OpenAI releases Symphony — open-source orchestration that turns project work into isolated, autonomous coding-agent implementation runs and surfaces the ones that pass, so teams manage outcomes instead of supervising sessions. Big Tech keeps raising the floor on what counts as a baseline harness.
'Harness Engineering: Anatomy, Architecture, and Evolution of Coding Agents' surveys the field — loops, tool interfaces, context management, memory and recovery — giving the emerging discipline its first comprehensive academic map.
xAI open-sources Grok Build — a Rust coding agent harness and fullscreen TUI around Grok models — unusually early for a first-party tool. It joins Claude Code, Codex and Gemini CLI as the fourth major first-party harness, now with a fourth open one.
Gemini 3 debuts with state-of-the-art agentic coding benchmarks, alongside Antigravity — a browser-based agentic development environment where agents plan, edit and execute tasks across editor and browser surfaces.
The AI-native editor's latest round makes it one of the fastest-growing software companies ever — a bellwether for how central agentic coding has become to the harness economy.