start_subscription
Begin a new Pro or Scale subscription for the project owner. Returns {checkoutUrl, plan} — surface the URL to the human for approval. Errors if the owner is already on an active paid plan (use change_plan instead). Owner-only; requires a token minted with the billing scope.
This record as markdown: /tools/dev-echorelay-management/start-subscription.md
What start_subscription does on EchoRelay
AI agents use start_subscription to commit financial operations through EchoRelay, usually the final step of a payment, billing, or trading workflow. A call moves real money.
| Parameter | Type | Required | Description |
|---|---|---|---|
plan | string | Yes |
Parameters from the server's own tool schema.
Why start_subscription is rated Critical
This tool initiates a paid subscription, directly committing a financial obligation on behalf of the project owner. Starting a subscription is a financial action that results in recurring charges. The severity is critical because an AI agent misusing this could enroll users in expensive plans without explicit consent.
From the tool's definition Begin a new Pro or Scale subscription for the project owner... billing scope
Attacks that exploit this kind of access
The rule that runs start_subscription 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 start_subscription, this is the rule to start with:
Any call to start_subscription is blocked until a human approves it. The rest of the server keeps working.
The button opens the PolicyLayer dashboard: create your workspace, connect EchoRelay, apply this rule, and every start_subscription call is checked against it from then on.
Questions about start_subscription
Begin a new Pro or Scale subscription for the project owner. Returns {checkoutUrl, plan} — surface the URL to the human for approval. Errors if the owner is already on an active paid plan (use change_plan instead). Owner-only; requires a token minted with the billing scope. It is categorised as a Financial tool in the EchoRelay MCP Server, which means it involves financial transactions. Block by default and require explicit approval.
start_subscription accepts 1 parameter: plan. Required: plan. 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 start_subscription: 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.
start_subscription is a Financial tool with critical risk. Critical-risk tools should be blocked by default and only enabled with explicit human approval.
Yes. Add a rate_limit block to the start_subscription 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 start_subscription. 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.
start_subscription 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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