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mcp: update to jsonschema that does not validate structs (#511)

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Update to the latest jsonschema commit, which removes the ability to
validate structs and changes the type of ForOptions.TypeSchemas.
This commit is contained in:
Jonathan Amsterdam 2025-09-22 15:28:04 -04:00 • committed by GitHub
commit 33ff851ef3
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GPG key ID: B5690EEEBB952194
11 changed files with 107 additions and 45 deletions
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6
docs/server.md
View file

@ -364,9 +364,9 @@ the `Tool.InputSchema` explicitly:
```go
// Distinguished Go types allow custom schemas to be reused during inference.
customSchemas := map[any]*jsonschema.Schema{
Probability(0): {Type: "number", Minimum: jsonschema.Ptr(0.0), Maximum: jsonschema.Ptr(1.0)},
WeatherType(""): {Type: "string", Enum: []any{Sunny, PartlyCloudy, Cloudy, Rainy, Snowy}},
customSchemas := map[reflect.Type]*jsonschema.Schema{
reflect.TypeFor[Probability](): {Type: "number", Minimum: jsonschema.Ptr(0.0), Maximum: jsonschema.Ptr(1.0)},
reflect.TypeFor[WeatherType](): {Type: "string", Enum: []any{Sunny, PartlyCloudy, Cloudy, Rainy, Snowy}},
}
opts := &jsonschema.ForOptions{TypeSchemas: customSchemas}
in, err := jsonschema.For[WeatherInput](opts)

2
examples/server/auth-middleware/go.mod
View file

@ -8,7 +8,7 @@ require (
)
require (
github.com/google/jsonschema-go v0.2.3 // indirect
github.com/google/jsonschema-go v0.3.0 // indirect
github.com/yosida95/uritemplate/v3 v3.0.2 // indirect
)

4
examples/server/auth-middleware/go.sum
View file

@ -2,8 +2,8 @@ github.com/golang-jwt/jwt/v5 v5.2.2 h1:Rl4B7itRWVtYIHFrSNd7vhTiz9UpLdi6gZhZ3wEeD
github.com/golang-jwt/jwt/v5 v5.2.2/go.mod h1:pqrtFR0X4osieyHYxtmOUWsAWrfe1Q5UVIyoH402zdk=
github.com/google/go-cmp v0.7.0 h1:wk8382ETsv4JYUZwIsn6YpYiWiBsYLSJiTsyBybVuN8=
github.com/google/go-cmp v0.7.0/go.mod h1:pXiqmnSA92OHEEa9HXL2W4E7lf9JzCmGVUdgjX3N/iU=
github.com/google/jsonschema-go v0.2.3 h1:dkP3B96OtZKKFvdrUSaDkL+YDx8Uw9uC4Y+eukpCnmM=
github.com/google/jsonschema-go v0.2.3/go.mod h1:r5quNTdLOYEz95Ru18zA0ydNbBuYoo9tgaYcxEYhJVE=
github.com/google/jsonschema-go v0.3.0 h1:6AH2TxVNtk3IlvkkhjrtbUc4S8AvO0Xii0DxIygDg+Q=
github.com/google/jsonschema-go v0.3.0/go.mod h1:r5quNTdLOYEz95Ru18zA0ydNbBuYoo9tgaYcxEYhJVE=
github.com/yosida95/uritemplate/v3 v3.0.2 h1:Ed3Oyj9yrmi9087+NczuL5BwkIc4wvTb5zIM+UJPGz4=
github.com/yosida95/uritemplate/v3 v3.0.2/go.mod h1:ILOh0sOhIJR3+L/8afwt/kE++YT040gmv5BQTMR2HP4=
golang.org/x/tools v0.34.0 h1:qIpSLOxeCYGg9TrcJokLBG4KFA6d795g0xkBkiESGlo=

2
examples/server/rate-limiting/go.mod
View file

@ -8,7 +8,7 @@ require (
)
require (
github.com/google/jsonschema-go v0.2.3 // indirect
github.com/google/jsonschema-go v0.3.0 // indirect
github.com/yosida95/uritemplate/v3 v3.0.2 // indirect
)

4
examples/server/rate-limiting/go.sum
View file

@ -1,7 +1,7 @@
github.com/google/go-cmp v0.7.0 h1:wk8382ETsv4JYUZwIsn6YpYiWiBsYLSJiTsyBybVuN8=
github.com/google/go-cmp v0.7.0/go.mod h1:pXiqmnSA92OHEEa9HXL2W4E7lf9JzCmGVUdgjX3N/iU=
github.com/google/jsonschema-go v0.2.3 h1:dkP3B96OtZKKFvdrUSaDkL+YDx8Uw9uC4Y+eukpCnmM=
github.com/google/jsonschema-go v0.2.3/go.mod h1:r5quNTdLOYEz95Ru18zA0ydNbBuYoo9tgaYcxEYhJVE=
github.com/google/jsonschema-go v0.3.0 h1:6AH2TxVNtk3IlvkkhjrtbUc4S8AvO0Xii0DxIygDg+Q=
github.com/google/jsonschema-go v0.3.0/go.mod h1:r5quNTdLOYEz95Ru18zA0ydNbBuYoo9tgaYcxEYhJVE=
github.com/yosida95/uritemplate/v3 v3.0.2 h1:Ed3Oyj9yrmi9087+NczuL5BwkIc4wvTb5zIM+UJPGz4=
github.com/yosida95/uritemplate/v3 v3.0.2/go.mod h1:ILOh0sOhIJR3+L/8afwt/kE++YT040gmv5BQTMR2HP4=
golang.org/x/time v0.12.0 h1:ScB/8o8olJvc+CQPWrK3fPZNfh7qgwCrY0zJmoEQLSE=

79
examples/server/toolschemas/main.go
View file

@ -54,27 +54,72 @@ func (t *manualGreeter) greet(_ context.Context, req *mcp.CallToolRequest) (*mcp
// Handle the parsing and validation of input and output.
//
// Note that errors here are treated as tool errors, not protocol errors.
// First, unmarshal to a map[string]any and validate.
if err := unmarshalAndValidate(req.Params.Arguments, t.inputSchema); err != nil {
return errf("invalid input: %v", err), nil
}
// Now unmarshal again to input.
var input Input
if err := json.Unmarshal(req.Params.Arguments, &input); err != nil {
return errf("failed to unmarshal arguments: %v", err), nil
}
if err := t.inputSchema.Validate(input); err != nil {
return errf("invalid input: %v", err), nil
}
output := Output{Greeting: "Hi " + input.Name}
if err := t.outputSchema.Validate(output); err != nil {
return errf("tool produced invalid output: %v", err), nil
}
outputJSON, err := json.Marshal(output)
if err != nil {
return errf("output failed to marshal: %v", err), nil
}
//
if err := unmarshalAndValidate(outputJSON, t.outputSchema); err != nil {
return errf("invalid output: %v", err), nil
}
return &mcp.CallToolResult{
Content: []mcp.Content{&mcp.TextContent{Text: string(outputJSON)}},
StructuredContent: output,
}, nil
}
// unmarshalAndValidate unmarshals data to a map[string]any, then validates that against res.
func unmarshalAndValidate(data []byte, res *jsonschema.Resolved) error {
var m map[string]any
if err := json.Unmarshal(data, &m); err != nil {
return err
}
return res.Validate(m)
}
var (
inputSchema = &jsonschema.Schema{
Type: "object",
Properties: map[string]*jsonschema.Schema{
"name": {Type: "string", MaxLength: jsonschema.Ptr(10)},
},
}
outputSchema = &jsonschema.Schema{
Type: "object",
Properties: map[string]*jsonschema.Schema{
"greeting": {Type: "string"},
},
}
)
func newManualGreeter() (*manualGreeter, error) {
resIn, err := inputSchema.Resolve(nil)
if err != nil {
return nil, err
}
resOut, err := outputSchema.Resolve(nil)
if err != nil {
return nil, err
}
return &manualGreeter{
inputSchema: resIn,
outputSchema: resOut,
}, nil
}
func main() {
server := mcp.NewServer(&mcp.Implementation{Name: "greeter"}, nil)
@ -90,27 +135,7 @@ func main() {
//
// We don't need to do all this work: below, we use jsonschema.For to start
// from the default schema.
var (
manual manualGreeter
err error
)
inputSchema := &jsonschema.Schema{
Type: "object",
Properties: map[string]*jsonschema.Schema{
"name": {Type: "string", MaxLength: jsonschema.Ptr(10)},
},
}
manual.inputSchema, err = inputSchema.Resolve(nil)
if err != nil {
log.Fatal(err)
}
outputSchema := &jsonschema.Schema{
Type: "object",
Properties: map[string]*jsonschema.Schema{
"greeting": {Type: "string"},
},
}
manual.outputSchema, err = outputSchema.Resolve(nil)
manual, err := newManualGreeter()
if err != nil {
log.Fatal(err)
}

31
examples/server/toolschemas/main_test.go Normal file
View file

@ -0,0 +1,31 @@
// Copyright 2025 The Go MCP SDK Authors. All rights reserved.
// Use of this source code is governed by an MIT-style
// license that can be found in the LICENSE file.
package main
import (
"context"
"encoding/json"
"testing"
"github.com/modelcontextprotocol/go-sdk/mcp"
)
func TestGreet(t *testing.T) {
manual, err := newManualGreeter()
if err != nil {
t.Fatal(err)
}
res, err := manual.greet(context.Background(), &mcp.CallToolRequest{
Params: &mcp.CallToolParamsRaw{
Arguments: json.RawMessage(`{"name": "Bob"}`),
},
})
if err != nil {
t.Fatal(err)
}
if res.IsError {
t.Fatalf("tool error: %q", res.Content[0].(*mcp.TextContent).Text)
}
}

2
go.mod
View file

@ -5,7 +5,7 @@ go 1.23.0
require (
github.com/golang-jwt/jwt/v5 v5.2.2
github.com/google/go-cmp v0.7.0
github.com/google/jsonschema-go v0.2.3
github.com/google/jsonschema-go v0.3.0
github.com/yosida95/uritemplate/v3 v3.0.2
golang.org/x/tools v0.34.0
)

4
go.sum
View file

@ -4,6 +4,10 @@ github.com/google/go-cmp v0.7.0 h1:wk8382ETsv4JYUZwIsn6YpYiWiBsYLSJiTsyBybVuN8=
github.com/google/go-cmp v0.7.0/go.mod h1:pXiqmnSA92OHEEa9HXL2W4E7lf9JzCmGVUdgjX3N/iU=
github.com/google/jsonschema-go v0.2.3 h1:dkP3B96OtZKKFvdrUSaDkL+YDx8Uw9uC4Y+eukpCnmM=
github.com/google/jsonschema-go v0.2.3/go.mod h1:r5quNTdLOYEz95Ru18zA0ydNbBuYoo9tgaYcxEYhJVE=
github.com/google/jsonschema-go v0.2.4-0.20250922144851-e08864c65371 h1:e1VCqWtKpTYBOBhPcgGV5whTlMFpTbH5Ghm56wpxBsk=
github.com/google/jsonschema-go v0.2.4-0.20250922144851-e08864c65371/go.mod h1:r5quNTdLOYEz95Ru18zA0ydNbBuYoo9tgaYcxEYhJVE=
github.com/google/jsonschema-go v0.3.0 h1:6AH2TxVNtk3IlvkkhjrtbUc4S8AvO0Xii0DxIygDg+Q=
github.com/google/jsonschema-go v0.3.0/go.mod h1:r5quNTdLOYEz95Ru18zA0ydNbBuYoo9tgaYcxEYhJVE=
github.com/yosida95/uritemplate/v3 v3.0.2 h1:Ed3Oyj9yrmi9087+NczuL5BwkIc4wvTb5zIM+UJPGz4=
github.com/yosida95/uritemplate/v3 v3.0.2/go.mod h1:ILOh0sOhIJR3+L/8afwt/kE++YT040gmv5BQTMR2HP4=
golang.org/x/tools v0.34.0 h1:qIpSLOxeCYGg9TrcJokLBG4KFA6d795g0xkBkiESGlo=

7
mcp/streamable_bench_test.go
View file

@ -8,6 +8,7 @@ import (
"context"
"net/http"
"net/http/httptest"
"reflect"
"testing"
"github.com/google/jsonschema-go/jsonschema"
@ -17,9 +18,9 @@ import (
func BenchmarkStreamableServing(b *testing.B) {
// This benchmark measures how fast we can handle a single tool on a
// streamable server, including tool validation and stream management.
customSchemas := map[any]*jsonschema.Schema{
Probability(0): {Type: "number", Minimum: jsonschema.Ptr(0.0), Maximum: jsonschema.Ptr(1.0)},
WeatherType(""): {Type: "string", Enum: []any{Sunny, PartlyCloudy, Cloudy, Rainy, Snowy}},
customSchemas := map[reflect.Type]*jsonschema.Schema{
reflect.TypeFor[Probability](): {Type: "number", Minimum: jsonschema.Ptr(0.0), Maximum: jsonschema.Ptr(1.0)},
reflect.TypeFor[WeatherType](): {Type: "string", Enum: []any{Sunny, PartlyCloudy, Cloudy, Rainy, Snowy}},
}
opts := &jsonschema.ForOptions{TypeSchemas: customSchemas}
in, err := jsonschema.For[WeatherInput](opts)

11
mcp/tool_example_test.go
View file

@ -9,6 +9,7 @@ import (
"encoding/json"
"fmt"
"log"
"reflect"
"time"
"github.com/google/jsonschema-go/jsonschema"
@ -34,8 +35,8 @@ func ExampleAddTool_customMarshalling() {
// In this case, you can use jsonschema.For along with jsonschema.ForOptions
// to customize the schema inference for your custom type.
inputSchema, err := jsonschema.For[Input](&jsonschema.ForOptions{
TypeSchemas: map[any]*jsonschema.Schema{
MyDate{}: {Type: "string"},
TypeSchemas: map[reflect.Type]*jsonschema.Schema{
reflect.TypeFor[MyDate](): {Type: "string"},
},
})
if err != nil {
@ -152,9 +153,9 @@ func ExampleAddTool_complexSchema() {
// !+customschemas
// Distinguished Go types allow custom schemas to be reused during inference.
customSchemas := map[any]*jsonschema.Schema{
Probability(0): {Type: "number", Minimum: jsonschema.Ptr(0.0), Maximum: jsonschema.Ptr(1.0)},
WeatherType(""): {Type: "string", Enum: []any{Sunny, PartlyCloudy, Cloudy, Rainy, Snowy}},
customSchemas := map[reflect.Type]*jsonschema.Schema{
reflect.TypeFor[Probability](): {Type: "number", Minimum: jsonschema.Ptr(0.0), Maximum: jsonschema.Ptr(1.0)},
reflect.TypeFor[WeatherType](): {Type: "string", Enum: []any{Sunny, PartlyCloudy, Cloudy, Rainy, Snowy}},
}
opts := &jsonschema.ForOptions{TypeSchemas: customSchemas}
in, err := jsonschema.For[WeatherInput](opts)