Helianthus is an open Energy gateway platform built around a protocol-agnostic semantic core. It separates transport, protocol decoding, registry/identity, semantic modeling, and consumer APIs so that new protocol adapters can plug into the same platform without forking the rest of the stack.

Today, eBUS is the active production track and the reference implementation. eeBUS support is being built as a native SHIP / SPINE stack, with helianthus-eebus-go and helianthus-eebusreg, and its public knowledge base in helianthus-docs-eebus. For Vaillant hardware, eBUS and eeBUS can coexist without duplicating device identities: eBUS exposes substantially richer raw data, while eeBUS more closely matches the user-facing myVaillant view.

Read-only MODBUS support is being developed through the vendor-neutral helianthus-modbus runtime and multi-vendor helianthus-modbusreg profile registry. The immediate sequence is Fronius/SunSpec solar-inverter support, then Huawei and Growatt inverter/BESS profiles. The helianthus-ebusgateway performs upstream raw/profile MCP composition; canonical promotion then produces the public GraphQL/M2M contract. A separate private eeBUS output binding, when introduced, consumes that public contract downstream rather than gateway or registry internals. The next planned target is Tesla Wall Connector Gen 3 FC100-FC102 MODBUS support. It does not yet have a public target repository or canonical planning artifact. Additional profiles can be contributed through the same shared runtime and registry boundaries. The wider goal is multi-protocol HVAC, EVSE, Solar Inverter, BESS interoperability: one semantic model, multiple buses, multiple operator surfaces, and reusable tooling for reverse engineering and documentation.

The eBUS edge firmware tracks are being deprecated: helianthus-tinyebus (adapter oracle, harness, and bridge) and helianthus-ebus-adapter-pic (PIC16F15356 firmware for eBUS adapter v3.x). The legacy helianthus-ebus-adapter-proxy is also being deprecated: its role is now integrated into the gateway's eBUS transport path/runtime mux in helianthus-ebusgateway, which wraps the reusable transports in helianthus-ebusgo.

• Curious user: you want Helianthus running in Home Assistant with the minimum number of moving parts.
• Protocol hacker: you want to inspect registers, use the MCP surface, script investigations, or work with eBUS tooling directly.
• Developer: you want to contribute code, docs, execution plans, and proof-backed changes across the Helianthus repos.

Cross-repo, milestone, architecture, protocol, and API work is planned in helianthus-execution-plans. That repository holds the human-readable guides and discussions that define scope, dependencies, and applicable gates. Execution reconciles the merged guide with current GitHub state; the guide itself neither authorizes nor automates work in code repositories.