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Show HN: MCP Server SDK in Bash

https://github.com/muthuishere/mcp-server-bash-sdk
135•muthuishere•1d ago

Comments

rcleveng•1d ago
I have to say this is a very readable implementation to see how it all works in practice as well as a good reminder that it's a pretty simple universal tool interface.
skeeter2020•19h ago
>> a good reminder that it's a pretty simple universal tool interface.

That's because it's not really doing anything new. MCP is a land-grab by one company, quickly supported by the rest as they desperately work to abstract and supplant with their own "protocols". Welcome to the era of thin veneers that add little but complexity over what we already had.

inercia•1d ago
Similar to https://github.com/inercia/MCPShell, but the MCPShell can sandbox the execution of the shell code for higher safety.
samuel•1d ago
I don't think they are comparable. MCPShell is a go program to run shell scripts, while the other one allows to define MCP operations as bash functions.

Not quite the same. The bash sdk can't be used to run arbitrary shell commands any more than to run arbitrary python programs.

sam_lowry_•1d ago
Did the AI help write this?
mathgeek•21h ago
I love that “the AI” has become a modern day “the Google”.
esafak•17h ago
"I AI'd it."
Too•1d ago
What does zero-overhead mean here?
rcarmo•1d ago
Raw protocol, really. No marshaling, no conversions, none of the overhead from type management you get with modern Python, none of the turtles-all-the-way-down dependencies of NodeJS equivalents. I like it, although I would probably port it back to “lightweight” Python in about half the size :)
tardyp•23h ago
Interesting to see ppl caring about marshalling overhead when working with LLMs
rcarmo•22h ago
Some of us still prize compute efficiency, especially those who have been using Python for a long time and are contemplating the new kinds of code patterns that have emerged from data science...
riobard•1d ago
This is neat but "zero runtime" is a misnomer. Bash _is_ runtime, not to mention external tools used in shell scripts like jq.
dotemacs•1d ago
It works great with Emacs :)

https://github.com/dotemacs/emacs-mcp

I like the fact that it's just Bash

cranberryturkey•23h ago
here's a node version of an MCP server: https://www.npmjs.com/package/@profullstack/mcp-server
pjmlp•22h ago
Runtime is called POSIX userspace.
baq•22h ago
Gross. I love it.
rvz•22h ago
> in pure Bash.

Not really in "pure bash". Also this needs to be labeled as a "toy".

Using an external tool like 'jq' especially written in C for parsing JSON, one can craft a exploitable JSON input to achieve code execution on the MCP server.

What could possibly go wrong? Maybe this CVE-2025-48060 [0] [1]?

[0] https://github.com/jqlang/jq/issues/3327

[1] https://nvd.nist.gov/vuln/detail/CVE-2025-48060

_heimdall•21h ago
Very cool! The docs here are a great overview of how MCP works, and a reminder to me of an old lesson:

We never should have abandoned REST. The whole point was for an interface to be self-describing; we wouldn't need MCP (or Swagger, or OpenAPI, etc) if we just stuck to REST instead of diverting down the JSON RPC route we've been on for 20 years.

0x445442•19h ago
By REST you mean HATEOAS?
wild_egg•19h ago
You can't have REST without it
_heimdall•18h ago
That's one constraint of REST, yes.
_verandaguy•18h ago
Wait, who's abandoned REST?

And in what way is OpenAPI an abandonment of REST? It's an API documentation system that can be leveraged for generating REST server boilerplate code. If anything, it builds up the quality-of-life around REST.

mcdow•16h ago
So the things we call "REST" in 2025 are not quite the same as the original specification of REST. One key aspect that has been abandoned is that sent data should be self-describing. That is, it shouldn't require any additional information to be useful. i.e. API documentation for JSON endpoints.

There's a great chapter on this in Hypermedia Systems[1]. Talks about both this and HATEOAS(Hypermedia as the engine of application state).

1. https://hypermedia.systems/components-of-a-hypermedia-system...

_heimdall•15h ago
I haven't seen a REST API in production for many years, maybe 15?

That's anecdotal obviously, but almost every, if not every, API I use today is an RPC call returning JSON.

Edit: to be clear, the distinction between what REST was defined as and what we use today often doesn't really matter. We use JSON APIs today, it is what it is. This is a case where it really matters though, LLM companies are now trying to push an entirely new protocol that tries to do roughly what REST did in the first place.

maxwellg•17h ago
Ha! I love this. There's nothing like a proper Bash script to make me realize how terribly gross all of mine are.

The drum I'm currently beating is that local MCP is a ton of fun for techies like us - if you're on this website you can `npx ...` or install whatever you want with a modicum of common sense - but local MCP is going to be a dead end for mass adoption. If we want to build MCP servers that get used by everyday people (or on mobile or other locked down ecosystems) then remote MCP + OAuth is the only realistic way forward. I can't get my dad to open up a terminal window - anything over stdio or touching environment variables and API keys is a nonstarter.

cruffle_duffle•15h ago
The infrastructure around MCP has a long ways to go before ordinary people can use it. Don’t forget you also have to edit configuration files.
maxwellg•14h ago
Oh absolutely - but the infrastructure required to support a "click link, get remote MCP URL added to config automatically" flow is _so_ much smaller than the infrastructure required for a "click link, download and install arbitrary software that may or may not depend on having existing tools installed" flow.
rcarmo•13h ago
I just rolled my own Python umcp library based on this, so thanks for the inspiration!

https://github.com/rcarmo/umcp

Beware of Fast-Math

https://simonbyrne.github.io/notes/fastmath/
36•blobcode•1h ago•2 comments

Photos taken inside musical instruments

https://www.dpreview.com/photography/5400934096/probe-lenses-and-focus-stacking-the-secrets-to-incredible-photos-taken-inside-instruments
592•worik•12h ago•26 comments

What's working for YC companies since the AI boom

https://jamesin.substack.com/p/whats-working-for-yc-companies-since
52•jseidel•18h ago•28 comments

Simpler Backoff

https://commaok.xyz/post/simple-backoff/
45•todsacerdoti•3h ago•11 comments

Valkey Turns One: Community fork of Redis

https://www.gomomento.com/blog/valkey-turns-one-how-the-community-fork-left-redis-in-the-dust/
162•cebert•10h ago•61 comments

Cerebras achieves 2,500T/s on Llama 4 Maverick (400B)

https://www.cerebras.ai/press-release/maverick
38•ByteAtATime•4h ago•14 comments

Gradients Are the New Intervals

https://www.mattkeeter.com/blog/2025-05-14-gradients/
8•surprisetalk•2h ago•0 comments

Surprisingly fast AI-generated kernels we didn't mean to publish yet

https://crfm.stanford.edu/2025/05/28/fast-kernels.html
267•mfiguiere•12h ago•75 comments

AccessOwl (YC S22) is hiring an AI TypeScript Engineer to connect 100s of SaaS

https://www.ycombinator.com/companies/accessowl/jobs/hfWAhVp-ai-enabled-senior-software-engineer-typescript-focus
1•mathiasn•1h ago

AI Responses May Include Mistakes

https://www.os2museum.com/wp/ai-responses-may-include-mistakes/
121•userbinator•2h ago•91 comments

The ‘white-collar bloodbath’ is all part of the AI hype machine

https://www.cnn.com/2025/05/30/business/anthropic-amodei-ai-jobs-nightcap
405•lwo32k•19h ago•684 comments

Beating Google's kernelCTF PoW using AVX512

https://anemato.de/blog/kctf-vdf
281•anematode•16h ago•87 comments

Reverse engineering of Linear's sync engine

https://github.com/wzhudev/reverse-linear-sync-engine
95•flashblaze•2d ago•11 comments

Show HN: MCP Defender – OSS AI Firewall for Protecting MCP in Cursor/Claude etc

https://mcpdefender.com
34•gsundeep•1d ago•31 comments

Mary Meeker's first Trends report since 2019, focused on AI

https://www.bondcap.com/reports/tai
137•kjhughes•12h ago•59 comments

Show HN: Icepi Zero – The FPGA Raspberry Pi Zero Equivalent

https://github.com/cheyao/icepi-zero
149•Cyao•2d ago•35 comments

Microsandbox: Virtual Machines that feel and perform like containers

https://github.com/microsandbox/microsandbox
295•makeboss•19h ago•133 comments

Systems Correctness Practices at Amazon Web Services

https://cacm.acm.org/practice/systems-correctness-practices-at-amazon-web-services/
325•tanelpoder•19h ago•118 comments

Java Virtual Threads Ate My Memory: A Web Crawler's Tale of Speed vs. Memory

https://dariobalinzo.medium.com/virtual-threads-ate-my-memory-a-web-crawlers-tale-of-speed-vs-memory-a92fc75085f6
68•dariobalinzo•1d ago•21 comments

Cap: Lightweight, modern open-source CAPTCHA alternative using proof-of-work

https://capjs.js.org/
131•tiagorangel•16h ago•87 comments

Google Duo will be replaced by Google Meet in Sept 2025

https://9to5google.com/2025/05/27/google-meet-legacy-duo-calling/
12•phantomathkg•1h ago•17 comments

Revenge of the Chickenized Reverse-Centaurs

https://pluralistic.net/2022/04/17/revenge-of-the-chickenized-reverse-centaurs/
90•GreenWatermelon•2d ago•28 comments

How large should your sample size be?

https://vickiboykis.com/2015/08/04/how-large-should-your-sample-size-be/
22•sebg•3d ago•14 comments

C++ to Rust Phrasebook

https://cel.cs.brown.edu/crp/
46•wcrichton•10h ago•1 comments

Ray Tracing in J

https://idle.nprescott.com/2020/ray-tracing-in-j.html
64•todsacerdoti•2d ago•8 comments

The Darwin Gödel Machine: AI that improves itself by rewriting its own code

https://sakana.ai/dgm/
177•birriel•20h ago•172 comments

Every 5x5 Nonogram

https://pixelogic.app/every-5x5-nonogram
57•eieio•8h ago•23 comments

Robot is 3D-printed upside-down in one piece, then walks out of the printer

https://newatlas.com/robotics/3d-printed-soft-robot-walks/
6•Brajeshwar•1d ago•0 comments

Silicon Valley finally has a big electronics retailer again: Micro Center opens

https://www.microcenter.com/site/mc-news/article/micro-center-santa-clara-photos.aspx
224•modeless•10h ago•117 comments

Anthropic launches a voice mode for Claude

https://techcrunch.com/2025/05/27/anthropic-launches-a-voice-mode-for-claude/
94•kordlessagain•2d ago•25 comments