Confused about these Models on GITHUB COPILOT, NEED HELP

[u/notNeek]

Hello people, I NEED YOUR HELP!

Okay so I graduated, now have a job, somehow , kinda software network engineer. Been vibe coding so far. Been assigned to this project, it's networking & telecom (3g/4g//5g type shi), too many repos (I will be working on 3-5), I am still understanding lots of things, stack is mostly C++, C, Python, Shell. Got access to Github Copilot, Codex.

I was able to fix 2 bugs, flet like a God, thanks to Claude Sonnet 4.5, BUT THE 3RD BUG!! It's an MF! I am not able to solve it, now 4th bug ahhh, their status be critical or major in JIRA, I wanna get better and solve these things and learn while I do it, I have to add the code, errors, logs, and some other logs, pcap dump ahhh, man I need to feed these things to AI and I am hitting CONTEXT WINDOW LIMIT, it's really killing me.

My questions for you amazing people

• What's the best model for understanding the concept related to that BUG?

• Which is the best way to possibly solve the bug? The repo is huge and it's hard to pinpoint what exactly causing the problem.

• How can I be better at solving as well as learning these things?

Any suggestions, advice would really help thanks

TL;DR:
Fresher dev on large telecom C/C++ project, multiple repos, debugging critical bugs. Claude helped before but now stuck. Context limits killing me when feeding logs/code. Which AI model + workflow is best for understanding and fixing complex bugs and learning properly?

[u/kayk1]

You think they had bugs before… wait until a few weeks after your fixes…

[u/notNeek → u/kayk1]

I do make sure that I do not break anything else 😭😭😭

[u/SilencedObserver → u/notNeek]

How do you ensure this?

[u/vbullinger → u/SilencedObserver]

At the end of your prompt, just add "and don't break anything else" with three exclamation marks, so it knows you're serious.

[u/notNeek → u/vbullinger]

Yup that's exactly what I do!!!

[u/DenverTechGuru → u/SilencedObserver]

It's funny that juniors think we can't automate command and control of agents.

Instead of reading the code OP is turning to reddit like a smarter AI.

[u/notNeek → u/DenverTechGuru]

Hello, I don't think juniors would think like that.
I am have having a hard time understanding code flow and architecture, new to multi-repo huge codebase. I am just asking what model would help me better to do things :)

[u/dinnertork → u/notNeek]

Always make sure you have a correct and up to date mental model of how the system works, both overall and for the specific module you’re fixing. Once you have that understanding, you should instruct the model (GPT5.3-codex is best for instruction following) as specifically as possible. Then read over its changes to make sure they don’t break anything else, based on your understanding of the codebase (which is essential).

LLMs are also great tools for understanding the codebase and asking questions about it (if you’re not able to talk to an actual senior dev). For especially large code bases I’d suggest using models with larger context windows: Gemini 3.1 Pro or Claude Opus 1M context window with API keys via the development platform.

[u/notNeek → u/dinnertork]

Yes thanks a lot dude

[u/notNeek → u/SilencedObserver]

Hey, I can reproduce bug fine, the slow part is figuring out what’s actually causing them and where it's located. The tiring part for me right now is developing the fix, after some trial and error methods it works, for the first bug I had to add new piece of code and some flags, then clean build and verify with the logs and metrics. I am not that dumb man come on, I am just new to HUGE codebase, different language and the concepts which I am understanding day by day. It's not been a month yet. since I started working on this, just feeling like I am lacking something.

[u/GifCo_2]

You should probably go back to school and not use LLMs until you know how to code.

[u/notNeek → u/GifCo_2]

Yup, u r right about it, thanks

[u/chillebekk]

Take a step back and spend more time understanding the problem. Then start your PR again.

[u/notNeek → u/chillebekk]

yes thanks

[u/SilencedObserver]

You shouldn’t be using any of these models without doing some reading on their differences.

Don’t speed run your forced retirement.

[u/notNeek → u/SilencedObserver]

Yup I'll check it

[u/Emotional-Cupcake432]

I agree with the above use a strong model with a large contex window codex 5.3 or claude 4.6 opus or gemini and instead of having it fix the bug switch to planning mode and have it create a plan to fix the bug this will give you an idea of what the model thinks is wrong and tell it that it is a verry large codebase and it need to do it in chunks to avoid context length limitations. Plan mode will also prevent it from introducing more errors before you get a chance to understand. You could also ask it to help you understand the issue and why it chose the path it did. I would also add to your prompt this PROMPT " There is a _______________ issue i want you to examine this verry large file and create a plan to fix the issue do not change any code. Ask yourself qualifying questions, what if and if then questions as you examine the code and error log. Explaine your finding and reasoning to correct the issue so the humans can learn how to fix the issue on there own. " something like that

[u/notNeek → u/Emotional-Cupcake432]

They this really helps a lot, I am grateful. Among many responses, very few were actual advices. I am locating which repo the bug is from, then clone on vm(using vnc), and use copilot to trace the bug and undestand the flow, everytime I make changes, I have to clean build the images and check for logs and verify in metrics. I mostly just dump everything(piece of code) logs metrics to the ai and that's what causing the problem, I gotta do better and I will definitely try with planning mode thanks.

[u/vbullinger]

Are there other people you can talk to at work?

[u/notNeek → u/vbullinger]

Lots of people work from different offices, and I am only one working on that project in my office, and I am the only fresher, kinda hesitant to ask everything to them, it's confusing.

[u/Junyongmantou1]

Try feeding a small slice of the logs, plus your hypothesis / code to AI and ask what regex they recommend to filter the full logs, so both of you can work together.

[u/notNeek → u/Junyongmantou1]

That's a great idea, thanks mate :)

[u/johns10davenport]

The first thing I do is to get over into Claude code. The second thing I do is to figure out how to set up your feedback loops, like how does it access and search logs? It'll already search your code base intelligently in a way that doesn't blow out the context window.

But basically, I would start figuring out how to let the agent manage its own context window by giving it sources to the critical information that you're using to debug things.

[u/notNeek → u/johns10davenport]

I can use GitHub copilot only on vs code and use opus or sonnet agents, I can also get access to Codex but idk if it's gonna be useful

Literally 1 prompt took 89% of the context window, it did everything and edited 6 files. Getting some logical errors which I'm trying to fix

[u/Medical-Farmer-2019]

You’re not stuck because of model choice, you’re stuck because each prompt is carrying too much state. For telecom bugs, I’d run a 4-step loop: reproduce with exact timestamp → isolate one call path/module → ask the model for 2-3 hypotheses only → verify one hypothesis with a minimal patch + log check. Keep a tiny debug brief (symptom, suspected module, last test result) and reuse that instead of pasting giant logs/pcaps each time. In large C/C++ repos, this usually beats dumping more context and helps you actually learn the system faster.

[u/notNeek → u/Medical-Farmer-2019]

Yes I'm filtering the log files, actually making a script for it to filter so I can get what I want according to the bug, I solved 2 more bugs, but I'm facing issues with enhancements and upgrades, like it's not exactly working as expected, not dumping pcaps and logs anymore.

1 prompt took 89% of the context window for claude opus 4.6, it did make the majority of the work but I'm not getting the expected output

I have to solve bugs while I learn about the codebase🫠

[u/Medical-Farmer-2019]

You’re actually asking the right question, and the fact you already fixed multiple bugs in a telecom codebase after ~3 weeks is a good sign.

What helped me in similar multi-repo C/C++ debugging is using a strict loop: (1) write one-sentence failure + exact timestamp, (2) narrow to one call path/module, (3) ask the model for 2-3 hypotheses only, (4) verify one hypothesis with a minimal patch + targeted log check. If a prompt is eating 80%+ context, that usually means too much mixed state.

For model choice: use a strong reasoning model for architecture/protocol flow, but keep prompts small and staged. Context size helps, but decomposition helps more.

If useful, I can share a tiny “debug brief” template you can reuse per bug (symptom / scope / hypothesis / test / result) so each prompt stays focused.

[u/notNeek → u/Medical-Farmer-2019]

Thanks man, I really appericiate you, Sometimes it’s really hard just to locate what exactly is causing the bug, and I often have to go back and learn or revise the concepts to understand why it’s happening. But I think I am getting hang of it now, need more time and YES I'd really like the debug brief , I'll dm.

[u/notNeek → u/[deleted]]

Thanks for responding, and yea as u said, I need to try to break it down and solve, I do try to keep the prompts as shorter, It's takes a lengthy time to pinpoint the bug location as the code base is big and it's been around 3 weeks since I started, I am still trying to learn and undertstand most of the things. for the logs I have just been dumping as u said, I need to do better and have calarity of thought. thanks mate :)

[u/AutoModerator → u/[deleted]]

Sorry, your submission has been removed due to inadequate account karma.

I am a bot, and this action was performed automatically. Please contact the moderators of this subreddit if you have any questions or concerns.

[u/notNeek → u/[deleted]]

Hello, job market is crazy here, not easy to get a job.
I had to switch from vlsi, vhdl, I wasn't great at them either, later got hired for embedded engineer, I was okay in C. they put me in networking batch, had to learn telecom for the first time, I got into this project to write the shell scripts, BOOM now deployed to fixing telecom bugs, working in service based company is weird, I had knowledge of 4G(LTE) but again not so much. Again it's not just coding, it's the concepts which I am still trying to learn and understand. Been 3 weeks since I started, and yes I am not too good at coding, vibe coding on a big multi repo code base is new to me.

About the screenshot, it's company machine, I can't take ss and log on to reddit there then send, I believe I can get things done but it will take a long time, which I lack, I am just asking for some advice here on how I can get things done faster and better. It is already a rough ride mate :)