clear_caches

THE RISK

Critical Risk

Why clear_caches needs a policy

Cache clearing is a destructive operation that cannot be undone. While it may not directly affect primary data, clearing caches can cause cascading failures in database performance, query results consistency, and application functionality. In the context of a SQL server MCP with enterprise-grade operations, unauthorized cache clearing could severely impact system availability and data integrity verification.

From the tool's definition Tool name 'clear_caches' combined with description 'Initialize cache data' indicates irreversible deletion or overwriting of cached data. 'Clear' is a destructive operation that removes data without recovery mechanism.

Documented attack patterns abuse exactly the kind of access clear_caches gives an agent:

POLICY

How to control clear_caches

PolicyLayer is an MCP gateway — it sits between your AI agents and MCP SQL Server, and nothing reaches the server without passing your rules. This is the rule we recommend for clear_caches:

policy.json

{
  "version": "1",
  "default": "deny",
  "hide": [
    "clear_caches"
  ]
}

clear_caches disappears from the agent's tool list entirely, and any attempt to call it is denied. The rest of the server keeps working.

Create a free account and register MCP SQL Server — nothing to install.
Add this policy — paste it, or build it visually.
Point your MCP client (Claude, Cursor, anything) at your gateway URL.

RESTRICT THIS TOOL →

Free to start. No card required.

EXPLORE

Related tools and policies

More MCP SQL Server tools

Execute execute_query Execute SQL queries Execute start_batch_processing Process multiple queries in batch Execute start_performance_monitoring Start performance monitoring Read describe_table Get structure of a specific table Read get_connection_pool_status Get database connection pool status Read get_query_stats Get query execution statistics Read get_schema Get database schema information Read get_schema_statistics Get schema statistics information

All 11 MCP SQL Server tools →

Destructive tools on other servers

Android Forensics ADB MCP Server create_full_backup 0xarchive web3_revoke_key Frida Game Hacking MCP clear_scan cPanel MCP Server clear_spam_box

Go deeper

Critical-risk tools in MCP SQL Server → Every critical-risk tool this server exposes, in one view.
All critical-risk MCP tools → Every critical-risk tool across the catalogue, and the policy pattern that contains them.
The MCP Attack Database → Documented attack patterns against MCP deployments — and the policies that stop them.
Blast radius → How much damage one compromised or confused agent can do — and how to bound it.
Tool call approval → Approval gates on individual tool calls: auto-allow, prompt, or deny.
Rate Limiting MCP Tool Calls: A Practical Guide →
MCP Security: Why Prompt Guardrails Aren't Enough →

FAQ

Questions about clear_caches

What does the clear_caches tool do? +

Initialize cache data. It is categorised as a Destructive tool in the MCP SQL Server MCP Server, which means it can permanently delete or destroy data. Block by default and require explicit approval.

How do I enforce a policy on clear_caches? +

Register the MCP SQL Server MCP server in PolicyLayer and add a rule for clear_caches: 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 MCP SQL Server. Nothing to install.

What risk level is clear_caches? +

clear_caches is a Destructive tool with critical risk. Critical-risk tools should be blocked by default and only enabled with explicit human approval.

Can I rate-limit clear_caches? +

Yes. Add a rate_limit block to the clear_caches 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.

How do I block clear_caches completely? +

Set action: deny in the PolicyLayer policy for clear_caches. 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.

What MCP server provides clear_caches? +

clear_caches is provided by the MCP SQL Server MCP server (ryudg/mcp-sql). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.

Enforce policy on every MCP SQL Server tool call.

Start from MCP SQL Server, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.

CHECK YOUR STACK →