HONEST COMPARISON
AgenticosCore vs big-bang rewrite
The big rewrite is the riskiest legacy modernization move on the table. The alternative is not a bigger plan — it is a smaller proof.
What the rewrite assumes
A big-bang rewrite only pays off when every one of these assumptions holds — and they usually do not:
- You fully understand the legacy behavior, including the undocumented parts.
- The business can wait quarters for the new system to reach parity.
- Nothing critical will break on cutover day — the one day there is no rollback for.
What a governed parallel run does instead
AgenticosCore keeps the legacy running and proves the replacement before anyone commits:
- The candidate agent receives the same input as the legacy system, in production, with zero cutover risk.
- Outputs are compared under an explicit equivalence contract: what must match, what counts as a blocker, who approves exceptions.
- Every exception gets a named owner and a decision path before anyone cuts over.
- The final cutover is a human decision with an evidence pack — not a leap of faith.
When a rewrite still makes sense
We are not dogmatic: sometimes the rewrite is right. The difference is how you get there:
- If the parallel run shows the candidate cannot reach equivalence, you learned that for the price of a proof — not the price of a program.
- If it does reach equivalence, the rewrite happens incrementally, process by process, with evidence at each step.
A rewrite is a bet. A parallel run is a proof. AgenticosCore is the proof.