Pre-execution verification for AI agents

The Bug a Duck Would've Caught

Add one API call between 'agent thinks' and 'agent acts.' A different AI model reviews the plan and says quack — or don't.

Sign up free. No credit card.

Every unreviewed agent action is a coin flip. Ducks don't flip coins.

rubber-duck verify --watch
plan.action: deploy_to_prodpending
plan.action: delete_all_userspending
plan.action: retry_payment(x3)pending
plan.action: send_notificationpending
plan.action: scale_instances(100)pending
Works with
LangChainCrewAIAutoGenOpenAI SDKAnthropic SDK
The Problem

Your agents are running blind

01

Same-model self-review is like grading your own exam — same blind spots every time

02

Manual plan review costs $14,200 per employee per year. Ducks work for free.

03

Langfuse and LangSmith show you the crash replay. We stop the crash.

GPT reviewing Claude catches structural errors that same-family review misses entirely

🛡️How It Protects

Three layers of defense

Playful illustration of two AI models checking each other's work
01

Cross-Model Verification

GPT reviews Claude. Claude reviews GPT. A second AI family catches blind spots the original model cannot see.

Playful illustration of a rubber duck stopping a loop spiral
02

Loop Detection & Circuit Breaker

Detects repeating plan patterns in real-time and recommends circuit-breaker actions before costs spiral.

Playful risk score gauge with duck-themed color segments
03

Risk Scores & Verdicts

Every plan gets an approve, flag, or reject verdict with a numeric risk score and actionable suggestions.

Integration

Four steps to verified agents

Waddle in
01

Add the middleware

One import. One line of config. Works with LangChain, CrewAI, and AutoGen.

Quack check
02

Agent submits plan

Before any action executes, the plan payload is sent to Rubber Duck for review.

Duck huddle
03

Cross-model verdict

A different model family analyzes the plan and returns approve / flag / reject.

Smooth sailing
04

Act with confidence

Your agent proceeds only when the plan is verified. Loops and bad plans never execute.

🎯The Promise

GPT checks Claude's work. Claude checks GPT's work. Nobody grades their own exam.

“GPT reviewing Claude catches structural errors that same-family review misses entirely”
Validated by research
Cross-model AI verification
🚀Start Now

Stop guessing. Start verifying.

Add pre-execution verification to your agent pipeline in under 5 minutes. Free loop detection included. No credit card required.

Every unreviewed agent action is a coin flip. Ducks don't flip coins.