Libretto
Freemium
Advanced prompt engineering and optimization platform for language models.
Key Information
Key Features
- Prompt optimization and testing automation
- LLM performance monitoring and drift detection
- Automated test case generation
- Production traffic analysis and evaluation
- Real-time toxicity and refusal detection
- Multi-model testing and comparison
- Event scoring with customer feedback
- Prompt chain monitoring capabilities
Pricing
- Free Plan – $0
- Custom Plan – Contact for pricing
What is Libretto?
Libretto AI is a prompt engineering platform that helps developers optimize their interactions with Large Language Models. The tool automates the testing and refinement process for LLM prompts, providing continuous monitoring, drift detection, and performance analytics. Libretto integrates directly into existing workflows through its SDK, enabling teams to improve AI applications systematically while tracking model performance changes over time.
Key Features
- Prompt optimization and testing automation: Libretto automatically refines prompts and generates comprehensive test sets from production traffic. The platform creates evaluation criteria and tests multiple prompt variations simultaneously, reducing manual testing time from hours to minutes.
- LLM performance monitoring and drift detection: The system continuously monitors LLM performance and detects when models change behavior without notification. Daily drift detection tests ensure prompts maintain consistent quality over time, alerting users to performance degradation.
- Automated test case generation: The platform samples real production traffic to create relevant test datasets. This feature generates up to 50 test cases per prompt template, ensuring comprehensive coverage of real-world scenarios.
- Production traffic analysis and evaluation: Libretto analyzes actual user interactions to identify patterns and issues in LLM responses. The system provides insights into cost, usage, and response quality through automated flagging systems.
- Real-time toxicity and refusal detection: Built-in safety mechanisms automatically identify toxic, unhelpful, or poor-quality LLM outputs. The detection system is SOC2-compliant and processes events in real-time to maintain application safety.
- Multi-model testing and comparison: Users can test new models or prompt strategies instantly using automatically generated test sets. The platform provides actionable results within seconds, enabling rapid iteration and optimization.
- Event scoring with customer feedback: The system includes customer evaluation scoring for up to 10 events daily. This feature incorporates user feedback directly into the optimization process for continuous improvement.
- Prompt chain monitoring capabilities: Libretto tracks complex LLM workflows and multi-step prompt sequences. The monitoring extends beyond single prompts to entire AI-powered application flows.
Pricing Details
Free Plan – $0
- 5 prompt templates
- 100 events daily
- 10KB per event limit
- Toxicity, refusal, and jailbreak detection
- Prompt chain monitoring
- 10 events scored with customer evaluations per day
- 1 active drift dashboard with GPT-4o mini or Claude Haiku
- 10 test runs per day
- 50 test cases per prompt template
Custom Plan – Contact for pricing
- All limits negotiable
- Unlimited features and capabilities
- Tailored solutions for enterprise needs
Please note: Prices are subject to change. Please check the official website for the most up-to-date prices.
Frequently Asked Questions
1. What does the free plan include?
The free tier provides 5 prompt templates and processes up to 100 events daily with a 10KB event limit. Users get access to toxicity and refusal detection, prompt chain monitoring, and customer evaluation scoring for 10 events per day. The free plan includes one active drift dashboard using GPT-4o mini or Claude Haiku, along with 10 test runs daily and 50 test cases per prompt template.
2. How does Libretto compare to other prompt engineering tools?
Libretto distinguishes itself through automated prompt optimization and real-time monitoring capabilities. Unlike general-purpose prompt libraries, Libretto focuses on performance at scale with production traffic analysis and drift detection. The platform offers SOC2-compliant monitoring and integrates directly into existing workflows through its SDK, making it more suitable for production environments than experimental tools.
3. What are the system requirements for using Libretto?
Libretto operates as a web-based platform compatible with standard web browsers. The tool integrates into applications through its drop-in SDK, requiring minimal setup time. No specific hardware requirements exist beyond internet connectivity for accessing the platform and integrating with existing development workflows.
4. How does the drift detection feature work?
Drift detection tests prompts daily to identify when models produce different responses than previously. The system compares current model outputs against historical baselines to detect performance changes. This feature helps users understand whether decreased performance stems from model updates or prompt degradation, ensuring consistent application behavior over time.
5. Can Libretto handle multiple LLM providers?
The platform supports testing across multiple LLM providers and models simultaneously. Users can compare performance between different models using the same test sets and evaluation criteria. This capability enables informed decisions about model selection and helps optimize prompts for specific LLM providers based on performance metrics.
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