Get the source code of a route handler function
AI agents call get_route_source to retrieve information from FastAPI MCP Server 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 from an existing FastAPI application. It performs no modifications, deletions, or external operations. While source code disclosure could pose information security risks in some contexts, the tool itself is purely informational and read-only.
From the tool's definition Tool description states 'Get the source code of a route handler function' — this is a retrieval operation with no side effects. The verb 'get' and context of 'source code viewing' (mentioned in server description) confirm read-only access.
Attacks that exploit this kind of access
Get the source code of a route handler function. It is categorised as a Read tool in the FastAPI MCP Server MCP Server, which means it retrieves data without modifying state.
Register the FastAPI MCP Server MCP server in PolicyLayer and add a rule for get_route_source: 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 FastAPI MCP Server. Nothing to install.
get_route_source 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 get_route_source 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 get_route_source. 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.
get_route_source is provided by the FastAPI MCP Server MCP server (nabeelshar/fastapi-mcp-server). 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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