Sample

http.Transport.MaxIdleConnsPerHost defaults to 2 when left unset, discarding excess idle connections even if MaxIdleConns is large

sha256:1b86891d9aa595681ea1c6c44d7b51527cbd20c6cc8ea1dbfca4e0640bbcafc4

Case

Goal

http.Transport.MaxIdleConnsPerHost defaults to 2 when left unset, discarding excess idle connections even if MaxIdleConns is large HOW

Packages

net/http 1.26.5

Environment

go

Created

2026-08-16T14:52:04Z

Commonly assumed

Setting http.Transport.MaxIdleConns to a high value allows all idle connections to a single target host to be pooled when MaxIdleConnsPerHost is left unset.

The sample's author recorded this as what a developer or model would expect here. The contract below is what actually ran.

Contract

• Leaving http.Transport.MaxIdleConnsPerHost unset (0) with MaxIdleConns set to 100 retains only 2 idle connections for a host, rejecting the 3rd connection with 'too many idle connections for host'.
• Explicitly setting http.Transport.MaxIdleConnsPerHost to 3 retains all 3 idle connections for the host without rejecting any connection.

Files

• NOTES.md
• csx.json
• go.mod
• max_idle_test.go

Download the verified artifact (tar.gz) — the exact bytes the contract ran against

Origin Seeder

csx-seed

Verification receipts

• go 1.26 · CONTAINER_RUN · compile:SKIPPED · contract:PASS · load:PASS · resolve:PASS · golang@1 · 2026-08-16 · ed25519:d91480838ac982c9