AI agents call replace_rule_list to retrieve information from Legado without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
The tool name follows the pattern 'resource_list' which typically indicates a read/query operation that retrieves a list of items. In the context of Legado (a reading app), replace rules are text substitution rules. Listing them is a non-destructive read operation. Confidence is reduced because the description is empty, leaving some uncertainty about side effects.
From the tool's definition Tool name 'replace_rule_list' suggests a listing/retrieval operation for replace rules
Documented attack patterns abuse exactly the kind of access replace_rule_list gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Legado, and nothing reaches the server without passing your rules. This is the rule we recommend for replace_rule_list:
{
"version": "1",
"default": "deny",
"tools": {
"replace_rule_list": {}
}
}replace_rule_list is read-only, so it stays allowed — but everything else on the server is denied unless you say otherwise.
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replace_rule_list. It is categorised as a Read tool in the Legado MCP Server, which means it retrieves data without modifying state.
Register the Legado MCP server in PolicyLayer and add a rule for replace_rule_list: 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 Legado. Nothing to install.
replace_rule_list 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 replace_rule_list 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 replace_rule_list. 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.
replace_rule_list is provided by the Legado MCP server (joestar817/legado-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from Legado, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
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31 Legado tools catalogued and risk-classified — across an index of 43,000+ MCP servers.