Materialize builds a curated workspace from a declaration of what may be present. We built it for experiments where the information a participant cannot see is part of the method.
The immediate need came from red-team work. We wanted an attacker that could inspect the system and work hard to defeat it without inheriting the defenders’ discussion, conclusions, or answer keys.
An instruction such as “do not read the design thread” does not create that condition. It asks the attacker to cooperate with the experiment. If the thread remains available, the claimed independence rests on compliance and later testimony.
Turn the boundary into absence
A Materialize manifest names the files and directories available during each phase of a job. The tool copies only those paths into a new workspace. It can place a brief, create declared writable directories, and keep the workspace free of Git history, Substrate rooms, findings, and other forbidden material.
The forbidden list is a backstop for mistakes in the manifest. If a declared path would copy something forbidden, Materialize refuses the workspace and removes it. A broad read declaration therefore fails instead of quietly carrying the answer key into the experiment.
The completed workspace contains MATERIALIZE_AUDIT.json. This record names the manifest and phase, lists the declared read and write surfaces, and records a SHA-256 hash for every copied file. The declaration becomes a filesystem and a receipt for its contents.
What the receipt can say
The audit records which bytes were placed in the workspace. It does not prove that a participant read, understood, or relied on them. It also does not replace operating-system containment. The experiment still has to run the participant within the intended boundary.
This distinction matters because a good record should stop where its evidence stops. Materialize establishes and reports a curated filesystem view. It does not claim access control or comprehension that it cannot observe.
An attack without the answer key
An early use of Materialize prepared a two-phase red-team workspace for Construct. The attacker began without the specification or design discussion. In the next phase, the specification became available while the discussion and prior findings remained absent.
That separation let the attacker approach the system without the defenders’ framing. The work found a milestone-inverting defect that an earlier review had accepted.
The same mechanism later prepared a construction workspace. A builder received a sealed specification, accepted design, source, and tests while the discussion, findings, evidence, and fixture facts remained absent.
Attack and construction called for different material, but the method held: state what is offered, remove what is excluded, and leave an inspectable record. A declared boundary is still only a plan. The workspace is where it becomes an experimental condition.