Exit Code 2 Behavior
PreToolUse - Blocks the tool call, shows error to Claude
This is great, it means you can set up complex concrete rules about commands CC is allowed to run (and with what arguments), rather than trying to coax these via CLAUDE.md.
Hooks will be important for "context engineering" and runtime verification of an agent's performance. This extends to things such as enterprise compliance and oversight of agentic behavior.
This closes a big feature gap. One thing that may not be obvious is that because of the way Claude Code generates commits, regular Git hooks won’t work. (At least, in most configurations.)
We’ve been using CLAUDE.md instructions to tell Claude to auto-format code with the Qlty CLI (https://github.com/qltysh/qlty) but Claude a bit hit and miss in following them. The determinism here is a win.
It looks like the events that can be hooked are somewhat limited to start, and I wonder if they will make it easy to hook Git commit and Git push.
So, form my limited understanding, this doesn't take up context, it's something auto where you can configure per tool use, and not MCP that Claude decides "when" to run it?!
An abstraction via a script should work, right? They document that it pipes the JSON data to your command's stdin,
```lint-monorepo.sh
# read that data
json_input=$(cat)
# do some parsing here with jq, get the file path (file_path)
if [$file_path" == "$dir1"*]
run lint_for_dir1
```
I've been playing with Claude Code the past few days. It is very energetic and maybe will help me get over the hump on some long-standing difficult problems, but it loses focus quickly. Despite explicit directions in CLAUDE.md to build with "make -j8" and run unit tests with "make -j8 check", I see it sometimes running make without -j or calling the test executable directly. I would like to limit it to doing certain essential aspects of workflow with the commands I specify, just as a developer would normally do. Are "Hooks" the right answer?
This doesn’t come without consideration. You can see I mention this in the original feature request.
Yes - it’s fine to think of it as handholding (or handcoding). These model providers cannot be responsible for ultimate alignment with their users. Today, they can at best enable integration so a user, or business, can express and ensure their own alignment at runtime.
The nature of these systems already requires human symbiosis. This is nothing more than a new integration point. Will empower agents beyond today’s capabilities, increase adoption.
Claude Code has basically grown to dominate my initial coding workflow.
I was using the API and passed $50 easily, so I upgraded to the $100 a month plan and have already reached $100 in usage.
I've been working on a large project, with 3 different repos (frontend, backend, legacy backend) and I just have all 3 of them in one directory now with claude code.
Wrote some quick instructions about how it was setup, its worked very well. If I am feeling brave I can have multiple claude codes running in different terminals, each working on one piece, but Opus tends to do better working across all 3 repos with all of the required context.
Still have to audit every change, commit often, but it works great 90% of the time.
Opus-4 feels like what OAI was trying to hype up for the better part of 6 months before releasing 4.5
Just started using Claude (very late to the game), and I am truly blown away. Instead of struggling for hours trying to get the right syntax for a Powershell script or to convert Python to Go, I simply ask Claude to make it happen. This helps me focus on content creation instead of the mind-bending experience of syntax across various languages. While some might call it laziness, I call it freedom as it helps me get my stuff done quicker.
I have been using it for other stuff (real estate, grilling recipes, troubleshooting electrical issues with my truck), and it seems to have a very large knowledge base. At this point, my goal is to get good at asking the right kinds of questions to get the best/most accurate answers.
It remains to be seen whether it's a net value once the VC firehose dries up and the true costs are revealed. It's quite possible that the profitable price is not worth it for most companies.
Yup, slowing down the AI is a really hard thing to do. I've mostly accomplished it, but I use extensive auto prompting and a large memory bank. All of it is designed explicitly to slow down the AI. I've taught it how to do what I call "Baby Steps", which is defined as: "The smallest possible change that still effectively moves the technology forward." Some of my prompting is explicit about human review and approval of every change including manual testing of the application in question BEFORE the model moves on to the next step.
Given the Anthropic legal terms forbid competing with them, what are we actually allowed to do with this? Seems confusing what is allowed.
No machine learning work? That would compete.
No writing stuff I would train AI on. Except I own the stuff it writes, but I can’t use it.
Can we build websites with it? What websites don’t compete with Anthropic?
Terminal games? No, Claude code is a terminal game, if you make a terminal game it competes with Claude?
Can their “trust and safety team” humans read everyone’s stuff just to check if we’re competing with LLMs (funny joke) and steal business ideas and use them at Anthropic?
Feels like the dirty secret of AI services is, every possible use case violates the terms, and we just have to accept we’re using something their legal team told us not to use? How is that logically consistent? Any safety concerns? This doesn’t seem like a law Asimov would appreciate.
It would be cool if the set of allowed use cases wasn’t empty. That might make Anthropic seem more intelligent
Anthropic's terms typically restrict training competing AI models with their outputs, not building standard applications or websites that simply use their API as a tool.
So many people yearn for LLM's to be like the Star Trek ship computer, which when asked a question unconditionally provides a response relevant and correct, needing no verification.
A better analogy is LLM's are closer to the "universal translator" with an occasional interaction similar to[0]:
Black Knight: None shall pass.
King Arthur: What?
Black Knight: None shall pass!
King Arthur: I have no quarrel with you good Sir Knight, But I must cross this bridge.
Black Knight: Then you shall die.
King Arthur: I command you, as King of the Britons, to stand aside!
Black Knight: I move for no man.
King Arthur: So be it!
[they fight until Arthur cuts off the Black Knight's left arm]
King Arthur: Now, stand aside, worthy adversary.
Black Knight: 'Tis but a scratch.
King Arthur: A scratch? Your arm's off!
Black Knight: No, it isn't.
King Arthur: Well, what's that then?
Black Knight: I've had worse.
E.g. you can allow
but preventYou can already do this in .Claude/settings.json
Ah you’re right, but for more complex logic it’s useful to be able to run it through a custom script
Really excited to see this implemented.
Hooks will be important for "context engineering" and runtime verification of an agent's performance. This extends to things such as enterprise compliance and oversight of agentic behavior.
Nice of Anthropic to have supported the idea of this feature from a github issue submission: https://github.com/anthropics/claude-code/issues/712
It is indeed. I don't use Claude Code. I use Cline which is a VS Code extension (cline.bot).
This is a pretty killer feature that I would expect to find in all the coding agents soon.
Would love to see this in Cursor. My workaround right now is using a bunch of rules that sort of work some of the time.
As an ex-Cursor user myself, is there any reason that you’re still using it? Genuinely curious.
That tab autocomplete and predicting what I'm going to edit next is the best I've found.
The rest I can take or leave (plenty of good or better alternatives)
Amazing how there's whole companies dedicated to this and yet claude code keeps leading the way.
Not to take away anything here, but hooks are present in other similar products. Atleast one example here - https://docs.aws.amazon.com/amazonq/latest/qdeveloper-ug/com...
This closes a big feature gap. One thing that may not be obvious is that because of the way Claude Code generates commits, regular Git hooks won’t work. (At least, in most configurations.)
We’ve been using CLAUDE.md instructions to tell Claude to auto-format code with the Qlty CLI (https://github.com/qltysh/qlty) but Claude a bit hit and miss in following them. The determinism here is a win.
It looks like the events that can be hooked are somewhat limited to start, and I wonder if they will make it easy to hook Git commit and Git push.
So, form my limited understanding, this doesn't take up context, it's something auto where you can configure per tool use, and not MCP that Claude decides "when" to run it?!
This needs a way to match directories for changes in monorepos. E.g. run this linter only if there were changes in this directory.
An abstraction via a script should work, right? They document that it pipes the JSON data to your command's stdin,
Whatever you run in the hook can check whatever conditions you want.
This can be implemented at the line level if the linter is Git aware
I've been playing with Claude Code the past few days. It is very energetic and maybe will help me get over the hump on some long-standing difficult problems, but it loses focus quickly. Despite explicit directions in CLAUDE.md to build with "make -j8" and run unit tests with "make -j8 check", I see it sometimes running make without -j or calling the test executable directly. I would like to limit it to doing certain essential aspects of workflow with the commands I specify, just as a developer would normally do. Are "Hooks" the right answer?
For the `-j` issue specifically, exporting `MAKEFLAGS=-j8` should work.
adding a hook to have it push to prod every time baby
We have to do this, otherwise China wins the "AI" race!
This also:
1) Assign coding task via prompt 2) Hook: Write test for prompt proves 3) Write code 4) Hook: Test code 5) Code passes -> Commit 6) Else go to 3.
you can just tell it do that or in your claude.md. don't need hooks
In some cases cc misses rules in CLAUDE.md.
In many cases.
so its back to hand coding stuff again.
They are going to slowly add "features" that brings handcoding back till its like 100% handcoding again.
This doesn’t come without consideration. You can see I mention this in the original feature request.
Yes - it’s fine to think of it as handholding (or handcoding). These model providers cannot be responsible for ultimate alignment with their users. Today, they can at best enable integration so a user, or business, can express and ensure their own alignment at runtime.
The nature of these systems already requires human symbiosis. This is nothing more than a new integration point. Will empower agents beyond today’s capabilities, increase adoption.
Claude Code has basically grown to dominate my initial coding workflow.
I was using the API and passed $50 easily, so I upgraded to the $100 a month plan and have already reached $100 in usage.
I've been working on a large project, with 3 different repos (frontend, backend, legacy backend) and I just have all 3 of them in one directory now with claude code.
Wrote some quick instructions about how it was setup, its worked very well. If I am feeling brave I can have multiple claude codes running in different terminals, each working on one piece, but Opus tends to do better working across all 3 repos with all of the required context.
Still have to audit every change, commit often, but it works great 90% of the time.
Opus-4 feels like what OAI was trying to hype up for the better part of 6 months before releasing 4.5
Just started using Claude (very late to the game), and I am truly blown away. Instead of struggling for hours trying to get the right syntax for a Powershell script or to convert Python to Go, I simply ask Claude to make it happen. This helps me focus on content creation instead of the mind-bending experience of syntax across various languages. While some might call it laziness, I call it freedom as it helps me get my stuff done quicker.
I have been using it for other stuff (real estate, grilling recipes, troubleshooting electrical issues with my truck), and it seems to have a very large knowledge base. At this point, my goal is to get good at asking the right kinds of questions to get the best/most accurate answers.
That’s great. Regardless of the naysayers about AI hype in tech, it was a major development for general society even if this is all it ends up being.
It remains to be seen whether it's a net value once the VC firehose dries up and the true costs are revealed. It's quite possible that the profitable price is not worth it for most companies.
[flagged]
Yup, slowing down the AI is a really hard thing to do. I've mostly accomplished it, but I use extensive auto prompting and a large memory bank. All of it is designed explicitly to slow down the AI. I've taught it how to do what I call "Baby Steps", which is defined as: "The smallest possible change that still effectively moves the technology forward." Some of my prompting is explicit about human review and approval of every change including manual testing of the application in question BEFORE the model moves on to the next step.
The key phrase is "Do not overengineer."
I say stuff like:
This code must be minimal.
Meet only the stated requirements.
Do not overengineer.
Create a numbered index of requirements.
Verify after you write the code that all requirements are met and no more.
[flagged]
Given the Anthropic legal terms forbid competing with them, what are we actually allowed to do with this? Seems confusing what is allowed.
No machine learning work? That would compete.
No writing stuff I would train AI on. Except I own the stuff it writes, but I can’t use it.
Can we build websites with it? What websites don’t compete with Anthropic?
Terminal games? No, Claude code is a terminal game, if you make a terminal game it competes with Claude?
Can their “trust and safety team” humans read everyone’s stuff just to check if we’re competing with LLMs (funny joke) and steal business ideas and use them at Anthropic?
Feels like the dirty secret of AI services is, every possible use case violates the terms, and we just have to accept we’re using something their legal team told us not to use? How is that logically consistent? Any safety concerns? This doesn’t seem like a law Asimov would appreciate.
It would be cool if the set of allowed use cases wasn’t empty. That might make Anthropic seem more intelligent
Anthropic's terms typically restrict training competing AI models with their outputs, not building standard applications or websites that simply use their API as a tool.
Would you argue that Cursor (valued at $10B) is breaking Anthropic's terms by making an IDE that competes with their Canvas feature?
Cursor isn't building models trained with the outputs of Anthropic models (I think). That's what the ToS is forbidding.
Is Cursor using Claude code to build? Or they just allow it to plug into Claude?
Yes.
Oh come on, your CRUD app is not competing with an LLMaaS
Oh come on, understand how contracts work before posting a comment like this one.
You’re only competing with them if you’re doing something they consider competitive. OpenAI is competitive, you are not
This is nice but I really wish they’d just let me fork the damn thing already.
So many people yearn for LLM's to be like the Star Trek ship computer, which when asked a question unconditionally provides a response relevant and correct, needing no verification.
A better analogy is LLM's are closer to the "universal translator" with an occasional interaction similar to[0]:
0 - https://en.wikiquote.org/wiki/Monty_Python_and_the_Holy_Grai...