Set the access token for a user after OAuth callback
AI agents use uber_set_access_token to create or update resources in MCP Uber Server — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your MCP Uber Server environment.
This tool creates or modifies user authentication credentials (access token) that enable subsequent ride-booking operations. While it doesn't directly move money or delete data, it irreversibly changes authentication state and grants the ability to book/manage rides on behalf of a user.
From the tool's definition Tool sets/modifies the access token state for a user account after OAuth callback. Description explicitly states 'Set the access token', which is a state modification operation.
Documented attack patterns abuse exactly the kind of access uber_set_access_token gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and MCP Uber Server, and nothing reaches the server without passing your rules. This is the rule we recommend for uber_set_access_token:
{
"version": "1",
"default": "deny",
"tools": {
"uber_set_access_token": {
"limits": [
{
"counter": "uber_set_access_token_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}uber_set_access_token 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.
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Set the access token for a user after OAuth callback. It is categorised as a Write tool in the MCP Uber Server MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the MCP Uber Server MCP server in PolicyLayer and add a rule for uber_set_access_token: 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 MCP Uber Server. Nothing to install.
uber_set_access_token is a Write tool with medium risk. Write tools should be rate-limited to prevent accidental bulk modifications.
Yes. Add a rate_limit block to the uber_set_access_token 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.
Set action: deny in the PolicyLayer policy for uber_set_access_token. 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.
uber_set_access_token is provided by the MCP Uber Server MCP server (199-mcp/mcp-uber). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from MCP Uber Server, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
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6 MCP Uber Server tools catalogued and risk-classified — across an index of 43,000+ MCP servers.