bd6ffe3b4c
Add an example that demonstrates how to customize a nested type schema, which is a recurring problem for our users (see #467). Fixes #467 Updates #368
93 lines
2.5 KiB
Go
93 lines
2.5 KiB
Go
// Copyright 2025 The Go MCP SDK Authors. All rights reserved.
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// Use of this source code is governed by an MIT-style
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// license that can be found in the LICENSE file.
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package mcp_test
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import (
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"context"
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"encoding/json"
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"fmt"
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"log"
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"time"
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"github.com/google/jsonschema-go/jsonschema"
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"github.com/modelcontextprotocol/go-sdk/mcp"
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)
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func ExampleAddTool_customTypeSchema() {
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// Sometimes when you want to customize the input or output schema for a
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// tool, you need to customize the schema of a single helper type that's used
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// in several places.
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//
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// For example, suppose you had a type that marshals/unmarshals like a
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// time.Time, and that type was used multiple times in your tool input.
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type MyDate struct {
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time.Time
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}
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type Input struct {
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Query string `json:"query,omitempty"`
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Start MyDate `json:"start,omitempty"`
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End MyDate `json:"end,omitempty"`
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}
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// In this case, you can use jsonschema.For along with jsonschema.ForOptions
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// to customize the schema inference for your custom type.
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inputSchema, err := jsonschema.For[Input](&jsonschema.ForOptions{
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TypeSchemas: map[any]*jsonschema.Schema{
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MyDate{}: {Type: "string"},
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},
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})
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if err != nil {
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log.Fatal(err)
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}
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server := mcp.NewServer(&mcp.Implementation{Name: "server", Version: "v0.0.1"}, nil)
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toolHandler := func(context.Context, *mcp.CallToolRequest, Input) (*mcp.CallToolResult, any, error) {
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panic("not implemented")
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}
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mcp.AddTool(server, &mcp.Tool{Name: "my_tool", InputSchema: inputSchema}, toolHandler)
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ctx := context.Background()
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session, err := connect(ctx, server) // create an in-memory connection
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if err != nil {
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log.Fatal(err)
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}
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defer session.Close()
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for t, err := range session.Tools(ctx, nil) {
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if err != nil {
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log.Fatal(err)
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}
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schemaJSON, err := json.MarshalIndent(t.InputSchema, "", "\t")
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if err != nil {
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log.Fatal(err)
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}
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fmt.Println(t.Name, string(schemaJSON))
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}
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// Output:
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// my_tool {
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// "type": "object",
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// "properties": {
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// "end": {
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// "type": "string"
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// },
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// "query": {
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// "type": "string"
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// },
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// "start": {
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// "type": "string"
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// }
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// },
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// "additionalProperties": false
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// }
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}
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func connect(ctx context.Context, server *mcp.Server) (*mcp.ClientSession, error) {
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t1, t2 := mcp.NewInMemoryTransports()
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if _, err := server.Connect(ctx, t1, nil); err != nil {
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return nil, err
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}
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client := mcp.NewClient(&mcp.Implementation{Name: "client", Version: "v0.0.1"}, nil)
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return client.Connect(ctx, t2, nil)
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}
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