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ChartAnt

by net.chartant
OverviewDiscussionsAdmin

Generate Column Chart

generate_column_chart
Read-onlyIdempotent

Draw a vertical column chart to compare values across categories or periods (sales by quarter, users by plan). Data [{category, value, group?}]; set group true for side-by-side series or stack true to stack them. For long labels or rankings use generate_bar_chart. Returns a hosted PNG link, a share page, alt text and editable PowerPoint/Excel links.

Tool call template

Replace each placeholder with a value matching the input schema. Only required parameters are included; add optional parameters as needed.

{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "arguments": {
      "data": "<data>"
    },
    "name": "generate_column_chart"
  }
}

Input Schema

NameRequiredDescriptionDefault
dataYesData for column chart, such as, [{ category: 'Category A', value: 10 }, { category: 'Category B', value: 20 }], when grouping or stacking is needed for column, the data should contain a 'group' field, such as, [{ category: 'Beijing', value: 825, group: 'Gas Car' }, { category: 'Beijing', value: 1000, group: 'Electric Car' }].
groupNoWhether grouping is enabled. When enabled, column charts require a 'group' field in the data. When `group` is true, `stack` should be false.
stackNoWhether stacking is enabled. When enabled, column charts require a 'group' field in the data. When `stack` is true, `group` should be false.
styleNoStyle configuration for the chart with a JSON object, optional.
themeNoSet the theme for the chart, optional, default is 'default'.default
titleNoSet the title of chart.
widthNoSet the width of chart, default is 600.
heightNoSet the height of chart, default is 400.
animatedNotrue for an animated GIF (bars grow, lines draw, pies sweep open) instead of a still PNG; for email, slides and chat posts. The first frame is the finished chart.
axisXTitleNoSet the x-axis title of chart.
axisYTitleNoSet the y-axis title of chart.
brandThemeNoName of a brand theme saved on the user's account (their colours and footer), only when the user asks for their theme. Or "colorblind" for colours that people with colour-vision deficiency can tell apart (anyone can use it).

Schema Changelog

Changes observed during successful MCP inspections.

  1. First observed

TDQS

A4.3/5.0
Behavior4/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare readOnly/idempotent/non-destructive, so the bar is lower, and the description adds genuinely new context: the tool returns a hosted PNG link, a share page, alt text and editable PowerPoint/Excel links. That return contract is disclosed nowhere else since there is no output schema. Minor gap: it doesn't clarify that the hosted artifact persists or how the share page is authorized.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness4/5

Is the description appropriately sized, front-loaded, and free of redundancy?

Four tightly packed sentences, front-loaded with purpose and immediately followed by the data contract, alternative and return values. Dense but nearly every clause earns its place; only the parenthetical examples are mildly redundant.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness4/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a 12-parameter generation tool with no output schema, the description covers purpose, data shape, sibling routing and the full return artifact set, which is what an agent needs to call it. Style/theme/size/brandTheme options are left entirely to the schema, which is acceptable given 100% coverage but means the description isn't exhaustive.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema coverage is 100%, so all 12 parameters are already documented; baseline 3 applies. The description restates the data shape and the group/stack intent, which is useful summarization but adds no format or syntax detail beyond the schema's own field descriptions.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

States a specific verb and resource ('Draw a vertical column chart') plus the comparison purpose, with concrete examples ('sales by quarter, users by plan'). It also names the sibling it is not (generate_bar_chart), so an agent can distinguish it without opening another schema.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines5/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

Gives a positive usage condition (comparing values across categories or periods) and an explicit alternative with the selecting condition ('For long labels or rankings use generate_bar_chart'). The routing decision is fully determined.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

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