# Rewrite, Refactor or Replatform — Decision Worksheet

Use this worksheet as an evidence record, not an automatic architecture recommendation.

Do not include passwords, tokens, secret values, customer records, production exports, private source code or confidential commercial figures. Store sensitive evidence in the approved system and link to its controlled location.

## 1. Decision scope

- Organization / product:
- Assessment owner:
- Reviewers:
- Decision date:
- Review date:
- Exact system / release / environment:
- Business capability that must change:
- Decision horizon:
- Explicitly out of scope:
- Critical users / operators:
- Critical business flows:
- Scale assumption:
- Acceptable outage / data-loss expectation:

## 2. Baseline gate

Mark each item `VERIFIED`, `NOT VERIFIED`, `UNAVAILABLE` or `N/A` with a reason.

| Baseline claim | Status | Evidence location | Owner | Next verification |
|---|---|---|---|---|
| Canonical source and history identified |  |  |  |  |
| Production revision / artifact identified |  |  |  |  |
| Build and deployment path reproducible |  |  |  |  |
| Runtime configuration schema known |  |  |  |  |
| Database migration state reconciled |  |  |  |  |
| Critical flows and acceptance criteria known |  |  |  |  |
| Data stores, jobs and consumers inventoried |  |  |  |  |
| Recovery / redeploy evidence available |  |  |  |  |
| Product, data, release and cutover owners named |  |  |  |  |

If a material baseline claim is `NOT VERIFIED` or `UNAVAILABLE`, record `ASSESS FIRST` unless an accountable owner accepts a bounded exception with mitigation.

## 3. Seven-factor evidence profile

Use:

- `2` — evidenced and workable;
- `1` — constrained;
- `0` — materially unsafe or incompatible;
- `U` — unknown or contradictory.

Do not convert `U` to zero or total the values into a rewrite threshold.

| Factor | State | Evidence / observed behavior | Confidence | Constraint or unknown | Owner |
|---|---:|---|---|---|---|
| 1. Critical behavior evidence |  |  |  |  |  |
| 2. Coupling and replaceable boundaries |  |  |  |  |  |
| 3. Knowledge, custody and change authority |  |  |  |  |  |
| 4. Platform and dependency viability |  |  |  |  |  |
| 5. Data and migration risk |  |  |  |  |  |
| 6. Business-change pressure and strategic fit |  |  |  |  |  |
| 7. Disruption and dual-operation capacity |  |  |  |  |  |

Evidence profile: `_ / _ / _ / _ / _ / _ / _`

## 4. Hard blockers

| Blocker | Present? | Evidence | Required action | Owner / date |
|---|---|---|---|---|
| Production source / artifact provenance unknown |  |  |  |  |
| Critical behavior lacks trustworthy specification |  |  |  |  |
| Material data / jobs / consumers unknown |  |  |  |  |
| Release or recovery depends on unavailable person/supplier |  |  |  |  |
| Target business capability undefined |  |  |  |  |
| No authority to stop, rollback and reconcile transition |  |  |  |  |

## 5. Option profiles

For each option record `SUPPORTED`, `CONSTRAINED`, `REJECTED` or `NOT VERIFIED`.

| Option | Status | Evidence that supports it | Main risk / cost | First proof |
|---|---|---|---|---|
| Stabilize and maintain |  |  |  |  |
| Incremental refactor |  |  |  |  |
| Replatform / staged modernization |  |  |  |  |
| Parallel replacement / rebuild |  |  |  |  |

## 6. Cost comparison

Use the same scope, unit and decision horizon for both views. Link controlled financial evidence rather than copying confidential figures here.

### Current-state cost

- Incident / unplanned work:
- Support / manual operations:
- Infrastructure / providers / licensing:
- Evidence-backed delivery delay:
- Security / support-horizon mitigation:
- Risk exposure with source, assumptions and owner:
- Business unit metric (per tenant / transaction / case / other):

### Transition cost

- Discovery / behavior characterization:
- Implementation / platform:
- Data migration / reconciliation:
- Dual operation / duplicated roadmap:
- Customer / operator migration and support:
- Security / testing / observability:
- Cutover / rollback / hypercare:
- Decommission / retention / residual contracts:

## 7. Decision record

- Result: `ASSESS FIRST / STABILIZE / INCREMENTAL REFACTOR / REPLATFORM-STAGED MODERNIZATION / PARALLEL REPLACEMENT`
- Selected path and evidence:
- Rejected alternatives and why:
- Facts that would reopen the decision:
- Known limitations:
- `NOT VERIFIED` areas:
- Accepted risks and accountable owner:

## 8. First reversible step

- Bounded capability / workload:
- Current behavior to preserve or deliberately change:
- Interface / seam:
- Data ownership and reconciliation:
- Observability:
- Acceptance evidence:
- Rollback trigger and method:
- Old-path deletion / completion condition:
- Owner:
- Start / decision date:

## 9. Sign-off

- Business owner:
- Product owner:
- Technical owner:
- Data / security reviewers as applicable:
- Decision status: `PROPOSED / ACCEPTED / CONDITIONAL / NO-GO`
- Review date:
- Notes:

This worksheet supports an engineering and business discussion. It is not legal, regulatory, security, financial or production-readiness certification.