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Coolhand Labs

You ship the AI products. We ensure they never stop improving.

Ruby Runway  ·  RubyConf 2026  ·  coolhandlabs.com

Michael Carroll

Michael Carroll

15 years in Ruby  ·  3× Founder

Founding Team — RubiconMD

Health tech built on Ruby. Acquired — now part of CVS Health.

VP of Engineering — Teladoc Health

Also Ruby! Oversaw 500+ engineers through the pandemic.

“One unifying theme of my career? Saving myself and others from the drudge work of engineering, so we could focus on building products.”

The promise of AI & agents

Remove engineering drudge work & enable fun new products.

The reality of maintaining AI:

⚠  Conflicting prompt instructions
🔍  Hunting down silent failures
🧠  Reasoning chain errors
🔁  Turning human feedback into improvements
💸  Fixing token inefficiencies
🔧  Broken tool calls
⚖  Right-sizing models
🧪  Updating evals
📈  Predicting token costs

Your time is better spent than on AI maintenance!

Coolhand is a team of agents that helps maintain your agents.

Coolhand data flow Five-column pipeline: LLM logs, tool outputs, human feedback, and outcome signals flow into the Coolhand API, which fans out to five investigative agents, converging to an optimization plan that produces agent fixes. Agentic data → passively gathered → expert analyzed → executive reviewed → turned to results LLM logs Tool outputs Human feedback Outcome signals Coolhand API Cost analyst Failure SWAT Product analyst AI engineer Prompt maintainer Optimization plan Agent fixes

No dependencies or black boxes, just code fixes.

↓ A real Coolhand Labs fix PR ↓
coolhand-bot opened this pull request · 3 hours ago

AI product search surfacing soft-deleted catalog entries

Users reported the assistant recommending products they couldn't add to cart. Coolhand traced the flagged sessions to search_catalog tool calls returning soft-deleted records — discontinued items with a non-nil deleted_at.

The tool was unscoped. Adding .where(deleted_at: nil) before the search filters is the fix.

fix(tools): scope search_catalog to exclude soft-deleted records Open
coolhand-bot wants to merge 1 commit into main
app/tools/search_catalog_tool.rb −1 +2
  def call(query:, category: nil, limit: 10)
-    Product.where("name ILIKE ?", "%#{'{'}query{'}'}%")
+    Product.where(deleted_at: nil)
+            .where("name ILIKE ?", "%#{'{'}query{'}'}%")
            .order(popularity_score: :desc).limit(limit)
👻 Soft-deleted "ghost products" eliminated from AI results
🙌 Improved user satisfaction
📉 Cost savings from reduced tokens

Built on Ruby, for Ruby.

A few Ruby clients that LOVE Coolhand:

“Coolhand forced us to rethink how we leverage agentic workflows.”

David Guilfoyle, CTO — wyd.

Culina Health
“I love reading the Coolhand optimization PRs we get! They aren’t just timely fixes but cutting-edge insights into building better AI products.”

Maneesh Anand, VP of Engineering — Culina Health

🚀 $1B public company — announcing soon
“Love this offering. Exactly what we needed but didn’t know we should be looking for.”

SVP of Engineering

Coolhand usage keeps growing over 100% each month

Python
Ruby
JavaScript

JavaScript more popular than Ruby for AI applications?!

I want to fix that — with you.

Free for Ruby apps until we make Ruby the top AI language!

Free

$0 below 10M tokens/week
  • Up to 10M tokens/week
    ✓ Ruby doesn't count against daily limits
  • Cost insights dashboard
  • 5 optimization suggestions/week
  • Direct code fixes (PRs) at $2 each
    ✓ Free for Ruby codebases
  • 21-day data retention
Get Started

Enterprise

$1 /million tokens
  • No token cap
    ✓ Ruby tokens aren't charged
  • Cost & performance insights
  • No optimization cap
  • Unlimited PRs
  • HIPAA compliance
  • Volume pricing available for annual plans
Talk to Us

Until the end of the year, Ruby apps get Coolhand 100% free

🌱
$500
for rising open source
AI + Ruby projects
5 projects  ·  50–500 GitHub stars
Funded from our revenues. No committee, no BS.
Come talk to me. 👋
&& 2

Build great AI products with Ruby.
Use Coolhand so they never stop improving.

coolhandlabs.com/ruby-is-the-language-for-ai

Coolhand Labs — Ruby Runway · RubyConf 2026

5-minute pitch · Ruby Runway startup showcase

Slide 1 — Title

Coolhand Labs. "You ship the AI products. We ensure they never stop improving." Ruby Runway · RubyConf 2026 · coolhandlabs.com

Slide 2 — About Our Founder

Michael Carroll. 15 years in Ruby. 3× founder. Founding team at RubiconMD — health tech built on Ruby, acquired by CVS Health. VP of Engineering at Teladoc Health — also Ruby, 500+ engineers through the pandemic. "One unifying theme of my career? Saving myself and others from the drudge work of engineering, so we could focus on building products."

Slide 3 — AI Agent Maintenance Costs

The promise of AI & agents: remove engineering drudge work and enable fun new products. The reality of maintaining AI: conflicting prompt instructions, hunting silent failures, reasoning chain errors, turning human feedback into improvements, fixing token inefficiencies, broken tool calls, right-sizing models, updating evals, predicting token costs.

Slide 4 — Automated Agent Maintenance

Your time is better spent than on AI maintenance! Coolhand is a team of agents that helps maintain your agents. LLM logs, tool outputs, human feedback, and outcome signals flow into Coolhand — which surfaces insights, improvement suggestions, and ships pull requests to your codebase.

Slide 5 — Automated Code Improvements

No dependencies or black boxes, just code fixes. A real Coolhand Labs fix PR. Example: AI product search surfacing soft-deleted catalog entries. Users reported the assistant recommending products they couldn't add to cart. Coolhand traced the flagged sessions to search_catalog tool calls returning soft-deleted records. Fix: .where(deleted_at: nil). Results: ghost products eliminated from AI results, improved user satisfaction, cost savings from reduced tokens.

Slide 6 — Ruby Client Results

Built on Ruby, for Ruby. A few Ruby clients that LOVE Coolhand. Includes Culina Health and other Ruby shops seeing real results.

Slide 7 — Coolhand Growth

Coolhand usage keeps growing over 100% each month. Bar chart showing cumulative LLM token volume analyzed by language — Ruby, JavaScript, and Python — across the last 6 months.

Slide 8 — Ruby vs JavaScript for AI

JavaScript more popular than Ruby for AI applications?! I want to fix that — with you.

Slide 9 — Supporting Ruby AI Apps

Free for Ruby apps until we make Ruby the top AI language! Pricing: Free tier ($0, below 10M tokens/week — Ruby doesn't count against daily limits, PRs free for Ruby codebases). Enterprise ($1/million tokens — Ruby tokens aren't charged, volume pricing for annual plans). Until the end of the year, Ruby apps get Coolhand 100% free. $500 grant for rising open source AI + Ruby projects (5 projects, 50–500 GitHub stars). Come talk to me.

Slide 10 — Thank You

Ruby AI agents are hot. Maintain them with a Coolhand. QR code → coolhandlabs.com/ruby-is-the-language-for-ai