get_middleware_chain
Trace middleware chain for a route URL (Express/NestJS/FastAPI/Flask). Use when you only need the middleware stack, not the full request flow. For full route→controller→service flow use get_request_flow instead. Read-only. Returns JSON: { url, middlewares: [{ name, file, order }] }.
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What get_middleware_chain does on Trace
AI agents call get_middleware_chain to retrieve information from Trace without modifying anything. It is typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
Why get_middleware_chain is rated Low
This tool retrieves and queries middleware configuration for a given route URL across multiple frameworks. It has no side effects—it only reads and returns structured data about the middleware stack. No code execution, data modification, or resource-altering operations occur. Classification as Read is appropriate for security analysis tools that perform static introspection of application architecture.
From the tool's definition Tool description explicitly states 'Read-only' and 'Trace middleware chain'. Returns middleware stack metadata (name, file, order) without modifying or executing code. Designed for querying/introspection of application structure.
Attacks that exploit this kind of access
The rule that runs get_middleware_chain safely
PolicyLayer is an MCP gateway: it sits between your AI agents and Trace, and checks every tool call against a rule you set before the call runs. Nothing changes on the server itself. For get_middleware_chain, this is the rule to start with:
get_middleware_chain is read-only, so it stays allowed. Everything else on the server is denied unless you say otherwise.
The button opens the PolicyLayer dashboard: create your workspace, connect Trace, apply this rule, and every get_middleware_chain call is checked against it from then on.
Questions about get_middleware_chain
Trace middleware chain for a route URL (Express/NestJS/FastAPI/Flask). Use when you only need the middleware stack, not the full request flow. For full route→controller→service flow use get_request_flow instead. Read-only. Returns JSON: { url, middlewares: [{ name, file, order }] }. It is categorised as a Read tool in the Trace MCP Server, which means it retrieves data without modifying state.
Register the Trace MCP server in PolicyLayer and add a rule for get_middleware_chain: 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 Trace. Nothing to install.
get_middleware_chain 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_middleware_chain 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_middleware_chain. 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_middleware_chain is provided by the Trace MCP server (nikolai-vysotskyi/trace-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
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