Think in quiet motion.
Halcyon watches how decisions propagate through your codebase and tells you, in plain English, what a change is going to touch before you ship it. No dashboards. No surprises.
A decision in one file echoes through forty others. Halcyon shows you where it lands.
Point Halcyon at a repository and it builds a reasoning graph — every function, every boundary, every implicit contract. Ask it a question in plain language and it returns a trace: a chain of files, reasons, and caveats, written out like a colleague would.
Reasoning graph
A live map of how your modules depend on each other, including the implicit contracts that linters miss. Regenerates on every push.
Plain-language traces
Ask "what does this change affect?" and get a chain of files, reasons, and caveats. No dashboards, no interpretation — just the trace.
Local first
The graph runs on your machine or your cluster. Your code never leaves your network. Bring your own model, or run ours offline.
From one question to a written answer, four steps.
We stopped having the same "wait, does this touch X?" meeting. Halcyon already knows. — Priya Natarajan · staff engineer, mid-stage fintech
Open the graph.
Free for small teams. No credit card. Runs on your machine.