AI agents write code faster than CI can check it. GitHub reports a 4x jump in Actions minutes since 2023, and Anthropic says CI became its biggest bottleneck after job volume grew 25x in six months.
Daniel Worku, co-founder and CTO of StarSling, joins Shane and Abhi to talk about what CI looks like when agents write most of the code. Faster hardware helps, but StarSling also runs a background agent, built on Mastra, that A/B tests changes to your CI and opens a PR when it finds a speedup.
Daniel explains why agents make CI so expensive: more PRs, piles of low-value unit tests, and stacked PRs that rerun everything. He also makes the case that most unit tests aren't worth running, and that CI as we know it may not survive.
You'll also hear how Mastra's own CI went from half-hour waits to a fraction of that, and why code review is the next bottleneck. StarSling's new Review Runners let you bring your own model and run reviews on the same infrastructure as your CI.
Recorded live on AI Agents Hour, a weekly livestream by Mastra CPO Shane Thomas and CTO Abhi Aiyer. Mondays 12PM Pacific.
👤 ABOUT DANIEL
Daniel Worku is the co-founder and CTO of StarSling, a YC company building self-improving CI for GitHub Actions. Before StarSling, he worked in Big Tech and at several startups, most recently at Netflix, where he led the team behind Netflix Console, the company's most used internal developer tool.
Daniel on X: https://x.com/dbworku
StarSling: https://starsling.dev
StarSling Review Runners: https://starsling.dev/products/review-runners
How Mastra got 6x faster GitHub Actions tests: https://starsling.dev/customers/mastra
High Performance Sandbox Benchmarks: https://github.com/starslingdev/hpc-sandbox-benchmarks
Anthropic on CI and test impact analysis: https://claude.com/blog/agentic-coding-is-straining-ci-heres-how-we-scaled-test-impact-analysis-at-anthropic
đź“š MASTRA RESOURCES
Mastra: https://mastra.ai
Mastra on X: https://x.com/mastra_ai
Mastra Discord: https://mastra.ai/community/discord
Mastra GitHub: https://github.com/mastra-ai
Learn Mastra: https://mastra.ai/learn
Principles of Building AI Agents (Book): https://mastra.ai/books/principles-of-building-ai-agents
Patterns for Building AI Agents (New Book): https://mastra.ai/books/patterns-of-building-ai-agents
WHAT IS MASTRA?
Mastra is an open-source TypeScript framework designed for building and shipping AI-powered applications and agents with minimal friction. It supports the full lifecycle of agent development—from prototype to production. You can integrate it with frontend and backend stacks (e.g., React, Next.js, Node) or run agents as standalone services. If you're a JavaScript or TypeScript developer looking to build an agentic or AI-powered product without starting from first principles, Mastra provides the scaffolding, tools, and integrations to accelerate that process.
⏱️ CHAPTERS
00:00 Cold open
00:23 Why CI became the bottleneck
01:25 Meet Daniel and StarSling
02:51 Why GitHub's runners are slow
03:58 Self-improving CI
05:06 Benchmarking sandboxes for CI
06:41 Why agents make CI so expensive
07:43 Most unit tests aren't useful
08:23 Stacked PRs
09:25 Mastra's CI story
11:48 The end of CI as we know it
13:26 Sharing infra between CI and code review
14:36 Code review is the new bottleneck
15:08 Bring your own model to code review
16:27 Outro
