ShaderMcp 0.1.1

ShaderMcp

Native MCP server and CLI for creating and testing deterministic Skia RuntimeEffect fragment shaders.

The runner does not use a browser, WebGL, Playwright, Puppeteer, HTML canvas, or a DOM rendering path. It compiles SkSL with SkiaSharp, renders offscreen to PNG, passes deterministic uniforms, supplies a known input texture, and returns structured diagnostics.

Shader Contract

Shader source defines fragmentMain:

half4 fragmentMain(float2 fragCoord, float2 uv) {
    return half4(uv.x, uv.y, 0.5, 1.0);
}

Built-ins injected by the runner:

• uniform float2 resolution
• uniform float time
• uniform float frame
• uniform float2 pointer
• uniform shader inputTexture
• manifest parameters as uniform float4 <name>

CLI

Install from NuGet:

dotnet tool install --global ShaderMcp
shader-mcp --help

Run once without installing globally:

dotnet dnx ShaderMcp --yes -- --help

Local development:

dotnet run --project src/ShaderMcp.Tool -- validate --source samples/gradient.sksl
dotnet run --project src/ShaderMcp.Tool -- render --source samples/gradient.sksl --out artifacts/gradient.png --width 512 --height 512 --time 0.25
dotnet run --project src/ShaderMcp.Tool -- sequence --source samples/gradient.sksl --out-dir artifacts/gradient-sequence --frames 12 --time-step 0.083333

MCP

Run the tool with no CLI args for stdio MCP mode:

[mcp_servers.shader-mcp]
command = "dotnet"
args = ["dnx", "ShaderMcp", "--yes"]

For local development:

[mcp_servers.shader-mcp]
command = "dotnet"
args = ["run", "--project", "/home/jmn/Repos/ShaderMcp/src/ShaderMcp.Tool"]

By default, MCP mode stores shaders and render artifacts under the user data folder, for example ~/.local/share/ShaderMcp on Linux. Set SHADER_MCP_WORKSPACE=/path/to/workspace to use a project-local or disposable workspace explicitly.

Main tools:

• create_shader
• update_shader
• validate_shader
• render_shader
• render_shader_sequence
• run_shader_tests
• instructions(page="tools")

License

Licensed under CC BY-NC 4.0. Attribution is required and commercial use is not permitted without separate permission.