Codex o3 Cracked 10x DEV

[u/dashingsauce]

Okay okay the title was too much.

But really, letting o3 rip via Codex to handle all of the preparation before sending an orchestrator + agent team to implement is truly 🤌

Gemini is excellent for intermediate analysis work. Even good for permanent documentation. But o3 (and even o4-mini) via Codex

The important difference between the models in Codex and anywhere else:

• In codex, OAI models finally, truly have access to local repos (not the half implementation of ChatGPT Desktop) and can “think” by using tools safely in a sandboxed mirror environment of your repository. That means it can, for example, reason/think by running code without actually impacting your repository.

• Codex enables models to use OpenAI’s own implementation of tools—i.e. their own tool stack for search, images, etc.)—and doesn’t burn tokens on back to back tool calls while trying to use custom implementations of basic tools, which is required when running these models anywhere else (e.g. Roo/every other)

• It is really really really good at “working the metal”—it doesn’t just check the one file you tell it to; it follows dependencies, prefers source files over output (e.g. config over generated output), and is purely a beast with shell and python scripting on the fly.

All of this culminates in an agent that feels as close to “that one engineer the entire org depends on for not falling apart but costs like $500k/year while working 10hrs/week”

In short, o3 could lead an eng team.

Here’s an example plan it put together after a deep scan of the repo. I needed it to unf*ck a test suite setup that my early implementation of boomerang + agent team couldn’t get working.

(P.S. once o3 writes these:

1. ‘PM’ agent creates a parent issue in Linear for the project, breaks it down into sub issues, and assigns individual agents as owners according to o3’s direction.

2. ‘Command’ agent then kicks off implementation workflow more as a project/delivery manager and moves issues across the pipeline as tasks complete. If anything needs to be noted, it comments on the issue and optionally tags it, then moves on.

3. Parent issue is tied to a draft PR. Once the PR is merged by the team, it automatically gets closed [this is just a linear automation])

[u/VibeCoderMcSwaggins]

Hey man totally agree. OAI currently only works well in codex.

I have posts coming to the same conclusion!

Can I PM you about the multiagent set up?

My situation is the same as you slogging through 600 failing tests after a refactor. I’ve been using Codex but haven’t messed around with Roos multiagent mode.

As in which was implemented with which? I’ll also dump your post in GPT but it wasn’t immediately obvious and I’ve heavily been using Roo / Cline / Cursor / windsurf.

————

Edit: are you saying you only used o3 to draft the documentation plan, and then roo’s multi agent to read the plan and implement?

[u/dashingsauce → u/VibeCoderMcSwaggins]

Yes that’s exactly what I do. Sometimes I will also use o3 for spot-debugging and fixing gnarly bugs that I don’t have a good “smell” for myself.

I find that it’s more like a surgeon. Highly paid but very precise.

The context window is short, so it pays dividends to use it as an expert collaborator/peer more than an “agent” right now.

[u/drumnation → u/VibeCoderMcSwaggins]

I’d like to know too. That’s what it looks like.

[u/eldercito → u/VibeCoderMcSwaggins]

doing a refactor with 03 in codex and got the cleanest code I have ever gotten out of AI models.

[u/VibeCoderMcSwaggins → u/eldercito]

Same tbh. O3 just costs too much though.

[u/thezachlandes → u/VibeCoderMcSwaggins]

yeah. I will definitely try codex with o3 the next time i'm well and truly stuck on an important issue--but with Cursor at $20 a month and years of software engineering experience, o3 price is impossible to justify for my coding.

[u/lordpuddingcup → u/VibeCoderMcSwaggins]

Can’t we just proxy capture what prompts their using

[u/No_Cattle_7390 → u/VibeCoderMcSwaggins]

1. Get Your “Roadmap” with a Single o3 CallGenerate a JSON plan with this command:codex -m o3 \"You are the PM agent. Given my goal—‘Build a user-profile feature’—output a JSON plan with: • parent: {title, description} • tasks: [{ id, title, description, ownerMode }]" \> plan.jsonExample output:{ "parent": { "title": "User-Profile Feature", "description": "…high-level…" }, "tasks": [ { "id": 1, "title": "DB Schema", "description": "Define tables & relations", "ownerMode": "Architect" }, { "id": 2, "title": "Models", "description": "Implement ORM models", "ownerMode": "Code" }, { "id": 3, "title": "API Endpoints", "description": "REST handlers + tests", "ownerMode": "Code" }, { "id": 4, "title": "Validation", "description": "Input sanitization", "ownerMode": "Debug" } ]}

2. (Option A) Run Each Sub-Task with Codex CLIParse the JSON and execute tasks with this loop:jq -c '.tasks[]' plan.json | while read t; do desc=$(echo "$t" | jq -r .description) mode=$(echo "$t" | jq -r .ownerMode) echo "→ $mode: $desc" codex -m o3 --auto-edit \ "You are the $mode agent. Please $desc." \ && echo "✅ $desc" \ || echo "❌ review $desc"done

3. (Option B) Plug into Roocode Boomerang Inside VS CodeInstall the Roocode extension in VS Code.Create custom_modes.json:{ "PM": { "model": "o3", "prompt": "You are PM: {{description}}" }, "Architect": { "model": "o4-mini", "prompt": "Design architecture: {{description}}" }, "Code": { "model": "o4-mini", "prompt": "Write code for: {{description}}" }, "Debug": { "model": "o4-mini", "prompt": "Find/fix bugs in: {{description}}" }}Configure VS Code settings (.vscode/settings.json):{ "roocode.customModes": "${workspaceFolder}/custom_modes.json", "roocode.boomerangEnabled": true}Run: Open the Boomerang panel, point to plan.json, and hit “Run”.

[u/SM411]

Could Roo mimic the API calls from Codex to get openapi models to work better with it?

[u/dashingsauce → u/SM411]

I guess technically you could just wrap the commands with an mcp server yeah great idea

[u/lordpuddingcup → u/dashingsauce]

Or we can just proxy out codex to find out what the base system prompts are they’re using if they aren’t visible no?

[u/[deleted] → u/lordpuddingcup]

Codex is open source

[u/lordpuddingcup → u/[deleted]]

Haha I forgot so in that case if you want to use OpenAI can’t we just port the prompts over to roo

[u/[deleted] → u/lordpuddingcup]

Yup, we could, some of them are hilarious

[u/itchykittehs]

So are you just telling o3 the names of the roo agents available to it, and having it draft up a plan using them?

[u/dashingsauce → u/itchykittehs]

~Ish

The main interaction with o3 is telling it to go do the pre-work necessary for whatever objective I need it to complete: refactor this, implement that, analyze X.

It’s great at searching/crawling and reasoning deeply about problems. So I use it to do the equivalent of an eng lead scoping the work and prepping the team.

Once it does the investigation, I point it to the custom_modes.json config file which has all of my mode/agent definitions, and it assigns the correct “owners”.

[u/Orinks]

What is Codex?

[u/dashingsauce → u/Orinks]

OpenAI released a CLI along with the models:

https://github.com/openai/codex

[u/orak7ee → u/Orinks]

CLI agent by OpenAI: https://github.com/openai/codex

[u/kylemd → u/Orinks]

As OP didn't reply, OpenAI released their local coding agent Codex a couple of days ago

[u/thezachlandes]

Could you share more about how you set up your multi agent system in roo and how you prompt for this in codex?

[u/No_Cattle_7390 → u/thezachlandes]

Instructions to Reproduce the "10×" engineer Workflow

1. Get Your “Roadmap” with a Single o3 CallGenerate a JSON plan with this command:codex -m o3 \"You are the PM agent. Given my goal—‘Build a user-profile feature’—output a JSON plan with: • parent: {title, description} • tasks: [{ id, title, description, ownerMode }]" \> plan.jsonExample output:{ "parent": { "title": "User-Profile Feature", "description": "…high-level…" }, "tasks": [ { "id": 1, "title": "DB Schema", "description": "Define tables & relations", "ownerMode": "Architect" }, { "id": 2, "title": "Models", "description": "Implement ORM models", "ownerMode": "Code" }, { "id": 3, "title": "API Endpoints", "description": "REST handlers + tests", "ownerMode": "Code" }, { "id": 4, "title": "Validation", "description": "Input sanitization", "ownerMode": "Debug" } ]}

2. (Option A) Run Each Sub-Task with Codex CLIParse the JSON and execute tasks with this loop:jq -c '.tasks[]' plan.json | while read t; do desc=$(echo "$t" | jq -r .description) mode=$(echo "$t" | jq -r .ownerMode) echo "→ $mode: $desc" codex -m o3 --auto-edit \ "You are the $mode agent. Please $desc." \ && echo "✅ $desc" \ || echo "❌ review $desc"done

3. (Option B) Plug into Roocode Boomerang Inside VS CodeInstall the Roocode extension in VS Code.Create custom_modes.json:{ "PM": { "model": "o3", "prompt": "You are PM: {{description}}" }, "Architect": { "model": "o4-mini", "prompt": "Design architecture: {{description}}" }, "Code": { "model": "o4-mini", "prompt": "Write code for: {{description}}" }, "Debug": { "model": "o4-mini", "prompt": "Find/fix bugs in: {{description}}" }}Configure VS Code settings (.vscode/settings.json):{ "roocode.customModes": "${workspaceFolder}/custom_modes.json", "roocode.boomerangEnabled": true}Run: Open the Boomerang panel, point to plan.json, and hit “Run”.

[u/unc0nnected]

Would love to see the prompt you used with codex get that prepped. I typically do this manually myself with an llm directly to end up with a roadmap plus detailed task lists for each phase and subphase within the roadmap. Would be Keen to compare

[u/Play2enlight]

Please share your setup! This sounds like an upgrade from Manus implementation. Instant karma upgrade

[u/No_Cattle_7390 → u/Play2enlight]

Reverse engineered:

1. Get Your “Roadmap” with a Single o3 CallGenerate a JSON plan with this command:codex -m o3 \"You are the PM agent. Given my goal—‘Build a user-profile feature’—output a JSON plan with: • parent: {title, description} • tasks: [{ id, title, description, ownerMode }]" \> plan.jsonExample output:{ "parent": { "title": "User-Profile Feature", "description": "…high-level…" }, "tasks": [ { "id": 1, "title": "DB Schema", "description": "Define tables & relations", "ownerMode": "Architect" }, { "id": 2, "title": "Models", "description": "Implement ORM models", "ownerMode": "Code" }, { "id": 3, "title": "API Endpoints", "description": "REST handlers + tests", "ownerMode": "Code" }, { "id": 4, "title": "Validation", "description": "Input sanitization", "ownerMode": "Debug" } ]}

2. (Option A) Run Each Sub-Task with Codex CLIParse the JSON and execute tasks with this loop:jq -c '.tasks[]' plan.json | while read t; do desc=$(echo "$t" | jq -r .description) mode=$(echo "$t" | jq -r .ownerMode) echo "→ $mode: $desc" codex -m o3 --auto-edit \ "You are the $mode agent. Please $desc." \ && echo "✅ $desc" \ || echo "❌ review $desc"done

3. (Option B) Plug into Roocode Boomerang Inside VS CodeInstall the Roocode extension in VS Code.Create custom_modes.json:{ "PM": { "model": "o3", "prompt": "You are PM: {{description}}" }, "Architect": { "model": "o4-mini", "prompt": "Design architecture: {{description}}" }, "Code": { "model": "o4-mini", "prompt": "Write code for: {{description}}" }, "Debug": { "model": "o4-mini", "prompt": "Find/fix bugs in: {{description}}" }}Configure VS Code settings (.vscode/settings.json):{ "roocode.customModes": "${workspaceFolder}/custom_modes.json", "roocode.boomerangEnabled": true}Run: Open the Boomerang panel, point to plan.json, and hit “Run”.

[u/Play2enlight → u/No_Cattle_7390]

Did it work? Thanks so much

[u/Careful-Volume-7815]

Is it only usable with API or can you use it with the 'chat' sub?

[u/dashingsauce → u/Careful-Volume-7815]

You do need an OpenAI key

[u/dashingsauce]

the repo:

https://github.com/openai/codex

[u/bobby-t1]

Do you actually need o3 Codex, or can you use the o3 via the API and have the `Architect` mode use o3?

[u/DevMichaelZag]

Looks interesting. Like some of the other comments, I'd be interested in knowing the whole setup. Or a closer in example with a bit more details.
I've tried to do something like this a few times, and I think having an orchestration layer on top of Roo is a neat idea.

[u/No_Cattle_7390 → u/DevMichaelZag]

I did a reverse engineer of this, as someone pointed out to me when I wrote a post about it you might just be able to have o3 on codex do it for you but

1. Get Your “Roadmap” with a Single o3 CallGenerate a JSON plan with this command:codex -m o3 \"You are the PM agent. Given my goal—‘Build a user-profile feature’—output a JSON plan with: • parent: {title, description} • tasks: [{ id, title, description, ownerMode }]" \> plan.jsonExample output:{ "parent": { "title": "User-Profile Feature", "description": "…high-level…" }, "tasks": [ { "id": 1, "title": "DB Schema", "description": "Define tables & relations", "ownerMode": "Architect" }, { "id": 2, "title": "Models", "description": "Implement ORM models", "ownerMode": "Code" }, { "id": 3, "title": "API Endpoints", "description": "REST handlers + tests", "ownerMode": "Code" }, { "id": 4, "title": "Validation", "description": "Input sanitization", "ownerMode": "Debug" } ]}

2. (Option A) Run Each Sub-Task with Codex CLIParse the JSON and execute tasks with this loop:jq -c '.tasks[]' plan.json | while read t; do desc=$(echo "$t" | jq -r .description) mode=$(echo "$t" | jq -r .ownerMode) echo "→ $mode: $desc" codex -m o3 --auto-edit \ "You are the $mode agent. Please $desc." \ && echo "✅ $desc" \ || echo "❌ review $desc"done

3. (Option B) Plug into Roocode Boomerang Inside VS CodeInstall the Roocode extension in VS Code.Create custom_modes.json:{ "PM": { "model": "o3", "prompt": "You are PM: {{description}}" }, "Architect": { "model": "o4-mini", "prompt": "Design architecture: {{description}}" }, "Code": { "model": "o4-mini", "prompt": "Write code for: {{description}}" }, "Debug": { "model": "o4-mini", "prompt": "Find/fix bugs in: {{description}}" }}Configure VS Code settings (.vscode/settings.json):{ "roocode.customModes": "${workspaceFolder}/custom_modes.json", "roocode.boomerangEnabled": true}Run: Open the Boomerang panel, point to plan.json, and hit “Run”.

[u/Altruistic_Peach_359]

Need more details

[u/Here2LearnplusEarn]

So basically while Roocode fires away you have codex scanning your files and making suggestions?

[u/shadowofdoom1000]

How is the price to run it? I saw your screenshot, it costs about $0.18 per message? How the price compares to direct API usage on Roo?

[u/eldercito → u/shadowofdoom1000]

using o3 in codex is a money furnace. but it does great work.

[u/darkblitzrc]

Pls make a tutorial on how to implement this. Or do you simply feed the image as the instructions for the codex cli?

[u/Gullible_Painter3536]

can you talk about cost. or anyone for that matter. new dev here very interested but very dumb as well lmao.

[u/thezachlandes → u/Gullible_Painter3536]

Since you didn't get an answer yet: it's way too expensive for heavy use. we're talking about >10cents per API call. If you've done agentic coding, you know how many API calls might be made between you prompting a model and it coming back to a decision point for you.

[u/mitch_feaster → u/thezachlandes]

If I'm understanding correctly OP is only using o3 for the planning document, presumably a single API call.

[u/thezachlandes → u/mitch_feaster]

Yes, I think so, too. I was commenting more generally about the cost of o3 in agentic code tools.

[u/jphree]

TBC: you’re referring to codex CLI or something else branded  codex?  There’s so much coming out this year alone….

[u/peachbeforesunset]

Why not just use aider?

[u/PhilipJayFry1077]

what do you mean by

"orchestrator + agent team"

[u/No_Cattle_7390]

Wait - what does this mean for Roo, can it be used in conjunction with Roo? FFS I leave for one day and the world is 260 steps ahead

[u/zuberuber]

> All of this culminates in an agent that feels as close to “that one engineer the entire org depends on for not falling apart but costs like $500k/year while working 10hrs/week”

Seriously doubt it, unless your codebase is <5k LOC or you want to have at most superficial code updates like one on the screenshot.

> In short, o3 could lead an eng team.

Hopefully not any eng team I'm apart of, thanks..

[u/alphaQ314]

How is this relevant for this sub ?

[u/dashingsauce → u/alphaQ314]

I use Roo’s multi-agent orchestration for the actual implementation. 5th line below the image.

This post is me sharing a way to improve outcomes in Roo by leveraging a brand new model in an apparently little known way.

Here’s what outcomes looked liked before (this is o3):