mcp/internal/tools/search_symbols.go

package tools

import (
	"context"

	"code.nochebuena.dev/einherjar/mcp/internal/index"
	"github.com/modelcontextprotocol/go-sdk/mcp"
)

type searchSymbolsInput struct {
	Query  string `json:"query" jsonschema:"text to match against symbol name, doc comment, sub-package, or module"`
	Limit  int    `json:"limit,omitempty" jsonschema:"max results (default 25)"`
	Module string `json:"module,omitempty" jsonschema:"restrict to one module by name"`
	Kind   string `json:"kind,omitempty" jsonschema:"restrict to one kind: type, interface, func, method, const, var"`
}

type searchSymbolsOutput struct {
	Results []index.Symbol `json:"results"`
	Total   int            `json:"total"`
}

func registerSearchSymbols(s *mcp.Server, idx *index.Index) {
	mcp.AddTool(s, &mcp.Tool{
		Name:        "search_symbols",
		Description: "Search Einherjar's exported symbols (types, interfaces, funcs, methods, consts, vars) by name or doc text. Structs also match on a field name, field type, or struct tag (e.g. an env-var key); interfaces also match on a required method. Optionally filter by module or kind. Use when you need to find where a type, function, field, or tag lives.",
	}, func(ctx context.Context, req *mcp.CallToolRequest, args searchSymbolsInput) (*mcp.CallToolResult, searchSymbolsOutput, error) {
		all := idx.SearchSymbols(args.Query, args.Limit*4+25)
		filtered := all[:0]
		for _, sym := range all {
			if args.Module != "" && sym.Module != args.Module {
				continue
			}
			if args.Kind != "" && sym.Kind != args.Kind {
				continue
			}
			filtered = append(filtered, sym)
		}
		limit := args.Limit
		if limit <= 0 {
			limit = 25
		}
		if len(filtered) > limit {
			filtered = filtered[:limit]
		}
		out := searchSymbolsOutput{Results: filtered, Total: len(filtered)}
		return jsonText(out), out, nil
	})
}