Removes the `eventStore` parameter from `mcpStatelessStreamableHttp`,
where it was never read or written.
closes#908
## Breaking Changes
Source-breaking only
## Types of changes
- [x] Bug fix (non-breaking change which fixes an issue)
- [ ] New feature (non-breaking change which adds functionality)
- [ ] Breaking change (fix or feature that would cause existing
functionality to change)
- [ ] Documentation update
## Checklist
- [x] I have read the [MCP
Documentation](https://modelcontextprotocol.io)
- [x] My code follows the repository's style guidelines
- [x] New and existing tests pass locally
- [x] I have added appropriate error handling
- [x] I have added or updated documentation as needed
## Summary
Adds optional SSE heartbeat configuration for streamable HTTP MCP server
connections.
This lets `Application.mcpStreamableHttp` callers pass Ktor's
`Heartbeat` configuration for SSE streams, including heartbeat period
and event payload. Heartbeats remain disabled by default, preserving the
existing stream behavior unless the new option is explicitly provided.
## Motivation and Context
Some MCP clients need heartbeat messages on SSE connections to keep the
connection alive. Without those heartbeats, the client may proactively
disconnect from the MCP server. MCP server developers need a way to
configure an SSE heartbeat mechanism so they can avoid unexpected client
disconnects.
In my case, my MCP server was consistently disconnected by Gemini CLI. I
worked around the issue with some fallback approaches, but I believe the
best implementation is to add heartbeat support by using Ktor's built-in
API.
## Implementation Notes
- Added a function overload of `Application.mcpStreamableHttp` to
introduce heartbeat parameter `sseHeartbeatConfig: (Heartbeat.() ->
Unit)?`.
- Applied the configuration inside the Ktor `sse { ... }` block before
handling the existing streamable HTTP transport request.
- Updated the server API dump for the new public API surface.
## How Has This Been Tested?
Added `StreamableHttpHeartbeatIntegrationTest` covering:
- Configured GET SSE streams apply the provided heartbeat configuration.
- GET SSE streams do not send default heartbeats when
`sseHeartbeatConfig` is omitted.
- Configured GET SSE streams emit heartbeat events repeatedly.
- Legacy MCP over SSE APIs do not expose the new heartbeat
configuration.
Verified locally with:
```bash
./gradlew :integration-test:jvmTest --tests "io.modelcontextprotocol.kotlin.sdk.integration.streamablehttp.StreamableHttpHeartbeatIntegrationTest"
```
Result: `BUILD SUCCESSFUL`.
## Breaking Changes
None.
This change adds a new `Application.mcpStreamableHttp` overload that
accepts
`sseHeartbeatConfig: (Heartbeat.() -> Unit)?` while keeping the existing
overload
unchanged. Existing callers continue to compile and keep the previous
behavior:
SSE heartbeats are not sent unless the new overload is used with an
explicit
heartbeat configuration.
## Types of changes
- [ ] Bug fix (non-breaking change which fixes an issue)
- [x] New feature (non-breaking change which adds functionality)
- [ ] Breaking change (fix or feature that would cause existing
functionality to change)
- [ ] Documentation update
## Checklist
- [x] I have read the [MCP
Documentation](https://modelcontextprotocol.io)
- [x] My code follows the repository's style guidelines
- [x] New and existing tests pass locally
- [x] I have added appropriate error handling
- [x] I have added or updated documentation as needed
## Additional context
Heartbeat behavior is delegated to Ktor's SSE heartbeat support, so
applications can use the same configuration semantics they would use in
native Ktor SSE routes.
Related issue: [SSE needs a heartbeat #344
](https://github.com/modelcontextprotocol/kotlin-sdk/issues/344)
---------
Co-authored-by: Pavel Gorgulov <devcrocod@gmail.com>
Make inbound message handling concurrent after the initialization
handshake, so a slow or peer-awaiting handler no longer blocks other
messages on the same connection
fixes#176, #572
## Motivation and Context
Inbound messages were processed serially on the transport read loop. One
slow or peer-awaiting request handler (sampling, elicitation, roots)
blocked every later message on that connection, including the responses
and `notifications/cancelled` those handlers depend on which could
deadlock request/response flows.
## How Has This Been Tested?
New and old tests
## Breaking Changes
- after the handshake, inbound handlers may run concurrently (processing
stays serial during initialization). There is no opt-out flag by design,
concurrency is bounded by `maxConcurrentHandlers` /
`maxInFlightHandlers`.
- `ProtocolOptions` / `ClientOptions` / `ServerOptions` gain new
parameters with defaults
- `RequestHandlerExtra` is now a coroutine-context element and is no
longer user-constructible
## Types of changes
- [x] Bug fix (non-breaking change which fixes an issue)
- [x] New feature (non-breaking change which adds functionality)
- [x] Breaking change (fix or feature that would cause existing
functionality to change)
- [ ] Documentation update
## Checklist
- [x] I have read the [MCP
Documentation](https://modelcontextprotocol.io)
- [x] My code follows the repository's style guidelines
- [x] New and existing tests pass locally
- [x] I have added appropriate error handling
- [x] I have added or updated documentation as needed
Caps the size of incoming HTTP POST bodies in both server transports so
an oversized request can no longer exhaust server memory
## How Has This Been Tested?
new tests
## Breaking Changes
binary incompatible for SseServerTransport constuctors
## Types of changes
- [x] Bug fix (non-breaking change which fixes a
- [x] New feature (non-breaking change which adds functionality)
- [x] Breaking change (fix or feature that would to change)
- [ ] Documentation update
## Checklist
- [x] I have read the [MCP Documentation](https:
- [x] My code follows the repository's style guidelines
- [x] New and existing tests pass locally
- [x] I have added appropriate error handling
- [x] I have added or updated documentation as needed
fixes#573fixes#574fixes#708
- Handlers ran on `Dispatchers.IO` → now `Dispatchers.Default`,
configurable via `handlerDispatcher`.
- Reader/writer dispatcher exposed as `ioDispatcher` (default
`IODispatcher.limitedParallelism(2)`).
- Optional caller-supplied `CoroutineScope` so the pipeline isn't
detached from the caller's tree.
- `CancellationException` consistently rethrown across all pumps.
- Unbounded channels → bounded with graceful drain on close (in-flight
outbound flushed before `onClose`).
- Input `Source` now closed on natural EOF / reader error (was leaking
for non-`System.in` sources).
- Race between `start()` and `close()` fixed via 3-state CAS +
`setupComplete` barrier replacing `AtomicBoolean`.
## How Has This Been Tested?
unit and integration tests
## Breaking Changes
- Handlers default to `Dispatchers.Default` (was `Dispatchers.IO`).
Override with `handlerDispatcher = Dispatchers.IO` if your handlers
perform blocking I/O.
- `send()` suspends under back-pressure instead of buffering unbounded.
- `StdioServerTransport(input, output)` ctor is `@Deprecated` (WARNING)
in favor of `StdioServerTransport(input, output) { ... }`. Still
binary-compatible.
## Types of changes
- [x] Bug fix (non-breaking change which fixes an issue)
- [x] New feature (non-breaking change which adds functionality)
- [ ] Breaking change (fix or feature that would cause existing
functionality to change)
- [ ] Documentation update
## Checklist
- [x] I have read the [MCP
Documentation](https://modelcontextprotocol.io)
- [x] My code follows the repository's style guidelines
- [x] New and existing tests pass locally
- [x] I have added appropriate error handling
- [x] I have added or updated documentation as needed
Add `DnsRebindingProtection` Ktor route-scoped plugin and enable it by
default across all http transports
## Motivation and Context
DNS rebinding protection was disabled by default
(`enableDnsRebindingProtection = false`), and sse endpoints
(`Route.mcp()`) had zero protection. Same vulnerability as typescript
sdk
[GHSA-w48q-cv73-mx4w](https://github.com/modelcontextprotocol/typescript-sdk/security/advisories/GHSA-w48q-cv73-mx4w)
## How Has This Been Tested?
all tests pass
## Breaking Changes
- `Route.mcp()`, `Application.mcp()` signatures changed (new
`enableDnsRebindingProtection`, `allowedHosts`, `allowedOrigins`
params), binary incompatible on JVM
- `enableDnsRebindingProtection` default changed from `false` to `true`
on `mcpStreamableHttp`/`mcpStatelessStreamableHttp`
- Default allowed hosts: `localhost`, `127.0.0.1`, `[::1]` — opt out
with `enableDnsRebindingProtection = false`
- Host validation is now port-agnostic (matches ts sdk)
- Origin validation now allows missing `Origin` header (non-browser
clients)
- `Configuration.enableDnsRebindingProtection`, `.allowedHosts`,
`.allowedOrigins` deprecated in favor of the plugin
## Types of changes
- [x] Bug fix (non-breaking change which fixes an issue)
- [x] New feature (non-breaking change which adds functionality)
- [x] Breaking change (fix or feature that would cause existing
functionality to change)
- [ ] Documentation update
## Checklist
- [x] I have read the [MCP
Documentation](https://modelcontextprotocol.io)
- [x] My code follows the repository's style guidelines
- [x] New and existing tests pass locally
- [x] I have added appropriate error handling
- [x] I have added or updated documentation as needed
closes#546
## How Has This Been Tested?
unit
## Breaking Changes
none
## Types of changes
- [ ] Bug fix (non-breaking change which fixes an issue)
- [x] New feature (non-breaking change which adds functionality)
- [ ] Breaking change (fix or feature that would cause existing
functionality to change)
- [ ] Documentation update
## Checklist
- [x] I have read the [MCP
Documentation](https://modelcontextprotocol.io)
- [x] My code follows the repository's style guidelines
- [x] New and existing tests pass locally
- [ ] I have added appropriate error handling
- [ ] I have added or updated documentation as needed
## Summary
Add `maxRequestBodySize` parameter to
`StreamableHttpServerTransport.Configuration`, allowing consumers to set
a custom request body size limit lower than the default 4 MB.
- Add `maxRequestBodySize: Long` property to `Configuration` with a
default of 4 MB (`4,194,304` bytes)
- Replace hardcoded `MAXIMUM_MESSAGE_SIZE` constant with the
configurable value in `parseBody()`
- Use `Long` for content-length comparison to avoid `Int` overflow on
large values
## Motivation and Context
Closes#521
The `StreamableHttpServerTransport` has a hardcoded 4 MB request body
limit. Consumers who need a lower limit currently have to manually count
the request payload size before passing it to the SDK. This change makes
the limit configurable via `Configuration`.
## How Has This Been Tested?
- Existing unit tests continue to pass (default 4 MB behavior unchanged)
- Added `POST with custom max request body size rejects oversized
payload` — verifies `PayloadTooLarge` is returned for payloads exceeding
the custom limit
- Added `POST at exactly custom max request body size is not rejected as
payload too large` — verifies payloads at exactly the limit are not
rejected by the size check
```bash
./gradlew :kotlin-sdk-server:jvmTest --tests "*.StreamableHttpServerTransportTest"
```
## Breaking Changes
None. The new parameter has a default value matching the previous
hardcoded limit.
## Types of changes
- [ ] Bug fix (non-breaking change which fixes an issue)
- [x] New feature (non-breaking change which adds functionality)
- [ ] Breaking change (fix or feature that would cause existing
functionality to change)
- [ ] Documentation update
## Checklist
- [x] I have read the [MCP
Documentation](https://modelcontextprotocol.io)
- [x] My code follows the repository's style guidelines
- [x] New and existing tests pass locally
- [x] I have added appropriate error handling
- [x] I have added or updated documentation as needed
Add URL mode elicitation support and typed `PrimitiveSchemaDefinition`
hierarchy to align with MCP specification 2025-11-25
closes#540
## How Has This Been Tested?
unit/integration/conformance
## Breaking Changes
- `ElicitRequestParams` changed from `data class` to `sealed interface`.
A deprecated factory function preserves source compatibility for
`ElicitRequestParams(message, requestedSchema)`.
- `RequestedSchema.properties` changed from `JsonObject` to `Map<String,
PrimitiveSchemaDefinition>`.
- `ElicitRequest.requestedSchema` is deprecated, use `(params as
ElicitRequestFormParams).requestedSchema`.
## Types of changes
- [ ] Bug fix (non-breaking change which fixes an issue)
- [x] New feature (non-breaking change which adds functionality)
- [x] Breaking change (fix or feature that would cause existing
functionality to change)
- [ ] Documentation update
## Checklist
- [x] I have read the [MCP
Documentation](https://modelcontextprotocol.io)
- [x] My code follows the repository's style guidelines
- [x] New and existing tests pass locally
- [x] I have added appropriate error handling
- [x] I have added or updated documentation as needed
Remove all deprecation with error level
## Motivation and Context
next minor release
## How Has This Been Tested?
-
## Breaking Changes
Removing it is a binary-incompatible change
## Types of changes
- [ ] Bug fix (non-breaking change which fixes an issue)
- [ ] New feature (non-breaking change which adds functionality)
- [ ] Breaking change (fix or feature that would cause existing
functionality to change)
- [ ] Documentation update
## Checklist
- [x] I have read the [MCP
Documentation](https://modelcontextprotocol.io)
- [x] My code follows the repository's style guidelines
- [x] New and existing tests pass locally
- [x] I have added appropriate error handling
- [x] I have added or updated documentation as needed
closes#543
## How Has This Been Tested?
unit
## Breaking Changes
binary compatibility in the Tool class
## Types of changes
- [ ] Bug fix (non-breaking change which fixes an issue)
- [x] New feature (non-breaking change which adds functionality)
- [ ] Breaking change (fix or feature that would cause existing
functionality to change)
- [ ] Documentation update
## Checklist
- [x] I have read the [MCP
Documentation](https://modelcontextprotocol.io)
- [x] My code follows the repository's style guidelines
- [x] New and existing tests pass locally
- [ ] I have added appropriate error handling
- [ ] I have added or updated documentation as needed
---------
Co-authored-by: Konstantin Pavlov <1517853+kpavlov@users.noreply.github.com>
## Introduce Configuration class for StreamableHttpServerTransport
Replace the six-parameter flat constructor of
`StreamableHttpServerTransport` with a typed `Configuration` class. This
improves API ergonomics, enables structural equality and copy(), and
provides a stable extension point for future options without further
breaking the constructor signature.
### Changes:
- Add `Configuration` as a public class nested directly on
`StreamableHttpServerTransport`, with `enableJsonResponse` as the first
parameter (most commonly set)
- Change the primary constructor to accept `Configuration`.
- Rename `retryIntervalMillis: Long?` to `retryInterval: Duration?` in
Configuration, aligning with Kotlin's type-safe time API
- Deprecate the old flat constructor with a compatibility bridge
- Update KotlinTestBase integration test to use the new constructor
- Enable test
AbstractResourceIntegrationTest.testSubscribeAndUnsubscribe() since #249
is closed
## Motivation and Context
The current StreamableHttpServerTransport API cannot be easily extended:
adding more parameters would be a breaking change. But this is already
needed for #521.
This PR is a prerequisite for #535
## How Has This Been Tested?
Regression tests
## Breaking Changes
No. Current StreamableHttpServerTransport constructor was deprecated
## Types of changes
<!-- What types of changes does your code introduce? Put an `x` in all
the boxes that apply: -->
- [ ] Bug fix (non-breaking change which fixes an issue)
- [x] New feature (non-breaking change which adds functionality)
- [ ] Breaking change (fix or feature that would cause existing
functionality to change)
- [ ] Documentation update
## Checklist
<!-- Go over all the following points, and put an `x` in all the boxes
that apply. -->
- [x] I have read the [MCP
Documentation](https://modelcontextprotocol.io)
- [x] My code follows the repository's style guidelines
- [x] New and existing tests pass locally
- [ ] I have added appropriate error handling
- [ ] I have added or updated documentation as needed
## Motivation and Context
Adds a `ClientConnection` context receiver to server call handlers,
which provides access to the client communication channel. This is
necessary to allow tools to send notifications, logging, elicitations,
etc.
Supersedes https://github.com/modelcontextprotocol/kotlin-sdk/pull/144,
discussed in
https://github.com/modelcontextprotocol/kotlin-sdk/issues/295.
## How Has This Been Tested?
With the added integration test.
## Breaking Changes
It breaks binary compatibility and breaks source compatibility for tool
handlers that already use `this`.
If you care a lot about maintaining compatibility, I could add some
overloads to ease the transition. But the new methods would likely need
to be named differently for resolution.
Future compatibility should be easier to maintain - `Context` is an
interface (with experimental opt-in subclassing), so new fields can be
added without breaking compatibility. Different types could also be
introduced for different handles without breaking compatibility, as long
as they extend `ClientConnection`.
## Types of changes
<!-- What types of changes does your code introduce? Put an `x` in all
the boxes that apply: -->
- [ ] Bug fix (non-breaking change which fixes an issue)
- [x] New feature (non-breaking change which adds functionality)
- [x] Breaking change (fix or feature that would cause existing
functionality to change)
- [ ] Documentation update
## Checklist
<!-- Go over all the following points, and put an `x` in all the boxes
that apply. -->
- [x] I have read the [MCP
Documentation](https://modelcontextprotocol.io)
- [x] My code follows the repository's style guidelines
- [x] New and existing tests pass locally
- [x] I have added appropriate error handling
- [x] I have added or updated documentation as needed
## Additional context
<!-- Add any other context, implementation notes, or design decisions
-->
---------
Co-authored-by: Konstantin Pavlov <1517853+kpavlov@users.noreply.github.com>
# Migrate Ktor extension functions from `Routing` to `Route` (#237)
- Replaced `Routing` with `Route` in MCP-related functions for better
composability in nested contexts.
- Updated tests to verify compatibility with nested routes and subpaths.
- Deprecated legacy signatures and removed redundant overloads.
## How Has This Been Tested?
Unit test
## Breaking Changes
`Routing.mcp(...) `extension was replaced with `Route.mcp(...)`
## Types of changes
- [X] Bug fix (non-breaking change which fixes an issue)
- [ ] New feature (non-breaking change which adds functionality)
- [x] Breaking change (fix or feature that would cause existing
functionality to change)
- [ ] Documentation update
## Checklist
<!-- Go over all the following points, and put an `x` in all the boxes
that apply. -->
- [x] I have read the [MCP
Documentation](https://modelcontextprotocol.io)
- [x] My code follows the repository's style guidelines
- [ ] New and existing tests pass locally
- [ ] I have added appropriate error handling
- [ ] I have added or updated documentation as needed
## Additional context
Based on #314 by @IainHull but that PR is too outdated.
## Motivation and Context
Adds Ktor extensions for streaming data over the server-side HTTP
transport
## How Has This Been Tested?
Integration test
## Breaking Changes
-
## Types of changes
- [ ] Bug fix (non-breaking change which fixes an issue)
- [x] New feature (non-breaking change which adds functionality)
- [ ] Breaking change (fix or feature that would cause existing
functionality to change)
- [ ] Documentation update
## Checklist
- [x] I have read the [MCP
Documentation](https://modelcontextprotocol.io)
- [x] My code follows the repository's style guidelines
- [x] New and existing tests pass locally
- [x] I have added appropriate error handling
- [x] I have added or updated documentation as needed
# [WIP] StreamableHttpServerTransport implementation
- Implement StreamableHttpServerTransport for MCP spec
- Support both SSE streaming and direct HTTP JSON responses
- Add event store interface for resumability
> [!IMPORTANT]
> The work is in progress. StreamableHttpServerTransport is not
production-ready yet!!!
Based on #235
## How Has This Been Tested?
<!-- Have you tested this in a real application? Which scenarios were
tested? -->
## Breaking Changes
None
## Types of changes
- [ ] Bug fix (non-breaking change which fixes an issue)
- [x] New feature (non-breaking change which adds functionality)
- [ ] Breaking change (fix or feature that would cause existing
functionality to change)
- [ ] Documentation update
## Checklist
- [x] I have read the [MCP
Documentation](https://modelcontextprotocol.io)
- [x] My code follows the repository's style guidelines
- [x] New and existing tests pass locally
- [x] I have added appropriate error handling
- [x] I have added or updated documentation as needed
<!-- Provide a brief summary of your changes -->
## Motivation and Context
<!-- Why is this change needed? What problem does it solve? -->
Implemented thread-safe notification service following eventual
consistency principle.
Fixes https://github.com/modelcontextprotocol/kotlin-sdk/issues/249
Contracts:
* If the client connection and feature update happened in the same
thread, the timestamps of the events will be consequent
```
server.connect(client)
server.add(feature)
// client will receive the notification
```
```
server.add(feature)
server.connect(client)
// client will NOT receive the notification
```
* If the client connection and feature update happened in the different
threads, both options can be possible
The flow of the notification is explained in the diagram:
<img width="663" height="413" alt="image"
src="https://github.com/user-attachments/assets/e2c4c108-53dd-408d-97ef-97110ce5c979"
/>
Documentation references:
https://modelcontextprotocol.io/specification/2025-06-18/server/prompts#list-changed-notificationhttps://modelcontextprotocol.io/specification/2025-06-18/server/tools#list-changed-notificationhttps://modelcontextprotocol.io/specification/2025-06-18/server/resources#list-changed-notificationhttps://modelcontextprotocol.io/specification/2025-06-18/server/resources#subscriptions
Questions:
* I haven't found the subscription confirmed response message content
docs, how it should look like?
## How Has This Been Tested?
<!-- Have you tested this in a real application? Which scenarios were
tested? -->
Multiple tests with various notification scenarios were added
## Breaking Changes
<!-- Will users need to update their code or configurations? -->
## Types of changes
<!-- What types of changes does your code introduce? Put an `x` in all
the boxes that apply: -->
- [ ] Bug fix (non-breaking change which fixes an issue)
- [x] New feature (non-breaking change which adds functionality)
- [ ] Breaking change (fix or feature that would cause existing
functionality to change)
- [ ] Documentation update
## Checklist
<!-- Go over all the following points, and put an `x` in all the boxes
that apply. -->
- [x] I have read the [MCP
Documentation](https://modelcontextprotocol.io)
- [x] My code follows the repository's style guidelines
- [x] New and existing tests pass locally
- [x] I have added appropriate error handling
- [x] I have added or updated documentation as needed
## Additional context
<!-- Add any other context, implementation notes, or design decisions
-->
Add support for `TransportSendOptions` in `Transport.send` method
## Motivation and Context
This change extends the `Transport.send` method signature to support
advanced transport features like resumption tokens and progress
callbacks. This is needed to enable:
- Long-running request resumption after reconnection
- Request-response association tracking
- Progress token handling in transport layer
needed for #235
## How Has This Been Tested?
All transport tests passed
## Breaking Changes
Yes, it’s necessary to update the custom Transport implementations.
For users who rely on the transports provided by the sdk, there’s no
breaking change
## Types of changes
- [x] Bug fix (non-breaking change which fixes an issue)
- [x] New feature (non-breaking change which adds functionality)
- [ ] Breaking change (fix or feature that would cause existing
functionality to change)
- [ ] Documentation update
## Checklist
- [x] I have read the [MCP
Documentation](https://modelcontextprotocol.io)
- [x] My code follows the repository's style guidelines
- [x] New and existing tests pass locally
- [x] I have added appropriate error handling
- [x] I have added or updated documentation as needed
<!-- Provide a brief summary of your changes -->
## Motivation and Context
<!-- Why is this change needed? What problem does it solve? -->
Add ids for server sessions (auto generated when created)
Support methods proxying from server to server session by id
## How Has This Been Tested?
<!-- Have you tested this in a real application? Which scenarios were
tested? -->
## Breaking Changes
<!-- Will users need to update their code or configurations? -->
## Types of changes
<!-- What types of changes does your code introduce? Put an `x` in all
the boxes that apply: -->
- [ ] Bug fix (non-breaking change which fixes an issue)
- [x] New feature (non-breaking change which adds functionality)
- [ ] Breaking change (fix or feature that would cause existing
functionality to change)
- [ ] Documentation update
## Checklist
<!-- Go over all the following points, and put an `x` in all the boxes
that apply. -->
- [ ] I have read the [MCP
Documentation](https://modelcontextprotocol.io)
- [ ] My code follows the repository's style guidelines
- [ ] New and existing tests pass locally
- [ ] I have added appropriate error handling
- [ ] I have added or updated documentation as needed
## Additional context
<!-- Add any other context, implementation notes, or design decisions
-->
Implement the last version of the mcp schema and complete restructuring
of the mcp schema implementation from a monolithic `types.kt` file into
separate files.
- #158
- #185
- #353
- #298
- #248
## Motivation and Context
The previous implementation of the mcp schema was outdated and contained
several issues. In addition, it stored all mcp types in a single large
file, which made maintenance and further development more difficult
## How Has This Been Tested?
All tests passed
## Breaking Changes
Yes. The new types are now located in a separate package. Additionally,
many types have new parameters and modified constructors
## Types of changes
- [x] Bug fix (non-breaking change which fixes an issue)
- [x] New feature (non-breaking change which adds functionality)
- [x] Breaking change (fix or feature that would cause existing
functionality to change)
- [ ] Documentation update
## Checklist
- [x] I have read the [MCP
Documentation](https://modelcontextprotocol.io)
- [x] My code follows the repository's style guidelines
- [x] New and existing tests pass locally
- [x] I have added appropriate error handling
- [x] I have added or updated documentation as needed
## Additional context
to adopt the new structure:
**Before:**
```kotlin
import io.modelcontextprotocol.kotlin.sdk.InitializeRequest
import io.modelcontextprotocol.kotlin.sdk.Resource
```
**After:**
```kotlin
import io.modelcontextprotocol.kotlin.sdk.types.InitializeRequest
import io.modelcontextprotocol.kotlin.sdk.types.Resource
```
<!-- Provide a brief summary of your changes -->
## Motivation and Context
The recently released openAI [Apps SDK
](https://developers.openai.com/apps-sdk/reference/#_meta-fields-the-client-provides)adds
a '__meta_' field on the Tool Descriptor. This would be in addition to
it being available on Messages. It remains optional and defaults to an
empty json object, following existing conventions.
## How Has This Been Tested?
Unit tests for serialization added
## Breaking Changes
N/A
## Types of changes
<!-- What types of changes does your code introduce? Put an `x` in all
the boxes that apply: -->
- [ ] Bug fix (non-breaking change which fixes an issue)
- [X] New feature (non-breaking change which adds functionality)
- [ ] Breaking change (fix or feature that would cause existing
functionality to change)
- [ ] Documentation update
## Checklist
<!-- Go over all the following points, and put an `x` in all the boxes
that apply. -->
- [X] I have read the [MCP
Documentation](https://modelcontextprotocol.io)
- [X] My code follows the repository's style guidelines
- [X] New and existing tests pass locally
- [X] I have added appropriate error handling
- [X] I have added or updated documentation as needed
## Additional context
https://developers.openai.com/apps-sdkhttps://developers.openai.com/apps-sdk/reference/#_meta-fields-the-client-provides
---------
Co-authored-by: Pavel Gorgulov <devcrocod@gmail.com>
- Rename `connect` to `createSession` in `Server.kt `to make naming more
clear
- Add block to configure build to `Server.kt`
- Move sse test to jvm to be able to run, small test refactoring
- Introduce base integration test for sse server / client
<!-- Provide a brief summary of your changes -->
## Motivation and Context
The
[schema](cca15204f6/schema/2025-03-26/schema.ts (L192))
for the InitializeResult contains an optional 'instructions' string
## Additional context
The instructions string is included in the schema for for version
"2025-03-26"
The instructions in the Server class are given as a provider function
with the result of the provider propagated to the underlying
ServerSession. As the ServerSession change is meant to allow for a
'Singleton scoped' server class, this provides the ability to
dynamically modify the instructions at the server level but have them be
immutable per session.
This also refactors the `serverInfo` and `instructions` properties to be
protected. This `Server` class is open and meant to be overridden, there
is no harm in having these immutable properties available to subclasses.
This adds the serverInstructions to the client as returned from the
InitializeResult. This is used to verify the response in the Server
tests.
Introduce a `ServerSession` to manage multiple connections to the mcp
server. `Protocall` logic of the `Server` was moved to `ServerSession`,
while MCP resources logic remained in `Server`
## Motivation and Context
1. Fix the multiple connection issues reported for SSE transport
2. Avoid server duplications during configurations: currently every connection
creates a session, but the server stays single
## How Has This Been Tested?
Added `SseIntegrationTest` and `WebSocketIntegrationTest` integration
tests to check connection with single and multiple clients
## Breaking Changes
This change caused several depreciations:
1. The `Server` -> `Protocol` inheritance (which caused single
connection issue) should be removed in future releases, now, all the
methods inherited from `Protocall` marked as `Deprecated` with a
`Warning`
2. Websocket Ktor server initialization changes in order not to create
server instance per connection
## Types of changes
- [ ] Bug fix (non-breaking change which fixes an issue)
- [x] New feature (non-breaking change which adds functionality)
- [ ] Breaking change (fix or feature that would cause existing
functionality to change)
- [ ] Documentation update
## Checklist
<!-- Go over all the following points, and put an `x` in all the boxes
that apply. -->
- [x] I have read the [MCP
Documentation](https://modelcontextprotocol.io)
- [x] My code follows the repository's style guidelines
- [x] New and existing tests pass locally
- [x] I have added appropriate error handling
- [x] I have added or updated documentation as needed
## Additional context
<!-- Add any other context, implementation notes, or design decisions
-->
---------
Co-authored-by: devcrocod <devcrocod@gmail.com>
fix#272
## How Has This Been Tested?
Locally
## Breaking Changes
No
## Types of changes
- [x] Bug fix (non-breaking change which fixes an issue)
- [ ] New feature (non-breaking change which adds functionality)
- [ ] Breaking change (fix or feature that would cause existing
functionality to change)
- [ ] Documentation update
## Checklist
- [x] I have read the [MCP
Documentation](https://modelcontextprotocol.io)
- [x] My code follows the repository's style guidelines
- [x] New and existing tests pass locally
- [ ] I have added appropriate error handling
- [ ] I have added or updated documentation as needed
* Modularize SDK: migrated client and server implementations to separate modules. Removed old configuration files and reorganized the source code structure
* add support native targets and update js/wasm configurations
* Refactor sample projects: add samples as composite builds, replace hardcoded dependencies with version catalog, remove obsolete gradle wrapper files
* Update .gitignore: exclude SWE agent directories (.claude/ and .junie/)
* Refine CodeQL workflow: update Kotlin build steps to target individual modules separately instead of building all at once
