Return a mock response for matched requests. Creates a mock rule.
AI agents use proxy_mock_response to create or update resources in Proxy — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Proxy environment.
This tool creates a mock rule that intercepts and substitutes responses for matched requests. It modifies proxy behavior by writing a new rule, which is reversible (rules can be removed). It does not execute arbitrary code or irreversibly destroy data, making Write the most appropriate category. Medium severity because misconfigured mocks could redirect or tamper with network traffic affecting dependent systems.
From the tool's definition Return a mock response for matched requests. Creates a mock rule.
Documented attack patterns abuse exactly the kind of access proxy_mock_response gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Proxy, and nothing reaches the server without passing your rules. This is the rule we recommend for proxy_mock_response:
{
"version": "1",
"default": "deny",
"tools": {
"proxy_mock_response": {
"limits": [
{
"counter": "proxy_mock_response_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}proxy_mock_response 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.
Free to start. No card required.
Return a mock response for matched requests. Creates a mock rule. It is categorised as a Write tool in the Proxy MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the Proxy MCP server in PolicyLayer and add a rule for proxy_mock_response: 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 Proxy. Nothing to install.
proxy_mock_response 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 proxy_mock_response 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 proxy_mock_response. 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.
proxy_mock_response is provided by the Proxy MCP server (yfe404/proxy-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from Proxy, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
Free to start. No card required.
89 Proxy tools catalogued and risk-classified — across an index of 43,000+ MCP servers.