EvalCore

Open-source CLI tool that records AI model responses and replays them in CI to catch regressions

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Quick facts
What is it Open-source CLI tool that records AI model responses and replays them in CI to catch regressions
Pricing Free
Free tier Yes
Platform Web Application
Best for Catching regressions when changing prompts, models, or dependencies, Running deterministic, offline eval suites in CI pipelines
Domain registered 2026

Data updated July 24, 2026

What does EvalCore do?

EvalCore is a lightweight CLI tool that helps you catch when your AI app starts behaving worse — before your users notice. You define evaluation cases in a simple YAML file plus a JSONL dataset, run it once against your real model to record every request and response in a local SQLite cache, then replay that recording on every future code or prompt change. The replay is offline, deterministic, and costs nothing in CI, so your team gets fast, reliable feedback without flaky tests or API bills.

What makes EvalCore stand out is how minimal it is. There's no SDK to integrate, no test framework to learn — just a single binary that speaks HTTP or shell to your app, whatever language it's written in. It works with OpenAI, vLLM, Ollama, any OpenAI-compatible gateway, or your own REST APIs. You can stack scorers (like checking for a keyword or using a judge rubric) to define what "good" means for each case. The record/replay model means the first live run captures cost and latency, and every subsequent CI run is instant and free.

This tool is built for developers shipping AI features — whether you're a solo dev iterating on prompts or a team managing multiple model versions. It's especially useful when you swap models, tweak prompts, or update dependencies and want to know immediately if anything broke. Because it runs fully offline in CI with no API keys, it fits naturally into existing PR workflows and gates on exit codes. If you've ever shipped a prompt change that silently made your chatbot dumber, EvalCore is the safety net you didn't know you needed.

#agent evaluation#ai behavior testing#ai testing#apache-2.0#baseline testing#ci for ai#cost-free ci#deterministic testing#eval runner#llm evals#llm regression testing#model comparison#no-server#no signup#no telemetry#offline replay#openai compatible#openinference traces#open source#opentelemetry traces#prompt regression testing#record replay#rest targets#shell targets#single-binary#snapshot testing#sqlite cassette#trial runs#yaml configuration

Key features

What makes it stand out
01
Record model responses once, replay deterministically in CI with no network or keys
02
Define evals in one YAML file with datasets, targets, and scorers — no SDK required
03
Works with any language or stack that speaks HTTP or shell commands
04
Supports OpenAI-compatible models, vLLM, Ollama, REST APIs, shell commands, and OTel traces
05
CI replay costs $0 and runs offline with byte-for-byte identical results

Who is EvalCore for?

Who benefits most from this tool
Catching regressions when changing prompts, models, or dependencies
Running deterministic, offline eval suites in CI pipelines
Comparing model outputs across versions or configurations

Trust & presence

Domain Domain registered 2026

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