Query the tables with the largest table fragments
AI agents call show_largest_table_fragment to retrieve information from Alibaba Cloud RDS OpenAPI MCP Server without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool queries and displays table metadata (fragment sizes) without modifying, deleting, or executing arbitrary code. The 'Query' verb and passive 'show' operation confirm it is a data retrieval function with no side effects. Severity is low because misuse would only expose existing database schema information, not compromise data integrity or enable destructive actions.
From the tool's definition Tool name includes 'show' and description states 'Query the tables with the largest table fragments' — both indicate a read-only retrieval operation that returns information about database tables.
Documented attack patterns abuse exactly the kind of access show_largest_table_fragment gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Alibaba Cloud RDS OpenAPI MCP Server, and nothing reaches the server without passing your rules. This is the rule we recommend for show_largest_table_fragment:
{
"version": "1",
"default": "deny",
"tools": {
"show_largest_table_fragment": {}
}
}show_largest_table_fragment is read-only, so it stays allowed — but everything else on the server is denied unless you say otherwise.
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Query the tables with the largest table fragments. It is categorised as a Read tool in the Alibaba Cloud RDS OpenAPI MCP Server MCP Server, which means it retrieves data without modifying state.
Register the Alibaba Cloud RDS OpenAPI MCP Server MCP server in PolicyLayer and add a rule for show_largest_table_fragment: 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 Alibaba Cloud RDS OpenAPI MCP Server. Nothing to install.
show_largest_table_fragment 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 show_largest_table_fragment 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 show_largest_table_fragment. 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.
show_largest_table_fragment is provided by the Alibaba Cloud RDS OpenAPI MCP Server MCP server (aliyun/alibabacloud-rds-openapi-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Deterministic rules across all 37 Alibaba Cloud RDS OpenAPI MCP Server tools. Per-identity grants. Full audit log. Live in minutes. Nothing to install.
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37 Alibaba Cloud RDS OpenAPI MCP Server tools catalogued and risk-classified — across an index of 42,500+ MCP servers.