sprang-diff

name	sprang-diff
description	Blast radius analysis for changed files — shows what will break if you change something. Use when the user says "/sprang-diff", "what will break", "blast radius", "impact analysis", or "what depends on this".

1. If $ARGUMENTS is provided, parse as space/comma-separated file paths. Otherwise run:

   git diff --name-only HEAD && git diff --name-only --cached
   

   and deduplicate.
2. Call sprang_diff_impact with the collected file paths to compute the full blast radius (BFS over incoming edges).
3. Report changed_nodes (what you directly touched) and impact_nodes (everything that transitively depends on those files).
4. Call sprang_node on the enriched result for each changed node to get layer, in_degree, out_degree, and has_annotation.
5. Flag all impact nodes with risk_score >= 0.7 as high-risk dependents requiring careful review.
6. For any high-risk node with circular_dependency or god_node in structural_warnings, explain the specific risk.
7. Write diff overlay for dashboard — create .sprang/diff-overlay.json:

   { "changedNodeIds": [...], "affectedNodeIds": [...], "blastRadius": N, "generatedAt": "<ISO>" }
   

   This enables amber/warm-gray highlighting in the Sprang dashboard's Graph view.
8. If total_impact > 10, recommend documenting the scope in the PR description.
9. Summarize: N files changed, M dependents affected, K high-risk. Include affected layer names. Safe to proceed or review recommended.