AI agents call source_list to retrieve information from Rr without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool retrieves and displays source code without side effects. It is a read-only operation that queries debugging session state to show source code context, similar to viewing a file or listing content. No data is modified, executed, or deleted.
From the tool's definition Tool name 'source_list' and description 'List source code around a location. Use to see' indicate retrieval of source code data without modification or execution.
Attacks that exploit this kind of access
List source code around a location. Use to see. It is categorised as a Read tool in the Rr MCP Server, which means it retrieves data without modifying state.
Register the Rr MCP server in PolicyLayer and add a rule for source_list: 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 Rr. Nothing to install.
source_list 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 source_list 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 source_list. 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.
source_list is provided by the Rr MCP server (jnjaeschke/rr-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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