nodecode-charts

JP Charts: a bar, line, stacked or share chart drawn as a PNG that reads well on a phone, with every bar and printed number checked against the table before it is returned. A Nodecode rewrite of TakeshiTGAL/hermes-plugin-charts by TakeshiTGAL.

Get it

Tell the agent "add the charts cell", or run nodecode add nc://charts.

Set it up

Nothing is required: the cell is on from the first message and draws at 1080x1350, in the language the data is in, into a charts folder under the agent's home. The charts section of the config refines that - preset (mobile, square or wide), locale (auto, ja or en), and directory for where a chart is written. config.example.jsonc is the section written out.

Use it

Ask for the graph in words ("chart this by prefecture", 「これを使って棒グラフにして」) and the model calls chart_render with the table and a chart spec; the answer carries a Markdown image line, so the picture is in the reply. A model can also call the tools from eval.

chart_render takes data - row objects, columns and rows, pasted CSV/TSV or a Markdown table, JSON text, or an absolute .csv/.tsv/.txt/.json path - and chart_spec with chart_type, unit and source. The unit and the source are always printed, so both are required.
chart_validate reads a table and reports what it makes of it (categories, series, unit, sort, the first rows) without drawing anything.
chart_types says what each type is for, the data formats and the limits: 8 series, 40 bar categories, 30 stacked, 15 share rows, 500 line points.
/charts says what the cell draws; /charts types lists the four types; (help :charts) is the manual the model reads.

data:  { "text": "pref,pop\nTokyo,14178000\nOsaka,8780000" }
spec:  { "chart_type": "bar", "title": "Population", "unit": "people",
         "source": "Statistics Bureau" }

What comes back:

{"success": true, "path": ".../charts/chart-20261110-000614-5c55cc18.png",
 "markdown": "![Bar chart: Population (people). largest Tokyo; smallest Osaka; ...](.../chart-...png)",
 "alt_text": "...", "chart": {"chart_type": "bar", "size_px": [1080, 1350], ...},
 "verification": {"status": "ok", "checked": 6}}

The picture is read back before it is answered: every bar's drawn length is compared with the value it stands for, and every printed number is parsed back out of the image's own text, so a chart that does not match the table is deleted rather than returned. The refusals say where and what next - a missing unit, a pie chart (answered with a share band), a cell that is not a number (named by its row), a date out of order (sorted, and said so).

What a chart carries: bars from zero, a share band that is 100% wide, dates in time order, a bar sorted largest first, one shared scale and one rounding for its numbers, 万/億 (or K/M) compact labels for large numbers, color-blind-safe colors, a note for a top-N cut and for the marks a statistics table uses for no value, and the source under the plot.

Two limits worth knowing: the numbers are drawn in a five-by-seven dot face, so a label in Japanese sets as dots-sized capitals on the picture while alt_text carries the same words in the reply; and a chart is written under the agent's home (charts/) unless the section names a directory.