set_outbound_allowlist
Narrow the project's outbound host allowlist — the hosts a target may point at. The current list is on get_project as outboundHostAllowlist (empty means any public host). This tool may only narrow it: patterns must be a strict subset of, or equal to, the current list, compared as exact strings — ...
This record as markdown: /tools/dev-echorelay-management/set-outbound-allowlist.md
What set_outbound_allowlist does on EchoRelay
AI agents use set_outbound_allowlist to create or update resources in EchoRelay, usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your EchoRelay environment.
| Parameter | Type | Required | Description |
|---|---|---|---|
patterns | array | Yes | The full replacement list of allowed hosts, e.g. ["api.stripe.com", "*.internal.example.com"]. Must be a subset of the current outboundHostAllowlist. |
Parameters from the server's own tool schema.
Why set_outbound_allowlist is rated Medium
An AI agent can call set_outbound_allowlist faster than any human can review: one bad instruction and it creates or modifies resources in EchoRelay by the hundred, each call as confident as the last.
Attacks that exploit this kind of access
The rule that runs set_outbound_allowlist safely
PolicyLayer is an MCP gateway: it sits between your AI agents and EchoRelay, and checks every tool call against a rule you set before the call runs. Nothing changes on the server itself. For set_outbound_allowlist, this is the rule to start with:
set_outbound_allowlist 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.
The button opens the PolicyLayer dashboard: create your workspace, connect EchoRelay, apply this rule, and every set_outbound_allowlist call is checked against it from then on.
Questions about set_outbound_allowlist
Narrow the project's outbound host allowlist — the hosts a target may point at. The current list is on get_project as outboundHostAllowlist (empty means any public host). This tool may only narrow it: patterns must be a strict subset of, or equal to, the current list, compared as exact strings — submitting a wildcard that would cover an existing exact host, or clearing to empty, is refused as a widen. Widening the list is web-only, in the panel. Refused when the project already has a target (inactive lines included) outside the submitted list. Requires edit access. It is categorised as a Write tool in the EchoRelay MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
set_outbound_allowlist accepts 1 parameter: patterns. Required: patterns. The full parameter table on this page comes from the server's own tool schema.
Register the EchoRelay MCP server in PolicyLayer and add a rule for set_outbound_allowlist: 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 EchoRelay. Nothing to install.
set_outbound_allowlist 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 set_outbound_allowlist 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 set_outbound_allowlist. 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.
set_outbound_allowlist is provided by the EchoRelay MCP server (https://mcp.echorelay.dev). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
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