marketplace_sso_token_exchange

THE RISK

High Risk

This tool performs an OAuth code exchange operation to obtain an OIDC token, which is an external authentication operation with side effects (token issuance/creation). It triggers an external auth flow rather than simply reading data, making Execute the most appropriate category. Misuse could result in unauthorized token generation or session hijacking.

From the tool's definition Exchange OAuth code for OIDC token

Documented attack patterns abuse exactly the kind of access marketplace_sso_token_exchange gives an agent:

HOW TO CONTROL MARKETPLACE_SSO_TOKEN_EXCHANGE

PolicyLayer is an MCP gateway — it sits between your AI agents and Vercel MCP Server, and nothing reaches the server without passing your rules. This is the rule we recommend for marketplace_sso_token_exchange:

policy.json

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

marketplace_sso_token_exchange 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.

Create a free account and register Vercel MCP Server — nothing to install.
Add this policy — paste it, or build it visually.
Point your MCP client (Claude, Cursor, anything) at your gateway URL.

RATE-LIMIT THIS TOOL →

Free to start. No card required.

EXPLORE

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All 154 Vercel MCP Server tools →

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Go deeper

High-risk tools in Vercel MCP Server → Every high-risk tool this server exposes, in one view.
All high-risk MCP tools → Every high-risk tool across the catalogue, and the policy pattern that contains them.
The MCP Attack Database → Documented attack patterns against MCP deployments — and the policies that stop them.
Rate Limiting MCP Tool Calls: A Practical Guide →
MCP Security: Why Prompt Guardrails Aren't Enough →

FAQ

What does the marketplace_sso_token_exchange tool do? +

Exchange OAuth code for OIDC token. It is categorised as a Execute tool in the Vercel 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 marketplace_sso_token_exchange? +

Register the Vercel MCP Server MCP server in PolicyLayer and add a rule for marketplace_sso_token_exchange: 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 Vercel MCP Server. Nothing to install.

What risk level is marketplace_sso_token_exchange? +

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

Can I rate-limit marketplace_sso_token_exchange? +

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

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

marketplace_sso_token_exchange is provided by the Vercel MCP Server MCP server (quegenx/vercel-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.

Enforce policy on every Vercel MCP Server tool call.

Deterministic rules across all 154 Vercel MCP Server tools. Per-identity grants. Full audit log. Live in minutes. Nothing to install.

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// WHAT MARKETPLACE_SSO_TOKEN_EXCHANGE ON VERCEL MCP SERVER DOES

// THE RISK

// HOW TO CONTROL MARKETPLACE_SSO_TOKEN_EXCHANGE

// EXPLORE