jsr_update_package_version · JSR MCP: Risk & Policy

WHAT IT DOES

What jsr_update_package_version does on JSR MCP

AI agents use jsr_update_package_version to create or update resources in JSR MCP — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your JSR MCP environment.

WHY IT NEEDS A POLICY

Why jsr_update_package_version needs a policy

The tool updates package version metadata (yanked status) rather than deleting data or executing arbitrary code. Yanking is a reversible operation (versions can be un-yanked), making it a Write rather than Destructive action.

From the tool's definition Tool description states 'Update package version yanked status' — this modifies the published state of a package version by changing its yanked status, which is a reversible metadata update.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

jsr_update_package_version Rate-limited

jsr_update_package_version stays usable, but capped — an agent stuck in a loop can't make hundreds of changes a minute. Everything else on the server is denied unless you say otherwise.

View as policy code

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "jsr_update_package_version": {
      "limits": [
        {
          "counter": "jsr_update_package_version_rate",
          "window": "minute",
          "max": 30,
          "scope": "grant"
        }
      ]
    }
  }
}

LIMIT THIS TOOL →

Instant setup, no code required.

PolicyLayer is an MCP gateway: every tool call is checked against your rule before it reaches JSR MCP, so you can run agents against it safely.

FAQ

Questions about jsr_update_package_version

What does the jsr_update_package_version tool do? +

Update package version yanked status (requires authentication and scope membership). It is categorised as a Write tool in the JSR MCP MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on jsr_update_package_version? +

Register the JSR MCP server in PolicyLayer and add a rule for jsr_update_package_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 JSR MCP. Nothing to install.

What risk level is jsr_update_package_version? +

jsr_update_package_version is a Write tool with medium risk. Write tools should be rate-limited to prevent accidental bulk modifications.

Can I rate-limit jsr_update_package_version? +

Yes. Add a rate_limit block to the jsr_update_package_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.

How do I block jsr_update_package_version completely? +

Set action: deny in the PolicyLayer policy for jsr_update_package_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.

What MCP server provides jsr_update_package_version? +

jsr_update_package_version is provided by the JSR MCP server (wyattjoh/jsr-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.