compare_versions

THE RISK

Low Risk

Why compare_versions needs a policy

This tool retrieves and analyzes existing version data to identify differences—a pure information-gathering operation with no side effects. It does not execute code, modify data, delete anything, or trigger external operations. The use case (tracking breaking changes) is diagnostic and analytical in nature, making it clearly a Read category tool with low severity.

From the tool's definition Tool performs comparison and analysis of Minecraft versions to 'find differences' without modifying any data. The description indicates it tracks and reports changes rather than executing code or altering game state.

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

POLICY

How to control compare_versions

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

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "compare_versions": {}
  }
}

compare_versions is read-only, so it stays allowed — but everything else on the server is denied unless you say otherwise.

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

CAP THIS TOOL →

Free to start. No card required.

EXPLORE

Related tools and policies

More Minecraft Dev MCP tools

Execute decompile_minecraft_version Decompile an entire Minecraft version. By default downloads the client JAR from Mojang, re Execute decompile_mod_jar Decompile a mod JAR file to readable Java source code. The JAR can be either the original Execute remap_mod_jar Remap a Fabric mod JAR from intermediary mappings to human-readable mappings. Useful for r Write index_minecraft_version Create a full-text search index for decompiled Minecraft source. Enables fast searching wi Write index_mod Create a full-text search index for decompiled mod source code. Enables fast searching wit Read analyze_mixin Analyze and validate Mixin code against Minecraft source. Parses @Mixin annotations, valid Read analyze_mod_jar Analyze a third-party mod JAR file to extract metadata, dependencies, entry points, mixins Read compare_versions_detailed Compare two Minecraft versions with detailed AST-level analysis. Shows method signature ch

All 20 Minecraft Dev MCP tools →

Read tools on other servers

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Go deeper

The MCP Attack Database → Documented attack patterns against MCP deployments — and the policies that stop them.
Data exfiltration → How read access becomes an exfiltration channel when chained with untrusted content.
MCP token cost → What connecting this server costs in context-window tokens on every request.
Rate Limiting MCP Tool Calls: A Practical Guide →
MCP Security: Why Prompt Guardrails Aren't Enough →

FAQ

Questions about compare_versions

What does the compare_versions tool do? +

Compare two Minecraft versions to find differences in classes or registry data. Useful for tracking breaking changes between versions. It is categorised as a Read tool in the Minecraft Dev MCP MCP Server, which means it retrieves data without modifying state.

How do I enforce a policy on compare_versions? +

Register the Minecraft Dev MCP server in PolicyLayer and add a rule for compare_versions: 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 Minecraft Dev MCP. Nothing to install.

What risk level is compare_versions? +

compare_versions is a Read tool with low risk. Read-only tools are generally safe to allow by default.

Can I rate-limit compare_versions? +

Yes. Add a rate_limit block to the compare_versions 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 compare_versions completely? +

Set action: deny in the PolicyLayer policy for compare_versions. 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 compare_versions? +

compare_versions is provided by the Minecraft Dev MCP server (mcdxai/minecraft-dev-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.

Enforce policy on every Minecraft Dev MCP tool call.

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

CHECK YOUR STACK →