posit-dev / posit-dev/mcptools
Non-blocking stdio serving (coexist with an event loop)
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- Dominant language
- R
- Stars
- 196
- Forks
- 21
- Avg merge
- 1h 14m
- Merged PRs (30d)
- 1
Description
The stdio transport blocks the process in nanonext::wait(cv), so a server that also needs to run a {later}/httpuv event loop (e.g. a live Shiny app speaking MCP over stdio to Claude Desktop) can't use it.
Shiny's dependency-free workaround: file(\"stdin\", blocking = FALSE) polled from a later::later() loop (Unix only; see R/mcp-stdio.R on the shiny branch). nanonext's read_stdin() could support the same pattern if exposed as a pollable/aio rather than a blocking loop.
Part of #115.
Contributor guide
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First steps
- Read the whole issue, then the project's contributing guide.
- Comment on the issue to say you are picking it up — it saves two people doing the same work.
- Fork the repository and make your change on a branch.
- Open a pull request that references the issue number.
Research direction
Start by reading the Shiny branch's R/mcp-stdio.R workaround and the current nanonext::wait(cv) path described in the issue. Then inspect how nanonext::read_stdin() could be exposed for polling or asynchronous use. Done means stdio serving can coexist with a later/httpuv event loop, such as a live Shiny app, without blocking the process.
Written by the indexing model from the issue text.
Assessment
- Tech stack
- r
- Domain
- backend
- Issue type
- Feature
- Difficulty
- 5/5
- Estimated time
- Over a week
- Activity status
- Quiet
- Clarity
- Mostly clear
- Newbie friendliness
- 45/100