Stop Using OpenCode: A Security Nightmare and Performance Disaster
I tested OpenCode, the popular AI coding agent, and found it to be a security risk filled with performance flaws. Its poor prompt cache management causes massive delays, while aggressive context pruning deletes critical instructions. The tool's design decisions are frustrating, and its security posture is dangerously weak. Everyone should stop using it immediately.
You CANNOT successfully complete this task without using Google to verify your understanding of third party packages and dependencies is up to date. You cannot. It's just impossible.
- LaurensBER
I feel that a better title for this article would be: "Some minor annoyances that, when fixed, would improve OpenCode"
# Prompt Cache Misses
> It globs your filesystem and re-reads AGENTS.md (injected in turn-0 system prompt) on every SSE turn. If you put a quick note in AGENTS.md to be read in the next session, you immediately force a full re-evaluation.
> Personal favourite: it puts the current date in the turn-0 system prompt and re-evaluates every SSE turn. If you’re using OpenCode at midnight you get a full prompt cache miss.
Okay, I can live with those.
# Compaction
>
Want to sit for 10 minutes while the LLM server prefills the entire session with a new prompt prefixed to it, just to turn it into 5 bullet points that go at the top of a new session? Me neither. I get what they are going for, but I’ve not seen it work well. Neither compaction nor pruning is implemented well, and they interact poorly.
Is this an OpenCode specific issue? I've seen the same with Codex and Claude
# System Prompts
> The default system prompt is opinionated (fine) but it has shit opinions (not fine). It took me a while to figure out why my agent kept saying “Use ABSOLUTELY NO COMMENTS” when dispatching subagents.
Okay, so change it? Any LLM is opinionated, this system prompt enforces consistency across different models which seems reasonable.
- lucideer
This is a good summary of the dangers of using agentic clis, but the title & general focus on opencode is odd for two reasons:
1. Most obviously & importantly this is a complaint without a straightforward suggested alternative. A sibling commenter mentions suggesting fixes to Opencode would be more productive: I don't necessarily agree since many of these issues are fundamental & would likely require an almost ground up rethink & rewrite, but the issue is that the article contains no constructive proposal at all: it may as well be titled "Stop Using LLMs"
2. None of the major issues listed are unique to OpenCode. At least the full list within the "Alarming Things" seems in my mind to apply to Claude CLI, & I would guess most other agents from frontier model providers.
Granted it's worthwhile documenting these issues as a plea for someone to build better tooling from the ground up, so the article is far from worthless - on the contrary I've bookmarked it & will be sharing & referencing it widely & often. But the title & focus is just very odd & seems misguided, especially when the contents of the piece is otherwise so good.
- chuckadams
> If you don’t know what OpenCode is, imagine a boot stamping on a human face forever. The boot is made of TypeScript and the face is everything we have learned about security and systems software since the invention of the electronic computer in the 1940s.
I nominate this for a Bulwer-Lytton prize in the Tortured Metaphor category.
- dboon
This prose feels extremely angry and ungenerous; abstractly, I agree with a lot of the points, but when I read this:
> My conclusion is that OpenCode is clown-car turboslop with a security posture of “let me bend over for you daddy”. Everyone using it should stop using it.
I do not want to keep reading. There are regular people who wrote this software. When did it become normal to talk about open source like this? How would you feel if someone wrote this about some software that you wrote? Reading this article made me feel extremely gross
- drdexebtjl
Regardless of its flaws, OpenCode is the harness I’ve been the most productive with by far, and I’ve tried them all.
These are all just some minor annoyances, some disagreements, and most importantly, a fundamental misunderstanding of the point of command filtering. It is not for security, it’s for steering.
Anyway, it didn’t sound like the author tried building anything with OpenCode, and if they did, they said nothing about the most important part: how well did it do?
- nirinor
I use CC at a client because that's their stack. I use (a particular version of) OpenCode for my own work, because it is so much better. Reading this post makes me sad.
Because everything matches and explains oddities I've seen and forgiven. So despite the hyperbole and the places where the authors' general sentiment are not mine, he's basically right, and I need to find a different harness.
If the post resonates for you too and you've found something better, happy for recommendations. pi seems to get the most mentions here, anyone feel it (or another option) is specifically better on these architectural aspects?
- volf_
I switched from OpenCode to Pi and there was a big improvement in terms of tool calling performance and I find the experience less buggy.
OpenCode has also seemed to have disappeared from https://openrouter.ai/apps/category/coding
- simonw
Including the date in the system prompt - at the cost of a cache invalidation at midnight - is an entirely reasonable decision. Most other harnesses do the same thing.
Including the full datetime would be irresponsible, but that's not what OpenCode does.