AI agents call jsr_get_package_version to retrieve information from JSR MCP without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool retrieves package metadata and version details without modifying, creating, deleting, or executing any code. It has no side effects and presents minimal risk even if invoked by an AI agent with incorrect parameters.
From the tool's definition Tool name and description indicate retrieval of information: 'Get detailed information about a specific version of a package.' The verb 'Get' combined with 'detailed information' clearly indicates a read-only query operation.
Attacks that exploit this kind of access
Get detailed information about a specific version of a package. It is categorised as a Read tool in the JSR MCP MCP Server, which means it retrieves data without modifying state.
Register the JSR MCP server in PolicyLayer and add a rule for jsr_get_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.
jsr_get_package_version 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 jsr_get_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.
Set action: deny in the PolicyLayer policy for jsr_get_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.
jsr_get_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.
Every MCP server has a record like this.
Type a name, get the same breakdown: verified identity, auth posture, risk grade, capabilities, recommended policy.
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