git:20261031.ac1ccdb to git:20261031.f8301a3

---

name: composition-quality-checker

description: Validate camera framing, subject placement, headroom/lead-room, and visual hierarchy against the scene brief before render.

---

# composition-quality-checker

## Purpose

Run a focused per-row Pass/Warn/Fail check on the camera and framing setup against composition rules (rule of thirds, subject placement, headroom/lead-room, negative space, visual hierarchy, depth cues, and lens/FOV plausibility) — emitting per-row verdicts, a top-line status, and remediation hints only, without expanding into camera planning, aspect-ratio locking, material validation, or lighting validation.

## Quick start

- read camera lens / FOV, position, and target description

- read framing intent and locked aspect ratio from the brief

- check rule of thirds, subject placement, and headroom/lead-room

- check negative space, visual hierarchy, depth cues, and lens/FOV plausibility

- emit per-row Pass/Warn/Fail verdicts, top-line status, and remediation hints (keep truth states separate and downgrade-only)

## When to use

- before render

- after a camera change request

- as a sub-check during full quality review

- when a render "feels off" but lighting and materials check out

## When not to use

## Trigger phrases

- "is the framing okay"

- "check composition"

- "subject feels off-center"

- "too much negative space"

## Prerequisites / readiness

- camera setup known (FOV / focal length / position / target / lens)

- framing intent known (from brief)

- subject identified

## Input schema

### Required inputs

| Input | Why it is required |

|---|---|

| Camera setup | Anchors lens/FOV plausibility and framing checks |

| Framing intent | Determines applicable composition expectations (close-up vs hero card vs wide) |

| Subject identification | Determines what counts as the primary subject for placement and hierarchy rules |

| Aspect ratio lock | Provided upstream (via `resolution-aspect-decision`) to evaluate framing boundaries |

### Optional inputs

| Input | Use |

|---|---|

| Reference image or preview | Allows visual cross-check of framing and depth cues |

### Assumptions to confirm

- Render aspect ratio is known and stable.

- "Subject" is unambiguous in the brief.

- Camera is locked (or animated path is documented).

## Output schema

### Primary output

A composition verdict table covering: rule of thirds, subject placement, headroom/lead-room, negative space, visual hierarchy, depth cues, and lens/FOV plausibility — each with a `Pass | Warn | Fail` verdict and notes.

### Secondary output

- top-line validation status (`Pass | Warn | Fail`)

- worst-offender highlighting

- remediation hints only (never camera edits or execution commands)

### Evidence / caveat output

Validation verdicts (`Pass | Warn | Fail`) are separate from runtime and artifact truth states. Truth states are downgrade-only (never upgrade), and `Artifact status` defaults to `Not Produced` unless concrete output evidence exists (classified via `render-export-evidence`).

```txt

Runtime status: Not Run | Attempted | Produced | Verified | Failed

Artifact status: Not Produced | Produced | Verified | Failed

Evidence used: <links, paths, logs, or "none">

Limitations: <known gaps>

```

## Required laws

- `../../laws/evidence-before-done.md`

- `../../laws/non-blender-user-language.md`

- `../../laws/no-arbitrary-python-interface.md`

- `../../laws/official-runtime-only.md`

## Official runtime boundary

This skill validates camera plans or measured scene snapshots only. It never moves the camera, never runs Blender, and never executes Python. Artifacts stay `Not Produced` unless concrete output evidence exists (classified by `render-export-evidence`), and truth states are strictly downgrade-only.

## Operating procedure

1. Read camera setup, framing intent, subject identification, and upstream aspect lock (from `resolution-aspect-decision`).

2. Check rule of thirds alignment against framing intent.

3. Check subject placement per intent.

4. Check headroom and lead-room balance.

5. Check negative space balance and visual hierarchy.

6. Check depth cues (foreground/midground/background separation).

7. Check lens / FOV plausibility for distortion or flattening against the brief.

8. Assign per-row `Pass | Warn | Fail` verdicts and remediation hints.

9. Compute top-line status and highlight worst offenders; record downgrade-only Runtime and Artifact truth states separately (defaulting Artifact status to `Not Produced`).

10. Hand off to `blender-scene-quality-checker` (broad review), `blender-composition-camera-planner` (camera re-plan), `resolution-aspect-decision` (aspect/resolution changes), or `render-export-evidence` (artifact evidence classification).

## Decision tree

```txt

Subject dead-center in 16:9 hero card?

→ Pass for symmetric hero; Warn for documentary/editorial mood

Subject in dead corner?

→ Fail unless intentional asymmetry called out in brief

Headroom > 30% of frame for portrait?

→ Warn (too much empty space above)

Headroom 0% (subject's head touching top)?

→ Fail

Lead room missing for moving subject?

→ Fail (subject "pressed against" frame)

Negative space carrying intentional weight?

→ Pass; verify with brief

FOV < 18mm equivalent on a hero close-up?

→ Warn (likely distortion); verify intent

```

## Playbooks

### Playbook A: Product hero card 16:9

Subject ~60% width, centered horizontally or on right third; clear negative space on the opposite side for headline / CTA; soft horizon line; FOV 50–85mm equivalent.

### Playbook B: Square 1:1 social

Subject centered; negative space minimal; tight crop OK if not cropping silhouette.

### Playbook C: Portrait 9:16 mobile

Subject in upper third; lower third reserved for text overlay; full silhouette visible.

### Playbook D: Cinematic 2.39:1

Wide negative space allowed; subject often off-center using rule of thirds; horizon at upper or lower third.

## Mode handling

### Text-only mode

Per-row `Pass | Warn | Fail` verdicts are based on the written camera plan/brief only. `Runtime status` stays `Not Run` and `Artifact status` stays `Not Produced`.

### Runtime-ready mode

Per-row verdicts cross-check the measured scene snapshot or preview. Truth states remain separate from row verdicts, are downgrade-only, and require `render-export-evidence` before any artifact state above `Not Produced` is recorded.

### Blocked runtime mode

Skip preview-dependent verification, flag limitations explicitly, keep `Artifact status: Not Produced`, and downgrade truth states accordingly.

## Validation checklist

- [ ] Camera setup stated

- [ ] Framing intent stated

- [ ] Aspect ratio lock confirmed (from `resolution-aspect-decision`)

- [ ] Rule of thirds verdict

- [ ] Subject placement verdict

- [ ] Headroom / lead-room verdict

- [ ] Negative space verdict

- [ ] Visual hierarchy verdict

- [ ] Depth cues verdict

- [ ] Lens / FOV plausibility verdict

- [ ] Top-line status derived from rows (kept separate from Runtime/Artifact truth states)

## Pass / Warn / Fail rubric

| Verdict | Criteria |

|---|---|

| Pass | All rows pass; framing matches brief; aspect ratio coherent. |

| Warn | One or two plausibility flags (centered when off-center expected, FOV at boundary); no hard violations. |

| Fail | Subject dead corner without justification; 0 or excessive headroom; lead-room missing for moving subject; FOV severely wrong (e.g. 8mm on hero close-up). |

## Failure handling

- Camera path animated → flag every keyframe individually if possible, or mark as Warn for static-rule scope.

- "Negative space minimal" intent vs measured negative space wide → Fail, not Warn.

- Aspect ratio missing → Fail until provided.

## Troubleshooting

| Problem | Remediation hint (do not execute) |

|---|---|

| Subject feels off-center or unbalanced | Hint: verify rule-of-thirds vs centered intent; route to `blender-composition-camera-planner` if camera re-aiming is needed. |

| Excessive or cramped headroom | Hint: adjust framing tightness or subject framing height in `blender-composition-camera-planner`. |

| Unintended close-up perspective distortion | Hint: increase camera distance and use a longer focal length / narrower FOV in `blender-composition-camera-planner`. |

| Flat staging with weak depth cues | Hint: increase foreground/background separation or staging depth in `blender-composition-camera-planner`. |

| Aspect ratio mismatch with target delivery | Hint: route to `resolution-aspect-decision` to lock the proper aspect ratio before re-planning framing. |

## Best practices

- Confirm the upstream aspect-ratio lock from `resolution-aspect-decision` before judging framing margins.

- Apply composition checks relative to framing intent, not as rigid universal formulas.

- Treat negative space and depth cues as intentional design elements anchored to the brief.

- Provide remediation hints only — leave camera edits to `blender-composition-camera-planner` and broad scene sign-off to `blender-scene-quality-checker`.

## Good examples

- "16:9 hero card; subject right-third 60% width; headroom 18%; lead room not applicable (static); negative space left for CTA; FOV 50mm equivalent. Verdict: Pass."

## Bad examples

- "Composition looks fine." — no per-row analysis.

- "Verified" without preview cross-check.

## User-facing response template

```txt

Aspect ratio lock: <from resolution-aspect-decision>

Framing intent: <hero card / portrait / wide / cinematic>

| Check | Verdict | Notes / Remediation Hint |

|---|---|---|

| Rule of thirds | Pass/Warn/Fail | |

| Subject placement | Pass/Warn/Fail | |

| Headroom / lead-room | Pass/Warn/Fail | |

| Negative space | Pass/Warn/Fail | |

| Visual hierarchy | Pass/Warn/Fail | |

| Depth cues | Pass/Warn/Fail | |

| Lens / FOV plausibility | Pass/Warn/Fail | |

Top-line verdict: <Pass / Warn / Fail>

Worst offenders: <list or "none">

Remediation hints: <hints only — no camera edits>

Runtime status: Not Run | Attempted | Produced | Verified | Failed

Artifact status: Not Produced | Produced | Verified | Failed (default: Not Produced)

Evidence used: <links, paths, logs, or "none">

Limitations: <gaps>

Next: blender-scene-quality-checker | blender-composition-camera-planner | resolution-aspect-decision | render-export-evidence

```

## Anti-patterns

- Editing the camera inside this skill.

- Inventing values.

- Marking Verified without preview.

- Mixing material / lighting checks here.

## Cross-skill handoff

## Non-goals

- Move or edit the camera (owned by `blender-composition-camera-planner`).

- Lock aspect ratio or resolution (owned by `resolution-aspect-decision`).

- Validate materials (`material-quality-checker`) or lighting (`lighting-quality-checker`).

- Replace broad scene review (`blender-scene-quality-checker`).

- Classify render or export artifact evidence (`render-export-evidence`).

- Run Blender or execute Python.

## References

- `references/composition-rules.md`

- `references/headroom-leadroom-rules.md`

- `references/aspect-ratio-rules.md`

- `../../laws/evidence-before-done.md`

- `../../docs/skill-system.md`