The problem

I kept seeing "what's a realistic sub-90 plan" posts here, and most answers were vibes-based. Coaches give you a number, but the number doesn't update as you train. I wanted to know: if I improve my wall ball PB by 30 seconds, how much does that move my projected finish?

What I built

A diagnostic-first Hyrox planner that does the math for you. The projection formula:

finish_time = 8 × (1km pace × fade_coefficient)
            + Σ (per-station PB × position_fatigue_multiplier)
            + 8 × roxzone_allowance

Where:

• Run fade coefficient is calibrated to your finisher tier (default 1.10 = 10% slower by run 8).
• Position fatigue multipliers per station are based on race-day fatigue data (sled-push fresh = 1.03 × PB; wall balls at end = 1.25 × PB).
• Roxzone allowance defaults to 8s × 8 transitions = 64s, configurable.

You log:

• 1km run PB (fresh)
• Per-station PB (sled push, sled pull, burpee broad jump, rowing, farmer's carry, sandbag lunges, wall balls, ski erg)
• The projection updates instantly.

Two extra modes

1. Guided 16-segment simulation. Full-screen workout player that walks you through 8 runs + 8 stations with live per-segment timing. Roxzone tracked automatically between every segment. On finish, auto-detects PB improvements and writes them.
2. Time Loss Analysis. Per-station gap-to-elite computed automatically. Returns top 3 stations ranked by recoverable seconds, so you know where to focus this training block.

Feedback I'd love

1. Position fatigue multipliers. I calibrated these against my own simulation data plus a handful of pro splits. Curious if these match other racers' experiences. Especially the wall ball multiplier (1.25 × PB feels right but undertested).
2. Run fade coefficient. Default 1.10 (10% slower by run 8). Anyone have data showing this should be higher/lower for sub-90 vs sub-75 finishers?
3. Missing stations. I have all 8 standard. Doubles / pairs / relay variations are not modeled yet. Worth adding?

Link

blacknave.com/products/hyrox-planner

30-day free trial, no card. After that it's part of a $14/mo subscription that includes 20 other tools (gym coach, macros, etc.) but the Hyrox tool is the main reason I built any of this.

Happy to answer formula questions in comments.

TL;DR: Built 21 AI coaches that share one memory layer. Ask the gym coach why your bench dropped, it already knows you slept five hours three nights in a row because it reads from the wellness tools. Free trial 30 days, no card.

The problem

For 18 months I tried 14 fitness/finance/career apps and kept restarting plans every Monday. Each app knew a sliver of my life. None of them talked to each other.

What I built

Blacknave — 21 AI tools (gym coach, debt planner, hyrox race coach, TDEE, FIRE planner, job tracker, gratitude journal, and 14 more) that share one personal memory layer.

The technical trick: a monkey-patched fetch wrapper. Every AI call reads relevant data from the other tools before it goes to Claude.

Concrete examples of what this unlocks

🏋️ Ask the Gym Coach "Why did my bench drop this week?"

>It already knows you logged 5 hours of sleep three nights in a row, reading from the wellness tools.

💰 Ask the Debt Planner "How much can I really apply this month?"

>It reads your real take-home minus your fixed costs minus your subs. Returns a number that isn't a guess.

🏃 Run a Hyrox simulation in the race planner

>Your projected finish time auto-updates and feeds the gym coach, so this week's strength session targets the station costing you the most seconds.

Tech

• Frontend: Next.js 14 (App Router) + Tailwind
• Backend: Supabase (auth + DB) + Vercel
• AI: Claude Haiku 4.5
• Architecture: ~21 single-file HTML apps in iframes
• The trick: shared _bn-cross-context.js that injects sibling-tool data into every AI request
• Memory: persists across sessions via _bn-memory.js

Stack is solo-built. 30-day free trial, no card. $14/month after that for the AI tier.

Two things I'd love feedback on

1. Does the cross-product idea actually resonate, or am I solving a problem only I have?
2. What's the first tool you'd actually use? Helps me prioritize the next 5 products.

🔗 blacknave.com