diff --git a/.golangci.yml b/.golangci.yml
index afb62f07e9..5212cb09a7 100644
--- a/.golangci.yml
+++ b/.golangci.yml
@@ -22,6 +22,7 @@ linters:
     - errname
     - errorlint
     - fatcontext
+    - forbidigo
     - gocheckcompilerdirectives
     - goprintffuncname
     - govet
@@ -70,11 +71,30 @@ linters:
             - pkg: 'encoding/json$'
               desc: 'Use "github.com/go-json-experiment/json" instead.'
 
+    forbidigo:
+      analyze-types: true
+      forbid:
+        - pattern: '.*'
+          msg: tspath should likely be used instead
+          pkg: ^(path|path/filepath)$
+        - pattern: '.*'
+          msg: a host implementation should likely be used instead
+          pkg: ^os/
+        - pattern: 'GOOS'
+          msg: a host implementation should likely be used instead
+          pkg: ^runtime$
+
   exclusions:
     rules:
       - path: internal/fourslash/tests/gen/
         linters:
           - misspell
+      - path: 'internal/(repo|testutil|testrunner|vfs|pprof|execute/tsctests|bundled)|cmd/tsgo'
+        text: should likely be used instead
+      - path: '(.+)_test\.go$'
+        text: should likely be used instead
+      - path: '_tools'
+        text: should likely be used instead
 
     presets:
       - comments
diff --git a/cmd/tsgo/lsp.go b/cmd/tsgo/lsp.go
index 35c973a3a0..0dd04c57fb 100644
--- a/cmd/tsgo/lsp.go
+++ b/cmd/tsgo/lsp.go
@@ -1,10 +1,14 @@
 package main
 
 import (
+	"context"
 	"flag"
 	"fmt"
 	"os"
+	"os/exec"
+	"os/signal"
 	"runtime"
+	"syscall"
 
 	"github.com/microsoft/typescript-go/internal/bundled"
 	"github.com/microsoft/typescript-go/internal/core"
@@ -49,9 +53,17 @@ func runLSP(args []string) int {
 		FS:                 fs,
 		DefaultLibraryPath: defaultLibraryPath,
 		TypingsLocation:    typingsLocation,
+		NpmInstall: func(cwd string, args []string) ([]byte, error) {
+			cmd := exec.Command("npm", args...)
+			cmd.Dir = cwd
+			return cmd.Output()
+		},
 	})
 
-	if err := s.Run(); err != nil {
+	ctx, stop := signal.NotifyContext(context.Background(), os.Interrupt, syscall.SIGTERM)
+	defer stop()
+
+	if err := s.Run(ctx); err != nil {
 		return 1
 	}
 	return 0
diff --git a/internal/fourslash/fourslash.go b/internal/fourslash/fourslash.go
index 8c64ea2f90..ddac550413 100644
--- a/internal/fourslash/fourslash.go
+++ b/internal/fourslash/fourslash.go
@@ -1,6 +1,7 @@
 package fourslash
 
 import (
+	"context"
 	"fmt"
 	"io"
 	"maps"
@@ -164,7 +165,7 @@ func NewFourslash(t *testing.T, capabilities *lsproto.ClientCapabilities, conten
 		defer func() {
 			outputWriter.Close()
 		}()
-		err := server.Run()
+		err := server.Run(context.TODO())
 		if err != nil {
 			t.Error("server error:", err)
 		}
diff --git a/internal/lsp/server.go b/internal/lsp/server.go
index 54f78f2e16..2265ebb344 100644
--- a/internal/lsp/server.go
+++ b/internal/lsp/server.go
@@ -5,14 +5,10 @@ import (
 	"errors"
 	"fmt"
 	"io"
-	"os"
-	"os/exec"
-	"os/signal"
 	"runtime/debug"
 	"slices"
 	"sync"
 	"sync/atomic"
-	"syscall"
 	"time"
 
 	"github.com/go-json-experiment/json"
@@ -39,6 +35,7 @@ type ServerOptions struct {
 	DefaultLibraryPath string
 	TypingsLocation    string
 	ParseCache         *project.ParseCache
+	NpmInstall         func(cwd string, args []string) ([]byte, error)
 }
 
 func NewServer(opts *ServerOptions) *Server {
@@ -59,6 +56,7 @@ func NewServer(opts *ServerOptions) *Server {
 		defaultLibraryPath:    opts.DefaultLibraryPath,
 		typingsLocation:       opts.TypingsLocation,
 		parseCache:            opts.ParseCache,
+		npmInstall:            opts.NpmInstall,
 	}
 }
 
@@ -157,6 +155,8 @@ type Server struct {
 	compilerOptionsForInferredProjects *core.CompilerOptions
 	// parseCache can be passed in so separate tests can share ASTs
 	parseCache *project.ParseCache
+
+	npmInstall func(cwd string, args []string) ([]byte, error)
 }
 
 // WatchFiles implements project.Client.
@@ -218,10 +218,7 @@ func (s *Server) RefreshDiagnostics(ctx context.Context) error {
 	return nil
 }
 
-func (s *Server) Run() error {
-	ctx, stop := signal.NotifyContext(context.Background(), os.Interrupt, syscall.SIGTERM)
-	defer stop()
-
+func (s *Server) Run(ctx context.Context) error {
 	g, ctx := errgroup.WithContext(ctx)
 	g.Go(func() error { return s.dispatchLoop(ctx) })
 	g.Go(func() error { return s.writeLoop(ctx) })
@@ -877,9 +874,7 @@ func (s *Server) SetCompilerOptionsForInferredProjects(ctx context.Context, opti
 
 // NpmInstall implements ata.NpmExecutor
 func (s *Server) NpmInstall(cwd string, args []string) ([]byte, error) {
-	cmd := exec.Command("npm", args...)
-	cmd.Dir = cwd
-	return cmd.Output()
+	return s.npmInstall(cwd, args)
 }
 
 func isBlockingMethod(method lsproto.Method) bool {
diff --git a/internal/tspath/extension.go b/internal/tspath/extension.go
index cc30d48a66..1b4422e791 100644
--- a/internal/tspath/extension.go
+++ b/internal/tspath/extension.go
@@ -51,7 +51,7 @@ func RemoveFileExtension(path string) string {
 		}
 	}
 	// Otherwise just remove single dot extension, if any
-	return path[:len(path)-len(filepath.Ext(path))]
+	return path[:len(path)-len(filepath.Ext(path))] //nolint:forbidigo
 }
 
 func TryGetExtensionFromPath(p string) string {