diff --git a/AGENTS.md b/AGENTS.md
index 4b7cb4b..4f8f18d 100644
--- a/AGENTS.md
+++ b/AGENTS.md
@@ -3,8 +3,9 @@
 ## Toolchain (mise)
 
 ```bash
-mise trust      # trust the mise.toml config (first time only)
-mise install    # installs go 1.26, node 22
+mise trust        # trust the mise.toml config (first time only)
+mise install      # installs go 1.26, node 22
+mise run gopls    # install gopls (Go LSP) — one-time dev setup
 ```
 
 All build/run tasks are defined in `mise.toml`:
diff --git a/main.go b/main.go
index b3c77f7..e3cb6a0 100644
--- a/main.go
+++ b/main.go
@@ -250,7 +250,9 @@ func cmdDownload(args []string) {
 	jobs := fs.Int("jobs", 2, "concurrent downloads")
 	_ = fs.Parse(args)
 
-	os.MkdirAll(*outDir, 0755)
+	if err := os.MkdirAll(*outDir, 0755); err != nil {
+		fatal("create %s: %v", *outDir, err)
+	}
 
 	var identifiers []string
 	if *identifier != "" {
@@ -383,7 +385,9 @@ func cmdExtract(args []string) {
 	jobs := fs.Int("jobs", 2, "concurrent extractions")
 	_ = fs.Parse(args)
 
-	os.MkdirAll(*outDir, 0755)
+	if err := os.MkdirAll(*outDir, 0755); err != nil {
+		fatal("create %s: %v", *outDir, err)
+	}
 
 	entries, err := os.ReadDir(*isoDir)
 	if err != nil {
diff --git a/mise.toml b/mise.toml
index 22ddba3..b794835 100644
--- a/mise.toml
+++ b/mise.toml
@@ -20,3 +20,4 @@ docker-build = "docker build -t akai-fetch ."
 check-toolchain = "bash scripts/check-toolchain.sh"
 check-docker-toolchain = "bash scripts/check-docker-toolchain.sh"
 check-all = { run = "bash scripts/check-toolchain.sh && echo '' && bash scripts/check-docker-toolchain.sh" }
+gopls = "go install golang.org/x/tools/gopls@latest"
diff --git a/scripts/check-toolchain.sh b/scripts/check-toolchain.sh
index 8e62e14..8ec0112 100755
--- a/scripts/check-toolchain.sh
+++ b/scripts/check-toolchain.sh
@@ -98,6 +98,19 @@ fi
 
 echo ""
 
+# ─── gopls (Go LSP) ────────────────────────────────────────────────────
+echo "gopls (Go language server):"
+if command -v gopls &>/dev/null; then
+    gopls_ver=$(gopls version 2>/dev/null)
+    ok "gopls found: $gopls_ver"
+else
+    warn "gopls not found (recommended for IDE support)"
+    echo "    Install: go install golang.org/x/tools/gopls@latest"
+    echo "    (ensure $(go env GOPATH)/bin is in PATH)"
+fi
+
+echo ""
+
 # ─── Node ──────────────────────────────────────────────────────────────
 echo "Node:"
 if command -v node &>/dev/null; then
diff --git a/serve.go b/serve.go
index 63f1593..1133939 100644
--- a/serve.go
+++ b/serve.go
@@ -158,7 +158,13 @@ func handleAPIDownload(w http.ResponseWriter, r *http.Request) {
 		outDir = "."
 	}
 
-	os.MkdirAll(outDir, 0755)
+	if abs, err := filepath.Abs(outDir); err == nil {
+		outDir = abs
+	}
+	if err := os.MkdirAll(outDir, 0755); err != nil {
+		writeJSON(w, map[string]any{"error": fmt.Sprintf("create %s: %v", outDir, err)})
+		return
+	}
 
 	files := getItemFiles(identifier)
 	if len(files) == 0 {
@@ -287,8 +293,6 @@ func handleAPIExtract(w http.ResponseWriter, r *http.Request) {
 		outDir = "./wavs"
 	}
 
-	os.MkdirAll(outDir, 0755)
-
 	entries, err := os.ReadDir(isoDir)
 	if err != nil {
 		writeJSON(w, map[string]any{"error": err.Error()})