kotlin-sdk-core

kotlin-sdk-core is the foundation of the MCP Kotlin SDK. It contains protocol message types, JSON handling, and transport abstractions used by both client and server modules. No platform-specific code lives here; everything is designed for Kotlin Multiplatform with explicit API mode enabled.

What the module provides

Protocol model: Complete MCP data classes for requests, results, notifications, capabilities, tools, prompts, resources, logging, completion, sampling, elicitation, and roots. DSL helpers (*.dsl.kt) let you build messages fluently without repeating boilerplate.
JSON utilities: A shared McpJson configuration (kotlinx.serialization) with MCP-friendly settings (ignore unknown keys, no class discriminator). Helpers for converting maps to JsonElement, EmptyJsonObject, and encoding/decoding JSON-RPC envelopes.
Transport abstractions: Transport and AbstractTransport define the message pipeline, callbacks, and error handling. WebSocketMcpTransport adds a shared WebSocket implementation for both client and server sides, and ReadBuffer handles streaming JSON-RPC framing.
Protocol engine: The Protocol base class manages request/response correlation, notifications, progress tokens, and capability assertions. Higher-level modules extend it to become Client and Server.
Errors and safety: Common exception types (McpException, parsing errors) plus capability enforcement hooks ensure callers cannot use endpoints the peer does not advertise.

Typical usage

Import MCP types to define capabilities and message payloads for your own transports or custom integrations.
Extend Protocol if you need a bespoke peer role while reusing correlation logic and JSON-RPC helpers.
Use the DSL builders to construct well-typed requests (tools, prompts, resources, logging, completion) instead of crafting raw JSON.

Example: building a tool call request

val request = CallToolRequest {
    name = "summarize"
    arguments = mapOf("text" to "Hello MCP")
}

Example: parsing a JSON-RPC message

val message: JSONRPCMessage = McpJson.decodeFromString(jsonString)

Use this module when you need the raw building blocks of MCP—types, JSON config, and transport base classes—whether to embed in another runtime, author new transports, or contribute higher-level features in the client/server modules. The APIs are explicit to keep the shared surface stable for downstream users.

kotlin-sdk-core is the foundation of the MCP Kotlin SDK. It contains protocol message types, JSON handling, and transport abstractions used by both client and server modules. No platform-specific code lives here; everything is designed for Kotlin Multiplatform with explicit API mode enabled.

What the module provides

Protocol model: Complete MCP data classes for requests, results, notifications, capabilities, tools, prompts, resources, logging, completion, sampling, elicitation, and roots. DSL helpers (*.dsl.kt) let you build messages fluently without repeating boilerplate.
JSON utilities: A shared McpJson configuration (kotlinx.serialization) with MCP-friendly settings (ignore unknown keys, no class discriminator). Helpers for converting maps to JsonElement, EmptyJsonObject, and encoding/decoding JSON-RPC envelopes.
Transport abstractions: Transport and AbstractTransport define the message pipeline, callbacks, and error handling. WebSocketMcpTransport adds a shared WebSocket implementation for both client and server sides, and ReadBuffer handles streaming JSON-RPC framing.
Protocol engine: The Protocol base class manages request/response correlation, notifications, progress tokens, and capability assertions. Higher-level modules extend it to become Client and Server.
Errors and safety: Common exception types (McpException, parsing errors) plus capability enforcement hooks ensure callers cannot use endpoints the peer does not advertise.

Typical usage

Import MCP types to define capabilities and message payloads for your own transports or custom integrations.
Extend Protocol if you need a bespoke peer role while reusing correlation logic and JSON-RPC helpers.
Use the DSL builders to construct well-typed requests (tools, prompts, resources, logging, completion) instead of crafting raw JSON.

Example: building a tool call request

val request = CallToolRequest {
    name = "summarize"
    arguments = mapOf("text" to "Hello MCP")
}

Example: parsing a JSON-RPC message

val message: JSONRPCMessage = McpJson.decodeFromString(jsonString)

Use this module when you need the raw building blocks of MCP—types, JSON config, and transport base classes—whether to embed in another runtime, author new transports, or contribute higher-level features in the client/server modules. The APIs are explicit to keep the shared surface stable for downstream users.

kotlin-sdk-core is the foundation of the MCP Kotlin SDK. It contains protocol message types, JSON handling, and transport abstractions used by both client and server modules. No platform-specific code lives here; everything is designed for Kotlin Multiplatform with explicit API mode enabled.

What the module provides

Protocol model: Complete MCP data classes for requests, results, notifications, capabilities, tools, prompts, resources, logging, completion, sampling, elicitation, and roots. DSL helpers (*.dsl.kt) let you build messages fluently without repeating boilerplate.
JSON utilities: A shared McpJson configuration (kotlinx.serialization) with MCP-friendly settings (ignore unknown keys, no class discriminator). Helpers for converting maps to JsonElement, EmptyJsonObject, and encoding/decoding JSON-RPC envelopes.
Transport abstractions: Transport and AbstractTransport define the message pipeline, callbacks, and error handling. WebSocketMcpTransport adds a shared WebSocket implementation for both client and server sides, and ReadBuffer handles streaming JSON-RPC framing.
Protocol engine: The Protocol base class manages request/response correlation, notifications, progress tokens, and capability assertions. Higher-level modules extend it to become Client and Server.
Errors and safety: Common exception types (McpException, parsing errors) plus capability enforcement hooks ensure callers cannot use endpoints the peer does not advertise.

Typical usage

Import MCP types to define capabilities and message payloads for your own transports or custom integrations.
Extend Protocol if you need a bespoke peer role while reusing correlation logic and JSON-RPC helpers.
Use the DSL builders to construct well-typed requests (tools, prompts, resources, logging, completion) instead of crafting raw JSON.

Example: building a tool call request

val request = CallToolRequest {
    name = "summarize"
    arguments = mapOf("text" to "Hello MCP")
}

Example: parsing a JSON-RPC message

val message: JSONRPCMessage = McpJson.decodeFromString(jsonString)

Use this module when you need the raw building blocks of MCP—types, JSON config, and transport base classes—whether to embed in another runtime, author new transports, or contribute higher-level features in the client/server modules. The APIs are explicit to keep the shared surface stable for downstream users.

kotlin-sdk-core is the foundation of the MCP Kotlin SDK. It contains protocol message types, JSON handling, and transport abstractions used by both client and server modules. No platform-specific code lives here; everything is designed for Kotlin Multiplatform with explicit API mode enabled.

What the module provides

Protocol model: Complete MCP data classes for requests, results, notifications, capabilities, tools, prompts, resources, logging, completion, sampling, elicitation, and roots. DSL helpers (*.dsl.kt) let you build messages fluently without repeating boilerplate.
JSON utilities: A shared McpJson configuration (kotlinx.serialization) with MCP-friendly settings (ignore unknown keys, no class discriminator). Helpers for converting maps to JsonElement, EmptyJsonObject, and encoding/decoding JSON-RPC envelopes.
Transport abstractions: Transport and AbstractTransport define the message pipeline, callbacks, and error handling. WebSocketMcpTransport adds a shared WebSocket implementation for both client and server sides, and ReadBuffer handles streaming JSON-RPC framing.
Protocol engine: The Protocol base class manages request/response correlation, notifications, progress tokens, and capability assertions. Higher-level modules extend it to become Client and Server.
Errors and safety: Common exception types (McpException, parsing errors) plus capability enforcement hooks ensure callers cannot use endpoints the peer does not advertise.

Typical usage

Import MCP types to define capabilities and message payloads for your own transports or custom integrations.
Extend Protocol if you need a bespoke peer role while reusing correlation logic and JSON-RPC helpers.
Use the DSL builders to construct well-typed requests (tools, prompts, resources, logging, completion) instead of crafting raw JSON.

Example: building a tool call request

val request = CallToolRequest {
    name = "summarize"
    arguments = mapOf("text" to "Hello MCP")
}

Example: parsing a JSON-RPC message

val message: JSONRPCMessage = McpJson.decodeFromString(jsonString)

Use this module when you need the raw building blocks of MCP—types, JSON config, and transport base classes—whether to embed in another runtime, author new transports, or contribute higher-level features in the client/server modules. The APIs are explicit to keep the shared surface stable for downstream users.

kotlin-sdk-core is the foundation of the MCP Kotlin SDK. It contains protocol message types, JSON handling, and transport abstractions used by both client and server modules. No platform-specific code lives here; everything is designed for Kotlin Multiplatform with explicit API mode enabled.

What the module provides

Protocol model: Complete MCP data classes for requests, results, notifications, capabilities, tools, prompts, resources, logging, completion, sampling, elicitation, and roots. DSL helpers (*.dsl.kt) let you build messages fluently without repeating boilerplate.
JSON utilities: A shared McpJson configuration (kotlinx.serialization) with MCP-friendly settings (ignore unknown keys, no class discriminator). Helpers for converting maps to JsonElement, EmptyJsonObject, and encoding/decoding JSON-RPC envelopes.
Transport abstractions: Transport and AbstractTransport define the message pipeline, callbacks, and error handling. WebSocketMcpTransport adds a shared WebSocket implementation for both client and server sides, and ReadBuffer handles streaming JSON-RPC framing.
Protocol engine: The Protocol base class manages request/response correlation, notifications, progress tokens, and capability assertions. Higher-level modules extend it to become Client and Server.
Errors and safety: Common exception types (McpException, parsing errors) plus capability enforcement hooks ensure callers cannot use endpoints the peer does not advertise.

Typical usage

Import MCP types to define capabilities and message payloads for your own transports or custom integrations.
Extend Protocol if you need a bespoke peer role while reusing correlation logic and JSON-RPC helpers.
Use the DSL builders to construct well-typed requests (tools, prompts, resources, logging, completion) instead of crafting raw JSON.

Example: building a tool call request

val request = CallToolRequest {
    name = "summarize"
    arguments = mapOf("text" to "Hello MCP")
}

Example: parsing a JSON-RPC message

val message: JSONRPCMessage = McpJson.decodeFromString(jsonString)

Use this module when you need the raw building blocks of MCP—types, JSON config, and transport base classes—whether to embed in another runtime, author new transports, or contribute higher-level features in the client/server modules. The APIs are explicit to keep the shared surface stable for downstream users.

kotlin-sdk-core

What the module provides

Typical usage

Example: building a tool call request

Example: parsing a JSON-RPC message

What the module provides

Typical usage

Example: building a tool call request

Example: parsing a JSON-RPC message

What the module provides

Typical usage

Example: building a tool call request

Example: parsing a JSON-RPC message

What the module provides

Typical usage

Example: building a tool call request

Example: parsing a JSON-RPC message

What the module provides

Typical usage

Example: building a tool call request

Example: parsing a JSON-RPC message

Packages