SCHEMA.md

# Field reference

Field-by-field detail for every file type in this repo. The
[README](README.md) is the overview; this is the part you read when writing a
parser.

---

## 1. `VQA_full/qa_jsons/vqa_NNNNNN_qa.json`

**Encoding gotcha:** the file is a JSON-encoded *string*, so it needs two
decodes — `json.loads(json.load(f))`. A single decode silently hands you a
`str`, not a `dict`.

Top level: `figure`, `plot0`, `VQA`, `vqa_id`.

### 1.1 `figure` — render parameters

| Field | Type | Notes |
|---|---|---|
| `dpi` | int | |
| `base` | int | base figure size before aspect scaling |
| `aspect ratio` | float | width / height |
| `nrows`, `ncols` | int | always `1` in this release |
| `plot style` | str | matplotlib style name, e.g. `seaborn-v0_8-muted` — ground truth for the `plot style` question |
| `color map` | str | e.g. `rainbow_r` — ground truth for `colormap` |
| `title fontsize`, `xlabel fontsize`, `ylabel fontsize`, `xlabel ticks fontsize`, `ylabel ticks fontsize` | int | |
| `plot indexes` | list | grid position of each panel, e.g. `[[0, 0]]` |
| `pixel width`, `pixel height` | int | rendered size; matches the JPEG |
| `figsize` | [float, float] | inches |
| `facecolor` | [r, g, b, a] | 0–1 floats |
| `figure_params` | dict | the fuller randomisation record: panel style, layout pads, `tight_layout`, `flipped font/face colors`, `fontcolor` |
| `font_params` | dict | per-element font sizes plus `csfont` (the chosen font family) |

### 1.2 `plot0` — the panel

| Field | Type | Notes |
|---|---|---|
| `type` | str | `contour` or `image of the sky` |
| `distribution` | str | `random` / `linear` / `gmm` for contour; `gmm` or `sky` for sky images |
| `data` | dict | `xs`, `ys`, `colors`, `data params` — see below |
| `data pixels` | dict | the same data in **pixel** coordinates, under `image` and/or `contour` |
| `data from plot` | dict | values read back off the rendered artists; non-serialisable entries are the string `"non serializable entry"` |
| `color bar` | dict | bounding box `xmin/ymin/xmax/ymax` plus placement `params` |
| `xticks`, `yticks`, `color bar ticks` | list of dict | one per tick: `data` (the label as typeset, LaTeX included), its box, and anchor `tx`/`ty` |
| `square` | dict | bounding box of the plot area itself |
| `title`, `xlabel`, `ylabel` | dict | box plus `words`; `title` is absent when the figure has none |

**Coordinate convention:** boxes are in pixels, origin bottom-left, matching
the rendered JPEG's `pixel width` / `pixel height`. Flip `y` for
image-library conventions with the origin at the top.

#### `plot0.data.data params`

For **synthetic** panels: the generating parameters.

For **real sky** panels (`distribution == "sky"`) it additionally carries:

| Field | Notes |
|---|---|
| `WCS` | `"non serializable entry"` — use the header strings instead |
| `WCS header string` | FITS WCS of the panel **as plotted** |
| `WCS header string (fetched)` | FITS WCS of the cutout **as retrieved** (before resampling) |
| `sky image params` | full provenance — see below |

#### `sky image params` (real sky panels only)

A dict — note it may be stored as its `repr`, in which case
`ast.literal_eval` recovers it.

| Field | Notes |
|---|---|
| `filename` | source FITS name; encodes bibcode, object, survey and cutout size |
| `header` | the original FITS header, verbatim |
| `survey header` | SkyView's survey descriptor |
| `survey` | SkyView category, e.g. `['Optical:DSS class=']` (a list) |
| `object` | resolved object name, e.g. `NAME Cas A`, `M  31` (SIMBAD spacing preserved) |
| `telescope`, `instrument` | often `None` for optical plate surveys |
| `bunit`, `btype` | physical units of the pixel values, e.g. `MJY/SR`, `JY/BEAM`, `K` |
| `pdf` | ADS-style bibcode of the source paper, e.g. `1995ApJS___97__347G` |
| `original img size`, `fetched img size` | pixel dimensions before/after retrieval |
| `resample transform` | how the cutout was resampled onto the panel grid |

### 1.3 `VQA` — the questions

Addressed as `VQA[level][kind][name]`, where `level` is `Level 1` / `Level 2` /
`Level 3` and `kind` is `Figure-level questions` or `Plot-level questions`.

**The two kinds nest differently:**

```
VQA['Level 1']['Figure-level questions']['plot style']           -> entry
VQA['Level 2']['Plot-level questions' ]['mean color']['plot0']   -> entry
                                                      ^^^^^^^^ panel key
```

Plot-level questions are keyed by panel underneath the question name. Every
figure here is single-panel, so the extra level is easy to miss; code that
omits it gets a `dict` where it expected a question. Detect by testing for the
`Q` key rather than by assuming depth:

```python
def question_entries(node):
    if 'Q' in node:
        yield None, node
    else:
        for panel, entry in node.items():
            yield panel, entry
```

A question **entry**:

| Field | Notes |
|---|---|
| `Q` | the assembled prompt: `persona + context + question + format` |
| `A` | **ground truth**. In the qa jsons this is *always* a one-key `dict`, e.g. `{"plot style": "seaborn-v0_8-muted"}`. (It is **not** always a dict in the run pickles — see §3.) |
| `persona` | system framing |
| `context` | scene-setting, and the multiple-choice list when one is offered |
| `question` | the question alone, without persona/context/format |
| `format` | the requested answer shape, e.g. `{"plot style":""}` |

**Parse `format` rather than hard-coding key names.** It states the exact JSON
key the model was asked to fill, so extraction can never drift from the prompt:

```python
def expected_key(fmt):
    if not fmt or '{' not in fmt:
        return None
    inner = fmt.split('{', 1)[1].split('}', 1)[0]
    return inner.split(':', 1)[0].strip().strip('"\'') if ':' in inner else None
```

Question counts: **21** per contour figure, **25** per sky figure. The
difference is the plot-level set — contour figures get x/y axis limits, colour
statistics and two distribution questions; sky figures get RA/Dec limits and
units, epoch, angular field size, colour statistics, provenance and pixel
scale.

---

## 2. `VQA_full/imgs/vqa_NNNNNN.jpeg`

JPEG, RGB, one per record, filename matching the `vqa_id`. Dimensions vary per
figure (roughly 2000–2700 px wide) and always equal `figure['pixel width']` x
`figure['pixel height']`.

---

## 3. `LMM_outputs_n255*/MODEL/vqa_NNNNNN_qa.pickle`

A 2-tuple: `(qa_list, model_id)`.

- `qa_list` — one dict per question asked of that figure, in ask order
- `model_id` — the exact model string used, e.g. `gpt-5.4-nano-2026-03-17`

### Entry fields, present for every model

| Field | Notes |
|---|---|
| `Q`, `persona`, `context`, `question`, `format` | copied verbatim from the qa json |
| `A` | ground truth, but **reshaped**: a `dict` for figure-level questions, unwrapped to a bare `str` or `float` for plot-level ones (see below) |
| `Level`, `type` | which level and kind the question came from |
| `reasoning` | the appended instruction asking for a separate explanation JSON |
| `prompt` | the full text sent to the API, including the reasoning instruction |
| `raw answer` | **the model's response, verbatim** — parse this |
| `Response`, `Response String` | the same text after light handling |

#### Ground-truth shape differs from the qa json

The qa json stores every `A` as a one-key dict. The runs unwrapped the
plot-level ones when assembling prompts, so in the pickles:

| Question kind | `A` type | Example |
|---|---|---|
| Figure-level (plot style, colormap, titles, labels, ticks, plot type) | `dict` | `{'plot style': 'seaborn-v0_8-muted'}` |
| Plot-level, categorical (epoch, finest unit, contour style, distribution) | `str` | `'gaussian mixture model'` |
| Plot-level, numeric (axis limits, colour stats, field size, pixel scale) | `float` | `-16.47` |

Two exceptions to keep in mind:

- **RA axis limits are `str`, not `float`** — they are sexagesimal, e.g.
  `'18h52m45.57s'`. Dec limits *are* floats, in degrees. Do not assume the two
  coordinate axes parse the same way.
- **Tick-value answers are lists, and double-nested**: `A` is
  `{'xtick values': [[label, label, ...]]}` — a list containing one list of
  tick labels, each a typeset string with LaTeX intact
  (`'18$\\mathregular{^h}$52$\\mathregular{^m}$'`). Unwrapping once gets you
  the inner list, which is the answer; these questions are not scalar-valued.

Each question is internally consistent in its type, so you can key the expected
shape off the question — but do not assume dict:

```python
def ground_truth(entry):
    a = entry.get('A')
    if isinstance(a, dict):
        a = next(iter(a.values()), None)
    return a[0] if isinstance(a, list) and a else a
```

### Provider-specific extras

| Field | Present for |
|---|---|
| `fac` | GPT — image downscale factor applied before sending |
| `usage` | Claude, Gemini — token accounting |
| `system prompt` | Claude, Gemini |
| `Response (raw)` | Gemini — the untouched SDK payload |

### Unpickling without the vendor SDKs

The pickles embed the provider's own response object, so a plain
`pickle.load` needs `anthropic` / `google-genai` importable. Every field listed
above is a plain string, so unknown classes can be stubbed:

```python
import pickle

class _Stub:
    def __init__(self, *a, **k): pass
    def __setstate__(self, s): self.__dict__.update(s if isinstance(s, dict) else {})

class TolerantUnpickler(pickle.Unpickler):
    def find_class(self, module, name):
        try:
            return super().find_class(module, name)
        except (ImportError, AttributeError):
            return type(name, (_Stub,), {})

with open(path, 'rb') as f:
    qa_list, model_id = TolerantUnpickler(f).load()
```

### Parsing a response

Responses are two JSON objects back to back — the answer, then the
explanation — and models are not reliable about it. Observed in these runs:
the requested key renamed (`plot_types` for `plot types`), trailing commas,
single quotes, unescaped LaTeX backslashes, mismatched braces, fenced code
blocks, and answer and explanation merged into one object.

A robust reader should: strip code fences; extract balanced `{...}` objects;
match the key from `format` up to spacing, underscores and case; treat the
non-`explanation` value as the answer if the key is absent entirely; and
distinguish "no answer recoverable" from "wrong answer". About 0.14% of
responses (48 of 36,210) yield no answer at all.

---

## 4. `LMM_outputs_n255_archive_light/archive_manifest.json`

`{vqa_id: recipe}` for all 255 aged figures. The identical recipe is also
written per figure as `MODEL/vqa_NNNNNN_qa_archive.json`.

| Field | Notes |
|---|---|
| `preset` | `"archive-light"` |
| `base_seed` | run-wide seed (`20260914`) |
| `seed` | this figure's seed, derived from its id — the reason all three models saw the same aged image |
| `effects` | effect names that fired, in order |
| `effects_by_phase` | the same, split into `ink`, `paper`, `post` |
| `grayscale` | whether this figure was converted to gray |
| `gray_prob` | the probability used for that draw (`0.6667`) |
| `page background` | RGB of the simulated paper |

`aged_imgs/vqa_NNNNNN.jpeg` holds the resulting images — the exact bytes sent
to the models. Re-running the aging is unnecessary.