate-limited and have argument validation enabled.

Can I rate-limit oauth_v2_access? +

Yes. Add a rate_limit block to the oauth_v2_access 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 oauth_v2_access completely? +

Set action: deny in the PolicyLayer policy for oauth_v2_access. 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 oauth_v2_access? +

oauth_v2_access is provided by the Slack MCP server (karbassi/slack-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.