Why shift-left testing is critical for agentic coding?

CI catches problems after code is pushed. By then your agent has moved on, the context is gone, and every fix means context switching and slower releases. Kerno shifts API regression testing and integration testing into your agent's development session, so it can catch breaking changes and fix them with context in every session.

CI vs local integration testing

Traditional CI

Validation feedback Loop

After push. Minutes to hours later depending on pipeline complexity. Agents can investigate CI failures, but the context from the original coding session is gone.

During development, in seconds, targeting only the blast radius of the code change. First environment setup takes minutes, after that each test run is fast.

Blast radius awareness

Runs whatever tests you've configured. No awareness of which endpoints your change actually affected.

Uses a compiler-level dependency graph (SCIP) to identify affected endpoints and tests only those.

Test environment

Remote runners (GitHub Actions, CircleCI, GitLab CI). Someone needs to maintain the environment config, and environments can drift over time.

Local Docker. Analyzes your codebase, generates Dockerfile and Compose files, orchestrates real dependencies, seeds data, and mocks third-party services. Regenerates when your project evolves.

Test creation & Execution

You write tests yourself or prompt AI agents to generate them. Either way, you decide what to test, what to cover, and when to update.

Indexes your codebase with SCIP, discovers HTTP endpoints, and generates behavioral scenarios covering functional workflows, contracts, error handling, auth, and edge cases.

Test execution

You configure how tests run in your pipeline. If setup, teardown, or data seeding fails, you debug it.

Handles the full cycle: starts the environment, seeds data, runs scenarios, captures results, and cleans up. Each run gets a fresh state.

Test maintenance

Manual. You update tests when APIs change, or use AI agents to help, but you need to guide them explicitly and remember to do it. Stale tests break builds or silently pass.

Flags behavioral diffs and proposes updates. Adds scenarios for new endpoints, retires removed ones. You approve or reject before anything changes

* Kerno also runs in CI for team-wide behavioral validation. But the biggest value is the local loop: catching issues while your agent still has the context to fix them.

What changes when your agent gets a local feedback loop?

Regressions get fixed in context

Your agent writes code, Kerno runs integration tests against your real stack, your agent fixes what it broke. The loop closes before code leaves your machine.

Less post-merge rework, and faster release cycles.

Fewer broken builds reach CI because behavioral issues are caught locally. CI still runs your full pipeline (linting, security scans, unit tests, deploys), but it stops being the first place you find out something broke.

Consistent validation across the team

QA quality no longer varies by who prompted the agent or who remembered to run which tests. Kerno validates consistently on every code change.

Trusted by AI-native engeneering teams to ship better software

Kerno was up and running in minutes with no manual work, and it made our API migration so much smoother. We could instantly validate that every change made by Cursor worked the way we expected, and now it's a core part of our how we build.

Misch Strotz

Co-Founder & CEO, LetzAI

Using Kerno with Claude Code has been a game changer. You get quick feedback with no manual effort, and it saves you a lot time and hassle debugging integration issues post-merge.

Jonathan Bernales

CTO, Germen

Kerno saves us a lot of manual work and helps us catch side effects and issues that would definitely break our projects' backends. Our engineering team loves it.

Santiago J. Valls

Co-Founder & CTO, Bewise

FAQs

Frequently asked questions

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