diff --git a/internal/agent/profile_controller.go b/internal/agent/profile_controller.go
index 416c60f0d..c1d093506 100644
--- a/internal/agent/profile_controller.go
+++ b/internal/agent/profile_controller.go
@@ -91,7 +91,7 @@ func (c *profileController) maybeEscalate() (PostureEscalation, bool) {
 	if c.policy == nil || c.escalated {
 		return PostureEscalation{}, false
 	}
-	if !(c.failureTripped || c.riskTripped || c.scTripped || c.uncertainTrip) {
+	if !c.failureTripped && !c.riskTripped && !c.scTripped && !c.uncertainTrip {
 		return PostureEscalation{}, false
 	}
 	c.escalated = true
diff --git a/internal/agenteval/score.go b/internal/agenteval/score.go
index 73002902a..174aa3cca 100644
--- a/internal/agenteval/score.go
+++ b/internal/agenteval/score.go
@@ -125,9 +125,7 @@ func Score(suite Suite, input ScoreInput) Report {
 	if len(task.RequiredTraceEvents) > 0 {
 		report.Results = append(report.Results, scoreTraceEvents(task.RequiredTraceEvents, input))
 	}
-	for _, result := range unknownCommandResults(input.CommandResults, seenCommands, input) {
-		report.Results = append(report.Results, result)
-	}
+	report.Results = append(report.Results, unknownCommandResults(input.CommandResults, seenCommands, input)...)
 	report.finishSummary()
 	return report
 }
diff --git a/internal/agentinit/agentinit.go b/internal/agentinit/agentinit.go
index 060fe4f68..a65b5486a 100644
--- a/internal/agentinit/agentinit.go
+++ b/internal/agentinit/agentinit.go
@@ -40,14 +40,14 @@ func FormatFacts(info repoinfo.Info) string {
 	b.WriteString("Pre-computed repository facts (from a local scan — verify and fill gaps):\n")
 
 	if info.PrimaryLanguage != "" {
-		b.WriteString(fmt.Sprintf("- Primary language: %s (of %d detected)\n", info.PrimaryLanguage, info.LanguageCount))
+		fmt.Fprintf(&b, "- Primary language: %s (of %d detected)\n", info.PrimaryLanguage, info.LanguageCount)
 	}
 	if langs := topLanguages(info.Languages, 5); langs != "" {
 		b.WriteString("- Languages: " + langs + "\n")
 	}
-	b.WriteString(fmt.Sprintf("- Size: ~%d files, ~%d LOC, max dir depth %d\n", info.FileCount, info.LOCEstimate, info.MaxDepth))
+	fmt.Fprintf(&b, "- Size: ~%d files, ~%d LOC, max dir depth %d\n", info.FileCount, info.LOCEstimate, info.MaxDepth)
 	if info.WorkspaceType != "" && info.WorkspaceType != "none" {
-		b.WriteString(fmt.Sprintf("- Workspace: %s (%d packages)\n", info.WorkspaceType, info.WorkspacePackageCount))
+		fmt.Fprintf(&b, "- Workspace: %s (%d packages)\n", info.WorkspaceType, info.WorkspacePackageCount)
 	}
 	if len(info.BuildTools) > 0 {
 		b.WriteString("- Build tools: " + strings.Join(info.BuildTools, ", ") + "\n")
diff --git a/internal/cli/agent_eval.go b/internal/cli/agent_eval.go
index e8cb80fef..d0f6e6ce8 100644
--- a/internal/cli/agent_eval.go
+++ b/internal/cli/agent_eval.go
@@ -515,9 +515,7 @@ func agentEvalReportFromBenchmark(suite agenteval.Suite, report agenteval.Benchm
 		if task.Agent.Truncated {
 			converted.Truncated = true
 		}
-		for _, failure := range agentEvalFailuresFromTaskReport(task) {
-			converted.Failures = append(converted.Failures, failure)
-		}
+		converted.Failures = append(converted.Failures, agentEvalFailuresFromTaskReport(task)...)
 	}
 	return converted
 }
diff --git a/internal/cli/mcp_config.go b/internal/cli/mcp_config.go
index 603fcd50a..6abd20365 100644
--- a/internal/cli/mcp_config.go
+++ b/internal/cli/mcp_config.go
@@ -734,14 +734,12 @@ func (cfg *mcpWritableConfig) setServerDisabled(name string, disabled bool) (boo
 		switch {
 		case legacyFound:
 			raw = legacyRaw
-			found = true
 		case config.IsDefaultMCPServer(name):
 			// A built-in default server isn't written to the file until the user
 			// overrides it. Treat it as present with an empty base so disabling it
 			// writes a minimal {"disabled":true} entry that merges over the default —
 			// letting `zero mcp disable <default>` work even though it lives in code.
 			raw = nil
-			found = true
 		default:
 			return false, false, nil
 		}
diff --git a/internal/cli/provider_detect.go b/internal/cli/provider_detect.go
index c4063bd90..8c06667c0 100644
--- a/internal/cli/provider_detect.go
+++ b/internal/cli/provider_detect.go
@@ -83,10 +83,10 @@ func runProvidersDetect(args []string, stdout io.Writer, stderr io.Writer, deps
 func parseProviderDetectArgs(args []string) (providerDetectOptions, bool, error) {
 	options := providerDetectOptions{}
 	for _, arg := range args {
-		switch {
-		case arg == "-h" || arg == "--help" || arg == "help":
+		switch arg {
+		case "-h", "--help", "help":
 			return options, true, nil
-		case arg == "--json":
+		case "--json":
 			options.json = true
 		default:
 			return options, false, execUsageError{fmt.Sprintf("unexpected argument %q", arg)}
diff --git a/internal/cli/usage.go b/internal/cli/usage.go
index 0c133d68e..bdffe2652 100644
--- a/internal/cli/usage.go
+++ b/internal/cli/usage.go
@@ -244,19 +244,19 @@ func parseUsageArgs(args []string) (usageOptions, bool, error) {
 func FormatReport(report usage.Report, insertions int, deletions int) string {
 	var builder strings.Builder
 	builder.WriteString("Usage report (cost is a reconstructed estimate)\n\n")
-	builder.WriteString(fmt.Sprintf("%-12s %10s %14s %14s\n", "date", "requests", "tokens", "est. cost"))
+	fmt.Fprintf(&builder, "%-12s %10s %14s %14s\n", "date", "requests", "tokens", "est. cost")
 	for _, bucket := range report.Buckets {
-		builder.WriteString(fmt.Sprintf("%-12s %10d %14s %14s\n",
-			bucket.Date, bucket.Requests, groupThousands(bucket.TotalTokens), formatUSD(bucket.TotalCost)))
+		fmt.Fprintf(&builder, "%-12s %10d %14s %14s\n",
+			bucket.Date, bucket.Requests, groupThousands(bucket.TotalTokens), formatUSD(bucket.TotalCost))
 	}
-	builder.WriteString(fmt.Sprintf("\n%-12s %10d %14s %14s\n",
-		"total", report.Total.Requests, groupThousands(report.Total.TotalTokens), formatUSD(report.Total.TotalCost)))
+	fmt.Fprintf(&builder, "\n%-12s %10d %14s %14s\n",
+		"total", report.Total.Requests, groupThousands(report.Total.TotalTokens), formatUSD(report.Total.TotalCost))
 
-	builder.WriteString(fmt.Sprintf("\nnet LOC (estimate): +%d / -%d = %d\n",
-		insertions, deletions, report.NetLOC))
+	fmt.Fprintf(&builder, "\nnet LOC (estimate): +%d / -%d = %d\n",
+		insertions, deletions, report.NetLOC)
 	if report.NetLOCPositive {
-		builder.WriteString(fmt.Sprintf("tokens per net LOC: %.1f\n", report.TokensPerNetLOC))
-		builder.WriteString(fmt.Sprintf("est. cost per net LOC: %s\n", formatUSD(report.CostPerNetLOC)))
+		fmt.Fprintf(&builder, "tokens per net LOC: %.1f\n", report.TokensPerNetLOC)
+		fmt.Fprintf(&builder, "est. cost per net LOC: %s\n", formatUSD(report.CostPerNetLOC))
 	} else {
 		builder.WriteString("tokens per net LOC: n/a (net LOC <= 0)\n")
 		builder.WriteString("est. cost per net LOC: n/a (net LOC <= 0)\n")
diff --git a/internal/config/mcp_merge.go b/internal/config/mcp_merge.go
index 816ccb54c..4a1717f38 100644
--- a/internal/config/mcp_merge.go
+++ b/internal/config/mcp_merge.go
@@ -87,7 +87,7 @@ func mergeMCPServer(base MCPServerConfig, next MCPServerConfig, canReenable bool
 		// server the user explicitly enabled. The only layer allowed to
 		// override an explicit higher-scope decision is the CLI override scope
 		// (canReenable=true).
-		if canReenable || !(baseDisabledSet && baseDisabled != next.Disabled) {
+		if canReenable || !baseDisabledSet || baseDisabled == next.Disabled {
 			base.Disabled = next.Disabled
 		}
 	}
diff --git a/internal/dictation/transcriber_deepgram.go b/internal/dictation/transcriber_deepgram.go
index b8b9319aa..d4a69ce7f 100644
--- a/internal/dictation/transcriber_deepgram.go
+++ b/internal/dictation/transcriber_deepgram.go
@@ -100,7 +100,7 @@ func (d *deepgramTranscriber) StreamTranscribe(ctx context.Context, chunks <-cha
 				}
 			default:
 			}
-			return compose(), fmt.Errorf("Deepgram stream error: %w", err)
+			return compose(), fmt.Errorf("Deepgram stream error: %w", err) //nolint:staticcheck // Preserve established user-facing error text.
 		}
 		if typ != websocket.MessageText {
 			continue
diff --git a/internal/imageinput/pdf_test.go b/internal/imageinput/pdf_test.go
index 72d61d081..614250ab3 100644
--- a/internal/imageinput/pdf_test.go
+++ b/internal/imageinput/pdf_test.go
@@ -48,7 +48,7 @@ func buildMinimalPDF(text string) []byte {
 	buf.WriteString("0 " + strconv.Itoa(len(offsets)+1) + "\n")
 	buf.WriteString("0000000000 65535 f \n")
 	for _, off := range offsets {
-		buf.WriteString(fmt.Sprintf("%010d 00000 n \n", off))
+		fmt.Fprintf(&buf, "%010d 00000 n \n", off)
 	}
 	buf.WriteString("trailer\n<< /Size " + strconv.Itoa(len(offsets)+1) + " /Root 1 0 R >>\n")
 	buf.WriteString("startxref\n" + strconv.Itoa(xrefStart) + "\n%%EOF\n")
@@ -277,7 +277,7 @@ func buildEmptyTextPDF() []byte {
 	buf.WriteString("0 " + strconv.Itoa(len(offsets)+1) + "\n")
 	buf.WriteString("0000000000 65535 f \n")
 	for _, off := range offsets {
-		buf.WriteString(fmt.Sprintf("%010d 00000 n \n", off))
+		fmt.Fprintf(&buf, "%010d 00000 n \n", off)
 	}
 	buf.WriteString("trailer\n<< /Size " + strconv.Itoa(len(offsets)+1) + " /Root 1 0 R >>\n")
 	buf.WriteString("startxref\n" + strconv.Itoa(xrefStart) + "\n%%EOF\n")
diff --git a/internal/lsp/navigate_test.go b/internal/lsp/navigate_test.go
index 2976a0e88..d209f7125 100644
--- a/internal/lsp/navigate_test.go
+++ b/internal/lsp/navigate_test.go
@@ -1,6 +1,7 @@
 package lsp
 
 import (
+	"context"
 	"encoding/json"
 	"testing"
 )
@@ -64,7 +65,7 @@ func TestDecodeSymbols(t *testing.T) {
 
 func TestNavigateUnknownOp(t *testing.T) {
 	m := NewManager(t.TempDir())
-	_, _, ok, err := m.Navigate(nil, NavRequest{Op: "bogus", Path: "x.go"})
+	_, _, ok, err := m.Navigate(context.TODO(), NavRequest{Op: "bogus", Path: "x.go"})
 	if err == nil {
 		t.Fatal("expected an error for an unknown nav op")
 	}
@@ -76,7 +77,7 @@ func TestNavigateUnknownOp(t *testing.T) {
 func TestNavigateUnsupportedExtensionDegrades(t *testing.T) {
 	// A file type with no configured server degrades to ok=false, no error.
 	m := NewManager(t.TempDir())
-	_, _, ok, err := m.Navigate(nil, NavRequest{Op: NavDefinition, Path: "notes.unknownext", Line: 1, Character: 1})
+	_, _, ok, err := m.Navigate(context.TODO(), NavRequest{Op: NavDefinition, Path: "notes.unknownext", Line: 1, Character: 1})
 	if err != nil {
 		t.Fatalf("unsupported extension should not error, got %v", err)
 	}
diff --git a/internal/providerhealth/providerhealth.go b/internal/providerhealth/providerhealth.go
index fe375a43f..b213a9d88 100644
--- a/internal/providerhealth/providerhealth.go
+++ b/internal/providerhealth/providerhealth.go
@@ -391,7 +391,7 @@ func validateEndpoint(ctx context.Context, endpoint string, resolver Resolver, a
 		return endpointSafetyError{message: "provider connectivity URL is unsafe: localhost hosts are blocked"}
 	}
 	if addr, err := netip.ParseAddr(normalized); err == nil {
-		if reason := blockedAddrReason(addr); reason != "" && !(allowLoopbackOrPrivate && (addr.IsLoopback() || addr.IsPrivate())) {
+		if reason := blockedAddrReason(addr); reason != "" && (!allowLoopbackOrPrivate || (!addr.IsLoopback() && !addr.IsPrivate())) {
 			return endpointSafetyError{message: "provider connectivity URL is unsafe: " + reason}
 		}
 		return nil
@@ -407,7 +407,7 @@ func validateEndpoint(ctx context.Context, endpoint string, resolver Resolver, a
 		return endpointSafetyError{message: "provider connectivity host resolved to no addresses"}
 	}
 	for _, addr := range addrs {
-		if reason := blockedAddrReason(addr); reason != "" && !(allowLoopbackOrPrivate && (addr.IsLoopback() || addr.IsPrivate())) {
+		if reason := blockedAddrReason(addr); reason != "" && (!allowLoopbackOrPrivate || (!addr.IsLoopback() && !addr.IsPrivate())) {
 			return endpointSafetyError{message: "provider connectivity URL is unsafe: " + reason}
 		}
 	}
@@ -529,7 +529,7 @@ func safeDialContext(resolver Resolver, allowLoopbackOrPrivate bool) func(contex
 			return nil, err
 		}
 		if addr, parseErr := netip.ParseAddr(host); parseErr == nil {
-			if reason := blockedAddrReason(addr); reason != "" && !(allowLoopbackOrPrivate && (addr.IsLoopback() || addr.IsPrivate())) {
+			if reason := blockedAddrReason(addr); reason != "" && (!allowLoopbackOrPrivate || (!addr.IsLoopback() && !addr.IsPrivate())) {
 				return nil, endpointSafetyError{message: "provider connectivity URL is unsafe: " + reason}
 			}
 			return dialer.DialContext(ctx, network, address)
@@ -542,7 +542,7 @@ func safeDialContext(resolver Resolver, allowLoopbackOrPrivate bool) func(contex
 			return nil, endpointSafetyError{message: "provider connectivity host resolved to no addresses"}
 		}
 		for _, addr := range addrs {
-			if reason := blockedAddrReason(addr); reason != "" && !(allowLoopbackOrPrivate && (addr.IsLoopback() || addr.IsPrivate())) {
+			if reason := blockedAddrReason(addr); reason != "" && (!allowLoopbackOrPrivate || (!addr.IsLoopback() && !addr.IsPrivate())) {
 				return nil, endpointSafetyError{message: "provider connectivity URL is unsafe: " + reason}
 			}
 		}
diff --git a/internal/provideronboarding/localruntime_test.go b/internal/provideronboarding/localruntime_test.go
index 29df60f2b..8889cc1d4 100644
--- a/internal/provideronboarding/localruntime_test.go
+++ b/internal/provideronboarding/localruntime_test.go
@@ -62,7 +62,7 @@ func TestDetectLocalRuntimesReportsReachableRuntime(t *testing.T) {
 	if !detected[0].Reachable {
 		t.Fatalf("runtime should be reachable: %#v", detected[0])
 	}
-	if detected[0].Models == nil || len(detected[0].Models) == 0 || detected[0].Models[0] != "llama3.1" {
+	if len(detected[0].Models) == 0 || detected[0].Models[0] != "llama3.1" {
 		t.Fatalf("expected discovered model list, got %#v", detected[0].Models)
 	}
 }
diff --git a/internal/repomap/prompt.go b/internal/repomap/prompt.go
index 42390a2fb..f92c64387 100644
--- a/internal/repomap/prompt.go
+++ b/internal/repomap/prompt.go
@@ -188,7 +188,7 @@ func writePromptLine(builder *strings.Builder, format string, args ...any) {
 	if builder.Len() > 0 {
 		builder.WriteByte('\n')
 	}
-	builder.WriteString(fmt.Sprintf(format, args...))
+	fmt.Fprintf(builder, format, args...)
 }
 
 func clampBudget(text string, budget int) string {
diff --git a/internal/sandbox/adapters.go b/internal/sandbox/adapters.go
index 41f5fef1c..24e01d2b5 100644
--- a/internal/sandbox/adapters.go
+++ b/internal/sandbox/adapters.go
@@ -225,7 +225,7 @@ func (backend Backend) SandboxEnvMarkers(policy Policy) []string {
 	if policy.Mode == ModeDisabled {
 		return nil
 	}
-	if !(backend.CommandWrapping && backend.Available) && backend.Name != BackendWSL {
+	if (!backend.CommandWrapping || !backend.Available) && backend.Name != BackendWSL {
 		return nil
 	}
 	name := backend.Name
diff --git a/internal/sandbox/command_prefix.go b/internal/sandbox/command_prefix.go
index e9f402adb..53a4efd4c 100644
--- a/internal/sandbox/command_prefix.go
+++ b/internal/sandbox/command_prefix.go
@@ -153,10 +153,7 @@ func unsafeCommandPrefix(prefix []string) bool {
 			return true
 		}
 	}
-	if unsafeCommandPrefixLauncher(prefix[0]) {
-		return true
-	}
-	return false
+	return unsafeCommandPrefixLauncher(prefix[0])
 }
 
 func unsafeCommandPrefixPart(part string) bool {
diff --git a/internal/sandbox/engine.go b/internal/sandbox/engine.go
index db66d54a9..ed7440780 100644
--- a/internal/sandbox/engine.go
+++ b/internal/sandbox/engine.go
@@ -249,7 +249,7 @@ func (engine *Engine) shellSandboxActive(policy Policy) bool {
 		return false
 	}
 	backend := engine.backend
-	if !(backend.Available && backend.Executable != "" && backend.CommandWrapping && backend.NativeIsolation) {
+	if !backend.Available || backend.Executable == "" || !backend.CommandWrapping || !backend.NativeIsolation {
 		return false
 	}
 	// On Windows the command is only actually wrapped once `zero sandbox setup`
diff --git a/internal/sandbox/landlock_other.go b/internal/sandbox/landlock_other.go
index ec221dfb5..b271e9650 100644
--- a/internal/sandbox/landlock_other.go
+++ b/internal/sandbox/landlock_other.go
@@ -4,7 +4,7 @@ package sandbox
 
 import "errors"
 
-var ErrLandlockUnsupported = errors.New("Landlock is only supported on Linux")
+var ErrLandlockUnsupported = errors.New("Landlock is only supported on Linux") //nolint:staticcheck // Preserve the exported sentinel's established text.
 
 func ApplyLandlockFilesystemProfile(profile PermissionProfile, cwd string) error {
 	return ErrLandlockUnsupported
diff --git a/internal/sandbox/windows_network.go b/internal/sandbox/windows_network.go
index 55fb419b6..0d614a0fc 100644
--- a/internal/sandbox/windows_network.go
+++ b/internal/sandbox/windows_network.go
@@ -10,7 +10,7 @@ import (
 	"strings"
 )
 
-var ErrWindowsNetworkEnforcementUnavailable = errors.New("Windows sandbox network enforcement is not available")
+var ErrWindowsNetworkEnforcementUnavailable = errors.New("Windows sandbox network enforcement is not available") //nolint:staticcheck // Preserve the exported sentinel's established text.
 
 const (
 	windowsWFPProviderKey = "2e31d31c-3948-4753-9117-e5d1a6496f41"
diff --git a/internal/specialist/exec.go b/internal/specialist/exec.go
index 6dac1d259..702360543 100644
--- a/internal/specialist/exec.go
+++ b/internal/specialist/exec.go
@@ -827,7 +827,7 @@ func runChildProcess(ctx context.Context, binaryPath string, args []string, prog
 				// ExitCode() is -1 when the child was terminated by a signal rather
 				// than exiting. ProcessState.String() is the portable description
 				// (e.g. "signal: killed") — capture it so the failure isn't opaque.
-				signalDesc = exitErr.ProcessState.String()
+				signalDesc = exitErr.String()
 			}
 		} else {
 			return ChildRunResult{Events: events, Stderr: stderr.String(), ExitCode: -1, Started: started}, fmt.Errorf("run specialist child: %w", err)
diff --git a/internal/tui/command_center.go b/internal/tui/command_center.go
index 8db9f822f..d3449a538 100644
--- a/internal/tui/command_center.go
+++ b/internal/tui/command_center.go
@@ -548,7 +548,7 @@ func (m model) switchProviderModel(providerName, modelID string) (model, string,
 	// and a stored OAuth login (e.g. ChatGPT) is a credential too — the profile stays
 	// keyless on purpose so newProvider attaches the bearer resolver + login key.
 	if strings.TrimSpace(target.APIKey) == "" && strings.TrimSpace(target.AuthHeaderValue) == "" &&
-		!(hasDescriptor && descriptor.Local) && !oauthLoginAvailable(target) {
+		(!hasDescriptor || !descriptor.Local) && !oauthLoginAvailable(target) {
 		return m, "Model\nprovider " + strconv.Quote(providerName) + " has no usable credential — run setup or `zero auth login " + providerName + "`.", false, nil
 	}
 	next, err := m.newProvider(target)
diff --git a/internal/tui/export_test.go b/internal/tui/export_test.go
index f9af6f45a..180e4b03d 100644
--- a/internal/tui/export_test.go
+++ b/internal/tui/export_test.go
@@ -8,7 +8,6 @@ import (
 	"strings"
 	"time"
 
-	tea "charm.land/bubbletea/v2"
 	"charm.land/lipgloss/v2"
 	"github.com/Gitlawb/zero/internal/dictation"
 )
@@ -87,10 +86,6 @@ func (m model) scrollableTranscriptLayoutView(header string, body transcriptBody
 	return m.renderScrollableTranscriptWindow(frame, bodyWindow, window, width, overlay)
 }
 
-func (m model) scrollableTranscriptView(header string, body string, footer string, width int, overlay string) string {
-	return m.scrollableTranscriptLayoutView(header, transcriptBodyLayout{lines: viewLines(body)}, footer, width, overlay)
-}
-
 func (m model) overlayMouseTop(overlayHeight int, width int) int {
 	return m.overlayMouseRect(overlayHeight, width).y
 }
@@ -230,17 +225,6 @@ func (d *streamingDecoder) tailLines() []string {
 	return out
 }
 
-// ensureAgeTickReschedule is a small helper used after a fade-state change
-// to start the tick if it's not already running. The age-tick case
-// short-circuits when fadeActive is false, so calling this on a no-op
-// transition (e.g. a 0-byte delta) is safe.
-func (m model) ensureAgeTickReschedule() tea.Cmd {
-	if !m.fadeActive {
-		return nil
-	}
-	return streamingFadeTick()
-}
-
 // newSTTDownloadPicker builds the model-download chooser, seeded with the
 // curated shortlist. The full model list from the release is fetched
 // asynchronously and merged in (see fetchSTTModelsCmd / handleSTTModelsFetched).
@@ -288,11 +272,6 @@ func transcriptViewportStartForFrame(body string, frame transcriptFrameLayout, s
 	return window.start, window.height, frame.bodyRect.y
 }
 
-func transcriptViewportStartForLayout(layout transcriptBodyLayout, frame transcriptFrameLayout, scrollOffset int) (int, int, int) {
-	window := transcriptViewportForLayout(layout, frame, scrollOffset).window()
-	return window.start, window.height, frame.bodyRect.y
-}
-
 func transcriptViewportForBody(body string, frame transcriptFrameLayout, offset int) transcriptViewport {
 	return newTranscriptViewport(len(viewLines(body)), frame.bodyRect.height, offset)
 }
diff --git a/internal/tui/files_git_sweep_test.go b/internal/tui/files_git_sweep_test.go
index 484392e39..cccdcb4d9 100644
--- a/internal/tui/files_git_sweep_test.go
+++ b/internal/tui/files_git_sweep_test.go
@@ -1,6 +1,7 @@
 package tui
 
 import (
+	"context"
 	"os"
 	"os/exec"
 	"path/filepath"
@@ -192,7 +193,7 @@ func TestGitSweepCmdAgainstRealRepo(t *testing.T) {
 	run("commit", "-q", "-m", "seed")
 	write("pre-existing.txt", "dirt\n") // dirty BEFORE the TUI "opens"
 
-	baseline := gitSweepCmd(nil, dir, true)().(gitSweepMsg)
+	baseline := gitSweepCmd(context.TODO(), dir, true)().(gitSweepMsg)
 	if !baseline.ok || len(baseline.files) != 1 || baseline.files[0].path != "pre-existing.txt" {
 		t.Fatalf("baseline should see only the pre-existing dirt: %+v", baseline)
 	}
@@ -201,7 +202,7 @@ func TestGitSweepCmdAgainstRealRepo(t *testing.T) {
 	write("scaffolded.txt", "hello\n")
 	write("tracked.txt", "one\ntwo\nthree\nfour\n")
 
-	sweep := gitSweepCmd(nil, dir, false)().(gitSweepMsg)
+	sweep := gitSweepCmd(context.TODO(), dir, false)().(gitSweepMsg)
 	if !sweep.ok {
 		t.Fatal("sweep failed")
 	}
@@ -224,7 +225,7 @@ func TestGitSweepCmdAgainstRealRepo(t *testing.T) {
 	run("commit", "-q", "-m", "second")
 	run("mv", "tracked.txt", "renamed.txt")
 	write("renamed.txt", "one\ntwo\nthree\nfour\nfive\n")
-	renameSweep := gitSweepCmd(nil, dir, false)().(gitSweepMsg)
+	renameSweep := gitSweepCmd(context.TODO(), dir, false)().(gitSweepMsg)
 	if !renameSweep.ok {
 		t.Fatal("rename sweep failed")
 	}
@@ -237,7 +238,7 @@ func TestGitSweepCmdAgainstRealRepo(t *testing.T) {
 	}
 
 	// Not-a-repo → ok=false (the sweep latches off).
-	if msg := gitSweepCmd(nil, t.TempDir(), false)().(gitSweepMsg); msg.ok {
+	if msg := gitSweepCmd(context.TODO(), t.TempDir(), false)().(gitSweepMsg); msg.ok {
 		t.Fatal("a non-repo should report ok=false")
 	}
 }
diff --git a/internal/tui/flush.go b/internal/tui/flush.go
index 8034500b8..0d5e1548e 100644
--- a/internal/tui/flush.go
+++ b/internal/tui/flush.go
@@ -46,7 +46,7 @@ func (m model) settledRow(row transcriptRow, rc rowContext) bool {
 		if row.id != "" && rc.resolved[rcKey(row.runID, row.id)] {
 			return true
 		}
-		return !(m.pending && row.runID != 0 && row.runID == m.activeRunID)
+		return !m.pending || row.runID == 0 || row.runID != m.activeRunID
 	case rowPermission:
 		event := row.permission
 		if event == nil || event.ToolCallID == "" || event.Action != agent.PermissionActionPrompt {
@@ -57,7 +57,7 @@ func (m model) settledRow(row transcriptRow, rc rowContext) bool {
 		}
 		// An undecided prompt renders live (with the modal card) until its
 		// decision lands or its run ends.
-		return !(m.pending && row.runID != 0 && row.runID == m.activeRunID)
+		return !m.pending || row.runID == 0 || row.runID != m.activeRunID
 	default:
 		// User/system/error/assistant/ask-user rows are appended in final form;
 		// welcome rows render nothing and settle trivially.
diff --git a/internal/tui/image_attach_test.go b/internal/tui/image_attach_test.go
index d4754028d..33a78b771 100644
--- a/internal/tui/image_attach_test.go
+++ b/internal/tui/image_attach_test.go
@@ -290,7 +290,7 @@ func writeTestPDF(t *testing.T, dir, name, text string) string {
 	xrefStart := buf.Len()
 	buf.WriteString("xref\n0 " + strconv.Itoa(len(offsets)+1) + "\n0000000000 65535 f \n")
 	for _, off := range offsets {
-		buf.WriteString(fmt.Sprintf("%010d 00000 n \n", off))
+		fmt.Fprintf(&buf, "%010d 00000 n \n", off)
 	}
 	buf.WriteString("trailer\n<< /Size " + strconv.Itoa(len(offsets)+1) + " /Root 1 0 R >>\nstartxref\n" + strconv.Itoa(xrefStart) + "\n%%EOF\n")
 
diff --git a/internal/tui/loop.go b/internal/tui/loop.go
index 0d0ea7392..03fb5803f 100644
--- a/internal/tui/loop.go
+++ b/internal/tui/loop.go
@@ -594,8 +594,8 @@ func (m model) loopListText() string {
 				when = "due"
 			}
 		}
-		b.WriteString(fmt.Sprintf("  %s · %s · iter %d · %s · %s\n",
-			l.id, l.cadenceText(), l.iteration, when, truncateLoopPrompt(l.prompt)))
+		fmt.Fprintf(&b, "  %s · %s · iter %d · %s · %s\n",
+			l.id, l.cadenceText(), l.iteration, when, truncateLoopPrompt(l.prompt))
 	}
 	b.WriteString("Stop with /loop stop <id> or /loop stop all.")
 	return b.String()
diff --git a/internal/tui/model_test.go b/internal/tui/model_test.go
index 65bc18fd4..f2be354aa 100644
--- a/internal/tui/model_test.go
+++ b/internal/tui/model_test.go
@@ -1396,7 +1396,7 @@ func TestBeginRunPreparesRunCompletionWarningEachTurn(t *testing.T) {
 	})
 
 	m = m.beginRun(nil)
-	m = m.beginRun(nil)
+	_ = m.beginRun(nil)
 
 	if prepares != 2 {
 		t.Fatalf("PrepareRunCompletionWarning called %d times, want once per run", prepares)
diff --git a/internal/tui/onboarding.go b/internal/tui/onboarding.go
index c4b26705c..ed09f3a87 100644
--- a/internal/tui/onboarding.go
+++ b/internal/tui/onboarding.go
@@ -218,20 +218,22 @@ func (m model) handleSetupKey(msg tea.KeyMsg) (tea.Model, tea.Cmd) {
 		}
 		return m, nil
 	case keyIs(msg, tea.KeyUp) || keyCtrl(msg, 'p'):
-		if m.setup.stage == setupStageMethod {
+		switch m.setup.stage {
+		case setupStageMethod:
 			m.moveSetupMethod(-1)
-		} else if m.setup.stage == setupStageProvider {
+		case setupStageProvider:
 			m.moveSetupProvider(-1)
-		} else if m.setup.stage == setupStageModel {
+		case setupStageModel:
 			m.moveSetupModel(-1)
 		}
 		return m, nil
 	case keyIs(msg, tea.KeyDown) || keyCtrl(msg, 'n'):
-		if m.setup.stage == setupStageMethod {
+		switch m.setup.stage {
+		case setupStageMethod:
 			m.moveSetupMethod(1)
-		} else if m.setup.stage == setupStageProvider {
+		case setupStageProvider:
 			m.moveSetupProvider(1)
-		} else if m.setup.stage == setupStageModel {
+		case setupStageModel:
 			m.moveSetupModel(1)
 		}
 		return m, nil
@@ -279,15 +281,17 @@ func (m model) handleSetupKey(msg tea.KeyMsg) (tea.Model, tea.Cmd) {
 	case "q":
 		return m, tea.Quit
 	case "k":
-		if m.setup.stage == setupStageProvider {
+		switch m.setup.stage {
+		case setupStageProvider:
 			m.moveSetupProvider(-1)
-		} else if m.setup.stage == setupStageModel {
+		case setupStageModel:
 			m.moveSetupModel(-1)
 		}
 	case "j":
-		if m.setup.stage == setupStageProvider {
+		switch m.setup.stage {
+		case setupStageProvider:
 			m.moveSetupProvider(1)
-		} else if m.setup.stage == setupStageModel {
+		case setupStageModel:
 			m.moveSetupModel(1)
 		}
 	}
@@ -360,16 +364,18 @@ func (m model) handleSetupMouse(msg tea.MouseMsg) (tea.Model, tea.Cmd) {
 	switch {
 	case mouseWheelUp(msg):
 		m.clearMouseSelection()
-		if m.setup.stage == setupStageProvider {
+		switch m.setup.stage {
+		case setupStageProvider:
 			m.moveSetupProvider(-1)
-		} else if m.setup.stage == setupStageModel {
+		case setupStageModel:
 			m.moveSetupModel(-1)
 		}
 	case mouseWheelDown(msg):
 		m.clearMouseSelection()
-		if m.setup.stage == setupStageProvider {
+		switch m.setup.stage {
+		case setupStageProvider:
 			m.moveSetupProvider(1)
-		} else if m.setup.stage == setupStageModel {
+		case setupStageModel:
 			m.moveSetupModel(1)
 		}
 	}
diff --git a/internal/tui/provider_wizard_test.go b/internal/tui/provider_wizard_test.go
index ef65cb426..1013bd917 100644
--- a/internal/tui/provider_wizard_test.go
+++ b/internal/tui/provider_wizard_test.go
@@ -687,7 +687,7 @@ func TestProviderWizardPersistsPastedKeyToUserConfig(t *testing.T) {
 	updated, _ = next.Update(testKey(tea.KeyEnter))
 	next = updated.(model)
 	updated, _ = next.Update(testKey(tea.KeyEnter))
-	next = updated.(model)
+	_ = updated.(model)
 
 	if captured.APIKey != secret {
 		t.Fatalf("captured APIKey = %q, want pasted secret", captured.APIKey)
diff --git a/internal/tui/rendering.go b/internal/tui/rendering.go
index c64a8c259..a5e6ec4ab 100644
--- a/internal/tui/rendering.go
+++ b/internal/tui/rendering.go
@@ -1473,7 +1473,7 @@ func renderToolResultCard(row transcriptRow, width int, rc rowContext, opts card
 	// scrollback clean. Skipped for: the uncapped detailed view (opts.bodyCap==0),
 	// diff tools whose body must stay reviewable, and short output.
 	collapsedFooter := ""
-	if opts.bodyCap > 0 && !toolCardAlwaysExpands(name) && !(!failed && (isExploreTool(name) || isLocalControlTool(name))) {
+	if opts.bodyCap > 0 && !toolCardAlwaysExpands(name) && (failed || (!isExploreTool(name) && !isLocalControlTool(name))) {
 		collapsedFooter = collapsedToolFooter(row.detail)
 	}
 	if collapsedFooter != "" && !row.expanded {
diff --git a/internal/tui/specialist_card.go b/internal/tui/specialist_card.go
index 0ba119ba3..2bd7160fd 100644
--- a/internal/tui/specialist_card.go
+++ b/internal/tui/specialist_card.go
@@ -393,10 +393,10 @@ func toolCallSummary(event streamjson.Event) string {
 	case "write_stdin":
 		sessionID := toolCallIntArg(args, "session_id")
 		chars, _ := args["chars"].(string)
-		switch {
-		case chars == "":
+		switch chars {
+		case "":
 			return fmt.Sprintf("poll session %d", sessionID)
-		case chars == "\x03":
+		case "\x03":
 			return fmt.Sprintf("interrupt session %d", sessionID)
 		default:
 			return fmt.Sprintf("send input to session %d", sessionID)
diff --git a/internal/tui/theme.go b/internal/tui/theme.go
index 4859fd45a..9e708c3b3 100644
--- a/internal/tui/theme.go
+++ b/internal/tui/theme.go
@@ -220,8 +220,3 @@ func (t tuiTheme) onPanel(style lipgloss.Style) lipgloss.Style {
 func (t tuiTheme) onSel(style lipgloss.Style) lipgloss.Style {
 	return style.Background(t.bgSel)
 }
-
-// onPerm paints on the permission-card tint.
-func (t tuiTheme) onPerm(style lipgloss.Style) lipgloss.Style {
-	return style.Background(t.bgPerm)
-}
diff --git a/internal/tui/transcript_selection.go b/internal/tui/transcript_selection.go
index a04fe1724..8a70bf08e 100644
--- a/internal/tui/transcript_selection.go
+++ b/internal/tui/transcript_selection.go
@@ -1360,7 +1360,7 @@ func (m model) handleTranscriptSelectionMouse(msg tea.MouseMsg) (model, tea.Cmd,
 			}
 			return m, nil, false
 		}
-		if line.permOption && !(m.pendingPermission != nil && m.pendingPermission.typing) {
+		if line.permOption && (m.pendingPermission == nil || !m.pendingPermission.typing) {
 			// A left-click on a permission-popup option resolves it directly. The
 			// typing guard is defence-in-depth: renderFocusedPermissionPrompt already
 			// returns nil offsets in feedback mode, so no option row is registered as
diff --git a/internal/update/apply.go b/internal/update/apply.go
index 29736de1a..4f97dd458 100644
--- a/internal/update/apply.go
+++ b/internal/update/apply.go
@@ -162,10 +162,11 @@ func applyStandaloneUpdate(ctx context.Context, result Result, executablePath st
 
 	binaryName := "zero"
 	optionalBinaries := linuxOptionalBinaries
-	if runtime.GOOS == "windows" {
+	switch runtime.GOOS {
+	case "windows":
 		binaryName = "zero.exe"
 		optionalBinaries = windowsOptionalBinaries
-	} else if runtime.GOOS == "darwin" {
+	case "darwin":
 		optionalBinaries = nil
 	}
 
diff --git a/internal/update/apply_test.go b/internal/update/apply_test.go
index 379273498..80e9d9f01 100644
--- a/internal/update/apply_test.go
+++ b/internal/update/apply_test.go
@@ -151,10 +151,11 @@ func TestApplyStandaloneUpdateReplacesBinary(t *testing.T) {
 func TestApplyStandaloneUpdateWarnsWhenHelperRefreshFails(t *testing.T) {
 	binaryName := "zero"
 	optionalName := "zero-seccomp"
-	if runtime.GOOS == "windows" {
+	switch runtime.GOOS {
+	case "windows":
 		binaryName = "zero.exe"
 		optionalName = "zero-windows-command-runner.exe"
-	} else if runtime.GOOS == "darwin" {
+	case "darwin":
 		t.Skip("macOS ships no optional helper binaries to refresh")
 	}
 
diff --git a/internal/update/update.go b/internal/update/update.go
index 43e875d84..b4b11d1f0 100644
--- a/internal/update/update.go
+++ b/internal/update/update.go
@@ -344,7 +344,7 @@ func releasePlatform(goos string) (string, error) {
 		// self-updating release asset. Point users at `npm update` rather
 		// than a source rebuild, since that's the documented Termux
 		// install/upgrade path and doesn't require a Go toolchain.
-		return "", fmt.Errorf("no published release for %q (release assets: linux, macos, windows). Your build is the current version of record. Upgrade with `npm update -g @gitlawb/zero` to get the latest.", goos)
+		return "", fmt.Errorf("no published release for %q (release assets: linux, macos, windows). Your build is the current version of record. Upgrade with `npm update -g @gitlawb/zero` to get the latest.", goos) //nolint:staticcheck // Preserve established user-facing error text.
 	}
 }
 
diff --git a/internal/usercommands/usercommands.go b/internal/usercommands/usercommands.go
index 3cb969ca9..f043e1bb9 100644
--- a/internal/usercommands/usercommands.go
+++ b/internal/usercommands/usercommands.go
@@ -109,7 +109,7 @@ func validCommandName(name string) bool {
 		return false
 	}
 	for _, r := range name {
-		if !(r >= 'a' && r <= 'z') && !(r >= '0' && r <= '9') && r != '-' {
+		if (r < 'a' || r > 'z') && (r < '0' || r > '9') && r != '-' {
 			return false
 		}
 	}