Sculptor — lessons for Forge

Primary source: https://github.com/imbue-ai/sculptor/blob/main/docs/help/integrated_harnesses.md

Observed source lessons

Sculptor explicitly chooses deep structured integration with coding harnesses to provide richer UI/lifecycle behavior. For Claude Code it uses streaming/control protocol integration and substitutes built-in question/plan tools with Sculptor-managed tools so the app can render and answer them natively. For Pi it uses RPC and extensions rather than terminal scraping.

Its integrated harness design supports persistent pending questions, message queues, and work surviving application interruption/crash.

Forge decisions influenced

• do not infer human-attention needs from terminal text when a structured backchannel can exist;
• injected/controlled escalation tool is a valid architectural choice;
• pending Decisions must be durable before UI notification;
• agent capability differences are product-visible and should be declared;
• structured protocol integration is worth per-provider cost for features Forge actually depends on.

What not to copy blindly

Forge is organized around engineering Tasks, Review, and Decisions rather than primarily harness conversation UX. Sculptor's provider adaptations are evidence for the adapter boundary, not a reason to make provider sessions the root product model.