KosmoKrator

rendering

Vega-Lite MCP Integration for LangGraph

Connect Vega-Lite to LangGraph through the local KosmoKrator MCP gateway with scoped tools, credentials, and write policy.

1 functions 0 read 1 write No credentials auth
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Connect Vega-Lite to LangGraph

Run KosmoKrator integration calls from LangGraph nodes while preserving local credentials and permissions.

Use a graph node that calls the KosmoKrator CLI for deterministic steps or an MCP client for dynamic tool selection. The gateway is local, scoped to this integration, and starts with --write=deny so LangGraph can inspect read-capable tools without receiving write access by default.

Vega-Lite MCP Config for LangGraph

Headless CLI calls fit repeatable graph edges; MCP fits exploratory agent nodes.

{
  "mcpServers": {
    "kosmokrator-vegalite": {
      "type": "stdio",
      "command": "kosmo",
      "args": [
        "mcp:serve",
        "--integration=vegalite",
        "--write=deny"
      ]
    }
  }
}

Run the Gateway Manually

kosmokrator mcp:serve --integration=vegalite --write=deny

Why Use KosmoKrator Here

Scoped tools

Expose only Vega-Lite instead of a broad multi-service tool list.

Local credentials

Reuse credentials already configured for the KosmoKrator CLI and Lua runtime.

Write policy

Start read-only, then opt into ask or allow for trusted workspaces.

Vega-Lite Tools Visible to LangGraph

LangGraph sees stable MCP tool names generated from the Vega-Lite integration catalog.

MCP toolSource functionTypeDescription
integration__vegalite__render_vegalite vegalite.render_vegalite Write Render a Vega-Lite visualization to a PNG image. Pass a complete Vega-Lite JSON specification and get back a markdown image embed. IMPORTANT: Always use inline data with "data": {"values": [...]}. Never use "data": {"url": "..."}. Example spec: { "$schema": "https://vega.github.io/schema/vega-lite/v5.json", "data": {"values": [ {"category": "A", "value": 28}, {"category": "B", "value": 55}, {"category": "C", "value": 43} ]}, "mark": "bar", "encoding": { "x": {"field": "category", "type": "nominal"}, "y": {"field": "value", "type": "quantitative"} } } Supported mark types: bar, line, point, area, rect, circle, square, arc, text, tick, rule, trail, boxplot. Always include "type" in encoding channels: "quantitative", "nominal", "ordinal", or "temporal".

Related Vega-Lite Pages

Vega-Lite CLIUse direct JSON commands instead of MCP discovery. Vega-Lite MCPFull gateway reference and MCP tool names. KosmoKrator for LangGraphClient-level gateway setup.