fix: stop windows server over named pipes

refs #1113

2 files changed, 22 insertions, 2 deletions

diff --git a/docs/next/CHANGELOG.md b/docs/next/CHANGELOG.md
index 8701dd24..36eade52 100644
--- a/docs/next/CHANGELOG.md
+++ b/docs/next/CHANGELOG.md
@@ -19,6 +19,7 @@
 
 ### Fixed
 - `herdr --remote` now prints clean remote attach failures and SSH authentication guidance instead of Rust Debug-formatted I/O errors when SSH authentication is denied. (#1034)
+- `herdr server stop` now stops Windows named-pipe servers instead of failing with `named pipes do not support I/O timeouts`. (#1113)
 - `herdr server stop` now waits until both server sockets are unreachable before returning, avoiding an immediate first-start failure when restarting right after replacing the binary.
 - macOS `herdr --remote` clients now bridge Finder-dropped image files to the remote pane instead of forwarding the local file path as typed text. (#828)
 - Grok Build agent detection now tracks the current Grok Build UI: panes report working while responses, tools, and subagents run, and blocked on permission prompts and question dialogs, instead of falling back to idle mid-turn. (#1017)
diff --git a/src/session.rs b/src/session.rs
index 4dfb2658..8abda3d1 100644
--- a/src/session.rs
+++ b/src/session.rs
@@ -325,7 +325,7 @@ fn send_stop_request(
         return Ok(None);
     };
     if let Err(err) = stream.set_send_timeout(Some(write_timeout)) {
-        if err.kind() != std::io::ErrorKind::InvalidInput {
+        if !stop_timeout_error_allows_wait(&err) {
             return Err(err.to_string());
         }
     }
@@ -354,7 +354,7 @@ fn send_stop_request_inner(
         return Ok(None);
     };
     if let Err(err) = stream.set_recv_timeout(Some(read_timeout)) {
-        if err.kind() == std::io::ErrorKind::InvalidInput {
+        if stop_timeout_error_allows_wait(&err) {
             return Ok(None);
         }
         return Err(err);
@@ -368,6 +368,11 @@ fn send_stop_request_inner(
     Ok(Some(line))
 }
 
+fn stop_timeout_error_allows_wait(err: &std::io::Error) -> bool {
+    err.kind() == std::io::ErrorKind::InvalidInput
+        || (cfg!(windows) && err.kind() == std::io::ErrorKind::Unsupported)
+}
+
 fn stop_request_error_allows_wait(err: &std::io::Error) -> bool {
     matches!(
         err.kind(),
@@ -505,6 +510,20 @@ mod tests {
     }
 
     #[test]
+    fn stop_timeout_invalid_input_waits_for_socket_state() {
+        let err = std::io::Error::from(std::io::ErrorKind::InvalidInput);
+
+        assert!(stop_timeout_error_allows_wait(&err));
+    }
+
+    #[test]
+    fn stop_timeout_unsupported_waits_for_socket_state_only_on_windows() {
+        let err = std::io::Error::from(std::io::ErrorKind::Unsupported);
+
+        assert_eq!(stop_timeout_error_allows_wait(&err), cfg!(windows));
+    }
+
+    #[test]
     fn socket_timeouts_are_never_zero_duration() {
         assert_eq!(socket_timeout_from_remaining(Duration::ZERO), None);
         assert_eq!(