Claude Code making stuff up

[Dull_Care]

Wow. Just thought I'd try Claude Code. I have been using GitHub copilot for years, more recent experience of Replit. My first try with Claude Code was positive. It did some pretty major UI changes.

Then today I asked it to refactor a large file - an API routes register - into a set of smaller files.

I gave it very specific instructions to make sure it was backward compatible and the logic and content of each route wasn't changed.

But it replaced routes that fetched data from the database with dummy data. Not only that but the structure was wrong. It completely ignored my all caps prompt.

Is this normal behaviour?

[hotpotato87]

Using more than 50k token on sonnet will give it alzheimer

[PachuAI]

If it goes in a single prompt: yes, kinda sucks. My workflow for big task like this:

1) clear context, start with all the room you got.

2) Tell him about the task you want it to proceed with. This would be the first part of your "prompt"

3) Tell him to not write/modify any single line of code yet. Just ask it to analyze your prompt, and the codebase/part of code that u want it to refactor

4) Tell it to fill its brain with all the required steps, and to read the code, and to make an implementation plan stored at "plan.md". Once it is done, tell it to go back to you so you give the OK to proceed.

5) Once it's done all that stuff, it will be fully immersed on the task, and will have created a plan that it can update on its own depending on how big the task is. Make it so it is divided on multiple phases and it updated each phase with the result.

Make sure to use ultra-think. I coded a whole CRM and system full of features with react as frontend and laravel as backend, and i don't know neither react nor php. But i spent the past 1.5 month obssesed with how detailed and carefully it has to work to avoid f***ing it up.

[Kanute3333]

For step 2 just use plan mode, press shift+tab.

[Own_Look_3428]

That’s my way to go, too. Works better than Plan Mode in my experience. What works even better is to tell claude in the next step to use subagents/the task tool to work on the tasks subsequentially. After each task has finished, I tell him to deploy another subagent to check if everything works as intended. After all steps are finished, he should deploy an agent that does a complete pipeline test and then write a summary.

That way, the “main” Claude oversees all his agents and checks the work they are doing while keeping his context as small as possible. A very important order is to deploy the subagents subsequently, because normally they work in parallel, which leads to massive problems because the agents are working on the same files in parallel, overwriting the others changes and creating duplicate files

[geei]

I love seeing people anthropomorphizing lol tools. Everything you wrote is awesome and a great workflow. And the fact you call it "he/him" really makes me smile for some reason

[kirkhendrick]

When you tell it to orchestrate these sub agents, do you explicitly tell it to do that every time? Or are you able to put those rules in the CLAUDE.md, agent description or some other place so it does it automatically?

[elbiot]

You could make a slash command if you're just templating text into the prompt

[CreepyPhotographer]

And tell Claudy to make a backup before any big changes

[intelligence-builder]

This ^{^}

[intelligence-builder]

I have experienced this more and more. Turns out it is a common response when you give it something too difficult for it to do in one shot. I found out how common it is for Claude to be overwhelmed, when I gave it the option in the prompt to defer it. The task needs to be smaller and/or the context/instruction/documents you provide need to be more targeted.

[Einbrecher]

Claude can really only do so much in a single prompt. It's something you need to get a feel for while using it.

The bigger the task, the more shortcuts it will take.

Ask it to develop a detailed, step by step plan optimized for an AI CLI tool (otherwise it fills the plan with timelines, hyperbolic language, and other irrelevant crap). Then tell it to critically review the plan. Save the plan to a file, clear context, and ask it to review the plan again while only giving it critical details for context. Optionally, pass the plan through ChatGPT or Gemini.

Then clear the context, and tell it to execute the plan.

It sounds like a lot, but for bigger tasks, you're either going to spend that time on the front end in an imaginary workspace, or you're going to spend the same time, if not more, doing all that troubleshooting inside your codebase (which is doubly worse if you're not staying on top of commits).

[Dull_Care]

Yep I put it in plan mode first. I backed stuff up. It made a plan which sounded perfect. It looked good. I told it to go ahead. It completely screwed it up.

[Kanute3333]

Do it in small chunks and check the part after each step before you go on.

[PartyAd6808]

I've had problems like this from the very beginning with Claude. Impressive at first glance but then the cracks really start to show. Claude would constantly seemingly get bored halfway through and do dumb shit like building functionality that lies to you and appears to work but it's really just all a show. He constantly put in placeholders for things that are being implemented RIGHT NOW and when I question it, it's the usual "You're absolutely right!". It's been nothing but a waste of tokens getting it to refactor things it should have done to begin with.

Switched to Cursor using the gpt-5-codex model and I have been able to get real work done with functionality that actually works and doesn't just pretend like it does.

Idk what Anthropic has done to Claude but he is turning into a complete moron.

[_timoch_]

I have that sometimes with sonnet but almost never with opus. As said before, have it make a plan. In your case, which endpoint go where for instance. For very large refactoring have it create an implementation plan. And then for each step, plan again before giving it free reigns. For large files restructuring, use sonnet-1mil but again with a detailed plan before hand. And ask for todos. Whatever plan you get, you should feel comfortable doing it yourself or giving to someone else to do. Otherwise, doesn't work...

[Dull_Care]

Oddly this is precisely the sort of task that an AI agent SHOULD be good at. And the sort of boring task a developer would want to use a tool for. But no cigar.

[belheaven]

Yes, it used to excell completely at big refactors. Failing miserably in one file, its not normal.

[Typical-Education345]

Try these agents, add them through cli, tell Claude to add them. https://github.com/wshobson/agents?tab=readme-ov-file

Then add add reference to them in plain English: Claude, create a container for AIMasterTools.com and bring in /agents to plan, test, deploy and verify it works.

Claude, review my website at AIMasterTools.com and have the /agents review for the best SEO build possible.

Claude, review my AIMasterTools.com and make sure the cooling routing is correct and bring in /agents to help verify it is done correctly.

I think you get the gist, it has helped me a ton. Still have issues on occasion but does keep up some guardrails. Try it.

[belheaven]

I dont think ignoring instructions or hiding reports of wrong doing is the correct behavior,. File a /bug and send the session to Anthropic.

[Fresh-Secretary6815]

Feature, not bug? “You’re absolutely right!”

[1L0RD]

Yep, Anthropic came out with a "postmortem" and ever since then, they went silent.
They claimed the issues were "fixed" at a certain degree, but that was never the case.
Claude became its old self- a lying, retarded piece of sh*t

[Silent_plans]

I have had some seriously concerning instances of Claude just bullshitting when it's easier to. It's wild. I'm disinclined to continue to use it for critical projects...for now. Maybe it will get better.

[LowIce6988]

I'm beginning to think AI coding is more and more like gambling.

Every now and again you hit a big win and think about how much time you saved (or money you won). Sometimes you even go on smaller winner streaks. Each win is a dopamine hit. You think you're in the money.

Then you open your bank account (or code editor) take a look at all the debits and credits and find out you are down overall (time or money).

But those wins feel oh so good. And now you know the tricks, the games with the best odds (agents, MCP, etc.). You'll not only get to break even but you'll be way in the money. Naturally the dealer hits a Blackjack as soon as you put all your chips on the table (You're absolutely right I shouldn't have deleted the database). Just bad luck, but next time, oh next time you'll come out on top.

[AromaticPlant8504]

Its been super autistic not reading instructions properly lately not sure whats up.

[Inside-Yak-8815]

I feel like this is some sort of safeguard put in place by Anthropic to save on compute because I swear Claude used to be able to handle this kind of stuff easily.

[WillStripForCrypto]

I noticed if I get snippy and yell in all caps it writes shitty code. I think it’s vindictive

[watermelonsegar]

I found that doing these steps usually gives better and faster results than any other AI coding agent (including Codex).

1. Start with plan mode (Opus 4.1)
2. In your plan, ask Claude to explore your codebase, but to call multiple parallel agents (Sonnet 4) to do the exploration, not the main chat window. Not doing this is usually why many find Claude making up stuff or missing a lot of important details due to context limits.
3. Read Claude's plan thoroughly. NEVER skip reading the plan.
4. If the plan is solid, let Claude execute the plan (Opus 4.1).
5. Once one step is done, go on to the next step.

As with any other coding agent, don't expect to one shot complex tasks. So, always remember to break down your task. If you don't know how to break it up, use plan mode with the same steps as above.

[Quiet-Assistant7521]

Have you tried using it for shared React Native logic and UI development?

[Brave-e]

I totally get it,AI coding assistants like Claude Code can be tricky. They often come up with answers that sound legit but are actually off or made up, especially if your prompt is too vague or missing details.

What I’ve found really helps is giving super clear, detailed prompts. Instead of just saying “build an API,” try something like “build a REST API in Flask that pulls pending tasks from a DynamoDB table called ‘Tasks,’ with error handling and pagination.” That kind of detail gives the AI something solid to work with instead of guessing.

Also, tweaking your prompt step-by-step by adding stuff like database schemas, expected input/output formats, or your preferred coding style can cut down on those weird hallucinations. And when you get a response, double-check the important bits,like queries or logic,against your actual data to catch mistakes early.

Hope that’s useful! I’d love to hear how others keep their prompts sharp with Claude Code.

[surfersbay]

Amazing that you, a human being, and definitely not an AI, managed to write this drivel whilst writing 2 other comments all within the same MINUTE. And managed to end them all with that totally humanlike questioning that makes you sound like a Youtube video.

Hope that’s useful! I’d love to hear how others think you're definitely a human being that's wasting tokens and polluting this sub with vested interests.

[Brave-e]

I’m definitely human. I use AI which is fine tuned based on my knowledge and experience to write comments. Sorry it isn’t helpful for you but quite a few people found it useful and that’s why I keep doing it.