All notable changes to this project will be documented in this file.
This release of Helidon MCP contains bugfixes, dependency upgrades and is recommended for all users.
- MicroProfile support
- Upgrade Helidon version to 4.5.0
- Migration from JSON-B to Helidon JSON
Helidon MCP 1.2.0 introduces API changes that are not backward compatible. To upgrade, refer to the
upgrade guide which documents each API change and provides upgrade guidance.
- Handle optional cancellation reasons 191
- Update Helidon version to 4.5.0 196
- Codegen emits invalid accessors for primitive numeric tool parameters 194
- Add @Mcp.Required annotation for tool parameters 176
- Remove timed-out resource subscriptions 192
- Handle empty collections in paginated MCP list responses 189
- Add a stateless server example 178
- Make session capacity configurable 163
- Fix headers check, notification error status, malformed cancellation request 171
This release of Helidon MCP contains bugfixes, dependency upgrades and is recommended for all users.
- Helidon MCP server can be used with more MCP client including Codex
- Stateless server support
- Add support for a stateless mode 172
- Set 202 status on notifications response 167
- Return proper JSON-RPC error for invalid session ID 152
This release of Helidon MCP adds support for the 2025-06-18 MCP specification.
- Elicitation feature support
- Resource Link support
- Structured tool output support
Helidon MCP 1.1.0 introduces API changes that are not backward compatible. To upgrade, refer to
the upgrade guide, which documents each API change and provides upgrade guidance.
- Add support for multi line block in description 144
- Upgrade Helidon version to 4.4.0 161
- Update documentation to reflect API change 159
- Make declarative MCP server a Helidon Service 160
- Add Elicitation feature 138
- Introduce new API design 150
- Refactor tests layout 145
- Update title to Optional field and add convenient method to McpParameters 143
- Add support for
_metafield in request 139 - Add Configurable Instructions Field to MCP Server Initialization Response 136
- Update negotiated version control 137
- Add support for resource links content 133
- Add context field to CompletionRequest 134
- Introduces structured output tool result 132
- Add tool annotations to Tool builder 130
- Add title field to required MCP components 127
- Add backward compatibility tests 126
- Add Json schema annotation to calendar declarative example 124
This release of Helidon MCP contains bugfixes, dependency upgrades and is recommended for all users.
- MCP Roots feature support
- MCP Sampling feature support
- MCP Name annotation can override MCP component names
- Include proper Content-Type header to client responses 99
- Support @Mcp.Name to override MCP component name 95
- Add MCP Roots feature 93
- Add Sampling feature 90
- Add a new completion content factory method 89
This release of Helidon MCP contains bugfixes and dependency upgrades and is recommended for all users. The calendar declarative is a mirror of the calendar example using Helidon MCP declarative.
- Replace Java util logger by
System.Loggerin all modules 83 - Fix subscriptions URI. We no longer expose the internal file URI to the clients. 82
- Make calendar examples more consistent. Add tests to declarative version. 81
- New calendar declarative example 78
- Improve logging in server and some updates for demo 76
This release of Helidon MCP contains bugfixes and dependency upgrades and is recommended for all users.
- Clean up duplicate and hard coded version 73
- Improve error handling 67
- Update Helidon version to 4.3.1 69
This is the main release of Helidon MCP. It supports Model Context Protocol 2024-11-05 and brings additional support for Model Context Protocol 2025-03-26. Helidon MCP is an incubating feature and its API is subject to change.
Helidon MCP 1.0.0 introduces major improvement on 2025-03-26 MCP specification support:
- Security
- Cancellation feature
- Resource subscription/unsubscription
Helidon MCP 1.0.0 release brings two backward incompatible changes.
- Prompt arguments returns a
Listinstead of aSet.
Due to issue with argument ordering using a Set, it now uses a List and stay consistent.
- JSON Schema annotation
@Mcp.JsonSchemais replaced by@JsonSchema.Schema.
Helidon MCP now leverages Helidon JSON Schema introduced in 4.3.0 release. POJOs used as tool inputs do not need
to provide their JSON Schema as string. Helidon will generate it for you!
- Add emergency level log method 64
- Initial support for Helidon JSON schema 61
- Add MCP security layer 63
- Declarative support for subscribers/unsubscribers and docs 62
- Add emergency log level 59
- Update Helidon and Langchain4j versions 57
- Add support for resource subscribers and unsubscribers 56
- Add Cancellation feature 46
- Improve support for prompt and resource completions 52
- Update arguments() method in McpPrompt to return a List instead of a Set in order to preserve ordering. 54
- Support for tool annotations 49
- Updates docs with new audio type. Some other minor fixes for consistency. 51
This is the second milestone release of Helidon MCP. It supports Model Context Protocol 2024-11-05 and introduces partial support for Model Context Protocol 2025-03-26. Helidon MCP is an incubating feature and its API is subject to change.
- Add support for message field in progress notifications 45
- Updates image content API and adds support for audio 44
- Contributing work from streamable-http branch into main 43
- Uptake Helidon version to 4.3.0-M3 41
- Add resolved parameters for Resource templates 38
- Adds initial support for Streamable HTTP transport 33
- Add Pagination feature 21
- Add calendar manager example 20
This is the first milestone release of Helidon MCP. It supports Model Context Protocol 2024-11-05. Helidon MCP is an incubating feature and its API is subject to change.
Requirements:
- Java 21
- Helidon 4.3.0 or newer
Initial release.