types

types Package

The types package provides shared type definitions used across multiple gh-aw packages to avoid circular dependencies.

Overview

This package defines common data structures that are shared between the parser and workflow packages. Centralizing these types here allows both packages to reference the same definitions without creating import cycles.

Types

BaseMCPServerConfig

The foundational configuration structure for MCP (Model Context Protocol) servers. This type is embedded by both parser.MCPServerConfig and workflow.MCPServerConfig.

MCP servers can run as:

• stdio processes: Command + Args, launched as a child process.
• HTTP endpoints: URL + optional Headers and Auth, reached over HTTP/HTTPS.
• Container services: Container image + optional Mounts, run inside a container.

import "github.com/github/gh-aw/pkg/types"

// Stdio MCP server
cfg := types.BaseMCPServerConfig{
    Type:    "stdio",
    Command: "npx",
    Args:    []string{"-y", "@modelcontextprotocol/server-filesystem"},
    Env: map[string]string{
        "ALLOWED_PATHS": "/workspace",
    },
}

// HTTP MCP server with OIDC auth
cfg := types.BaseMCPServerConfig{
    Type: "http",
    URL:  "https://my-mcp-server.example.com",
    Auth: &types.MCPAuthConfig{
        Type:     "github-oidc",
        Audience: "https://my-mcp-server.example.com",
    },
}

Fields

MCPAuthConfig

Authentication configuration for HTTP MCP servers. When configured, the MCP gateway dynamically acquires tokens and injects them as Authorization headers on each outgoing request.

auth := &types.MCPAuthConfig{
    Type:     "github-oidc", // Currently the only supported type
    Audience: "https://my-service.example.com",
}

TokenWeights

Defines custom model cost information for effective token computation. Specified under engine.token-weights in workflow frontmatter and stored in aw_info.json at runtime.

weights := types.TokenWeights{
    Multipliers: map[string]float64{
        "gpt-4o": 2.5,
    },
    TokenClassWeights: &types.TokenClassWeights{
        Input:  1.0,
        Output: 3.0,
    },
}

TokenClassWeights

Per-token-class weights for effective token computation. Each field corresponds to one token class; a zero value means "use the default weight".

Design Notes

• This package has no dependencies on other gh-aw packages, making it safe to import from anywhere.
• All struct fields use both json and yaml struct tags so they can be round-tripped through both serialization formats.
• BaseMCPServerConfig is designed to be embedded — packages add domain-specific fields and validation on top of the shared base.