preview_plan_change
Preview what would happen if change_plan were called with this plan: the immediate-charge amount (cents), the next-invoice amount, the effective date, and the kind (applied for in-cycle upgrade, scheduled for at-period-end downgrade / cancel). Owner-only; requires a token minted with the billing ...
This record as markdown: /tools/dev-echorelay-management/preview-plan-change.md
What preview_plan_change does on EchoRelay
AI agents call preview_plan_change to retrieve information from EchoRelay without modifying anything. It is typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
| Parameter | Type | Required | Description |
|---|---|---|---|
plan | string | Yes | Target plan to preview a switch to. |
Parameters from the server's own tool schema.
Why preview_plan_change is rated Low
This tool only simulates/previews a plan change and returns calculated financial figures (amounts, dates, kind). It does not actually charge the customer, change the plan, or commit any financial obligation. It is a read/query operation. However, it involves billing data and is a precursor to financial action, so severity is medium.
From the tool's definition Preview what would happen if change_plan were called... the immediate-charge amount... next-invoice amount... effective date
Attacks that exploit this kind of access
The rule that runs preview_plan_change 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 preview_plan_change, this is the rule to start with:
preview_plan_change is read-only, so it stays allowed. 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 preview_plan_change call is checked against it from then on.
Questions about preview_plan_change
Preview what would happen if change_plan were called with this plan: the immediate-charge amount (cents), the next-invoice amount, the effective date, and the kind (applied for in-cycle upgrade, scheduled for at-period-end downgrade / cancel). Owner-only; requires a token minted with the billing scope. It is categorised as a Read tool in the EchoRelay MCP Server, which means it retrieves data without modifying state.
preview_plan_change 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 preview_plan_change: 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.
preview_plan_change is a Read tool with low risk. Read-only tools are generally safe to allow by default.
Yes. Add a rate_limit block to the preview_plan_change 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 preview_plan_change. 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.
preview_plan_change 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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