CI cannot keep up with agents: Linear cut PR wait time to 5 minutes with a test suite four times larger

PR check wait times have nevertheless decreased: to just over 5 minutes from more than six, while runner time per test has roughly halved (Linear blog, 21.09.2026). Company engineer Mufiz Amjad broke the pipeline into parts and sped up each one.

This is the same constraint facing any team that has agents writing tests: the suite gains a thousand or two checks a week, while a developer's patience at the waiting screen does not grow.

Type checking. Linear switched to the native tsgo compiler, and the weekly median type-checking time fell by 73%. Install it with `npm install -D @typescript/native-preview`; the binary is called tsgo and runs as tsc. On the Sentry codebase, type checks took more than a minute and now take under 7 seconds (TypeScript blog, 22.05.2025). tsgo still lacks `--build`, declaration emit, and downlevel emit.

Linting. The rules were rewritten for static analysis without type information, and Oxlint was added. API linting became 68% faster, while linting the whole repository became 55% faster. Install it with `pnpm add -D oxlint`; the docs promise 50-100 times the speed of ESLint and more than 865 rules (Oxc docs, 22.09.2026).

Tests. Vitest shards increased to 8 from 4, while the heaviest API tests moved into a separate project with isolation disabled. The slowest shard fell from 300-379 seconds to about 195, and the full run from 32,8 minutes to 22. That is around 17% of monthly runner spend.

Enable it in vitest.config with `test: { isolate: false }`, then distribute it selectively through poolOptions. Vitest docs promise a 2-5x speedup if tests do not leak state, and warn that isolation cannot be disabled with the vmThreads pool; threads are required.

Jobs and setup. Seven independent checks were combined into two jobs. That saves around 87 000 runner minutes per month, 11,8% of total spend. pnpm installs only the necessary workspaces in 16-18 seconds instead of 44-73, while the test database starts in 1-2 seconds instead of 12.

Runners. Linear moved workloads from GitHub Actions to third-party machines with faster CPUs, storage, and caching. The post does not name the provider. In a Hacker News thread, practitioners recommend Blacksmith: Ubuntu x64 costs $0,004 per minute there, 67% less than GitHub, the first 3000 minutes a month are free, and migration comes down to editing the runs-on line.

A full switch from tsc awaits feature flags: tsgo still lacks `--build` and declaration emit.