What probably matters to youSection of the release
What
In -p mode, Claude Code can build the query engine once and submit each prompt to it, keeping the model, tools, MCP clients and read-file cache warm across prompts, instead of rebuilding everything per prompt. Set CLAUDE_CODE_PRINT_ENGINE_LOOP to use it; unset, the existing per-prompt path runs.
Evidence
CLAUDE_CODE_PRINT_ENGINE_LOOP
Strings lifted out of the shipped bundle, so the claim above can be checked against them.
