AI agents call list_pyfilters to retrieve information from Firegex without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool retrieves or queries information about Python filters present in service code. It has no side effects—it does not create, modify, delete, or execute anything. It is purely informational, making it a Read category tool. Severity is low because reading metadata about filters poses minimal risk; an AI agent querying this information cannot cause damage or execute arbitrary code through this tool alone.
From the tool's definition Tool name 'list_' and description 'List Python filters' indicate a retrieval operation. The verb 'List' and the read-only nature of discovering/enumerating existing filters without modification confirm this is a query/retrieval action.
Attacks that exploit this kind of access
List Python filters discovered in the service code. It is categorised as a Read tool in the Firegex MCP Server, which means it retrieves data without modifying state.
Register the Firegex MCP server in PolicyLayer and add a rule for list_pyfilters: 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 Firegex. Nothing to install.
list_pyfilters 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 list_pyfilters 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 list_pyfilters. 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.
list_pyfilters is provided by the Firegex MCP server (umbra2728/firegex-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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