HELIX Engine – Antigravity Edition

HELIX Engine – Antigravity Edition is an open-source, MIT-licensed project by SuperHelix77 that adds a local evidence, memory and deterministic execution layer to coding agents. This edition is tuned for Google Antigravity (agy) and Gemini 3.8 Flash High. It re-architects the context management of the Codex-oriented HELIX 1.0 around Gemini's prompt-caching behavior.

What It Is

HELIX sits between a coding agent and its tool output. It keeps exact tool results in a local encrypted evidence archive and returns compact receipts to the model instead. It exposes goal, context and memory tools over MCP and runs as a local loopback service. It can be started from the CLI, and an Electron desktop app shows runtime state, evidence, memory and troubleshooting.

How the Antigravity Edition Manages Context

• Lean Switch (lean_run) condenses long pytest or git diff output into verified status receipts, keeps error tracebacks, and stores the full raw output locally for recovery on demand.
• Continuous Context Control (seal) archives completed task turns into encrypted stores and carries forward a compact handoff receipt (helix.handoff.v1).
• Two-Tier Context Optimizer combines scoped task retirement with intra-task aging, turning older tool results into compact references while preserving recovery handles.
• batch_inspect replaces many small file reads with one atomic multi-file range inspection.
• Memory keeps explicit project and task notes in local SQLite, with no LLM observer needed.

Setup Path

HELIX requires Node.js 22.19+, npm and Git; Python 3 is optional for AST-aware Python indexing. After building from source, users symlink the CLI into the Antigravity binary directory and start the daemon. Antigravity then discovers the HELIX MCP tools and the /helixcontext skill. The same stdio MCP entrypoint can also serve Codex or other MCP clients.

Benchmark Claims and Boundaries

The README reports a 50-task SWE-bench-style run comparing vanilla Gemini 3.8 Flash High with HELIX. It lists 10 solves for HELIX against 11 for vanilla, with billable tokens reduced by 61.95% and cached context by 86.42%. These are the author's own figures. The author states that a 95% savings figure is a target, not a result. HELIX runs authorized commands with the host account's permissions and is not a sandbox.