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The R file detection chained `is.character(tools) && file.exists(tools)`, which errors under R >= 4.3 when `tools` names more than one tool group. Use `is_string()` so the file branch only considers a single path. Fixes posit-dev#206
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Fixes #206
Summary
btw_mcp_server()checks whethertoolsis a path to an R file withis.character(tools) && file.exists(tools) && .... Whentoolsnames more than one tool group, e.g.btw_mcp_server(c("docs", "env", "sessioninfo")),file.exists()returns a vector and&&errors under R >= 4.3, so the server fails on startup. This swapsis.character()foris_string(), so the file branch only applies to a single path.Verification
The new test in
test-mcp.Rcallsbtw_mcp_server(tools = c("docs", "env"))withmcptools::mcp_server()mocked. It errors onmainwith'length = 2' in coercion to 'logical(1)'and passes with this change.