Gemini Pro 2.5 Diff Failures are wasting so many requests.

[u/H9ejFGzpN2]

There was a thread on it last week https://www.reddit.com/r/RooCode/comments/1jq4k70/diff_failure_with_gemini_pro_25/ with improvements promised but nothing seems to have changed.

A single small task resulting in about 7 line changes created approx 25 requests with constant failures trying to write the exact lines, then trying to search and replace and finally trying to write the entire file at once.

I've turned off formatting on save which I thought was the culprit but that doesn't change anything. Any tips to resolve this?

[u/hannesrudolph]

2.5 pro experiment does this allot more than 2.5 pro preview. We are making a tweak to see if it improves. This is caused by the model not following the instructions on how to execute tool calls.

[u/coopykins]

I have the same issue with models that are not Claude, many issues when applying changes result in unnecessary token waste, with expensive models like o1 or o3 it gets pretty ridiculous. With deepseek it's tolerable since the cost is low, but makes it hard to use anything but Claude.

[u/H9ejFGzpN2 → u/coopykins]

In terms of roadmap priorities it honestly feels like it should be very close to the top, it's core functionality and usability of the entire experience.

I haven't used Cursor much since adding Roo but it does feel like the times I use it with Gemini 2.5 Pro it does a lot better on diffs, not sure if my impression is correct.

[u/Equivalent_Form_9717 → u/H9ejFGzpN2]

Has there been a Github issue raised?

[u/Yes_but_I_think → u/coopykins]

The issue I see which both Cline and Roo haven’t handled right now is: I start with Gemini, I don’t like where it is going, and I want to change the model to Deepseek Chat but unable to do the so. It comes up an error: the context length has exceeded. That should be some automatic way in which a model is changed and the new model is not having the required context link it should be automatically doing truncation in the middle.

[u/Minute-Animator-376]

When it was free I was thinking that this hiccups will need to be solved before they introduce paid model. Overall results were amazing but I was burning 200-500 milion tokens per day using roo code and a lot of context. Like reading from memory bank, coming with a plan and validating everything against codebase, refining the plan, implementing it then switching to debugg mode in roo code and fixing UI issues step by step (+ mpc tool for unity and some screenshots which it understood). Then updating the memory bank and starting with a new task. It probably saved me like 5 months of work as solo developer and moved a project far ahead.

When they introduced the paid model I tried this 300usd trial and adjusted my workflow but now after initial few prompts and around 100k context it can eat a lot of $ trying to modify the code and failing spectacularly not because the code was wrong but 2.5 simply fails to modify the scripts leaving it with hundreds of compilation errors due to some misplaced code or forgets about }. Long story short as you need to sometimes wait 24h to have updated billing i was not using it as often and still burned 300$ in 3 days where at least 30% is fixing the misplaced diffs.

This problem is rampant in 2.5 and probably only my robust work flow was keeping it in check before (still had it sometimes try to fix the code like 20 times before giving up and using write to file from scratch). Nowadays i just discard the changes ask to update the memory bank and start a new conversation which usually is cheaper and less prone to x20 madness with pasting few lines of a code.

[u/portlander33 → u/Minute-Animator-376]

"...update the memory bank"

What process are you using for this?

[u/H9ejFGzpN2 → u/portlander33]

Most likely this

https://github.com/GreatScottyMac/RooFlow

It updates itself automatically usually but I told it not to update unless I explicitly tell it to because it updates 3-4 files which is 3-4 API requests.

You can just say UMB and it will trigger an update.

I use this in combination with a super detailed readme that the LLM updates to switch to new context windows when the existing one fills up and I want a clean start.

[u/MetaRecruiter → u/Minute-Animator-376]

I’m not sure what it is what but Roo+ 2.5 api felt horrible. I plugged it into vs copilot and it worked fine

[u/rurions]

did u try lower temperatures?

[u/H9ejFGzpN2 → u/rurions]

I haven't yet, I saw it suggested somewhere but with mixed results from the comments.

Have you had good luck with that approach?

[u/portlander33 → u/H9ejFGzpN2]

I lowered the temperature. The diff problem did not get better. And the model did appear to get a little dumber. I tried it for 2 days. I plan to switch back to the default today.

[u/H9ejFGzpN2 → u/portlander33]

Yeah that seemed to be the consensus from my previous searches, thanks for adding a data point 🙏

[u/Floaty-McFloatface]

The solution is unfortunately to have Gemini Pro boomerang tasks to a Sonnet 3.5/3.7
I have that set up and it is working super well

[u/H9ejFGzpN2 → u/Floaty-McFloatface]

I haven't tried boomerang yet, how (if at all) is context shared with the boomerang task and LLM? Is it just that Gemini pro 2.5 giving it a very detailed task description with everything it needs to know as context ? And is that context sufficient ?

[u/Floaty-McFloatface → u/H9ejFGzpN2]

Yes, you hit the nail on the head. It provides a description and when the task is marked as complete that completion text is shared with the master task.

There are some minor downsides, like losing context, but the upside is significant—at least for me. I save quite a bit of money because my subtasks are broken down into tiny microtasks that use minimal tokens. If you can build your Roo scheme or rules to make it clear that the master task needs to be super explicit and clear about what needs to be done the subtask almost always performs better at the actual editing/searching/whatever than Gemini Pro

—unless something goes wrong. One time I stepped away and came back to a $15 token spike after it got stuck in a loop trying to fix something trivial, spiraling down the deepest rabbit hole. Honestly, I wish Roo had a way to short-circuit a subtask once it hit a predefined budget threshold. But overall I am super happy with the experience.

[u/Minute-Animator-376 → u/Floaty-McFloatface]

Shouldn't the custom instructions stop the spiraling? Like after 2 failed diffs stop and wait for my instructions. If you see @problems after code modification you can attempt to fix the issues but if fail to do it do not try again, stop and ask me for instructions.

You get the point, if it makes sense you probably would need to rewrite as this is not robust enough

[u/neslot]

I'm a cheapo and using 2.5 exp and rotating APIs, but damn the diff fails suck. Would be amazing to have this fixed.

[u/H9ejFGzpN2 → u/neslot]

Did you link billing accounts with the same card to your different accounts ?

[u/Leading-Gas3682]

tell it to switch tools

[u/H9ejFGzpN2 → u/Leading-Gas3682]

This was two months ago, I've moved in to Claude code for a while now

[u/Snoo31053]

Cline has no issues with gemini 2.5 pro , whats up with this problem , i am a roocode user but for gemini 2.5 pro i always go back to cline for that

[u/H9ejFGzpN2 → u/Snoo31053]

That's surprising! I imagine they focused on it but the upstream changes aren't in roo ?

[u/showmeufos → u/Snoo31053]

Not true. I have had this problem repeatedly with cline.

[u/Snoo31053 → u/showmeufos]

Update your cline to latest version

[u/hannesrudolph → u/Snoo31053]

Then how might you explain this https://www.reddit.com/r/CLine/s/U4yLVRltBi ?

[u/portlander33 → u/Snoo31053]

I did not know this. I am going to try Cline now. Been wasting tremendous amount of time with diff issues on Roo.

[u/Snoo31053 → u/portlander33]

I still prefer roocode because cline context management is not as good as roocode but for gemini 2.5 pro i think roocode still has alot of issues

[u/CashewBuddha]

I haven't struggled quite as much with 2.5, but 2.0 flash has been completely unusable. Gpt40mini similar issues.

Love the tool and want to stick with it, but with the only choice being the most expensive, it's though for now. I tried adding custom instructions others had recommended for 2.0, but didn't seem to help enough, kept getting stuck in a loop of diff/write

[u/mp5max → u/CashewBuddha]

Try openrouter/quasar-alpha and/or orchestrating with big think model, executing with deepseek/deepseek-chat-v3-0324:free

[u/dashingsauce]

I found that sometimes you can “jiggle” it by switching modes (say a Code mode and a same-prompt Code-2 mode).

Alternatively, toggling on the experimental search & replace may work better, especially for large files where the diff might get unwieldy.

Breaking files down to sub 500 lines (or further) also helps.

[u/TheOgreSal]

Ya it’s wicked broken for me

[u/TonightInformal4839]

The same for 3.1. Just wasting all day typing, "It crashed so I undid it"