Get tools from MCP servers

Starts the servers in an mcptools configuration file and returns their tools, ready to register on an Agent. MCP (Model Context Protocol) servers give agents tools for services such as GitHub, Slack or Google Drive.

Usage

tools_mcp(config = NULL, servers = NULL)

Arguments

config

Path to an MCP configuration file. Defaults to mcptools' default location, ~/.config/mcptools/config.json.

servers

Names of the servers to load, matched exactly. Servers not named are not started. NULL (the default) loads every configured server.

Value

A list of tools. If mcptools isn't installed or loading fails, tools_mcp() warns and returns an empty list.

Details

The configuration file uses the Claude Desktop format:

{
  "mcpServers": {
    "github": {
      "command": "npx",
      "args": ["-y", "@modelcontextprotocol/server-github"],
      "env": {"GITHUB_TOKEN": "..."}
    }
  }
}

Deputy supports mcptools 1.0.2 and 1.0.3; other versions give a warning and no tools. Annotations a server leaves out get cautious defaults, so MCP tools usually need web = TRUE in Permissions(). tool_metadata() shows what a tool declares.

Loading a server again restarts it and breaks the tools from the earlier load; register the new ones with replace = TRUE. A stdio server that takes more than about 4 seconds to answer a call is stopped, and the call fails. McpConnection gives you a fixed tool allowlist, timeouts and control over shutdown.

See also

The mcptools package for configuration, and vignette("mcp").

Examples

if (FALSE) { # \dontrun{
# Get all MCP tools from the default config
mcp_tools <- tools_mcp()

# Create an agent with MCP tools
agent <- Agent$new(
  chat = ellmer::chat("anthropic/claude-sonnet-5"),
  tools = c(tools_file(), mcp_tools),
  permissions = Permissions(web = TRUE)
)

# Use custom config file
mcp_tools <- tools_mcp(config = "path/to/config.json")

# Load tools from specific servers only
mcp_tools <- tools_mcp(servers = c("github", "slack"))
} # }