First of all: windows user here 😄

What happens

When I run pnpm build in the repo root, most of the time I get:

Tasks:    3 successful, 25 total
Cached:    0 cached, 25 total
  Time:    19.131s
Failed:    @ai-sdk/anthropic#build

 ERROR  run failed: command  exited (1)
 ELIFECYCLE  Command failed with exit code 1.

There are no additional error messages or logs. The failing package changes randomly (each run fails in a different package), so I’ll refer to it as "errored-package" below.

Observations

At first, I suspected the issue might be related to Turborepo, but:

I can reproduce the same failure by running pnpm build inside packages/errored-package directly. Out of 10 runs, about 5 fail — in random order. ➡️ So it’s not Turbo’s fault.

Lets take test-server as an example as it doesnt have any workspace dependencies besides the tsconfig.

I changed the build script from:

"scripts": {
    "build": "pnpm clean && tsup --tsconfig tsconfig.build.json",
    ...

to:

"scripts": {
    "build": "tsup --tsconfig tsconfig.build.json",
    ...

This eliminates clean or &&–related issues. ➡️ The problem is still reproducible.

When the build succeeds, the output looks like this:

CLI Building entry: src/index.ts
CLI Using tsconfig: tsconfig.build.json
CLI tsup v8.3.0
CLI Using tsup config: C:\GIT\ai\packages\test-server\tsup.config.ts
CLI Building entry: src/with-vitest.ts
CLI Using tsconfig: tsconfig.build.json
CLI tsup v8.3.0
CLI Using tsup config: C:\GIT\ai\packages\test-server\tsup.config.ts
CLI Target: es2018
CJS Build start
ESM Build start
CLI Target: es2020
CJS Build start
ESM Build start
CJS dist\index.js     6.57 KB
CJS dist\index.js.map 11.10 KB
CJS ⚡️ Build success in 33ms
CJS dist\with-vitest.js     6.89 KB
CJS dist\with-vitest.js.map 12.58 KB
CJS ⚡️ Build success in 31ms
ESM dist\index.mjs     5.41 KB
ESM dist\index.mjs.map 10.89 KB
ESM ⚡️ Build success in 36ms
ESM dist\with-vitest.mjs     5.71 KB
ESM dist\with-vitest.mjs.map 12.53 KB
ESM ⚡️ Build success in 33ms
DTS Build start
DTS Build start
DTS ⚡️ Build success in 1320ms
DTS dist\index.d.ts  2.05 KB
DTS dist\index.d.mts 2.05 KB
DTS ⚡️ Build success in 1474ms
DTS dist\with-vitest.d.ts  2.01 KB
DTS dist\with-vitest.d.mts 2.01 KB

When the build fails, the output ends like this:

CLI Building entry: src/index.ts
CLI Using tsconfig: tsconfig.build.json
CLI tsup v8.3.0
CLI Using tsup config: C:\GIT\ai\packages\test-server\tsup.config.ts
CLI Building entry: src/with-vitest.ts
CLI Using tsconfig: tsconfig.build.json
CLI tsup v8.3.0
CLI Using tsup config: C:\GIT\ai\packages\test-server\tsup.config.ts
CLI Target: es2018
CJS Build start
ESM Build start
CLI Target: es2020
CJS Build start
ESM Build start
CJS dist\index.js     6.57 KB
CJS dist\index.js.map 11.10 KB
CJS ⚡️ Build success in 27ms
CJS dist\with-vitest.js     6.89 KB
CJS dist\with-vitest.js.map 12.58 KB
CJS ⚡️ Build success in 29ms
ESM dist\index.mjs     5.41 KB
ESM dist\index.mjs.map 10.89 KB
ESM ⚡️ Build success in 34ms
ESM dist\with-vitest.mjs     5.71 KB
ESM dist\with-vitest.mjs.map 12.53 KB
ESM ⚡️ Build success in 33ms
 ELIFECYCLE  Command failed.