From cb11b7915960dcf4884e187bc032f84f4939fd7a Mon Sep 17 00:00:00 2001
From: shikokuchuo <53399081+shikokuchuo@users.noreply.github.com>
Date: Wed, 30 Apr 2025 10:29:47 +0100
Subject: [PATCH 1/5] Use `nanonext::write_stdout()`

---
 DESCRIPTION | 3 ++-
 R/proxy.R   | 6 +++---
 2 files changed, 5 insertions(+), 4 deletions(-)

diff --git a/DESCRIPTION b/DESCRIPTION
index 2614f07..3516c94 100644
--- a/DESCRIPTION
+++ b/DESCRIPTION
@@ -26,7 +26,7 @@ Imports:
     ellmer,
     jsonlite,
     later,
-    nanonext,
+    nanonext (>= 1.5.2.9009),
     promises,
     rlang
 Depends: R (>= 4.1.0)
@@ -35,3 +35,4 @@ BugReports: https://github.com/simonpcouch/acquaint/issues
 Config/Needs/website: tidyverse/tidytemplate
 Remotes:
     posit-dev/btw
+    r-lib/nanonext
diff --git a/R/proxy.R b/R/proxy.R
index 29a3f60..6601a15 100644
--- a/R/proxy.R
+++ b/R/proxy.R
@@ -108,8 +108,8 @@ handle_message_from_server <- function(data) {
 
   logcat("FROM SERVER: ", data)
 
-  # The response_text is alredy JSON, so we'll use cat() instead of cat_json()
-  cat(data, "\n", sep = "")
+  # The response_text is already JSON, so we'll use cat() instead of cat_json()
+  nanonext::write_stdout(data)
 }
 
 schedule_handle_message_from_server <- function() {
@@ -132,7 +132,7 @@ logcat <- function(x, ..., append = TRUE) {
 }
 
 cat_json <- function(x) {
-  cat(to_json(x), "\n", sep = "")
+  nanonext::write_stdout(to_json(x))
 }
 
 capabilities <- function() {

From df2e0e0c992dafe681ece4c5c3815bdaa07da5fb Mon Sep 17 00:00:00 2001
From: shikokuchuo <53399081+shikokuchuo@users.noreply.github.com>
Date: Wed, 30 Apr 2025 10:32:10 +0100
Subject: [PATCH 2/5] Save send_aio reference

---
 R/proxy.R  |  2 +-
 R/server.R | 31 ++++++++++++++++---------------
 2 files changed, 17 insertions(+), 16 deletions(-)

diff --git a/R/proxy.R b/R/proxy.R
index 6601a15..cf14db3 100644
--- a/R/proxy.R
+++ b/R/proxy.R
@@ -120,7 +120,7 @@ schedule_handle_message_from_server <- function() {
 forward_request <- function(data) {
   logcat("TO SERVER: ", data)
 
-  nanonext::send_aio(the$proxy_socket, data)
+  the$saio <- nanonext::send_aio(the$proxy_socket, data)
 }
 
 # This process will be launched by the MCP client, so stdout/stderr aren't
diff --git a/R/server.R b/R/server.R
index 520eef0..4f2f54b 100644
--- a/R/server.R
+++ b/R/server.R
@@ -1,16 +1,16 @@
 #' Model context protocol for your R session
-#' 
+#'
 #' @description
 #' Together, these functions implement a model context protocol server for your
 #' R session.
-#' 
-#' @section Configuration: 
-#' 
+#'
+#' @section Configuration:
+#'
 #' [mcp_proxy()] should be configured with the MCP clients via the `Rscript`
 #' command. For example, to use with Claude Desktop, paste the following in your
-#' Claude Desktop configuration (on macOS, at 
+#' Claude Desktop configuration (on macOS, at
 #' `file.edit("~/Library/Application Support/Claude/claude_desktop_config.json")`):
-#' 
+#'
 #' ```json
 #' {
 #'   "mcpServers": {
@@ -21,31 +21,31 @@
 #'   }
 #' }
 #' ```
-#' 
+#'
 #' Or, to use with Claude Code, you might type in a terminal:
-#' 
+#'
 #' ```bash
 #' claude mcp add -s "user" r-acquaint Rscript -e "acquaint::mcp_proxy()"
 #' ```
-#' 
+#'
 #' **mcp_proxy() is not intended for interactive use.**
-#' 
+#'
 #' The proxy interfaces with the MCP client on behalf of the server hosted in
 #' your R session. **Use [mcp_serve()] to start the MCP server in your R session.**
 #' Place a call to `acquaint::mcp_serve()` in your `.Rprofile`, perhaps with
 #' `usethis::edit_r_profile()`, to start a server for your R session every time
 #' you start R.
-#' 
+#'
 #' @examples
 #' if (interactive()) {
 #' mcp_serve()
 #' }
-#' 
+#'
 #' @name mcp
 #' @export
 mcp_serve <- function() {
-  # HACK: If a server is already running in one session via `.Rprofile`, 
-  # `mcp_serve()` will be called again when the client runs the command 
+  # HACK: If a server is already running in one session via `.Rprofile`,
+  # `mcp_serve()` will be called again when the client runs the command
   # Rscript -e "acquaint::mcp_serve()" and the existing server will be wiped.
   # Returning early in this case allows for the desired R session server to be
   # running already before the client initiates the proxy.
@@ -99,7 +99,8 @@ handle_message_from_proxy <- function(msg) {
   }
   # cat("SEND:", to_json(body), "\n", sep = "", file = stderr())
 
-  nanonext::send_aio(the$server_socket, to_json(body))
+  # TODO: consider if better / more robust using synchronous sends
+  the$saio <- nanonext::send_aio(the$server_socket, to_json(body))
 }
 
 schedule_handle_message_from_proxy <- function() {

From 071ce559452d4388a2fcf139c5b942f1834d26b8 Mon Sep 17 00:00:00 2001
From: shikokuchuo <53399081+shikokuchuo@users.noreply.github.com>
Date: Wed, 30 Apr 2025 10:38:50 +0100
Subject: [PATCH 3/5] Avoid R serialization completely

---
 R/proxy.R  | 4 ++--
 R/server.R | 4 ++--
 2 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/R/proxy.R b/R/proxy.R
index cf14db3..38e36b2 100644
--- a/R/proxy.R
+++ b/R/proxy.R
@@ -113,14 +113,14 @@ handle_message_from_server <- function(data) {
 }
 
 schedule_handle_message_from_server <- function() {
-  r <- nanonext::recv_aio(the$proxy_socket)
+  r <- nanonext::recv_aio(the$proxy_socket, mode = "string")
   promises::as.promise(r)$then(handle_message_from_server)
 }
 
 forward_request <- function(data) {
   logcat("TO SERVER: ", data)
 
-  the$saio <- nanonext::send_aio(the$proxy_socket, data)
+  the$saio <- nanonext::send_aio(the$proxy_socket, data, mode = "raw")
 }
 
 # This process will be launched by the MCP client, so stdout/stderr aren't
diff --git a/R/server.R b/R/server.R
index 4f2f54b..70a06c4 100644
--- a/R/server.R
+++ b/R/server.R
@@ -100,11 +100,11 @@ handle_message_from_proxy <- function(msg) {
   # cat("SEND:", to_json(body), "\n", sep = "", file = stderr())
 
   # TODO: consider if better / more robust using synchronous sends
-  the$saio <- nanonext::send_aio(the$server_socket, to_json(body))
+  the$saio <- nanonext::send_aio(the$server_socket, to_json(body), mode = "raw")
 }
 
 schedule_handle_message_from_proxy <- function() {
-  r <- nanonext::recv_aio(the$server_socket)
+  r <- nanonext::recv_aio(the$server_socket, mode = "string")
   promises::as.promise(r)$then(handle_message_from_proxy)$catch(function(e) {
     print(e)
   })

From 85521438066555444486fc266c2ffbe054f7378f Mon Sep 17 00:00:00 2001
From: shikokuchuo <53399081+shikokuchuo@users.noreply.github.com>
Date: Wed, 30 Apr 2025 11:32:08 +0100
Subject: [PATCH 4/5] Open stdin in blocking mode to avoid potentially buggy
 behaviour on MacOS

---
 R/proxy.R | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/R/proxy.R b/R/proxy.R
index 38e36b2..2a19835 100644
--- a/R/proxy.R
+++ b/R/proxy.R
@@ -11,8 +11,7 @@ mcp_proxy <- function() {
 
   # Note that we're using file("stdin") instead of stdin(), which are not the
   # same.
-  the$f <- file("stdin")
-  open(the$f, blocking = FALSE)
+  the$f <- file("stdin", open = "r")
 
   schedule_handle_message_from_client()
   schedule_handle_message_from_server()

From 1be2a73f2f60b661497f8884bda21a3043ac0fb6 Mon Sep 17 00:00:00 2001
From: shikokuchuo <53399081+shikokuchuo@users.noreply.github.com>
Date: Wed, 30 Apr 2025 12:59:53 +0100
Subject: [PATCH 5/5] Correct remotes

---
 DESCRIPTION | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/DESCRIPTION b/DESCRIPTION
index 3516c94..9315e21 100644
--- a/DESCRIPTION
+++ b/DESCRIPTION
@@ -34,5 +34,5 @@ URL: https://github.com/simonpcouch/acquaint, https://simonpcouch.github.io/acqu
 BugReports: https://github.com/simonpcouch/acquaint/issues
 Config/Needs/website: tidyverse/tidytemplate
 Remotes:
-    posit-dev/btw
+    posit-dev/btw,
     r-lib/nanonext