prodigycorp
a month ago
The best part about this is that you know the type of people/companies using langchain are likely the type that are not going to patch this in a timely manner.
peab
a month ago
Langchain is great because it provides you an easy method to filter people out when hiring. Candidates who talk about langchain are, more often than not, low quality candidates.
babyshake
a month ago
Would you say the same for Mastra? If so, what would you say indicates a high quality candidate when they are discussing agent harnessing and orchestration?
avaer
a month ago
I somewhat take issue as a LangChain hater + Mastra lover with 20+ years of coding experience and coding awards to my name (which I don't care about, I only mention it for context).
Langchain is `left-pad` -- a big waste of your time, and Mastra is Next.js -- mostly saving you infrastructure boilerplate if you use it right.
But I think the primary difference is that Python is a very bad language for agent/LLM stuff (e.g. static typesystem, streaming, isomorphic code, strong package management ecosystem is what you want, all of which Python is bad with). And if for some ungodly reason you had to do it in Python, you'd avoid LangChain anyway so you could bolt on strong shim layers to fix Python's shortcomings in a way that won't break when you upgrade packages.
Yes, I know there's LangChain.js. But at that point you might as well use something that isn't a port from Python.
> what would you say indicates a high quality candidate when they are discussing agent harnessing and orchestration?
Anything that shows they understand exactly how data flows through the system (because at some point you're gonna be debugging it). You can even do that with LangChain, but then all you'd be doing is complaining about LangChain.
runeblaze
a month ago
> And if for some ungodly reason you had to do it in Python
I literally invoke sglang and vllm in Python. You are supposed to (if not using them over-the-network) use the two fastest inference engines there is via Python.
stingraycharles
a month ago
Python being a very bad language for LLM stuff is a hot take I haven’t heard before. Your arguments sound mostly like personal preferences that apply to any problem, not just agentic / LLM.
If we’re going to throw experience around, after 30+ years of coding experience, I really don’t care too much anymore as long as it gets the job done and it doesn’t get in the way.
LangChain is ok, LangGraph et al I try to avoid like the plague as it’s too “framework”-ish and doesn’t compose well with other things.
avaer
a month ago
I used to write web apps in C++, so I totally understand not caring if it gets the job done.
I guess the difference where I draw the line is that LLMs are inherently random I/O so you have to treat them like UI, or the network, where you really have no idea what garbage is gonna come in and you have to be defensive if you're going to build something complex -- otherwise, you as a programmer will not be able to understand or trust it and you will get hit by Murphy's law when you take off your blinders. (if it's simple or a prototype nobody is counting on, obviously none of this matters)
To me insisting that stochastic inputs be handled in a framework that provides strong typing guarantees is not too different from insisting your untrusted sandbox be written in a memory safe language.
stingraycharles
a month ago
What does static type systems provide you with that, say, using structured input / output using pydantic doesn’t?
I just don’t follow your logic of “LLMs are inherently random IO” (ok, I can somehow get behind that, but structured output is a thing) -> “you have to treat them like UI / network” (ok, yes, it’s untrusted) -> static typing solves everything (how exactly?)
This just seems like another “static typing is better than dynamic typing” debate which really doesn’t have a lot to do with LLMs.
saidnooneever
a month ago
he says its bad for agents, nit 'LLM stuff'. python is fine to throw task to the GPU. it is absolutely dreadful at any real programming. so if you want to write an agent that _uses_ LLMs etc like an agent, there are much better languages, for performance, safety and your sanity.
stingraycharles
a month ago
so the argument boils down to “untyped languages are dreadful for real programming” ?
peab
a month ago
I'm not familiar with it. My first question would be: Are there any prominent projects that use it?
A lot of these frameworks are lauded, but if they were as good as they claim you would run into them in all sorts of apps. The only agents that i ever end up using are coding agents, i think they're obviously the most popular implementations of agents. Do they use langchain? No, i don't think so. They probably use in house logic cus it's just as easy and gives them more flexibility and less dependencies
stingraycharles
a month ago
What makes you say that? Because it’s popular?
peab
a month ago
Because it tries to solve non existent problems (prompt templates for example) and adds complexity, instead of abstracting
stingraycharles
a month ago
Ok I agree with that, I think they had some weird idea of managing templates in LangSmith and then being able to load them dynamically from LangChain.
LangSmith’s prompt engineering workflow is okay-ish but a lot of work and gets quite expensive quite fast, and only works for a specific set of prompts (ie one-turn prompts, multi-turn never works).
PydanticAI seems more lightweight and gets out of the way.
peab
a month ago
Yes, Pydantic ai successfully abstracts the tool call loop, and makes it easy to test out different models.
isoprophlex
a month ago
Because it's shit.
whattheheckheck
a month ago
Have you seen hamilton/burr python packages for building the state machines for llm work?
deepsquirrelnet
a month ago
It also helps with jobseeking as well. Easy to know which places to avoid.
notnullorvoid
a month ago
Curious what your critique is for LangChain?
I found the general premise of the tools (in particular LangGraph) to be solid. I was never in the position to use it (not my current area of work), but had I been I may have suggested building some prototypes with it.
peab
a month ago
I think there are probably lots of thorough critiques, but for me it boiled down to this:
Langchain claimed to be an abstraction on top of LLMs, but in fact, added additional unecessary complexity.
Prompt management was such a buzzword when langchain came out, but 99% of LLM use cases don't need prompt management - GitHub and strings works just fine.
wilkystyle
a month ago
Can you elaborate? Fairly new to langchain, but didn't realize it had any sort of stereotypical type of user.
int_19h
a month ago
I'll admit that I haven't looked it in a while, but as originally released, it was a textbook example on how to complicate a fundamentally simple and well-understood task (text templates, basically) with lots of useless abstractions that made it all sound more "enterprise". People would write complicated langchains, but then when you looked under the hood all it was doing is some string concatenation, and the result was actually less readable than a simple template with substitutions in it.
phyzome
a month ago
Huh, kind of sounds like they used LLMs to design it. :-)
gcr
a month ago
What do you suggest instead? Handrolled code with “import openai”? BAML?
hhh
a month ago
yes, in an industry that has rapidly changing features and 7000 of these products that splinter and lose user base so quickly you should write your own orchestration for this stuff. It’s not hard and gives you a very easy path to implementing new features or optimizations.
llmslave2
a month ago
Oh gosh, not that legacy "hand rolled code"
int_19h
a month ago
For what LangChain does, yes, handrolled code. There won't be much of it because it doesn't actually do all that much.
As for "import openai", that's actually somewhat orthogonal, but if what you want is a common API for different providers then there are many options around that do just that. But then again at that point you probably also want something like OpenRouter, which has its own generic API.
jmogly
a month ago
I’ve been using the following pattern since gpt3, the only other thing I have changed was added another parameter for schema for structured output. People really love to overcomplicate things.
class AI(Protocol):
def call_llm(prompt: str) -> str: …
never_inline
a month ago
Have you heard of `def`?
gcr
a month ago
It was an earnest question. I didn’t intend to be sarcastic.
alzoid
a month ago
I went through evaluating a bunch of frameworks. There was Langchain, AG2, Firebase Gen AI / Vertex / whatever Google eventually lands on, Crew AI, Microsoft's stuff etc.
It was so early in the game none of those frame works are ready. What they do under the hood when I looked wasn't a lot. I just wanted some sort of abstraction over the model apis and the ability to use the native api if the abstraction wasn't good enough. I ended up using Spring AI. Its working well for me at the moment. I dipped into the native APIS when I needed a new feature (web search).
Out of all the others Crew AI was my second choice. All of those frameworks seem parasitic. One your on the platform you are locked in. Some were open source but if you wanted to do anything useful you needed an API key and you could see that features were going to be locked behind some sort of payment.
Honestly I think you could get a lot done with one of the CLI's like Claude Code running in a VM.
never_inline
a month ago
Which abstractions in langchain do you find so useful which require significant code to replicate yourself in functions with OpenAI SDK / LiteLLM?
XCSme
a month ago
I am not sure what's the stereotype, but I tried using langchain and realised most of the functionality actually adds more code to use than simply writing my own direct API LLM calls.
Overall I felt like it solves a problem doesn't exist, and I've been happily sending direct API calls for years to LLMs without issues.
teruakohatu
a month ago
JSON Structured Output from OpenAI was released a year after the first LangChain release.
I think structured output with schema validation mostly replaces the need for complex prompt frameworks. I do look at the LC source from time to time because they do have good prompts backed into the framework.
majormajor
a month ago
IME you could get reliable JSON or other easily-parsable output formats out of OpenAI's going back at least to GPT3.5 or 4 in early 2023. I think that was a bit after LangChain's release but I don't recall hitting problems that I needed to add a layer around in order to do "agent"-y things ("dispatch this to this specialized other prompt-plus-chatgpt-api-call, get back structured data, dispatch it to a different specialized prompt-plus-chatgpt-api-call") before it was a buzzword.
nostrebored
a month ago
Can guarantee this was not true for any complicated extraction. You could reliably get it to output json but not the json you wanted
Even on smallish ~50k datasets error was still very high and interpretation of schema was not particularly good.
avaer
a month ago
It's still not true for any complicated extraction. I don't think I've ever shipped a successful solution to anything serious that relied on freeform schema say-and-pray with retries.
avaer
a month ago
To this day many good models don't support structured outputs (say Opus 4.5) so it's not a panacea you can count on in production.
The bigger problem is that LangChain/Python is the least set up to take advantage of strong schemas even when you do have it.
Agree about pillaging for prompts though.
teruakohatu
a month ago
> so it's not a panacea you can count on in production.
OpenAI and Gemini models can handle ridiculously complicated and convoluted schemas, if I needed complicated JSON output I wouldn’t use anything that didn’t guarantee it.
I have pushed Gemini 2.5 Pro further than I thought possible when it comes to ridiculously over complicated (by necessity) structured output.
jmogly
a month ago
100% Gemini + pydantic you don’t need a wrapper library in 2025
Insanity
a month ago
When my company organized an LLM hackathon last year, they pushed for LangChain.. but then instead of building on top of it I ended up creating a more lightweight abstraction for our use-cases.
That was more fun than actually using it.
prodigycorp
a month ago
No dig at you, but I take the average langchain user as one who is either a) using it because their C-suite heard about at some AI conference and had it foisted upon them or b) does not care about software quality in general.
I've talked to many people who regret building on top of it but they're in too deep.
I think you may come to the same conclusions over time.
inlustra
a month ago
Great insight that you wouldn’t get without HN, thank you! What would you and your peers recommend?
baobabKoodaa
a month ago
LangChain does not solve any actual problem, so there is no need to replace it with anything. Just build without it.
peab
a month ago
There's a great talk called Pydantic is all you need that i highly recommend
sumitkumar
a month ago
pydantic/pydanticAI in builder mode or llamaindex in solution architect mode.
wilkystyle
a month ago
Thanks for the reply, and no offense taken. I've inherited some code that uses LangChain, and this is my first experience with it.
anonzzzies
a month ago
Yep, not sure why anyone is using it still.
echelon
a month ago
These guys raised $125M at $1.3B post on $12M ARR? What.
> Today, langchain and langgraph have a combined 90M monthly downloads, and 35 percent of the Fortune 500 use our services
What? This seems crazy. Maybe I'm blind, but I don't see the long term billion dollar business op here.
Leftpad also had those stats, iirc.
anonzzzies
a month ago
They were the first, very very early in the gpt hype start.
blcknight
a month ago
What would you use instead?
I built an internal CI chat bot with it like 6 months ago when I was learning. It’s deployed and doing what everyone needs it to do.
Claude Code can do most of what it does without needing anything special. I think that’s the future but I hate the vendor lock in Anthropic is pushing with CC.
All my python tools could be skills, and some folks are doing that now but I don’t need to chase after every shiny thing — otherwise I’d never stop rewriting the damn thing.
Especially since there’s no standardizing yet on plugins/skills/commands/hooks yet.
esperent
a month ago
> I hate the vendor lock in Anthropic is pushing with CC.
Accepting any kind of vendor lock in within this space at the moment is an incredibly bad idea. Who knows what will get released next week, let alone the next year. Anthropic might be dead in the water in six months. It's unlikely but not impossible. Expand that to a couple of years and it's not even that unlikely.