chart block

This canonical lookup describes the published chart interaction shape, the present renderer support, its return path, and the trust boundary that applies when it is shown to a person.

Type	Contract	Agent may send	Platform may produce	Web renderer	Mobile renderer
chart	Published	Allowed	No documented platform producer.	ChartBlock	ChartBlockView

chart

Allowed

A chart the platform draws from numbers and labels the agent sends: bar, line, pie or scatter.

Return path

None; this is display content. Hovering a point shows its value locally and reports nothing back.

Trust and visibility

Agent-supplied numbers and short labels only. The schema refuses colours, SVG, HTML and code, and every string is drawn as text, so a chart cannot carry markup or a claim of platform authority beyond its own labels.

Stability

Valid ONLY in a final reply; a partial carrying one is refused. A refusal keeps the usual code and names the path plus one reason token: chart_data_key_missing, chart_y_axis_range, chart_pie_negative, chart_scatter_x_not_number or chart_category_too_long. An older client that does not know chart shows the newer-app notice.

Field	Required	Published constraint
type	Yes	literal "chart"
chart_type	Yes	"bar" \| "line" \| "pie" \| "scatter"
meta	No	object { title: string · 0–80 characters · ^[^<>]$, description: string · 0–200 characters · ^[^<>]$, footer: string · 0–200 characters · ^[^<>]*$ }
x_key	Yes	string · ^[a-z][a-z0-9_]{0,39}$
layout	No	"vertical"
series	Yes	array · 1–4 items · items: object { data_key: string · ^[a-z][a-z0-9_]{0,39}$, label: string · 0–40 characters · ^[^<>]$, axis_label: string · 0–40 characters · ^[^<>]$, value_format: "integer" \| "compact" \| "raw", value_prefix: string · 0–40 characters · ^[^<>]$, value_suffix: string · 0–40 characters · ^[^<>]$ }
data	Yes	array · 1–100 items · items: object { }
x_axis_label	No	string · 0–60 characters · ^[^<>]*$
y_axis_min	No	number
y_axis_max	No	number
x_axis_scale	No	"linear"

JSON

{
  "type": "chart",
  "chart_type": "bar",
  "meta": {
    "title": "Fare by month",
    "description": "Cheapest HAN to SGN fare found",
    "footer": "Source: fare search"
  },
  "x_key": "month",
  "series": [
    {
      "data_key": "fare",
      "label": "Fare",
      "axis_label": "Coins",
      "value_format": "integer",
      "value_suffix": " coin"
    }
  ],
  "data": [
    {
      "month": "Jan",
      "fare": 128
    },
    {
      "month": "Feb",
      "fare": 112
    },
    {
      "month": "Mar",
      "fare": 95
    },
    {
      "month": "Apr",
      "fare": 121
    }
  ]
}

Web preview

Fare by monthCheapest HAN to SGN fare found

Source: fare search

	Fare
Jan	128 coin
Feb	112 coin
Mar	95 coin
Apr	121 coin