What shall Bitcoin become?

Run the unmodified node beside any other node program on this machine: another release, Bitcoin Knots, or a build of a proposed change. The lab gives both the same blocks and transactions and reports what each did. The program runs inside the sandbox, on a throwaway private chain. The lab never downloads one for you: get it from a source you trust and check its signature first.

A shared request is the sender's words, never their code. Words are still instructions to an AI agent, so an imported request is treated as untrusted: it is shown to you first, it always stops for your review, it is never applied or started automatically, and the agent that reads it can edit files and nothing else.

The agent writes a proposal in an isolated copy of the source. It can read and edit files there; it cannot run commands or use the network. The lab then compiles the proposal inside an operating-system sandbox, runs Bitcoin Core's unit tests on it, and starts it beside an unmodified node on a throwaway private chain. Each node is handed the other's blocks and a few test transactions, and the lab reports what each one did. Only then are you asked whether to keep the change. Applying it saves exactly the revision that was built.

Consensus rules decide whether a block is valid at all. Every node checks them for itself, and a block that breaks them is refused however much mining power produced it. Policy is a node's local choice about which unconfirmed transactions to keep and pass on; it never applies to transactions already in a block.

Change a consensus rule and one of two things happens. Tighten it, and your node refuses blocks everyone else accepts: it stops following the network at the first such block. That shape of change is called a soft fork, and others follow it only if most mining power enforces it. Loosen it, and nothing visible happens until a block uses the looser rule, which every unmodified node then refuses. That shape is called a hard fork.

Compiled: the change builds. Unit tests: which of Bitcoin Core's own tests still pass; when a change alters a rule on purpose, the tests that pin that rule fail, and their names tell you what changed. Comparison: what an unmodified node did with this build's blocks and transactions, and the reverse. The comparison covers block rewards, one reward halving, two kinds of transaction and block exchange in both directions. A change to something it never exercises will show no difference. None of this proves a change is safe on a real network.

If the proposal does not compile, nothing has changed: read the compiler's output under Technical activity, then refine the request or ask the agent to fix the error. If a new build will not start, the previous build is started again. To undo a saved change, use Revert in the history, or Restore the baseline source above.

Everything here happens on your own machine. The same questions are worked on in the open:

bitcoin4plebs is a companion project that walks you through Bitcoin Core's real source, with no coding required. Bitcoin Inquisition is where proposed consensus changes are switched on for real on signet, a shared test network. Bitcoin Optech explains the proposals themselves. Nothing made in this lab is offered to Bitcoin Core.

The ready-made experiments need no AI. To rehearse the request workflow, run ./vibes --engine mock: a stand-in agent makes one harmless edit to the manual.