{
  "title": "Edits need regression tests",
  "caption": "Figure 2. A unique edit target permits a write, then tests check locale isolation and cache reuse. Ambiguous targets cause no write in this example; other tools may partly apply edits before failing. Playback is illustrative, not measured runtime.",
  "alt": "Flow diagram: a unique edit target leads to a write and regression tests; an ambiguous target returns a no-write error.",
  "sources": [
    {
      "title": "Original author teaching trace",
      "file": "diagram.svg",
      "sha256": "56b9fe5a2418bebcc80c06b311504908a52e3446c397027e0cfdd303e33ad779"
    },
    {
      "title": "Pi v0.80.6 edit contract",
      "url": "https://github.com/earendil-works/pi/blob/v0.80.6/packages/coding-agent/src/core/tools/edit.ts"
    },
    {
      "title": "Article evidence and version ledger",
      "file": "SOURCE.md"
    }
  ],
  "limitations": [
    "The code and regression outcomes are constructed teaching examples, not a measured repair campaign.",
    "The ambiguous branch guarantees zero writes only in this example. Other tools or multi-file batches can apply changes before reporting failure.",
    "A completed write still needs behavior tests. The focused regression checks only the stated locale isolation and reuse cases.",
    "Playback timing is illustrative, not measured runtime."
  ]
}