multi-model prompt comparison via unified experiment interface
Executes the same prompt across multiple LLM providers (OpenAI, Anthropic, etc.) in a single experiment run by implementing a polymorphic Experiment base class that abstracts provider-specific API calls. Each provider gets a concrete implementation (OpenAIChatExperiment, AnthropicExperiment) that handles authentication, request formatting, and response parsing, allowing developers to compare outputs side-by-side without writing provider-specific code.
Unique: Implements a polymorphic Experiment base class with concrete provider implementations (OpenAIChatExperiment, etc.) that abstracts away provider-specific API details, allowing identical test code to run against different LLMs without conditional logic or provider detection
vs alternatives: Simpler than building custom integrations for each provider and more flexible than single-provider tools like OpenAI's playground, as it unifies comparison logic across any provider with a Python SDK
parameterized prompt template experimentation with cartesian product expansion
Generates a full factorial experiment matrix by accepting prompt templates with variable placeholders and a dictionary of parameter values, then expanding all combinations (e.g., 3 prompts × 2 models × 4 temperature values = 24 test cases). The harness system orchestrates these expanded experiments, executing each combination and collecting results in a unified output table for systematic evaluation of prompt variations.
Unique: Implements automatic cartesian product expansion of prompt templates and parameters through the Harness system, generating all combinations declaratively without manual loop nesting, and provides unified result collection across the entire experiment matrix
vs alternatives: More systematic than manual prompt iteration and less error-prone than hand-written nested loops; provides structured result collection that tools like LangSmith require custom code to achieve
cost estimation and tracking for llm api experiments
Calculates estimated and actual costs for experiments based on token counts, model pricing, and API usage, providing cost breakdowns per model, prompt, and parameter combination. Developers can set cost budgets, receive warnings when approaching limits, and analyze cost-effectiveness of different prompt variations relative to quality metrics.
Unique: Integrates cost estimation and tracking into the experiment framework, calculating costs based on token counts and model pricing, and providing cost breakdowns per parameter combination without requiring external cost tracking tools
vs alternatives: More integrated than manual cost calculation and provider dashboards; enables cost-aware experiment design and optimization that tools like LangSmith require custom analysis to achieve
batch experiment execution with result aggregation and statistical analysis
Supports running multiple experiment instances in sequence or parallel, aggregating results across runs and computing statistical summaries (mean, std dev, confidence intervals) for each metric. Developers can run the same experiment multiple times to account for model variability and generate robust performance estimates with statistical confidence.
Unique: Extends the experiment framework to support batch execution with automatic result aggregation and statistical analysis, computing confidence intervals and summary statistics across multiple runs without requiring external statistical tools
vs alternatives: More integrated than manual result aggregation and statistical analysis; enables robust model evaluation with statistical confidence that single-run experiments cannot provide
automated metric-based evaluation of llm outputs with pluggable scorers
Applies a registry of evaluation functions (scorers) to experiment results after execution, computing metrics like BLEU, ROUGE, semantic similarity, or custom business logic. The evaluation step is decoupled from execution, allowing developers to define custom scorer functions that accept model outputs and reference answers, then aggregate scores across all experiment runs for comparative analysis.
Unique: Decouples evaluation from execution through a pluggable scorer registry, allowing custom evaluation functions to be applied post-hoc to any experiment results without modifying experiment code, and supports both built-in metrics (BLEU, ROUGE) and user-defined scorers
vs alternatives: More flexible than hardcoded evaluation in experiment classes and more accessible than building custom evaluation pipelines; integrates seamlessly with experiment results without requiring external evaluation frameworks
interactive web-based playground for real-time prompt testing
Provides a browser-based UI (built with Streamlit or similar) that allows non-technical users to test prompts interactively without writing code. The playground loads experiment definitions from Python files, exposes UI controls for parameter adjustment, executes experiments on-demand, and displays results with visualizations, enabling rapid iteration and exploration of prompt behavior.
Unique: Wraps the core Experiment system in a Streamlit-based web interface that automatically generates UI controls from experiment parameters, enabling non-technical users to run experiments without code while maintaining full access to the underlying evaluation and visualization capabilities
vs alternatives: More accessible than command-line tools and Jupyter notebooks for non-technical users; faster iteration than rebuilding UI for each experiment type, though less customizable than purpose-built web applications
vector database retrieval experimentation with multi-provider support
Extends the Experiment system to test vector databases (Pinecone, Weaviate, Chroma, etc.) by implementing VectorDatabaseExperiment subclasses that handle embedding generation, vector storage, and retrieval evaluation. Developers can compare retrieval quality across different databases, embedding models, and query strategies using the same experiment framework as LLM testing.
Unique: Extends the polymorphic Experiment base class to support vector database testing with the same prepare/run/evaluate/visualize workflow as LLM experiments, enabling unified comparison of retrieval systems across different providers and embedding models
vs alternatives: Unifies RAG evaluation with LLM evaluation in a single framework, whereas most tools require separate testing pipelines for retrieval and generation; supports multiple vector database providers without provider-specific code
experiment result visualization and export with multiple output formats
Generates tabular and graphical visualizations of experiment results using matplotlib and pandas, supporting exports to CSV, JSON, and HTML formats. The visualization step is built into the experiment workflow, automatically creating comparison charts, heatmaps, and summary tables that highlight differences across parameter combinations and model outputs.
Unique: Integrates visualization and export as a built-in step in the experiment workflow (prepare/run/evaluate/visualize), automatically generating comparison tables and charts without requiring separate visualization code, and supports multiple output formats from a single experiment run
vs alternatives: More convenient than manual result export and visualization; less flexible than dedicated BI tools but requires no external dependencies or data pipeline setup
+4 more capabilities