sPTC overview Data-flow diagram showing streamed code feeding a shadow REPL, speculative tools, a future store, and the real REPL reusing cached outputs. MODEL STREAM SHADOW REPL ASYNC TOOLS REAL REPL 01 STREAM 02 PEEK 03 LAUNCH 04 STORE 05 REUSE TOKENS SPEC FUTURE CACHED FINAL CODE LLM root model streaming code PARSE peek code known inputs TOOL sub-call starts early FUT promise store call id + future EXEC real repl same semantics LEGEND speculated work cached future final code path