crush/internal/agent/tools/mcp-tools.go

package tools

import (
	"context"
	"fmt"

	"charm.land/fantasy"
	"github.com/charmbracelet/crush/internal/agent/tools/mcp"
	"github.com/charmbracelet/crush/internal/permission"
)

// GetMCPTools gets all the currently available MCP tools.
func GetMCPTools(permissions permission.Service, wd string) []*Tool {
	var result []*Tool
	for mcpName, tools := range mcp.Tools() {
		for _, tool := range tools {
			result = append(result, &Tool{
				mcpName:     mcpName,
				tool:        tool,
				permissions: permissions,
				workingDir:  wd,
			})
		}
	}
	return result
}

// Tool is a tool from a MCP.
type Tool struct {
	mcpName         string
	tool            *mcp.Tool
	permissions     permission.Service
	workingDir      string
	providerOptions fantasy.ProviderOptions
}

func (m *Tool) SetProviderOptions(opts fantasy.ProviderOptions) {
	m.providerOptions = opts
}

func (m *Tool) ProviderOptions() fantasy.ProviderOptions {
	return m.providerOptions
}

func (m *Tool) Name() string {
	return fmt.Sprintf("mcp_%s_%s", m.mcpName, m.tool.Name)
}

func (m *Tool) MCP() string {
	return m.mcpName
}

func (m *Tool) MCPToolName() string {
	return m.tool.Name
}

func (m *Tool) Info() fantasy.ToolInfo {
	parameters := make(map[string]any)
	required := make([]string, 0)

	if input, ok := m.tool.InputSchema.(map[string]any); ok {
		if props, ok := input["properties"].(map[string]any); ok {
			parameters = props
		}
		if req, ok := input["required"].([]any); ok {
			// Convert []any -> []string when elements are strings
			for _, v := range req {
				if s, ok := v.(string); ok {
					required = append(required, s)
				}
			}
		} else if reqStr, ok := input["required"].([]string); ok {
			// Handle case where it's already []string
			required = reqStr
		}
	}

	return fantasy.ToolInfo{
		Name:        m.Name(),
		Description: m.tool.Description,
		Parameters:  parameters,
		Required:    required,
	}
}

func (m *Tool) Run(ctx context.Context, params fantasy.ToolCall) (fantasy.ToolResponse, error) {
	sessionID := GetSessionFromContext(ctx)
	if sessionID == "" {
		return fantasy.ToolResponse{}, fmt.Errorf("session ID is required for creating a new file")
	}
	permissionDescription := fmt.Sprintf("execute %s with the following parameters:", m.Info().Name)
	p := m.permissions.Request(
		permission.CreatePermissionRequest{
			SessionID:   sessionID,
			ToolCallID:  params.ID,
			Path:        m.workingDir,
			ToolName:    m.Info().Name,
			Action:      "execute",
			Description: permissionDescription,
			Params:      params.Input,
		},
	)
	if !p {
		return fantasy.ToolResponse{}, permission.ErrorPermissionDenied
	}

	content, err := mcp.RunTool(ctx, m.mcpName, m.tool.Name, params.Input)
	if err != nil {
		return fantasy.NewTextErrorResponse(err.Error()), nil
	}
	return fantasy.NewTextResponse(content), nil
}