Decompile an entire Minecraft version. By default downloads the client JAR from Mojang, remaps it to the chosen mapping, and runs VineFlower across every class — subsequent calls use cached results. To work with a Forge/NeoForge patched Minecraft JAR (which adds loader hooks, deprecated method ov...
AI agents invoke decompile_minecraft_version to trigger actions in Minecraft Dev MCP. What it does depends on the arguments the agent supplies, and its effects often reach beyond the immediate call — builds kicked off, notifications sent, workflows started.
This tool performs multiple external operations: downloading a JAR from a remote server, executing a remapping pipeline, and running a decompiler (VineFlower) across all classes. These are active execution operations with significant resource usage and external network calls. While results are cached, the initial run triggers substantial compute and I/O.
From the tool's definition Decompile an entire Minecraft version... downloads the client JAR from Mojang, remaps it to the chosen mapping, and runs VineFlower across every class
Risk signalsBulk/mass operation — affects multiple targets
Documented attack patterns abuse exactly the kind of access decompile_minecraft_version gives an agent:
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 decompile_minecraft_version:
{
"version": "1",
"default": "deny",
"tools": {
"decompile_minecraft_version": {
"limits": [
{
"counter": "decompile_minecraft_version_rate",
"window": "minute",
"max": 10,
"scope": "grant"
}
]
}
}
}decompile_minecraft_version stays usable, but rate-capped — a runaway agent can't fire it dozens of times a minute. Everything else on the server is denied unless you say otherwise.
Free to start. No card required.
Decompile an entire Minecraft version. By default downloads the client JAR from Mojang, remaps it to the chosen mapping, and runs VineFlower across every class — subsequent calls use cached results. To work with a Forge/NeoForge patched Minecraft JAR (which adds loader hooks, deprecated method overloads, interface injection, etc.), pass. It is categorised as a Execute tool in the Minecraft Dev MCP MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.
Register the Minecraft Dev MCP server in PolicyLayer and add a rule for decompile_minecraft_version: 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.
decompile_minecraft_version is a Execute tool with high risk. Execute tools should be rate-limited and have argument validation enabled.
Yes. Add a rate_limit block to the decompile_minecraft_version 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 decompile_minecraft_version. 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.
decompile_minecraft_version 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.
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.
Free to start. No card required.
20 Minecraft Dev MCP tools catalogued and risk-classified — across an index of 43,000+ MCP servers.