diff --git a/coordinator/cmd/worker-agent/main.go b/coordinator/cmd/worker-agent/main.go
index e3602ed..28875ad 100644
--- a/coordinator/cmd/worker-agent/main.go
+++ b/coordinator/cmd/worker-agent/main.go
@@ -7,6 +7,7 @@ package main
 
 import (
 	"context"
+	"errors"
 	"flag"
 	"fmt"
 	"log/slog"
@@ -93,7 +94,7 @@ func loadConfig(configPath string) (*agent.Config, error) {
 	}
 	envPath := os.Getenv("SCIMESH_WORKER_CONFIG")
 	if envPath != "" {
-		if _, err := os.Stat(envPath); err == nil {
+		if _, err := os.Stat(envPath); err == nil { //nolint:gosec // G703: path is the operator's own env var
 			return agent.LoadConfigFile(envPath)
 		}
 	}
@@ -153,7 +154,7 @@ func runSetup(args []string) int {
 	// Block until the signal arrives (never returns an error that matters: a
 	// cancelled context is the normal exit path).
 	err = server.Serve(ctx, listener)
-	if err != nil && err != http.ErrServerClosed {
+	if err != nil && !errors.Is(err, http.ErrServerClosed) {
 		logger.Error("setup wizard stopped", "err", err)
 		return 1
 	}
@@ -172,7 +173,8 @@ func openBrowser(url string) {
 		if err != nil {
 			continue
 		}
-		_ = exec.Command(binary, candidate[1:]...).Start()
+		//nolint:gosec // G204: candidates are our own fixed list; the url is a loopback literal
+		_ = exec.CommandContext(context.Background(), binary, candidate[1:]...).Start()
 		return
 	}
 }
diff --git a/coordinator/internal/agent/check.go b/coordinator/internal/agent/check.go
index 6b788fd..c243ffb 100644
--- a/coordinator/internal/agent/check.go
+++ b/coordinator/internal/agent/check.go
@@ -80,6 +80,7 @@ func CheckEnvironment(ctx context.Context) CheckReport {
 		return report
 	}
 	report.Python = CheckItem{Name: "python", OK: true, Detail: python}
+	//nolint:gosec // G204: python comes from LookPath, the argument list is constant
 	cmd := exec.CommandContext(ctx, python, "-c", "import scimesh; print(scimesh.__version__ if hasattr(scimesh, '__version__') else 'installed')")
 	out, err := cmd.Output()
 	if err != nil {
diff --git a/coordinator/internal/agent/configfile.go b/coordinator/internal/agent/configfile.go
index 57e63f7..fc9e54d 100644
--- a/coordinator/internal/agent/configfile.go
+++ b/coordinator/internal/agent/configfile.go
@@ -41,6 +41,7 @@ func DefaultConfigPath() string {
 // created by the wizard with 0600 permissions, so no credential is exposed to
 // other local users.
 func LoadConfigFile(path string) (*Config, error) {
+	//nolint:gosec // G304: path is --config or SCIMESH_WORKER_CONFIG, operator-supplied
 	raw, err := os.ReadFile(path)
 	if err != nil {
 		return nil, fmt.Errorf("read config file: %w", err)
diff --git a/coordinator/internal/agent/setupui/server.go b/coordinator/internal/agent/setupui/server.go
index 6b098dd..6561912 100644
--- a/coordinator/internal/agent/setupui/server.go
+++ b/coordinator/internal/agent/setupui/server.go
@@ -107,12 +107,15 @@ func (s *PIDSupervisor) Start(configPath, logPath string) (int, error) {
 	if err != nil {
 		return 0, fmt.Errorf("resolve worker binary: %w", err)
 	}
+	//nolint:gosec // G304: logPath lives in the wizard's own config directory
 	logFile, err := os.OpenFile(logPath, os.O_CREATE|os.O_APPEND|os.O_WRONLY, 0o600)
 	if err != nil {
 		return 0, fmt.Errorf("open worker log: %w", err)
 	}
 	defer func() { _ = logFile.Close() }()
-	cmd := exec.Command(exe, "--config", configPath)
+	//nolint:gosec // G204: exe is os.Executable, configPath is the wizard's own file;
+	// Background ctx: the child's lifecycle is managed by the supervisor, not the context
+	cmd := exec.CommandContext(context.Background(), exe, "--config", configPath)
 	cmd.Stdout = logFile
 	cmd.Stderr = logFile
 	cmd.Stdin = nil
@@ -218,7 +221,7 @@ func New(log *slog.Logger, opts Options) *Server {
 // Listen binds the loopback listener and returns it; Serve runs the server on
 // it. Split so tests can inspect the actual ephemeral port.
 func (s *Server) Listen() (net.Listener, error) {
-	return net.Listen("tcp", fmt.Sprintf("127.0.0.1:%d", s.port))
+	return (&net.ListenConfig{}).Listen(context.Background(), "tcp", fmt.Sprintf("127.0.0.1:%d", s.port))
 }
 
 // OpenBrowser hands the wizard URL to the configured opener (default: no-op).
diff --git a/coordinator/internal/agent/setupui/server_test.go b/coordinator/internal/agent/setupui/server_test.go
index d751e7a..1272d6b 100644
--- a/coordinator/internal/agent/setupui/server_test.go
+++ b/coordinator/internal/agent/setupui/server_test.go
@@ -80,7 +80,7 @@ func (f *fakeSup) Alive() bool {
 
 func postJSON(t *testing.T, base, path string, body any) (*httptest.ResponseRecorder, map[string]any) {
 	t.Helper()
-	req, err := http.NewRequest(http.MethodPost, base+path, strings.NewReader(mustJSON(t, body)))
+	req, err := http.NewRequestWithContext(context.Background(), http.MethodPost, base+path, strings.NewReader(mustJSON(t, body)))
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -105,7 +105,7 @@ func postJSON(t *testing.T, base, path string, body any) (*httptest.ResponseReco
 // gets a different port, so nothing can collide or share pooled connections.
 func freePort(t *testing.T) int {
 	t.Helper()
-	listener, err := net.Listen("tcp", "127.0.0.1:0")
+	listener, err := (&net.ListenConfig{}).Listen(context.Background(), "tcp", "127.0.0.1:0")
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -194,7 +194,7 @@ func TestWizardStartStopLifecycle(t *testing.T) {
 	}
 
 	// Status reflects the running state.
-	req, _ := http.NewRequest(http.MethodGet, base+"/api/status", nil)
+	req, _ := http.NewRequestWithContext(context.Background(), http.MethodGet, base+"/api/status", nil)
 	resp, err := http.DefaultClient.Do(req)
 	if err != nil {
 		t.Fatal(err)
@@ -218,7 +218,7 @@ func TestWizardStatusPrefillsSavedConfig(t *testing.T) {
 	postJSON(t, base, "/api/config", map[string]any{
 		"coordinator_url": "http://10.0.0.5:8080", "worker_key": "smk_abc", "work_dir": "/w", "worker_name": "n1",
 	})
-	req, _ := http.NewRequest(http.MethodGet, base+"/api/status", nil)
+	req, _ := http.NewRequestWithContext(context.Background(), http.MethodGet, base+"/api/status", nil)
 	resp, err := http.DefaultClient.Do(req)
 	if err != nil {
 		t.Fatal(err)
diff --git a/coordinator/internal/storage/sqlite/admin_m2_test.go b/coordinator/internal/storage/sqlite/admin_m2_test.go
index ef3a060..46f5c3d 100644
--- a/coordinator/internal/storage/sqlite/admin_m2_test.go
+++ b/coordinator/internal/storage/sqlite/admin_m2_test.go
@@ -2,6 +2,7 @@ package sqlite
 
 import (
 	"context"
+	"errors"
 	"testing"
 	"time"
 
@@ -83,7 +84,7 @@ func TestWorkerSetTrust(t *testing.T) {
 	if err := repo.SetTrust(ctx, worker.ID, domain.WorkerTrusted); err != nil {
 		t.Fatal(err)
 	}
-	if err := repo.SetTrust(ctx, uuid.New(), domain.WorkerTrusted); err != domain.ErrWorkerNotFound {
+	if err := repo.SetTrust(ctx, uuid.New(), domain.WorkerTrusted); !errors.Is(err, domain.ErrWorkerNotFound) {
 		t.Errorf("unknown worker trust err = %v, want ErrWorkerNotFound", err)
 	}
 }
diff --git a/coordinator/internal/transport/http/ui_auth.go b/coordinator/internal/transport/http/ui_auth.go
index 42f7bc9..cf46ea2 100644
--- a/coordinator/internal/transport/http/ui_auth.go
+++ b/coordinator/internal/transport/http/ui_auth.go
@@ -93,6 +93,7 @@ func (s *Server) handleUILogin(w http.ResponseWriter, r *http.Request) {
 	if next == "" || !strings.HasPrefix(next, "/ui/") {
 		next = "/ui"
 	}
+	//nolint:gosec // G710: next is validated to start with /ui/ just above
 	http.Redirect(w, r, next, http.StatusSeeOther)
 }