FAQs

A collection of answers to frequently asked questions about Kerno

What is Kerno?

Kerno is local CI for AI-generated backend code. It gives your coding agent (or IDE) the feedback loop it needs to verify and fix its work in context, so what ships works as part of your system.

Unlike static code review tools or unit tests that run in isolation, Kerno runs every change against your real stack and validates it across functional behavior, error handling, edge cases, security, auth, and response content.

What makes Kerno different from other tools

Most code tools either statically analyze your code or run unit tests in isolation against mocks. Kerno does neither.

It knows the exact blast radius of every change. Kerno indexes your code deterministically with SCIP, so it can tell you precisely which endpoints a change affects, not approximate matches from vector embeddings.

It tests against your real stack. Kerno spins up your databases, queues, and caches in Docker and runs scenarios against the live stack, not mocks.

The tests maintain themselves. Scenarios are auto-generated and self-healing, staying in sync as your code evolves without you writing or updating them.

Does Kerno support my backend stack?

TypeScript, JavaScript, and Python on the application side. For dependencies, Kerno spins up real Docker services for PostgreSQL, MySQL, MariaDB, MongoDB, Redis, Kafka, RabbitMQ, Clickhouse, Zitadel, and Azure Blob/Queue/Table Storage. External APIs Kerno can't stand up locally (payment providers, email services, third-party APIs) are mocked. The full matrix lives in Supported technologies.

Does Kerno store my code

No. Kerno never stores your code on its servers. Relevant excerpts pass through Kerno's proxy to LLM providers (Anthropic, OpenAI, Google) configured with zero-data-retention tiers, so nothing is persisted on the provider side either.

Does Kerno use my code for training or fine tuning LLMs?

No. Kerno doesn't train models. The LLM providers Kerno uses run on zero-data-retention tiers, so your code isn't stored, logged, or used for training on their side.

What there discounts available for startups

Kerno offers free usage for qualified Open Source Projects and a significant discounts for pre-Series A startups. Drop us a note to check your availability.

Does Kerno work with my coding agent?

Yes, if your agent supports MCP. Kerno exposes a set of MCP tools your agent calls to set up the local environment, capture baselines, validate changes, and search your code. Claude Code, Cursor, Windsurf, and Codex CLI are the verified setups. See Set up Kerno MCP for connection details.

Do I need an IDE extension?

No. You can drive Kerno entirely from your coding agent via MCP. The IDE extension is an alternative for editor-driven workflows, with a panel that shows endpoints, scenario plans, diffs, and reports. You can use both surfaces side by side. See Set up Kerno MCP for connection details.

What if I'm not using a coding agent?

Kerno still works. The IDE extension gives you a panel-driven workflow for the same loop (build the environment, capture a baseline, validate a change) without needing a coding agent.

If you encounter issues or have questions, message us on Discord, and we’ll gladly help.