I Use Three AI Coding Tools at Once. Here’s Why That’s Not Crazy.

Workflow · AI Tooling · 8 min read

Everyone’s looking for the one AI coding tool to rule them all. I stopped looking. Instead I run three — and I’ve never shipped faster.

🔴 The honest problem with picking one model

Every AI coding tool has a lane. And none of them are honest about the lanes they’re bad at.

I kept bouncing between tools mid-project — not because the model I was using was broken, but because a different one was clearly better for the next task. I was fighting the tool instead of using it. So I stopped fighting and leaned in.

Now I run three models in rotation: Claude Code, Codex, and Gemini. Each has a job. None of them do each other’s job as well. And together they’re better than any single one at full throttle.

⚡ The three-model stack

🧠 Claude Code → Pure coding tasks

If I need something built — logic, API integrations, refactoring, debugging, anything that’s fundamentally code — Claude Code is my first call. It reasons through problems before it writes, catches edge cases I didn’t think of, and its output holds up under pressure.

It’s also the best at maintaining context across a session when you give it the right docs (CLAUDE.md, standup.md — more on that below).

Use Claude Code when:
→ Building features from scratch
→ Debugging complex logic
→ Refactoring or restructuring code
→ Anything requiring multi-step reasoning

🎨 Codex → Matching a design

When I have a design to implement — a Figma file, a screenshot, a component I want to replicate — Codex is sharper at translating visual intent into markup. It reads spatial relationships well and tends to produce cleaner HTML/CSS that actually looks like what I handed it.

Claude will get you there too, but Codex does it faster when the brief is visual.

Use Codex when:
→ Implementing a Figma design
→ Pixel-accurate component work
→ Front-end layout and styling tasks
→ Matching an existing design system

✨ Gemini → Creative design generation

When I need to create something visual rather than implement something specified, Gemini is where I go. It’s generative in a way the others aren’t — better at producing design ideas, colour systems, layout concepts, and UI patterns from a loose brief.

Use Gemini when:
→ Generating design directions from scratch
→ Exploring layout and visual options
→ Creative briefs without a reference design
→ Producing design variants to choose from

🔁 The double-pass review

Here’s the thing nobody talks about: models have blind spots for their own output.

Claude will miss things that Codex spots. Codex will miss things that Claude spots. So I end complex sessions with a cross-check — Claude reviews Codex’s output, Codex reviews Claude’s. It takes five minutes and catches more issues than a single pass ever did.

End of session review flow:

Claude output → paste into Codex → "Review this for bugs, edge cases, anything I missed"
Codex output  → paste into Claude → "Review this for logic errors, performance issues, anything off"

It’s not about distrust. It’s about using the fact that different models have different failure modes to your advantage.

💸 The budget reality (£20 × 3)

I’m cheap. I pay for the base paid plan on each — £20/month each, roughly. I hit limits constantly.

But here’s the thing: having three tools means I’m never actually stuck. When Claude Code hits its limit mid-session, I switch to Codex. When Codex caps out, I’m in Gemini. The work keeps moving. I’ve never had all three capped at the same time.

Running one premium plan and one free backup is worse. You’ll always be mid-session when the premium one dies. Three mid-tier plans spread the risk better than one top-tier plan concentrates it.

Monthly cost breakdown:
Claude Code Pro  →  ~£20/mo
Codex (ChatGPT+) →  ~£20/mo
Gemini Advanced  →  ~£20/mo
─────────────────────────────
Total            →  ~£60/mo

vs. hitting one tool's wall mid-session: priceless

🔧 The habit that makes it all work

Here’s where most people using multiple models fail: they don’t close sessions cleanly.

They bounce between tools mid-thought, carrying context in their head, assuming the next model knows what the last one did. It doesn’t. Every new session is a blank slate.

The fix is one habit at the end of every session, with every tool:

1 → Update your standup.md

## Session: 2026-05-19 · Claude Code

### 🟢 Completed
- Wired Supabase real-time subscription to task list
- Fixed race condition in useTaskStore

### 🔵 Next
- Optimistic UI on task completion (hand off to Codex for styling)

### 🧠 Notes
- Don't touch RLS policies until Stripe webhook is live

2 → Leave a handoff note for the next model

If you know you’re switching tools for the next task, say so explicitly in your standup:

### 🔀 Next model: Codex
Picking up the task card component. Design ref in /designs/task-card-v2.fig.
Claude built the data layer — don't change the props interface.

3 → Update CLAUDE.md with anything that changed

If you made an architectural decision, changed the stack, or resolved a known issue — update the master context file before you close. The next session (with any tool) reads that file first.

🟢 The session start checklist

Before any session, with any tool:

□  Read CLAUDE.md
□  Read docs/standup.md
□  Check if the last session left a handoff note
□  Know which model you're using and why
□  Have the right reference open (code, design, spec)

Sixty seconds. Every time. It’s the difference between a session that moves fast and a session that spends twenty minutes re-establishing context you already had.

💎 The mental model that unlocks it

Stop thinking of Claude, Codex, and Gemini as competitors you’re choosing between. Think of them as specialists on the same team.

You wouldn’t ask your frontend engineer to do database architecture. You wouldn’t ask your designer to write business logic. Same principle. Each model has a domain where it genuinely excels — and using it outside that domain is a tax you’re paying for no reason.

The three-model stack isn’t about covering for weaknesses. It’s about spending most of your time in each tool’s strength zone.

Claude Code  →  the engineer who thinks before they type
Codex        →  the frontend dev who reads the design and gets it
Gemini       →  the creative who fills the blank canvas

Route the right work to the right tool. End every session clean. Do the double-pass on anything that matters. That’s the whole system.

This is how I personally run my AI workflow across Valdris Consulting and side projects — tested against real deadlines, real limits, and a very real £60/month budget.