Adapt Change

Adapt to Change (Re-propagation Engine)

Desired Outcome

Apply a change to an existing product design with minimal, reversible re-runs:

1. Change log — reports/05_adaptation/change-log.md: the change (description, --type,

timestamp) and a before/after diff summary for every re-run artifact (for reversibility).

1. Impact analysis — reports/05_adaptation/impact-analysis.md: "change → impacted ID →

re-evaluate? + reason", i.e. the candidate blast radius after the judgment pass.

1. Updated artifacts — the affected skills re-run with existing artifacts as input, and the

corresponding edges in work/traceability.json updated.

Invocation

/product:adapt-change --change="" [--type=constraint|market|competitor|tech|regulation] [--auto] [--lang=ja|en]

| Argument/Flag | Required | Description | |---------------|----------|-------------| | --change="" | Required | What changed (free text) | | --type=... | Recommended | Where the change enters the graph: constraint / market / competitor / tech / regulation | | --auto | Optional | Skip the human confirmation step (apply the judged impact set directly) | | --lang | Optional | Override output language |

Decision Criteria

• Minimal re-run. Never touch a skill the change does not reach. The graph proposes the

candidate set; the judgment pass decides whether each upstream reference still holds.

• Deterministic candidates, judged scope. Step 2 (transitive closure) is pure graph work;

step 3 (opus) expands/shrinks it with recorded reasons.

• Reversibility. Record a before/after diff summary for every rewritten artifact.
• Human checkpoint. Confirm the impact set before rewriting anything (unless --auto).
• Stop condition: change logged, impact set judged and confirmed, affected skills re-run,

traceability.json updated, and review run for coherence.

Prerequisites

| Input | Required/Recommended | Source | If missing/empty | |-------|---------------------|--------|------------------| | --change | Required | User | block with a message — nothing to propagate | | work/traceability.json | Required | all prior skills | block with a message — the engine reads only this | | existing artifacts | Required | prior skills | block — there must be a design to adapt |

Process

1. Intake — record the change in change-log.md (description, --type, timestamp passed in).

Apply @rules/product/adaptation-engine.md.

1. Candidate blast radius (deterministic) — seed from the --type hint, then walk

traceability.json upstream edges in reverse to get the downstream transitive closure.

1. Judgment pass (opus) — for each candidate decide if its upstream reference still holds;

expand/shrink the set; write "change → impacted ID → re-evaluate? + reason" to impact-analysis.md.

1. Confirm — present the impact set via AskUserQuestion (skip under --auto).
2. Minimal re-run — re-run only the confirmed affected skills with existing artifacts as input;

record before/after diffs; update the affected edges in traceability.json.

1. Coherence check — invoke /product:review (consistency + traceability lenses) to catch

contradictions introduced by the re-propagation.

1. Record — finalize both files; append the change summary to work/context.md.

Output

reports/05_adaptation/change-log.md, reports/05_adaptation/impact-analysis.md, the re-run artifacts, and an updated work/traceability.json.

Reference Materials

| Resource | Purpose | |----------|---------| | @rules/product/adaptation-engine.md | Edge store, transitive-closure + judgment algorithm, principles |

Related Skills

| Skill | Relationship | |-------|-------------| | /product:review | Downstream — runs the coherence check after re-propagation | | /product:validate-assumptions | Related — a change may re-open the gate | | any pipeline skill | Re-invoked selectively as the confirmed impact set requires |

Source & license

This open-source skill is cataloged on AgentStack and links to its original source — we do not rehost the code.

• Author: wfukatsu
• Source: wfukatsu/nexus-architect
• License: MIT

Install and usage instructions live in the source repository linked above.