NEWS

---

mcptools 0.2.1.9000

mcptools 0.2.1 (2026-03-17)

• mcp_server() now ensures that inputSchema always includes a properties field, even for tools with no arguments (#91 by @itkonen).

• mcp_server() now negotiates the protocol version with clients, supporting versions 2024-11-05 through 2025-11-25 (#92 by @itkonen).

mcptools 0.2.0 (2025-10-29)

Server

• mcp_server() now supports HTTP transport in addition to stdio. Use type = "http" to start an HTTP server, with optional host and port arguments. For now, the implementation is authless.

• mcp_server() now formats tool results in the same way as ellmer (#78 by @gadenbuie).

• mcp_server() gains logical argument session_tools, allowing users to opt-out of presenting R session tools (that make it possible to communicate with mcp_session()s) to clients.

• Several tightenings-up of the implementation:

  • JSON-RPC responses now retain an explicit id = NULL value, ensuring parse-error replies conform to the MCP specification.
  • mcp_tools() now sends and receives a "notifications/initialized" (#77 by @galachad).
  • The implementation now supports the 2025-06-18 protocol version, updated from 2024-11-05.

• mcp_session() now invisibly returns the nanonext socket used for communicating with the server.

Client

• Notably, mcp_tools() did not gain an implementation of the HTTP transport. Instead, we now recommend the mcp-remote tool for serving local MCP servers via the HTTP transport in the documentation.

• mcp_tools() now errors more informatively when an MCP server process exits unexpectedly (#82).

mcptools 0.1.1 (2025-09-08)

• Addressed an issue in tests on r-devel-linux-x86_64-fedora-clang.

mcptools 0.1.0 (2025-07-18)

• Initial CRAN submission.

Before the initial release of the package, mcptools was called acquaint and supplied a default set of tools from btw, currently a GitHub-only package, when R was used as an MCP server. The direction of the dependency has been reversed; to use the same functionality from before, transition acquaint::mcp_server() to btw::btw_mcp_server() and acquaint::mcp_session() to btw::btw_mcp_session().