Sorry folks, this is a rollout artifact, we needed a way to turn this off remotely via feature flags if it broke something, and with telemetry off you don't get those. It's already been fixed as part of v2.1.281 releasing today.
The AGENTS.md support was implemented via our new extensibility system for CC, called Mods, which is launching soon-ish. A mod is a plugin with a new type of hook, which we call a function hook.
The only difference between CLAUDE.md and AGENTS.md is the filename. Do you really need a whole plugin system to support that use case? Feels like this could have been a one line change.
Don't you run bizantine ralph loops on remote environments with codex security checks, coupled with jev, grok, open router and a fully independent openclaw (on a maxed out mac mini inside a caveau in an undisclosed location, with open telegram) to change constants? You're going to be left behind.
The plugin system itself was probably already in the making, and they just chose to implement this tiny feature as a plugin to try it out.
As for the only difference being the file name, that's an untested assumption. Up until now, Claude hadn't supported AGENTS.md, and it's a simple application of Hyrum's Law that somebody, somewhere, was taking advantage of that to give one set of instructions to Claude, and a different set of instructions to some other provider. The correct behaviour in the presence of both files is not obvious, either.
Having a kill switch for the change is a perfectly reasonable safety measure in case something goes horribly wrong.
> The only difference between CLAUDE.md and AGENTS.md is the filename. Do you really need a whole plugin system to support that use case? Feels like this could have been a one line change.
I don't think this is a reasonable assumption. The document format in CLAUDE.md is whatever Anthropic specifies, where AGENTS.md is a common ground format that is expected to be supported by any agent, be it from Anthropic or not.
I think you're giving these files too much credit. There are no specs, they are freeform text. In this sense they are the same. The expectation of what could be in it by each vendor means nothing unless it's enforced.
Really loved this Tibo-level responsiveness, if Anthropic can keep it up with this level of service, I am pretty sure a lot of people will just ditch their ChatGPT subscription and just move to Claude.
On the other hand, if Anthropic is to follow the industry standards, this would never have happened in the first place. It's not like the feature gates are the frontier of software development.
Based on my experience with these tools so far, this seems exactly the kind of subtle but extremely severe bug that sneaks in when you start piling up layers of AI generated patches to a codebase without caring too much about the code.
Yep, especially with long contexts (and moreso if the last thing you were working on in the same context involved telemetry too). AI sneaks in weird conditions like this and then does the entire "You're absolutely right" thing if you're paying enough attention to catch it.
"extremely severe" - aren't we laying it on a bit thick here? The whole impact seems to be that users who have telemetry turned off got this feature ~2 days later, when the bug was noticed.
I used to actively use Msty for local models because it just worked and had a lot of nice advanced features. A few months ago they released their beta version of a Claw-like UI and mentioned using a version of it to develop Msty itself. Well, that was around the time I stopped using Msty because every update started breaking things and two updates in a row included bugs which wiped all my configs, chats, and history.
> It seems to be exactly the opposite, a "fully human error"
"LLMize the succeses, humanize the failures." is the PR strategy at play here. Anything goes well it's because AI did it, anything goes bad it's because a human didn't catch it.
It's been like this at least months. I turned telemetry off a few months ago and it basically prevented all stages rollouts of new features from working.
Anthropic commonly gates behind feature flags that require telemetry until they're "promoted" and defaulted on.
A little bit annoying you can't manually control the flags without telemetry but I think the title is a bit click bait.
This in some way sounds like VSCode's bug of always adding Copilot as a co-author of git commit regardless of user settings.
If people only glance over the code agents generate for them and don't bother to spend even half a minute thinking through what's actually happening, this is inevitable.
Certainly this kind of things happened before LLMs existed. But I'm not optimistic about the direction of how things are going.
Claude Code also doesn't read AGENTS.md by default if there's a CLAUDE.md it can read instead. This isn't limited to your repo, e.g. if you have a ~/CLAUDE.md then no AGENTS.md will be read.
To always read both, you have to switch the 'Project instructions' setting to the non-default `claude-md-and-agents-md`.
Just in case anyone is wondering why their AGENTS.md still isn't being read.
I like to give my graces to people and the companies who are typically not trillions of dollars. Have an incredible amount of resources that many countries would like to have, with fewer of the obligations. I'm going to chalk this up to its intended
I use cursor and claude, its kinda annoying having to have the same skills in both so I made a ~/.agents/skills folder then ln both cursor and claude skills to point to that folder.
which works except that claude uses .skills/synced which is uses to sync changes to skills from claude servers into the skills folder.
every other agent I have used just directly syncs into .skills so it ends up duplicating skills
Nice find, though I'd rather read the prompt that was used to write this article. It is about ten times longer than it needs to and is quite painful to read.
Uhm I turned off everything there is to turn off in my Pro plan, and Claude just read my agents.md with no issue? So... What telemetry am I missing? Or did they JUST update? (I updated my docker image 40 minutes ago to get Opus 5.5, am on version 2.1.280, so not the mentioned 2.1.277, so it's fixed?)
Even if this was an honest rollout mistake, the design is indefensible. Reading a local file should never depend on a remote feature flag, and silently skipping it with no warning is worse. I've tried to give Claude Code the benefit of the doubt, but this crosses a line.
The number of people raw-dogging software that executes arbitrary instructions on their machine coming from a 3rd party server just absolutely baffles me.
The same people who've spent years of their career making sure that never happens.
It's not open source. It's more "source available", since it's published, but you legally can't do anything with it. Other than maybe build it yourself, for yourself, I guess.
The mod is source available here: https://github.com/anthropics/claude-code/tree/main/mods/age...
Apologies again folks, this was a fully human error on my part - I should've found a better way to launch with a kill-switch.
If folks play around with it, I would love feedback on the relevant issue: https://github.com/anthropics/claude-code/issues/91870
Mods allow quite a bit more customizability and control. I really believe in the idea.
As for the only difference being the file name, that's an untested assumption. Up until now, Claude hadn't supported AGENTS.md, and it's a simple application of Hyrum's Law that somebody, somewhere, was taking advantage of that to give one set of instructions to Claude, and a different set of instructions to some other provider. The correct behaviour in the presence of both files is not obvious, either.
Having a kill switch for the change is a perfectly reasonable safety measure in case something goes horribly wrong.
I don't think this is a reasonable assumption. The document format in CLAUDE.md is whatever Anthropic specifies, where AGENTS.md is a common ground format that is expected to be supported by any agent, be it from Anthropic or not.
https://agents.md/
You might argue that differences are small or negligible, but that is just an expectation.
There is no rhyme or reason to the structure of this file, just like with most things in AI. It's best effort human language.
Q: Do Anthropic actually specify a document format?
At least make an argument for switching vendors based on the quality or price of their service.
I've had to send such messages, but internally at work, not on HN!
Have a great day, human.
Blink twice if you need help
Would be interesting to know how much time you/your team spent on that design decision
https://news.ycombinator.com/item?id=49815363
Nothing to do with AI patches at all, nor was it a bug. It was intentional human behavior, a temporary rollout setting, that seems to have made sense.
But I guess that doesn't fit the "narrative".
"LLMize the succeses, humanize the failures." is the PR strategy at play here. Anything goes well it's because AI did it, anything goes bad it's because a human didn't catch it.
Not sure if they later move the code from inside the flag check to the main code or that they keep the flag check.
But if they would keep all features behind a flag that would not make most sense as you then would have not many features without telemetry.
Anthropic commonly gates behind feature flags that require telemetry until they're "promoted" and defaulted on.
A little bit annoying you can't manually control the flags without telemetry but I think the title is a bit click bait.
> Added AGENTS.md support: in a project with no CLAUDE.md, Claude Code reads AGENTS.md instead
My dumb brain tells me none of this is rolled out progressively (as of that version). You either have it or not.
If people only glance over the code agents generate for them and don't bother to spend even half a minute thinking through what's actually happening, this is inevitable.
Certainly this kind of things happened before LLMs existed. But I'm not optimistic about the direction of how things are going.
To always read both, you have to switch the 'Project instructions' setting to the non-default `claude-md-and-agents-md`.
Just in case anyone is wondering why their AGENTS.md still isn't being read.
Not sure what y’all are thinking with these unwritten conspiracy theories that begin and end with “it’s intentional”
https://www.thatprivacyguy.com/blog/anthropic-spyware/
+ not letting users change their email, or remove their payment methods, etc.
which works except that claude uses .skills/synced which is uses to sync changes to skills from claude servers into the skills folder.
every other agent I have used just directly syncs into .skills so it ends up duplicating skills
The same people who've spent years of their career making sure that never happens.
[0] https://news.ycombinator.com/item?id=49760449
So I am unsure if it is fitting to call it a "closed source" harness.
[0] https://github.com/anthropics/claude-code
AGI was reached like 2 weeks ago, latest claude 5.x models rule supreme and oftware engineering is solved?