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Claude Code v2.1.269 ·

Bun JIT policy is throttled down 10s after startup

Claude Code now throttles Bun's JIT policy 10 seconds after startup outside fast-path launches

TierUnder the hoodhow much it should matter to you
Useful1my rating, 1 to 5
Signal1worth watching, 1 to 5
AreaElsewherewhat it touches
KindInternal Changesin v2.1.269,
Under the hood

Claude Code now throttles Bun's JIT policy 10 seconds after startup outside fast-path launches

What

On most CLI startups (excluding the --preload and --bg-spare fast paths), Claude Code now starts a background timer that, 10 seconds after launch, calls Bun.unsafe.setJITPolicy?.(1).

Why

This is an internal runtime tuning change, likely adjusting how Bun's just-in-time compiler behaves once the code needed for startup has already run, though the finding does not specify the exact effect.

How sure we are
Something disagreesSomething we can check disagrees with this entry, or the writer said they could not settle it.
The writer flagged doubtWhat effect JIT policy 1 has on performance or behavior is not stated in the evidence.

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