The Startup Ideas Podcast – "Reviewing Claude Opus 4.5"
Host: Greg Isenberg
Guest: The Boring Marketer (James)
Date: November 26, 2025
Theme: Live comparative review—Claude Opus 4.5 vs. Gemini 3 Pro as coding agents for building MVP SaaS landing pages and apps, plus deep-dive into workflow, design, and prompting skills.
Episode Overview
Greg Isenberg and guest, James (The Boring Marketer), conduct a hands-on challenge between Anthropic’s Claude Opus 4.5 and Google’s Gemini 3 Pro. They use both models to generate a conversion-optimized landing page (and prototype app) for a startup idea, discuss prompt techniques, tools, and model integrations, and offer actionable tips for leveraging Claude’s new features. The episode also explores broader trends in AI-assisted coding and design, emphasizing practical skills for non-developers.
Key Discussion Points & Insights
1. Setting Up the Challenge ([00:00]–[03:15])
- Premise: Which AI model is the world's best coding agent?
- James & Greg build a SaaS MVP side-by-side with both Claude Opus 4.5 and Gemini 3 Pro.
- Startup Idea to Build: "Estate Clear"—a dashboard for family estate communication during probate.
- Goal: See which AI generates a more effective landing page and app with minimal direction.
Notable Quote ([01:16])
"Can we live play with 4.5 Opus 4.5 and see what happens?"
— Greg [01:16]
2. The Live Build-Off: Prompting & First Impressions
Initial Prompts & Predictions ([03:15]–[08:40])
- Method: Both models receive almost identical, minimal prompts to test their out-of-the-box creativity and quality.
- Prediction:
- James expects Gemini to be more "outside the box."
- Greg thinks Gemini will add unexpected AI features, while Claude will deliver solid, conventional SaaS.
Notable Quote ([07:36])
"I think Gemini's gonna come up with something more outside of the box. I think Claude is going to create something a little more of like what you'd expect."
— James [07:36]
Notable Quote ([08:12])
"...My guess is Opus is going to come and do like a very solid, fully featured SaaS app..."
— Greg [08:12]
3. Results: Landing Page Comparison ([09:18]–[15:39])
Claude Opus 4.5 Output
- Clean, subtle design.
- Tailored for a sensitive workflow (family & probate), avoiding generic AI gradients and excessive colors.
- Copywriting is solid even without dedicated copy skills.
- Good MVP foundation; "retention is probably insane".
- [10:54] Button (“Start Free Trial”) isn’t wired up but easy to expand.
"…Like, it's got, like a nice sort of, like, subtle tone to it. It's not like screaming in my face with a bunch of wild colors… Clearly it is not just using the same kind of purples and typical AI stuff."
— James [09:45]
Gemini 3 Pro Output
- Strong, clear headline: “Keep the Family United.”
- Built-in AI suggestion: “Let AI write the update.”
- Engaging “social” and “human” touches (emojis, illustrations).
- UX not as direct or as visually appealing as Claude; some sections mimicked standard templates.
"I like the copy. I can get that initial visual, like, right away without needing to scroll or scan down the page."
— James [12:53]
Feature vs. Design
- Gemini wowed with creative features (AI update writer), but Claude’s overall “aesthetic” and depth won the initial round.
4. Building Clickable Prototypes ([15:39]–[36:02])
- Next Step: Generating a full clickable prototype of the app with both models.
- Discussion: Backend stack options (Neon, Vercel, Clerk, Stripe), Google’s full toolchain integration advantage for rapid app dev.
"…from just a convenience perspective for most people is a really powerful value proposition..."
— James [19:53]
- Output (Claude):
- Consistent, elegant, dashboard-style prototype.
- Maintained visual and copy coherence.
- Built relevant subviews (document storage, updates, milestones, family roster).
- Potential expansion: Financial advisory integrations, recurring workflow.
"It maintained the aesthetic perfectly, like down to the font. You know, it's not your typical build a SaaS dashboard AI look, you know, at all…"
— James [26:59]
- Output (Gemini):
- Clean, but less refined.
- Polished display, social/AI-driven features prominent.
- "Timeline" visualization less core.
- Slightly shallower product logic.
"My take is I feel that Opus went a little bit deeper in terms of thinking through the product."
— James [35:03]
5. Bonus: Anti Gravity, Nano Banana, and Advanced Workflows ([36:38]–[44:20])
- Testing with Anti Gravity (Google IDE fork with tighter browser integration and Chrome extension).
- Gemini 3 Pro generates high-fidelity mockups using Nano Banana before building the HTML.
- Feels more like a real design workflow (image->code pass).
- AI Studio generally outputs better one-shot results.
"Anti Gravity may surprise us here. ... It's generating a custom dashboard mockup image first to make the page look real..."
— James [41:14]
- Integrations: Nano Banana Pro (for infographics, visuals), Glyph (for better prompting), ad/creative use cases.
- Ultra-fast ideation, rapid launch cycles for marketing experiments.
"Like, you can open up Gemini 3 for example and you can say, hey, go and research the top performing ad formats for me across these industries..."
— James [26:54]
6. Pro Prompting: Claude Opus 4.5 "Skills" ([44:20]–[54:53])
- Skills: Modular instruction sets for Claude, e.g., for copywriting, brand voice, and design best practices.
- How:
- Research top copywriters/marketers (Cody Sanchez, Alex Hormozi).
- Analyze & synthesize their playbooks (contrarian hooks, irresistible offers, value stacking).
- Feed personal writing (tweets, transcripts) for a personalized brand voice.
- Use these as “skills” to maintain tone, persuasion, clarity across outputs.
- Combining with Design Skill:
- Use Claude's front end design skill plugin (prevents generic "AI-style" outputs).
- Massive boost in one-shot quality for both design and copy.
- Systematic landing page frameworks: Hero, Problem/Agitate/Solution, Social Proof, Transformation, CTAs.
"So I rebuilt my entire website using this, and it's been working pretty well. So definitely leverage skills. And with the tool use and the context ability of 4.5, it's going to do a really good job with those."
— James [47:57]
"Skills are just like long sets of prompts or instructions … avoid the typical AI stuff, build production grade designs and interfaces…"
— James [53:25]
7. Key Takeaways & TL;DR ([56:42]–[58:12])
- Claude Opus 4.5: Delivers better design, more logical depth, and easier prompting—especially with the front end design skill and direct response copy skill.
- Gemini 3 Pro: Creative, strong AI assist features, but output occasionally “shallower.”
- Anti Gravity: High potential due to browser/visual integrations—great for iterating.
- General Principle:
- Doing foundational (boring) work up front (research, skills) pays off for one-shot prompts.
- Great design and especially great copy are key to conversion.
- The ecosystem is exploding—massive opportunities for fast, solo builder workflows.
"If you level up that design ... with actual good copy that's geared toward conversion ... you're going to be unstoppable."
— James [57:03]
Memorable Quotes & Moments
-
On the “Vibe Coding” Revolution ([11:16]):
"It does feel like we've entered a new stratosphere of vibe coding. Would you agree?"
— Greg [11:16] -
On Speed & Accessibility ([26:54]):
"You can take that knowledge in a snap, go create a good image and then launch a campaign. That could potentially generate fresh sales or revenue for you. ...the barriers dissolving is just, I don't know, pretty mind blowing."
— James [26:54] -
On Copy as the Ultimate Conversion Lever ([55:28]):
"In a lot of ways the content is the ux, so. And what is the content? It's the words. And so if you can create great copy, you're going to probably be able to convert even if the design isn't drop dead gorgeous."
— Greg [55:28]
Timestamps for Key Segments
- 00:00 — Episode intro, challenge set-up
- 01:55 — Startup idea selection: Estate Clear
- 03:15 — Head-to-head prompt design and predictions
- 09:18 — Claude 4.5 landing page review
- 12:27 — Gemini 3 Pro landing page review
- 15:39 — Building clickable prototypes & backend discussion
- 18:03 — Full-stack integration chat (Google vs. Anthropic ecosystems)
- 24:03 — Nano Banana use cases, ad creative riffing
- 28:43 — Estate Clear MVP walkthrough, recurring use cases
- 36:38 — TL;DR: Claude's MVP > Gemini's
- 37:14 — Bonus: Testing Gemini in Anti Gravity
- 44:20 — Claude skills: front-end design, brand voice, direct response
- 50:45 — Landing page architecture framework
- 54:35 — One-shot landing page demos
- 56:42 — Main lessons: design + copy = conversion, Opus 4.5 recommendations
- 58:12 — Wrap-up, where to find resources and community
Final Recommendations
- For Non-Technical Builders: Claude Opus 4.5, especially with curated “skills” for design and copy, is a powerful one-prompt solution.
- For Marketers & Founders: Invest in building your own brand voice and direct response skills; pair them with Claude’s design skills for best results.
- For Power Users: Explore Anti Gravity and Nano Banana for rich visuals and deeper workflow integration.
- For Everyone: The builder’s landscape is shifting—take advantage of agentic tools, but remember fundamentals (especially copywriting) remain the kingpin in product success.
“It's a playground out there right now.”
— James [58:10]
Follow James (Boring Marketer) on X, YouTube, and via his toolkit/community at TheVideoMarketer.com for more resources and AI-driven marketing strategies.