Why the conventional model fails.
How do we read the legacy comprehensively enough that the target falls out of it?
Most migration programs begin with a target architecture written against assumptions about how the legacy system behaves. Six months in, the team discovers that the legacy behavior has drifted from the documentation in dozens of subtle ways. Scope explodes. Timelines slip. The program becomes a partial migration that leaves two systems running in parallel the problem it was supposed to solve.
The root cause is uniform. Teams treated the legacy system as an input specification when it was really the entire specification. Everything meaningful about the migration is encoded in the legacy assets. Substrate for Migrations is built around that inversion.
How context shifts.
Migrations mode requires two surfaces held in view at the same time.
- Source trees
- Runtime traces
- Database schemas
- Integration maps
- Historical incidents the quirks the documentation missed
- Framework conventions
- Organizational standards for the new stack
- Compliance constraints that must survive the transition
Substrate reasons bidirectionally on every story.
What does the legacy actually do?
What does the target actually require?
What is the minimum-risk path between them?
The variants
The Variant roster reorganizes around the translation problem: extrapolate the ground truth, then preserve it through the rewrite.
Substrate
Click to release
SYSTEMS OF RECORD
Every system of record in the migration is built around Substrate
Scattered Artifacts
Migration knowledge is spread across spreadsheets, documents, and individuals, making it hard to track.
Knowledge Loss
Critical insights are often lost or forgotten by the end of the migration.
Centralized System
All artifacts are captured and fed into Substrate for structured use.
Persistent Specs
Behavior specifications are stored as long-term, reusable assets.
Continuous Validation
Parity between systems is verified continuously, not just once.
Managed Cutover
Cutover plans are maintained directly within the system.
Machine-Readable Legacy
A complete, structured view of legacy behavior is created.
Lasting Value
The migration builds a reusable knowledge base for the future.
Turn legacy into a working plan.
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