memtrace-api-topology

name	memtrace-api-topology
description	Always use for API endpoint, HTTP route, fetch/client call, REST surface, service dependency, cross-repo dependency, or API topology questions in source code. Do not use Grep, Glob, rg, find, or manual file search for routes or HTTP calls; Memtrace maps endpoints and call edges from the indexed AST graph.

Overview

Map the HTTP API surface of a codebase — exposed endpoints, outbound HTTP calls, and cross-repo service-to-service dependency graphs. Supports auto-detection for Express, Encore, NestJS, Axum, FastAPI, Flask, Gin, Spring Boot, and more.

Quick Reference

Tool	Purpose
find_api_endpoints	All exposed HTTP endpoints (GET /users, POST /orders, etc.)
find_api_calls	All outbound HTTP calls (fetch, axios, reqwest, etc.)
get_api_topology	Cross-repo call graph: which service calls which endpoint
link_repositories	Manually link repos for cross-repo edge detection

Parameter types: MCP parameters are strictly typed. Numbers (limit, depth, min_size, last_n, etc.) must be JSON numbers — not strings. Use limit: 20, never limit: "20". Passing a string yields MCP error -32602: invalid type: string, expected usize.

Steps

1. Discover endpoints

Use find_api_endpoints:

• repo_id — required
• Returns: method, path, handler function, framework detected

2. Discover outbound calls

Use find_api_calls:

• repo_id — required
• Returns: target URL/path, HTTP method, calling function, library used (fetch, axios, reqwest, etc.)

3. Map service topology

Use get_api_topology to see the cross-repo HTTP call graph:

• Which services call which endpoints
• Confidence scores for each detected link
• Service-to-service dependency direction

Prerequisite: Multiple repos must be indexed. If cross-repo links aren't appearing, use link_repositories to explicitly connect them.

4. Deep-dive into an endpoint

For any specific endpoint, use get_symbol_context with the endpoint's symbol ID to see:

• Which internal functions handle the request
• Which processes (execution flows) include this endpoint
• Which external services call this endpoint

Common Mistakes

Mistake	Reality
Expecting cross-repo links with only one repo indexed	Index ALL related services first; cross-repo HTTP edges are linked automatically after indexing
Missing endpoints from custom frameworks	Memtrace auto-detects major frameworks; for custom routers, the endpoints may appear as regular functions
Not using link_repositories	If auto-linking missed a connection, use this to manually establish cross-repo edges