git:20260918.a67d3f0 to git:20260918.bc2ef40

---

name: illustration-reverse-template

description: "Reverse a reference picture into a style prompt, show the user pictures made from it, revise until they approve, then save it as their template. Use when a user uploads an image style to reuse, asks to extract a prompt from a picture, wants their own image template, asks to train, forge or lock a new illustration style, or asks for more images in the style of a picture they supplied."

---

# Turn a reference picture into the user's own style

Input: images of one style, or a brief when no reference exists. Output: the

user's own style, saved once they have seen what it makes and said it is right.

No reversal is complete. Measurement settles canvas, ground, palette, stroke,

coverage and placement. Medium, drawing and subject convention are read by eye

and are partly wrong on the first pass. The user closes that gap by looking at

pictures, so the path is: reverse, show, revise, save.

Choose among your own candidates without asking — the gate ranks them. Stop

before saving, always: never save a prompt the user has not seen pictures from.

Run every command below from `reverse-template/illustration/`.

## Before anything — a style, or this one picture?

A style makes new pictures: another subject, another scene, the same look. A

picture is one arrangement the user wants back.

For one picture, write the prompt that recreates it and stop. Continue here

only for a style.

## Prerequisites

```bash

python3 -c "import pymupdf" # else: pip install pymupdf

```

## Steps

### 1. Collect the references

Download every `[Web file]` with `okou web download-file`.

The scripts read PNG, JPEG, TIFF, BMP, GIF, JPEG 2000 and Netpbm. They do not

read WebP, AVIF, HEIC or ICO — the formats a phone or a web page hands over.

Convert those before step 2, and keep the original:

```bash

ffmpeg -loglevel error -y -i <ref.webp> <ref.png>

```

Ask for what is missing, and nothing else:

- **intended use** — blog cover, product card, marketing poster, in-app spot

illustration. It decides the canvas and the frame.

- **a slug** — kebab-case, the name the saved style is called by. Propose two

or three from the reference if the user has none.

With no reference at all, write the frame from the brief and go to step 4.

Steps 2 and 3 need pixels.

Three or more references separate a locked axis from a dial. With one, ask for

more; if none arrive, record in `design-system.md` which axes stay unsettled

and give them no range.

Ask for files at least 400px on the short side. Below that the palette fills

with anti-alias blends and the stroke is one pixel wide, so colour and line

describe the downscaling.

### 2. Measure

```bash

python3 scripts/measure_style.py <ref> [<ref> ...] --json style.json

```

Take these numbers over your own reading of the image. The verdict column

decides where each axis goes:

| Verdict | Where it goes |

|---|---|

| `CONSTANT` | the locked frame, as a value |

| `RANGE` | the locked frame, as a range |

| `VARIES` | a dial |

The shared-colour line is the locked palette; every other colour is a palette

dial.

### 3. Read what the numbers cannot reach

Keep two records apart:

- **content** — subject, action, props, setting, placement;

- **style** — how it is drawn, carrying no content noun.

Then delete every subject, object, place and name from the style record. What

remains must still describe a way of drawing; move anything else back to

content.

Write every style line as a drawing instruction that names the near miss it

excludes. A line that only names the family collapses into the nearest common

style — flat vector, cel anime, stock watercolour — whatever the reference

actually was.

| Instead of | Write |

|---|---|

| flat gouache shapes | paint varies in value inside every shape, never a flat digital fill |

| thin dark contour | shapes meet at their colour edges, no outline; only the eyes and leaf veins carry a drawn line |

| botanical motifs | each sprig painted with its own texture and veins, not a single-colour silhouette |

| soft watercolour | wet washes that bloom and granulate; almost nothing in the picture is a flat area |

| closed eyes | heavy lids as grey-shadowed lens shapes under one fine dark line |

State the style under these heads, from the references only:

| Head | State |

|---|---|

| Medium | painted, inked, vector, 3D, collage, print, photographic, mixed |

| Line | the measurement's contour verdict first, then closed or open, uniform or tapered, cap shape |

| Shape | rounded or angular, geometric or organic, how forms simplify |

| Value | flat fill, cel steps and how many, gradient modelling, hatching, wash |

| Colour | what the lead, support and accent each do |

| Texture | brush, grain, paper, halftone, noise — and where it sits |

| Detail | which areas carry detail, which stay plain |

| Light | direction, rim, glow, haze, or no light description at all |

| Composition | crop, weight, repeated shapes, the rhythm every reference keeps |

| Frame | how the art meets the canvas: edge to edge, a vignette, or a visible margin — and how wide |

| Finish | grade, bloom, chromatic shift, fade, print registration |

| Subject convention | face treatment, cast, count, scale, what the subject does |

Then name the dials — what changes from piece to piece. Three to seven. These

carry across styles:

| Dial | What it varies |

|---|---|

| Palette | a hex set, or a named palette family |

| Scene metaphor | the per-piece concept. The scene IS the metaphor — never a generic filing cabinet with relabelled tabs |

| Complexity | L1 single subject / L2 small scene / L3 full vignette |

| Cast | the character in this piece, not a mascot the style is stuck with |

| Props | native to the theme — a crane for construction, a press for publishing |

| Accent marks | the small repeated motif: dots, ticks, sparkles, ink dabs |

| Mood | posture and register, built from what is visible |

### 4. Write the style prompt

Write the prompt first; it is the deliverable. Its first third carries the

locked frame, then the subject, then the dials, then what must not appear.

- **Locked frame** — one line per axis, measured values included. State the

contour width in pixels at the canvas the package delivers, not only as a

percentage: the references are rarely that size. State how much of the sheet

the art covers and whether the ground stays unpainted — without it the model

floods the sheet and the paper stops being a colour.

- **Dials** — one line per dial named in step 3, with the values the

references used and what else the dial may take.

- **Not in the frame** — techniques absent from every reference.

- **Prompt template** — one prompt with a placeholder per dial, opening on the

locked frame.

- **References** — one line per file naming the dial values it demonstrates.

`design-system.md` carries the measurement table per reference, the verdict

table, and the axes a single reference could not settle.

Write the prompt template so the locked frame occupies its first third.

### 5. Generate, measure, choose

```bash

npx --yes --package="${CLI_PKG_URL}" okou generate image --provider built-in \

--raw-prompt "<the style prompt, dials filled in>"

python3 scripts/check_piece.py --refs <ref> [<ref> ...] --piece <generated> [...]

```

Generate three at a time — that is the ceiling on generations in flight —

each on a subject the references do not carry, and each moving a different

dial: another scene metaphor, another complexity level, another palette value.

Three pieces of the same subject show the style sitting still, not flexing.

Keep the ones with the fewest axes outside range. Use the built-in image model;

if it fails for this style, say so and ask how to proceed rather than routing

to another provider.

Read the failing axes: they name what the prompt did not hold. Correct the

prompt and generate again.

Some axes never come back from the prompt. When two rounds do not move one,

stop rewriting and fix it after the fact where that is possible. Scale and

placement on a plain ground is the common one:

```bash

python3 scripts/compose.py --ref <reference> --piece <generated> --out <placed>

```

It scales the drawing's ink box to the fractions the reference measures and

places it at the reference's margins, touching nothing inside the drawing.

Show only pieces the gate passes. When an axis will not come back, keep the

best set and carry that one sentence into step 6.

The check cannot see medium, line quality, shape language, subject conventions,

motif or composition. Look at the kept piece for those before delivering.

### 6. Show the pictures and ask whether the style is right

Put in the reply:

- the pictures as markdown images, one line under each naming its subject and

the dials it moved — "L1, sage palette, single character";

- one line saying these were generated from the style in their reference.

Then ask one question: does this style look right.

This is a yes or no, not a survey. Do not list the axes, do not ask what to

fix, do not offer options. When something still departs from the reference

after step 5 did what it could, say it in one plain sentence — the lines came

out heavier than the reference, the palette runs warmer — and leave it there.

Show the prompt only if the user asks for it.

Stop. Save nothing yet.

### 7. Revise, then show again

The user speaks about the look — the lines are too heavy, it is too colourful,

the faces are wrong. Turn each correction into one line of the locked frame

that names the near miss it excludes, the same form as step 3. Nothing else in

the prompt changes.

Regenerate the set with step 5 and show it again. One round of corrections at a

time; do not bundle two rounds into one reply.

Repeat until the user says it is right.

### 8. Save it as the user's template

Only after the user says the style is right.

```text

<slug>/

SKILL.md frontmatter with the trigger phrases, the locked

frame, the dials, the prompt with its placeholders,

and two or three example briefs

ref-<subject>-<dial>.png the approved pictures

```

## Rules

- Reproduce the references. Do not correct a palette, a proportion or a

stroke you would have drawn differently.

- Present in every reference is locked; present in one is a dial; with a

single reference, neither — say so rather than guessing.

- A technique absent from every reference is part of the locked frame. A

subject or content type absent from them is not a rule.

- Name observable technique, never an artist, studio, brand or product.

- Numbers in the package come from step 2, not from reading the image.

- Step 5 is mandatory. Show pictures you generated, never only a prompt.

- Choose among your own candidates yourself. Do not hand the user a menu of

variations.

- Step 6 stops, and asks one yes-or-no question. Saving before the user has

seen pictures and approved them is the one thing this skill must never do.

- A correction from the user is one more line in the locked frame, not a

rewrite of the prompt.

- Rotate the cast and the scene across a series. A locked frame is not a

locked mascot.

- Use the built-in image model. When it cannot hold a style, say so; do not

route to another provider without asking.

## Troubleshooting

| Symptom | Action |

|---|---|

| Generated pieces repeat the reference's subject | The subject leaked into the style record; run the deletion test in step 3 again and rewrite the prompt template |

| `check_piece.py` fails on line width | Step 2's measurement, not your estimate, goes in the package |

| Generated pieces carry outlines the reference has none of | The measurement said `NO drawn contour`; remove every outline word from the prompt and say shapes meet at their colour edges |

| A generated piece mounts the art inside a paper border | The Frame line is missing or too weak; say the paint reaches all four edges |

| Generated pieces read as flat vector against a painted reference | Flatness under about 60% means paint varies inside each shape; say so, and name what must not be flat |

| Every generated piece looks the same | Too few dials, or the prompt template has no placeholders |

| A colour appears that no reference uses | The palette dial has no list of allowed values |

| Generated pieces flood the whole canvas | The locked frame is missing the ink coverage and the unpainted ground; "vignette" alone does not hold |

| The medium drifts to pencil or crayon | Name the wet behaviour — washes pooling at the stroke edges — and name the media to avoid |

| A generated piece renders on a black ground | It is RGBA with a transparent ground; the scripts composite over white, and so must anything you hand the user |

| The drawing fills the frame however the prompt words it | Two rounds is enough; place it with `compose.py` |

| The check passes but the piece looks wrong | Medium, shape language or subject convention is missing from the locked frame |

| `LOW RES` in the measurement | Ask for a larger file. Keep aspect, ground colour, ink coverage and centring; leave colour and stroke out of the locked frame |

| The reference is a scan or a photograph of a painting | Its hairline border is stepped past, and the ground axis is skipped when the art covers the canvas. Nothing else changes |

| The generator has no canvas at the reference's ratio | Generate at the nearest size and crop centrally to the reference's ratio |

| `unknown image file format` on a reference | It is WebP, AVIF, HEIC or ICO. Convert to PNG with ffmpeg and measure that |

| Background reads as `textured` on a flat style | The reference is a JPEG; re-export as PNG or accept the grain figure it reports |

| One reference only | Record the unsettled axes; do not write ranges you cannot support |

| The user approves without comment on the first showing | Save it. Do not invite more rounds |

| The user asks what could be better | Now name the axes that still fail, two or three, shortest first |

| The user's correction contradicts the reference | Follow the user. Note in the saved file which axis now departs from the reference |

| Two corrections arrive at once | Fold both into the locked frame, regenerate once, show once |