diff --git a/Cargo.lock b/Cargo.lock
index 0e4b61c2..634ae318 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -3704,7 +3704,7 @@ dependencies = [
 
 [[package]]
 name = "solidcraft"
-version = "0.13.0"
+version = "0.13.1"
 dependencies = [
  "block2 0.6.2",
  "eframe",
@@ -3733,7 +3733,7 @@ dependencies = [
 
 [[package]]
 name = "solidcraft-cli"
-version = "0.13.0"
+version = "0.13.1"
 dependencies = [
  "serde_json",
  "solidcraft-engine",
@@ -3742,7 +3742,7 @@ dependencies = [
 
 [[package]]
 name = "solidcraft-derive"
-version = "0.13.0"
+version = "0.13.1"
 dependencies = [
  "proc-macro2",
  "quote",
@@ -3751,7 +3751,7 @@ dependencies = [
 
 [[package]]
 name = "solidcraft-doc"
-version = "0.13.0"
+version = "0.13.1"
 dependencies = [
  "log",
  "serde",
@@ -3768,7 +3768,7 @@ dependencies = [
 
 [[package]]
 name = "solidcraft-engine"
-version = "0.13.0"
+version = "0.13.1"
 dependencies = [
  "log",
  "serde",
@@ -3784,7 +3784,7 @@ dependencies = [
 
 [[package]]
 name = "solidcraft-geom"
-version = "0.13.0"
+version = "0.13.1"
 dependencies = [
  "serde",
  "serde_json",
@@ -3793,7 +3793,7 @@ dependencies = [
 
 [[package]]
 name = "solidcraft-gpu"
-version = "0.13.0"
+version = "0.13.1"
 dependencies = [
  "log",
  "naga",
@@ -3806,7 +3806,7 @@ dependencies = [
 
 [[package]]
 name = "solidcraft-io"
-version = "0.13.0"
+version = "0.13.1"
 dependencies = [
  "quick-xml",
  "serde",
@@ -3821,7 +3821,7 @@ dependencies = [
 
 [[package]]
 name = "solidcraft-kernel"
-version = "0.13.0"
+version = "0.13.1"
 dependencies = [
  "log",
  "rayon",
@@ -3839,7 +3839,7 @@ dependencies = [
 
 [[package]]
 name = "solidcraft-mcp"
-version = "0.13.0"
+version = "0.13.1"
 dependencies = [
  "serde_json",
  "solidcraft-engine",
@@ -3847,7 +3847,7 @@ dependencies = [
 
 [[package]]
 name = "solidcraft-render"
-version = "0.13.0"
+version = "0.13.1"
 dependencies = [
  "image",
  "moxcms",
@@ -3860,7 +3860,7 @@ dependencies = [
 
 [[package]]
 name = "solidcraft-sketch"
-version = "0.13.0"
+version = "0.13.1"
 dependencies = [
  "serde",
  "serde_json",
@@ -3871,7 +3871,7 @@ dependencies = [
 
 [[package]]
 name = "solidcraft-ui-egui"
-version = "0.13.0"
+version = "0.13.1"
 dependencies = [
  "egui",
  "egui-wgpu",
@@ -3892,7 +3892,7 @@ dependencies = [
 
 [[package]]
 name = "solidcraft-web"
-version = "0.13.0"
+version = "0.13.1"
 dependencies = [
  "eframe",
  "egui",
@@ -5381,7 +5381,7 @@ checksum = "e450f9b2ed1dff33c94c12589a87338689467b9c4f5d8a5710bd09a847d2c8a7"
 
 [[package]]
 name = "xtask"
-version = "0.13.0"
+version = "0.13.1"
 dependencies = [
  "serde_json",
  "sha2",
diff --git a/Cargo.toml b/Cargo.toml
index a35256e3..a091f727 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -5,7 +5,7 @@ members = ["crates/*", "apps/*", "xtask"]
 exclude = ["vendor"]
 
 [workspace.package]
-version = "0.13.0"
+version = "0.13.1"
 edition = "2024"
 license = "MIT OR Apache-2.0"
 rust-version = "1.95"
diff --git a/crates/ui-egui/src/agent_chat/discover.rs b/crates/ui-egui/src/agent_chat/discover.rs
index fcd09660..24fffffa 100644
--- a/crates/ui-egui/src/agent_chat/discover.rs
+++ b/crates/ui-egui/src/agent_chat/discover.rs
@@ -184,13 +184,30 @@ pub fn search_dirs() -> Vec<PathBuf> {
     dirs
 }
 
-/// The first `program` in `dirs` (on Windows also with `.exe`/`.cmd`).
+/// The first `program` in `dirs` (on Windows with `.exe`/`.cmd`/`.bat`).
 pub fn find_in(program: &str, dirs: &[PathBuf]) -> Option<PathBuf> {
-    let names: Vec<String> =
-        if cfg!(windows) { ["", ".exe", ".cmd", ".bat"].iter().map(|e| format!("{program}{e}")).collect() } else { vec![program.to_string()] };
+    let names = names_for(program, cfg!(windows));
     dirs.iter().flat_map(|d| names.iter().map(move |n| d.join(n))).find(|p| p.is_file())
 }
 
+/// The file names `program` can have. On Windows only ones it can run: npm puts a Unix shell
+/// script with the bare name next to the `.cmd` shim, and starting that fails with "not a valid
+/// Win32 application".
+fn names_for(program: &str, windows: bool) -> Vec<String> {
+    if windows { [".exe", ".cmd", ".bat"].iter().map(|e| format!("{program}{e}")).collect() } else { vec![program.to_string()] }
+}
+
+/// A Windows command saved without an extension (`…\npm\codex-acp`, from an older version's
+/// lookup): the `.exe`/`.cmd`/`.bat` beside it, if there is one.
+pub fn runnable_sibling(program: &Path) -> Option<PathBuf> {
+    if program.extension().is_some() {
+        return None;
+    }
+    let dir = program.parent()?;
+    let name = program.file_name()?.to_str()?;
+    names_for(name, true).into_iter().map(|n| dir.join(n)).find(|p| p.is_file())
+}
+
 /// `program --version`'s first line, or `None` after `limit` (the probe is then stopped).
 fn version(program: &Path, limit: Duration) -> Option<String> {
     let mut cmd = if cfg!(windows) && program.extension().is_some_and(|e| e.eq_ignore_ascii_case("cmd") || e.eq_ignore_ascii_case("bat")) {
@@ -279,6 +296,25 @@ mod tests {
         let _ = std::fs::remove_dir_all(root);
     }
 
+    #[test]
+    fn on_windows_only_runnable_shims_are_candidates() {
+        // npm's bare `codex-acp` is a shell script; Windows can't start it (os error 193).
+        assert_eq!(names_for("codex-acp", true), ["codex-acp.exe", "codex-acp.cmd", "codex-acp.bat"]);
+        assert_eq!(names_for("codex-acp", false), ["codex-acp"]);
+    }
+
+    #[test]
+    fn a_saved_bare_npm_path_runs_its_cmd_shim() {
+        let root = std::env::temp_dir().join(format!("sc-agent-shim-{}", std::process::id()));
+        std::fs::create_dir_all(&root).unwrap();
+        std::fs::write(root.join("codex-acp"), "#!/bin/sh").unwrap();
+        std::fs::write(root.join("codex-acp.cmd"), "@echo off").unwrap();
+        assert_eq!(runnable_sibling(&root.join("codex-acp")), Some(root.join("codex-acp.cmd")));
+        assert_eq!(runnable_sibling(&root.join("codex-acp.cmd")), None);
+        assert_eq!(runnable_sibling(&root.join("gemini")), None);
+        let _ = std::fs::remove_dir_all(root);
+    }
+
     #[test]
     fn the_version_number_is_picked_out_of_the_line() {
         assert_eq!(version_of("@agentclientprotocol/codex-acp 2.2.2"), "2.2.2");
diff --git a/crates/ui-egui/src/agent_chat/process.rs b/crates/ui-egui/src/agent_chat/process.rs
index 4fc64484..e7049972 100644
--- a/crates/ui-egui/src/agent_chat/process.rs
+++ b/crates/ui-egui/src/agent_chat/process.rs
@@ -51,8 +51,11 @@ impl ProcessHandle {
     }
 }
 
-/// On Windows, npm installs `.cmd` shims, which only `cmd.exe` runs.
+/// On Windows, npm installs `.cmd` shims, which only `cmd.exe` runs. A command saved as the bare
+/// npm path (a shell script there) runs the shim beside it.
 fn command_for(program: &str) -> Command {
+    let shim = if cfg!(windows) { super::discover::runnable_sibling(std::path::Path::new(program)) } else { None };
+    let program = shim.as_deref().and_then(|p| p.to_str()).unwrap_or(program);
     let lower = program.to_ascii_lowercase();
     if cfg!(windows) && (lower.ends_with(".cmd") || lower.ends_with(".bat")) {
         let mut c = Command::new("cmd");