Gain is a behavioral mixing board for Claude. Four tracks — Mode, Confidence, Scope, Voice — write to a system prompt in real time. The Compare engine runs the same prompt through two presets and scores exactly what changed.
Open Gain All ToolsGain gives you four behavioral tracks. Each one controls a different dimension of how Claude reasons. Faders set intensity. Knobs set depth. Mode buttons switch between discrete behavioral states — EXPLORE, BUILD, DECIDE, and others. Move anything and the system prompt updates instantly.
The result is measurably different output from the same model, using the same user message, because the behavioral framing changes what the model optimizes for. EXPLORE asks for analysis and open questions. BUILD executes a single approach without alternatives. The same sentence, run through both, produces fundamentally different work.
The core feature is Compare. Save two presets — any two behavioral configurations — then run the same prompt through both. Gain runs them sequentially, then feeds both outputs to a scoring model that evaluates the difference on six metrics and writes a plain-English behavioral diagnosis.
Every run appends to a local stats database. Over time, per-preset averages emerge — you can see which configurations consistently produce deeper analysis, which produce tighter code, which waste tokens.
Gain supports the Korg nanoKONTROL2 MIDI controller as a primary hardware interface. Faders 1–4 map to intensity, certainty, scope, and room. Knobs 1–4 map to depth, risk, bandwidth, and decay. S and R buttons trigger the mode switches. LED feedback is fully wired — the hardware reflects the current state.
The result: behavioral control without touching the mouse. The cursor stays still while the system prompt changes under your hands. This is what Gain was built to demonstrate.
Prompt engineering is mostly intuition. Gain makes it empirical. If you use Claude heavily — for writing, coding, analysis, research — and you've ever wondered whether a different framing would produce better output, Compare gives you the answer with numbers.
Gain is also built for teams and organizations through AiGain, an enterprise layer that extends behavioral control to org-level, team-level, and individual throttles. Contact us for enterprise access.