ruby-sdk/test/mcp/server_progress_test.rb
Koichi ITO bbe637612b Support progress notifications per MCP specification
## Motivation and Context

The MCP specification defines `notifications/progress` for reporting incremental progress
during long-running tool operations. The Ruby SDK did not yet support this, so tools had no way to
send progress updates to clients. This caused the `tools-call-with-progress` conformance test to fail.

This adds an `MCP::ServerContext` wrapper that provides a `report_progress` method on
`server_context`. Tools call `server_context.report_progress(value, total:, message:)` to send
notifications back to the client. The method is a no-op when no `progressToken` was provided,
so tools can call it unconditionally without checking for a token.

This design is consistent with the TypeScript and Python SDKs, which provide progress
reporting through a context object rather than a separate parameter.

On the client side, `Client#call_tool` now accepts a `progress_token:` parameter that sets
`_meta.progressToken` in the request.

Ref: https://modelcontextprotocol.io/specification/latest/server/utilities/progress

## How Has This Been Tested?

Added comprehensive tests in `test/mcp/server_progress_test.rb` covering `notify_progress`,
tool integration with progress, block-defined tools, `**kwargs` tools, and no-op behavior
without a token.

Added client tests for `progress_token:` parameter inclusion and omission.

Added `test/mcp/server_context_test.rb` test for non-Hash `server_context` preservation
when `_meta` is present.

Conformance: `tools-call-with-progress` removed from expected failures.

## Breaking Change

`server_context` is now always an `MCP::ServerContext` instance when passed to tools,
even if the server has no context configured. Code that checks `server_context ?` to
detect a nil context will need to be updated, as `ServerContext` is always truthy.
`ServerContext` delegates method calls to the underlying context object via
`method_missing`, so `server_context[:key]` and other accessor patterns continue to work.

In practice, this is unlikely to affect users. A tool that declares `server_context:`
is opting in to use the context; if the server has no context configured, that is a
server configuration issue rather than something the tool should handle with a nil check.
2026-03-10 01:49:09 +09:00

365 lines
12 KiB
Ruby

# frozen_string_literal: true
require "test_helper"
module MCP
class ServerProgressTest < ActiveSupport::TestCase
class MockTransport < Transport
attr_reader :notifications
def initialize(server)
super
@notifications = []
end
def send_notification(method, params = nil)
@notifications << { method: method, params: params }
true
end
def send_response(response); end
def open; end
def close; end
def handle_request(request); end
end
# Tool without progress parameter.
class SimpleToolWithoutProgress < Tool
tool_name "simple_without_progress"
description "A tool that doesn't use progress"
input_schema(properties: { message: { type: "string" } }, required: ["message"])
class << self
def call(message:)
Tool::Response.new([{ type: "text", text: "SimpleToolWithoutProgress: #{message}" }])
end
end
end
# Tool with progress via server_context.
class ToolWithProgress < Tool
tool_name "tool_with_progress"
description "A tool that uses progress"
input_schema(properties: { message: { type: "string" } }, required: ["message"])
class << self
def call(message:, server_context:)
server_context.report_progress(50, total: 100, message: "halfway")
server_context.report_progress(100, total: 100, message: "done")
Tool::Response.new([{ type: "text", text: "ToolWithProgress: #{message}" }])
end
end
end
# Tool with server_context accessing both context data and progress.
class ToolWithContextAndProgress < Tool
tool_name "tool_with_context_and_progress"
description "A tool that uses both server_context and progress"
input_schema(properties: { message: { type: "string" } }, required: ["message"])
class << self
def call(message:, server_context:)
server_context.report_progress(100)
context_info = server_context[:user] || "none"
Tool::Response.new([{ type: "text", text: "ToolWithContextAndProgress: #{message} context=#{context_info}" }])
end
end
end
# Tool with **kwargs.
class ToolWithKwargs < Tool
tool_name "tool_with_kwargs"
description "A tool that uses **kwargs"
class << self
def call(**kwargs)
context = kwargs[:server_context]
context.report_progress(75)
Tool::Response.new([{ type: "text", text: "ToolWithKwargs: progress=#{context ? "present" : "absent"}" }])
end
end
end
setup do
@server = Server.new(
name: "test_server",
version: "1.0.0",
tools: [SimpleToolWithoutProgress, ToolWithProgress, ToolWithContextAndProgress, ToolWithKwargs],
server_context: { user: "test_user" },
)
@mock_transport = MockTransport.new(@server)
@server.transport = @mock_transport
end
test "#notify_progress sends correct notification through transport with all params" do
@server.notify_progress(progress_token: "token-1", progress: 50, total: 100, message: "halfway")
assert_equal 1, @mock_transport.notifications.size
notification = @mock_transport.notifications.first
assert_equal Methods::NOTIFICATIONS_PROGRESS, notification[:method]
assert_equal "token-1", notification[:params]["progressToken"]
assert_equal 50, notification[:params]["progress"]
assert_equal 100, notification[:params]["total"]
assert_equal "halfway", notification[:params]["message"]
end
test "#notify_progress omits total and message when nil" do
@server.notify_progress(progress_token: "token-1", progress: 50)
assert_equal 1, @mock_transport.notifications.size
notification = @mock_transport.notifications.first
assert_equal Methods::NOTIFICATIONS_PROGRESS, notification[:method]
assert_equal "token-1", notification[:params]["progressToken"]
assert_equal 50, notification[:params]["progress"]
refute notification[:params].key?("total")
refute notification[:params].key?("message")
end
test "#notify_progress does nothing without transport" do
server_without_transport = Server.new(name: "test_server")
assert_nothing_raised do
server_without_transport.notify_progress(progress_token: "token-1", progress: 50)
end
end
test "#notify_progress handles transport errors gracefully" do
error_transport = Class.new(MockTransport) do
def send_notification(method, params = nil)
raise StandardError, "Transport error"
end
end.new(@server)
@server.transport = error_transport
@server.configuration.exception_reporter.expects(:call).once.with do |exception, context|
assert_kind_of StandardError, exception
assert_equal "Transport error", exception.message
assert_equal({ notification: "progress" }, context)
true
end
assert_nothing_raised do
@server.notify_progress(progress_token: "token-1", progress: 50)
end
end
test "tool with progress parameter receives Progress instance and sends notifications via _meta.progressToken" do
request = {
jsonrpc: "2.0",
id: 1,
method: "tools/call",
params: {
name: "tool_with_progress",
arguments: { message: "Hello" },
_meta: { progressToken: "token-abc" },
},
}
response = @server.handle(request)
assert response[:result]
assert_equal "ToolWithProgress: Hello", response[:result][:content][0][:text]
assert_equal 2, @mock_transport.notifications.size
first = @mock_transport.notifications[0]
assert_equal Methods::NOTIFICATIONS_PROGRESS, first[:method]
assert_equal "token-abc", first[:params]["progressToken"]
assert_equal 50, first[:params]["progress"]
assert_equal 100, first[:params]["total"]
assert_equal "halfway", first[:params]["message"]
second = @mock_transport.notifications[1]
assert_equal Methods::NOTIFICATIONS_PROGRESS, second[:method]
assert_equal "token-abc", second[:params]["progressToken"]
assert_equal 100, second[:params]["progress"]
assert_equal 100, second[:params]["total"]
assert_equal "done", second[:params]["message"]
end
test "tool without progress parameter works normally" do
request = {
jsonrpc: "2.0",
id: 1,
method: "tools/call",
params: {
name: "simple_without_progress",
arguments: { message: "Hello" },
},
}
response = @server.handle(request)
assert response[:result]
assert_equal "SimpleToolWithoutProgress: Hello", response[:result][:content][0][:text]
assert_equal 0, @mock_transport.notifications.size
end
test "server_context.report_progress is a no-op when no progressToken in request" do
received_context = :unset
tool_class = Class.new(Tool) do
tool_name "progress_nil_tool"
define_singleton_method(:call) do |server_context:|
received_context = server_context
Tool::Response.new([{ type: "text", text: "done" }])
end
end
server = Server.new(
name: "test_server",
tools: [tool_class],
server_context: { user: "test" },
)
server.transport = @mock_transport
request = {
jsonrpc: "2.0",
id: 1,
method: "tools/call",
params: {
name: "progress_nil_tool",
arguments: {},
},
}
server.handle(request)
assert_instance_of ServerContext, received_context
assert_nothing_raised { received_context.report_progress(50) }
assert_equal 0, @mock_transport.notifications.size
end
test "tool with both server_context and progress receives both" do
request = {
jsonrpc: "2.0",
id: 1,
method: "tools/call",
params: {
name: "tool_with_context_and_progress",
arguments: { message: "Hello" },
_meta: { progressToken: "token-xyz" },
},
}
response = @server.handle(request)
assert response[:result]
assert_equal "ToolWithContextAndProgress: Hello context=test_user", response[:result][:content][0][:text]
assert_equal 1, @mock_transport.notifications.size
notification = @mock_transport.notifications.first
assert_equal Methods::NOTIFICATIONS_PROGRESS, notification[:method]
assert_equal "token-xyz", notification[:params]["progressToken"]
assert_equal 100, notification[:params]["progress"]
end
test "tool with **kwargs receives Progress instance" do
request = {
jsonrpc: "2.0",
id: 1,
method: "tools/call",
params: {
name: "tool_with_kwargs",
arguments: {},
_meta: { progressToken: "token-kwargs" },
},
}
response = @server.handle(request)
assert response[:result]
assert_equal "ToolWithKwargs: progress=present", response[:result][:content][0][:text]
assert_equal 1, @mock_transport.notifications.size
notification = @mock_transport.notifications.first
assert_equal Methods::NOTIFICATIONS_PROGRESS, notification[:method]
assert_equal "token-kwargs", notification[:params]["progressToken"]
assert_equal 75, notification[:params]["progress"]
end
test "block-defined tool with progress via server_context works" do
server = Server.new(name: "test_server")
server.transport = @mock_transport
server.define_tool(name: "block_tool") do |server_context:|
server_context.report_progress(42, total: 100)
Tool::Response.new([{ type: "text", text: "block_tool done" }])
end
request = {
jsonrpc: "2.0",
id: 1,
method: "tools/call",
params: {
name: "block_tool",
arguments: {},
_meta: { progressToken: "block-token" },
},
}
response = server.handle(request)
assert response[:result]
assert_equal "block_tool done", response[:result][:content][0][:text]
assert_equal 1, @mock_transport.notifications.size
notification = @mock_transport.notifications.first
assert_equal Methods::NOTIFICATIONS_PROGRESS, notification[:method]
assert_equal "block-token", notification[:params]["progressToken"]
assert_equal 42, notification[:params]["progress"]
assert_equal 100, notification[:params]["total"]
end
test "multiple progress notifications during tool execution" do
server = Server.new(name: "test_server")
server.transport = @mock_transport
server.define_tool(name: "multi_progress_tool") do |server_context:|
(1..5).each do |i|
server_context.report_progress(i * 20, total: 100)
end
Tool::Response.new([{ type: "text", text: "done" }])
end
request = {
jsonrpc: "2.0",
id: 1,
method: "tools/call",
params: {
name: "multi_progress_tool",
arguments: {},
_meta: { progressToken: "multi-token" },
},
}
server.handle(request)
assert_equal 5, @mock_transport.notifications.size
@mock_transport.notifications.each_with_index do |n, i|
assert_equal Methods::NOTIFICATIONS_PROGRESS, n[:method]
assert_equal "multi-token", n[:params]["progressToken"]
assert_equal (i + 1) * 20, n[:params]["progress"]
assert_equal 100, n[:params]["total"]
end
end
test "incoming notifications/progress is handled as no-op" do
request = {
jsonrpc: "2.0",
method: "notifications/progress",
params: {
progressToken: "token-1",
progress: 50,
},
}
# Should not raise and should return nil (notification, no id).
result = @server.handle(request)
assert_nil result
end
end
end