StdioMcpClient

This docs was updated at: 2026-02-23

com.paragon.mcp.StdioMcpClient  ·  Class

Extends McpClient

---

MCP client that communicates with a subprocess via stdio.

This client launches an MCP server as a subprocess and communicates using stdin/stdout. This is the standard transport for local MCP servers.

Example Usage

try (var mcp = StdioMcpClient.builder()
        .command("npx", "-y", "@modelcontextprotocol/server-filesystem", "/tmp")
        .build()) {
    mcp.connect();
    Agent agent = Agent.builder()
        .name("FileAssistant")
        .tools(mcp.asTools())
        .build();
    var result = agent.interact("List files in the directory");
}

See Also

• McpClient

Methods

builder

public static @NonNull Builder builder()

Creates a new builder for StdioMcpClient.

Returns

a new builder

---

command

public @NonNull Builder command(@NonNull String... command)

Sets the command to run.

Parameters

Name	Description
command	the command and arguments

Returns

this builder

---

command

public @NonNull Builder command(@NonNull List<String> command)

Sets the command to run.

Parameters

Name	Description
command	the command and arguments

Returns

this builder

---

environment

public @NonNull Builder environment(@NonNull String name, @NonNull String value)

Adds an environment variable.

Parameters

Name	Description
name	the variable name
value	the variable value

Returns

this builder

---

environment

public @NonNull Builder environment(@NonNull Map<String, String> environment)

Sets environment variables.

Parameters

Name	Description
environment	the environment variables

Returns

this builder

---

workingDirectory

public @NonNull Builder workingDirectory(@NonNull Path directory)

Sets the working directory for the subprocess.

Parameters

Name	Description
directory	the working directory

Returns

this builder

---

objectMapper

public @NonNull Builder objectMapper(@NonNull ObjectMapper objectMapper)

Sets the ObjectMapper for JSON serialization.

Parameters

Name	Description
objectMapper	the object mapper

Returns

this builder

---

build

public @NonNull StdioMcpClient build()

Builds the StdioMcpClient.

Returns

a new StdioMcpClient

Throws

Type	Condition
IllegalArgumentException	if command is empty