update_oauth_client · Posterly MCP: Risk & Policy

WHAT IT DOES

What update_oauth_client does on Posterly

AI agents use update_oauth_client to create or update resources in Posterly — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Posterly environment.

WHY IT NEEDS A POLICY

Why update_oauth_client needs a policy

This tool modifies OAuth client configuration, which is a reversible write operation on sensitive authentication credentials. The high severity reflects that misconfigured OAuth settings could compromise authentication security and enable unauthorized access to user accounts or data. However, it is not destructive (changes can be reverted) and not financial.

From the tool's definition Tool description explicitly states 'WRITE' and describes updating OAuth client configuration including 'redirect URIs, scopes, and active state'. These are modifications to security-critical OAuth settings.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

update_oauth_client Rate-limited

update_oauth_client stays usable, but capped — an agent stuck in a loop can't make hundreds of changes a minute. Everything else on the server is denied unless you say otherwise.

View as policy code

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "update_oauth_client": {
      "limits": [
        {
          "counter": "update_oauth_client_rate",
          "window": "minute",
          "max": 30,
          "scope": "grant"
        }
      ]
    }
  }
}

LIMIT THIS TOOL →

Instant setup, no code required.

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

FAQ

Questions about update_oauth_client

What does the update_oauth_client tool do? +

Update a self-serve OAuth developer client. WRITE: confirm changed redirect URIs, scopes, and active state before calling. It is categorised as a Write tool in the Posterly MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on update_oauth_client? +

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

What risk level is update_oauth_client? +

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

Can I rate-limit update_oauth_client? +

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

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

update_oauth_client is provided by the Posterly MCP server (posterly-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.