Anthropic removes ability to pin to a specific Claude model version
Users discovered Anthropic no longer allows fixing API requests to a specific model snapshot, eliminating the primary defense against silent model swaps.
What changed
before— removed
API consumers could pin to dated model snapshots
after+ current
Pinning removed; requests resolve to the floating model
word-level diff
PinningAPI removed;consumers requestscould resolvepin to the floatingdated model snapshots
Context
On April 15, 2026 a Tell HN post surfaced that Anthropic had removed the ability to pin requests to a specific dated model snapshot. This eliminates the core engineering practice for guarding against quality regressions and effectively forces users to live with whatever the floating latest model becomes.