Mewra Pounce — Reverse Call Trace

See every route that can reach your function — at a glance.

Mewra Pounce is an open-source VS Code extension that walks the reverse call hierarchy of any function and renders an interactive directed graph, highlighting every API route, background worker, and cron job that can reach it.

Mewra PreFlight companion

Install Mewra PreFlight alongside Pounce. On activation, Pounce registers its diff-scoped Blast Radius check with PreFlight. When a supported route declaration changes, the PreFlight dashboard shows affected entry points and includes Mermaid route summaries in the generated PR/MR description.

This companion check inspects only the Git diff; it does not run the editor's Call Hierarchy provider. Use Mewra Pounce: Trace Callers for the interactive, function-level reverse call graph.

Website: pounce.mewra.app · Part of the Mewra developer tooling ecosystem.
Source code: github.com/mewra-lab/mewra-pounce

Mewra Pounce — Reverse Call Trace in action

Why

VS Code's built-in Call Hierarchy is a text tree. You expand it level by level to understand the full blast radius of a change. For deeply nested service code this takes minutes.

Mewra Pounce does the traversal for you and renders the result as a navigable graph — in seconds.

Mewra Pounce Blast Radius Detection

You place cursor on:  discordLogger.error()

Mewra Pounce traces:  error() (discord-logger.service.ts:118)
                       ├── auth.controller.ts (credentialLogin, verifyPhoneOtp)
                       ├── booking-expiration.controller.ts (runCronExpiration)
                       └── payment-recovery.controller.ts (runCronReconciliation)
                       ⚠ Impacts 4 Routes | 27 Callers

Features

One shortcut or right-click — Alt+T / ⌥T or right-click Trace Callers on any function name
Blast radius summary — ⚠ Impacts 4 API Routes | 1 Background Worker
Multi-language & framework detection — TS/JS (Express, Fastify, NestJS, Next.js), Python (FastAPI, Flask, Django, Celery), Go (Gin, Echo, Chi, net/http), Rust (Actix, Axum, Rocket), C/C++ (Crow, Drogon, Embedded), Java/Kotlin (Spring Boot), C# (ASP.NET Core), PHP (Laravel, Symfony), Swift (Vapor, iOS), Flutter (Dart)
Interactive graph — pan, zoom, click any node to view file/line in the inspector and jump directly to editor
Filter controls — toggle test files (Alt+Shift+T) or filter to entry point routes only
Mermaid export — one click to copy a Mermaid diagram ready for your PR description
Local-first — no AI, no network calls, no telemetry, zero cloud dependency

Demo

Action	Result
`Alt+T` on a function	Graph opens beside the editor
Click a node	Jumps to that file and line
`Alt+Shift+T`	Toggles test files in the graph
Copy as Mermaid button	Copies Mermaid markdown to clipboard

Install

From the VS Code Marketplace

Search Mewra Pounce in the Extensions panel (Ctrl+Shift+X / Cmd+Shift+X), or launch Quick Open (Ctrl+P / Cmd+P) and paste:

ext install mewra.mewra-pounce

Or install via terminal:

code --install-extension mewra.mewra-pounce

From a release VSIX

Download mewra-pounce-x.y.z.vsix from GitHub Releases
In VS Code: open Extensions panel (Ctrl+Shift+X / Cmd+Shift+X) → ··· (Views and More Actions) → Install from VSIX…

Commands

Command	Title	Default keybinding
`mewra-pounce.trace`	Mewra Pounce: Trace Callers	`Alt+T`
`mewra-pounce.toggleTestFiles`	Mewra Pounce: Toggle Test Files in Graph	`Alt+Shift+T`
`mewra-pounce.exportMermaid`	Mewra Pounce: Copy Graph as Mermaid	(webview button)
`mewra-pounce.clearCache`	Mewra Pounce: Clear Entry Point Cache	—

Settings

Setting	Default	Description
`mewraPounce.maxDepth`	`12`	Maximum traversal depth
`mewraPounce.hideTestFilesByDefault`	`true`	Hide test file nodes by default
`mewraPounce.frameworks`	all four	Frameworks to detect as entry points
`mewraPounce.cacheEntryPoints`	`true`	Cache detected entry points per workspace

Supported Frameworks & Languages

Framework	What is detected
Express	`app.get/post/put/patch/delete/use`, `router.*`
Fastify	`fastify.get/post/route/register`
NestJS	Files ending in `.controller.ts` / `.resolver.ts` / `.gateway.ts`
Next.js App Router	`route.ts` files exporting `GET`/`POST`/…
Next.js Pages Router	`pages/api/*/.ts` exporting `default`
Workers & Cron Jobs	BullMQ, Inngest, Celery, `.worker.`, `.cron.`, `@Cron`
FastAPI (Python)	`@app.get/post/...`, `@router.*`, `routers/`, `endpoints/`
Flask (Python)	`@app.route`, `@bp.route`, blueprints, views
Django (Python)	`urls.py` patterns, `views.py` `View` / `ViewSet` / `APIView`
Gin (Go)	`router.GET/POST/...`, `group.`, handlers with `gin.Context`
Echo (Go)	`e.GET/POST/...`, `g.*`, handlers with `echo.Context`
Chi (Go)	`r.Get/Post/...`, `r.Route`, `r.Mount`
Standard net/http	`http.HandleFunc`, `http.Handle`, `ServeHTTP`
Plain Python / CLI	`main.py`, `cli.py`, `def main()`, `@click`, `typer`
Plain Go	`main.go`, `func main()`
Rust	`main.rs`, `fn main()`, Actix-web, Axum, Rocket macros
C / C++	`main.c/cpp`, `main()`, Embedded `app_main`, Crow, Drogon
Java / Kotlin	Spring Boot `@*Mapping`, `@Scheduled`, `@KafkaListener`, `main`
C# (.NET)	ASP.NET Core `[Http]`, Minimal API `app.Map`, `Program.cs`
PHP	Laravel `Route::*`, Symfony `#[Route]`, `ShouldQueue`, `index.php`
Swift	Vapor `app.get/post`, SwiftUI `@main`, UIKit `viewDidLoad`, `@IBAction`
Flutter / Dart	`main.dart`, `runApp`, `build`, Shelf `router.*`, `@pragma('vm:entry-point')`

Mermaid export example

graph TD
    N0["validateUserInput<br/>validate.ts:42"]
    N1["createUser<br/>user.service.ts:18"]
    N2["POST /api/users<br/>user.routes.ts:9"]
    N3["QueueWorker: onUserCreated<br/>user.worker.ts:5"]
    N0 --> N1
    N1 --> N2
    N1 --> N3
    style N0 fill:#3b82f6,color:#fff
    style N2 fill:#22c55e,color:#fff
    style N3 fill:#22c55e,color:#fff

Developing

See CONTRIBUTING.md for the full guide.

Quick start:

git clone https://github.com/mewra-lab/mewra-pounce.git
cd mewra-pounce
pnpm install
pnpm build

Press F5 in VS Code to launch the Extension Development Host.

Quality gate:

pnpm validate

Runs: format check → TypeScript check → unit tests → build.

Stack

TypeScript · VS Code Extension API (Call Hierarchy LSP)
Preact · Cytoscape.js · ts-morph · Zod
esbuild · Vitest · Prettier · Husky + lint-staged
pnpm 12.3.4

Roadmap

Version	Status	Scope
0.1.1	Current	Reverse call hierarchy engine via LSP, interactive Cytoscape.js directed graph, polyglot framework entry point detection (TS/JS, Python, Go, Rust, Java, C#, PHP, Swift, Dart), blast radius summary, Mermaid diagram export
0.2.0	Planned	Active file-watcher cache invalidation, keyboard-first graph navigation (pan/zoom/focus), filter nodes by entry-point type (HTTP route, worker, cron)
0.3.0	Planned	Deep AST pattern matching for dynamic dispatch, export graph as SVG/PNG, Mewra PreFlight integration (surface blast radius & affected routes in pre-push checks)
1.0.0	Future	Cross-package & monorepo workspace tracing, first official stable release

Documentation

SPEC.md — full product and technical specification
docs/ARCHITECTURE.md — architecture, data flow, and trust boundaries
docs/GIT-WORKFLOW.md — Git, branch, Conventional Commits & PR workflow
docs/UX.md — Webview UX, interaction patterns, and styling
docs/TESTING.md — unit and extension testing strategy
docs/RELEASE.md — release and packaging guidelines
CONTRIBUTING.md — contributing guide and PR rules
SECURITY.md — security policy and threat model
PRIVACY.md — local-first privacy statement

Contributing

Contributions are welcome. Please read CONTRIBUTING.md and docs/GIT-WORKFLOW.md before submitting a Pull Request.

Security

Please report security issues privately. See SECURITY.md.

Privacy

Mewra Pounce is 100% local. See PRIVACY.md.

License

MIT