ruby-sdk/test/mcp/tool/input_schema_test.rb
Koichi ITO 99cbefc610 Allow $ref in Tool::Schema for protocol version 2025-11-25
`Tool::Schema` rejected `$ref` with an `ArgumentError`.
Earlier MCP spec versions (2024-11-05 through 2025-06-18) did not define
a JSON Schema dialect or reference the `$ref` keyword. `inputSchema` was described
only as "JSON Schema defining expected parameters" with no further constraints:

- https://modelcontextprotocol.io/specification/2024-11-05/server/tools
- https://modelcontextprotocol.io/specification/2025-06-18/server/tools

The MCP spec 2025-11-25 introduced a "JSON Schema Usage" section that adopts
JSON Schema 2020-12 as the default dialect. Since `$ref` is a core keyword in 2020-12,
it is now allowed for protocol version 2025-11-25 and later.

- https://modelcontextprotocol.io/specification/2025-11-25/basic#json-schema-usage
- https://modelcontextprotocol.io/specification/2025-11-25/server/tools
- https://json-schema.org/draft/2020-12/release-notes

For backward compatibility with older protocol versions (2025-06-18 and earlier),
`Server#validate!` continues to raise `ArgumentError` when a tool input schema contains `$ref`.
This preserves the existing behavior for servers targeting those spec versions.
2026-02-27 14:33:36 +09:00

151 lines
6.1 KiB
Ruby

# frozen_string_literal: true
require "test_helper"
module MCP
class Tool
class InputSchemaTest < ActiveSupport::TestCase
test "required arguments are converted to strings" do
input_schema = InputSchema.new(properties: { message: { type: "string" } }, required: [:message])
assert_equal ["message"], input_schema.schema[:required]
end
test "to_h returns a hash representation of the input schema" do
input_schema = InputSchema.new(properties: { message: { type: "string" } }, required: ["message"])
assert_equal(
{ type: "object", properties: { message: { type: "string" } }, required: ["message"] },
input_schema.to_h,
)
end
test "to_h returns a hash representation of the input schema with additionalProperties set to false" do
input_schema = InputSchema.new(properties: { message: { type: "string" } }, required: ["message"], additionalProperties: false)
assert_equal(
{ type: "object", properties: { message: { type: "string" } }, required: ["message"], additionalProperties: false },
input_schema.to_h,
)
end
test "missing_required_arguments returns an array of missing required arguments" do
input_schema = InputSchema.new(properties: { message: { type: "string" } }, required: ["message"])
assert_equal ["message"], input_schema.missing_required_arguments({})
end
test "missing_required_arguments returns an empty array if no required arguments are missing" do
input_schema = InputSchema.new(properties: { message: { type: "string" } }, required: ["message"])
assert_empty input_schema.missing_required_arguments({ message: "Hello, world!" })
end
test "valid schema initialization" do
schema = InputSchema.new(properties: { foo: { type: "string" } }, required: ["foo"])
assert_equal({ type: "object", properties: { foo: { type: "string" } }, required: ["foo"] }, schema.to_h)
end
test "invalid schema raises argument error" do
assert_raises(ArgumentError) do
InputSchema.new(properties: { foo: { type: "invalid_type" } }, required: ["foo"])
end
end
test "schema without required arguments is valid" do
assert_nothing_raised do
InputSchema.new(properties: { foo: { type: "string" } })
end
end
test "validate arguments with valid data" do
schema = InputSchema.new(properties: { foo: { type: "string" } }, required: ["foo"])
assert_nil(schema.validate_arguments({ foo: "bar" }))
end
test "validate arguments with invalid data" do
schema = InputSchema.new(properties: { foo: { type: "string" } }, required: ["foo"])
assert_raises(InputSchema::ValidationError) do
schema.validate_arguments({ foo: 123 })
end
end
test "validate arguments with valid data when additionalProperties set to nil (default)" do
schema = InputSchema.new(properties: { foo: { type: "string" } }, required: ["foo"])
assert_nil(schema.validate_arguments({ foo: "bar", extra: 123 }))
end
test "validate arguments with valid data when additionalProperties set to true (default)" do
schema = InputSchema.new(properties: { foo: { type: "string" } }, required: ["foo"], additionalProperties: true)
assert_nil(schema.validate_arguments({ foo: "bar", extra: 123 }))
end
test "validate arguments with invalid data when additionalProperties set to false" do
schema = InputSchema.new(properties: { foo: { type: "string" } }, required: ["foo"], additionalProperties: false)
assert_raises(InputSchema::ValidationError) do
schema.validate_arguments({ foo: "bar", extra: 123 })
end
end
test "unexpected errors bubble up from validate_arguments" do
schema = InputSchema.new(properties: { foo: { type: "string" } }, required: ["foo"])
JSON::Validator.stub(:fully_validate, ->(*) { raise "unexpected error" }) do
assert_raises(RuntimeError) do
schema.validate_arguments({ foo: "bar" })
end
end
end
test "accepts schemas with $ref references" do
schema = InputSchema.new(
properties: {
foo: { type: "string" },
},
definitions: {
bar: { type: "string" },
},
required: ["foo"],
)
assert_includes schema.to_h.keys, :definitions
end
test "accepts schemas with $ref string key and includes $ref in to_h" do
schema = InputSchema.new({
"properties" => {
"foo" => { "$ref" => "#/definitions/bar" },
},
"definitions" => {
"bar" => { "type" => "string" },
},
})
assert_equal "#/definitions/bar", schema.to_h[:properties][:foo][:$ref]
end
test "accepts schemas with $ref symbol key and includes $ref in to_h" do
schema = InputSchema.new({
properties: {
foo: { :$ref => "#/definitions/bar" },
},
definitions: {
bar: { type: "string" },
},
})
assert_equal "#/definitions/bar", schema.to_h[:properties][:foo][:$ref]
end
test "== compares two input schemas with the same properties, required fields" do
schema1 = InputSchema.new(properties: { foo: { type: "string" } }, required: ["foo"])
schema2 = InputSchema.new(properties: { foo: { type: "string" } }, required: ["foo"])
assert_equal schema1, schema2
schema3 = InputSchema.new(properties: { bar: { type: "string" } }, required: ["bar"])
refute_equal schema1, schema3
schema4 = InputSchema.new(properties: { foo: { type: "string" } }, required: ["bar"])
refute_equal schema1, schema4
schema5 = InputSchema.new(properties: { bar: { type: "string" } }, required: ["foo"])
refute_equal schema1, schema5
schema6 = InputSchema.new(properties: { foo: { type: "string" } }, required: ["foo"], additionalProperties: false)
refute_equal schema1, schema6
end
end
end
end