CONTEXT_RESERVE_TOKENS

const CONTEXT_RESERVE_TOKENS: 32000 = 32_000;

Defined in: core/src/context.ts:16

What the answer needs after the prompt: an output budget, plus the tools’ own schemas, plus the slack no provider documents.

Absolute rather than a percentage on purpose: a 1M window does not need a 100k cushion, and a 128k window needs more than 12k.