aisdk.mcp

Model Context Protocol (MCP) support for the aisdk toolkit.

• Client — connect to and use tools from local (stdio) or remote MCP servers: create_mcp_client() (stdio), create_mcp_sse_client() (legacy HTTP+SSE), create_mcp_http_client() (Streamable HTTP).
• Server — expose R functions as MCP tools (create_mcp_server()).
• Discovery — discover and integrate external MCP tools into agents.

All three clients share one tool API, so a model does not care which transport delivered the tools:

client$list_tools()                     # what the server offers
client$call_tool("name", list(...))     # raw MCP result
client$call_tool_data("name", list(...))# payload as plain R data
client$as_sdk_tools()                   # hand them to an aisdk agent

One agent can talk to several servers at once; combine_mcp_tools() merges their tools and prefixes the names with each server's own, so two databases that both expose query_gene cannot shadow each other:

tools <- combine_mcp_tools(gpsadb = client_a, uniprot = client_b)
# gpsadb__query_gene, uniprot__search, ...

A self-contained MCP protocol implementation; depends only on the core aisdk contract (tool, generate_text, schema builders), which is why it extracts cleanly with no changes to core.

Installation

# install.packages("remotes")
remotes::install_github("YuLab-SMU/aisdk")       # core
remotes::install_github("YuLab-SMU/aisdk.mcp")   # this package

Which remote transport?

Server advertises	Use
One endpoint answering JSON-RPC POST (MCP 2025-06-18 Streamable HTTP)	create_mcp_http_client(url)
A GET event stream that announces a separate POST endpoint (2024-11-05 HTTP+SSE)	create_mcp_sse_client(url)

If in doubt, try Streamable HTTP first: a Streamable HTTP endpoint answers GET with HTTP 405, while a legacy SSE endpoint accepts it. Most public/hosted MCP servers today are Streamable HTTP.

Usage

library(aisdk)
library(aisdk.mcp)

# local (stdio) server
client <- create_mcp_client(command = "my-mcp-server", args = character(0))

# remote server over Streamable HTTP — no key needed for this public one
client <- create_mcp_http_client("https://gpsadb.gzdlab.com/mcp")
client$server_info$name          # "gpsadb"
client$list_tools()              # 11 tools
info <- client$call_tool_data("get_database_info")

# use the discovered tools with an aisdk agent...
generate_text(
  model = "deepseek:deepseek-chat",
  prompt = "How many perturbation datasets does GPSAdb hold?",
  tools = client$as_sdk_tools()
)

client$close()