AI agents use save_case to create or update resources in OpenTester — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your OpenTester environment.
This tool creates or modifies test case data reversibly. It does not execute tests (which would be Execute), nor does it permanently delete data (which would be Destructive). Saving is a write operation that can be undone through update or deletion.
From the tool's definition Tool name is 'save_case' and description states 'Save a test case.' The action of saving creates or modifies a test case artifact in the system.
Documented attack patterns abuse exactly the kind of access save_case gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and OpenTester, and nothing reaches the server without passing your rules. This is the rule we recommend for save_case:
{
"version": "1",
"default": "deny",
"tools": {
"save_case": {
"limits": [
{
"counter": "save_case_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}save_case 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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Save a test case. It is categorised as a Write tool in the OpenTester MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the OpenTester MCP server in PolicyLayer and add a rule for save_case: 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 OpenTester. Nothing to install.
save_case 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 save_case 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 save_case. 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.
save_case is provided by the OpenTester MCP server (kznr02/opentester). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from OpenTester, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
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23 OpenTester tools catalogued and risk-classified — across an index of 43,000+ MCP servers.