Sharpsir Charts

License: MIT

Local, privacy-preserving Chart.js rendering for MCP-compatible agents.

sharpsir-charts-mcp-server turns structured data into PNG, SVG, PDF, or JSON chart outputs. It runs entirely on your machine, returns an inline preview, and defaults to a restrained Sotheby's International Realty-inspired editorial design. The active design can be configured by the calling agent for the current MCP session.

Use it when an AI agent needs beautiful, deterministic, server-side charts for real-estate reporting, executive dashboards, financial analysis, market comparisons, presentations, or print collateral without sending data to a third-party chart service.

Quick start

Clone the repository and build it locally:

git clone https://github.com/gca-ltd/sharpsir-charts-mcp-server.git
cd sharpsir-charts-mcp-server
npm install
npm run build
CHARTS_TRANSPORT=stdio node dist/index.js

The server has no data connector. The caller supplies the data, which keeps rendering private and deterministic.

Features

• Server-side Chart.js rendering with deterministic PNG, SVG, PDF and JSON output.
• Luxury editorial defaults inspired by Sotheby's International Realty, plus Sharp Matrix, mono-print and neutral references.
• Session-scoped design configuration with strict schemas, OKLCH palette ramps, contrast warnings and bundled OFL fonts.
• Inline PNG previews, full-resolution files, configurable public URLs and retention cleanup.
• Local stdio transport or authenticated Streamable HTTP with rate limiting, request limits and concurrency guards.

MCP client configuration

For Cursor, Claude Desktop or another stdio MCP client:

{
  "mcpServers": {
    "sharpsir-charts": {
      "command": "node",
      "args": ["/home/bitnami/sharpsir-charts-mcp-server/dist/index.js"],
      "env": {
        "CHARTS_TRANSPORT": "stdio"
      }
    }
  }
}

For the hosted Streamable HTTP deployment, use the MCP URL https://intranet.sharpsir.group/charts/mcp and send Authorization: Bearer <CHARTS_API_TOKEN>. Never commit the token.

Gallery

Sotheby's-inspired series chart

Editorial KPI card

Sharp Matrix reference

Agent workflow

1. Call a render tool with no design to get a SIR-styled chart immediately.
2. Call get_design to inspect the active design.
3. Call describe_design_schema or get_design_reference when changing the look.
4. Call configure_design, then preview_design to review the result.
5. Render production charts and read the returned warnings.

The design is held in memory per MCP session. It is never written to disk or shared with another caller. The default is sothebys; neutral is available only when an agent explicitly asks for unbranded output.

Tools

Tool	Use
render_series_chart	Bar, line, area, dot, lollipop, dumbbell and slope charts
render_part_to_whole	Small part-to-whole comparisons (pie / doughnut / polar)
render_waterfall	Variance bridges with floating bars
render_bullet	Actual versus target with qualitative bands
render_funnel	Conversion stages with drop-off percentages
render_scatter	Numeric correlation and outliers
render_small_multiples	Shared-scale panels across cuts
render_chart	Advanced Chart.js configurations not covered above
render_kpi_card	Editorial typographic KPI with optional sparkline
render_kpi_row	Two to four KPI cells with hairline dividers
configure_design	Session-wide design configuration
preview_design	Specimen render for visual QA
describe_design_schema	Strict annotated design contract
get_design_reference	SIR, Sharp Matrix, mono-print and neutral references
get_design	Current resolved design
list_fonts	Fonts actually available to the renderer

Every tool has detailed WHAT / WHEN TO USE / INPUTS / RETURNS / CONSTRAINTS / EXAMPLES guidance. Styling belongs in the design system, not in chart data. JavaScript callbacks are not accepted.

Output

PNG is the default and returns a downscaled inline preview plus a full output path or hosted URL. SVG and PDF are vector outputs. JSON returns the resolved Chart.js configuration without an image.

Development

npm run typecheck
npm test
npm run build

See docs/DESIGN-SYSTEM.md, docs/USER_GUIDE.md, and docs/INSTALL.md.

Licence and brand notice

The software is MIT licensed. The sothebys design reference reproduces publicly published affiliate guidance for Sharp SIR; it does not grant rights to Sotheby's International Realty marks. See NOTICE.md.