> ## Documentation Index
> Fetch the complete documentation index at: https://docs.kynva.ai/llms.txt
> Use this file to discover all available pages before exploring further.

# Details & fix_patch

> How to read error.details and apply fix_patch operations to recover automatically.

For validation, style-lock, and policy errors, Kynva often returns a `details[]` array. Each entry can include:

* **`fix_patch`** — a list of RFC 6902 JSON Patch ops to apply to your request body to make it pass.
* **`violation_rect`** — a bounding box for visual issues, useful for highlighting in your UI.

These let you build "did-you-mean" flows and one-click fixes without writing rule-specific logic.

## Example: applying a `fix_patch`

The server says color `#FF00FF` violates a BrandKit lock and suggests `#7C3AED`:

```json theme={null}
{
  "error": {
    "code": "STYLE_LOCK_VIOLATION",
    "details": [{
      "path": "$.brief.color",
      "severity": "error",
      "message": "Color is locked to '#7C3AED'.",
      "fix_patch": [
        { "op": "replace", "path": "/brief/color", "value": "#7C3AED",
          "rationale": "Match locked primary color." }
      ]
    }]
  }
}
```

Apply it before retrying:

<CodeGroup>
  ```typescript TypeScript theme={null}
  import { applyPatch } from "fast-json-patch";

  async function renderWithAutoFix(body: object, attempt = 0): Promise<Response> {
    const res = await fetch("https://api.kynva.ai/api/v1/facade/generate", {
      method: "POST",
      headers: {
        Authorization: `Bearer ${process.env.KYNVA_API_KEY!}`,
        "Content-Type": "application/json",
        "Idempotency-Key": crypto.randomUUID(),
      },
      body: JSON.stringify(body),
    });

    if (res.ok || attempt >= 1) return res;

    const err = await res.clone().json();
    const patches = err.error?.details?.flatMap((d: any) => d.fix_patch ?? []);
    if (!patches?.length) return res;

    const patched = applyPatch(structuredClone(body), patches).newDocument;
    return renderWithAutoFix(patched, attempt + 1);
  }
  ```

  ```python Python theme={null}
  import os, copy, uuid, requests, jsonpatch

  def render_with_auto_fix(body, attempt=0):
      res = requests.post(
          "https://api.kynva.ai/api/v1/facade/generate",
          headers={
              "Authorization": f"Bearer {os.environ['KYNVA_API_KEY']}",
              "Content-Type": "application/json",
              "Idempotency-Key": str(uuid.uuid4()),
          },
          json=body,
          timeout=60,
      )

      if res.ok or attempt >= 1:
          return res

      err = res.json()
      patches = [op for d in err.get("error", {}).get("details", [])
                    for op in d.get("fix_patch", [])]
      if not patches:
          return res

      patched = jsonpatch.JsonPatch(patches).apply(copy.deepcopy(body))
      return render_with_auto_fix(patched, attempt + 1)
  ```
</CodeGroup>

## When *not* to auto-apply

* **Policy errors** — applying the patch may produce something semantically different from what your user asked for. Always confirm.
* **More than one detail with conflicting patches** — apply the first, retry, and let the server tell you about the next one.
* **High-trust contexts** (e.g., billing copy) — patches are *suggestions*; surface them as "did you mean…?" in your UI rather than silently applying.

## `violation_rect`

For visual errors (text overflow, image clipping), the server returns the offending rectangle so you can highlight it:

```json theme={null}
{
  "violation_rect": { "x": 32, "y": 96, "w": 256, "h": 48 }
}
```

Coordinates are in the **rendered output's pixel space** (top-left origin). Overlay this on top of the preview image to point users at the problem.