diff --git a/pkg/agent/context.go b/pkg/agent/context.go
index b7c6e11080..6fccbaf53f 100644
--- a/pkg/agent/context.go
+++ b/pkg/agent/context.go
@@ -7,6 +7,7 @@ import (
 	"os"
 	"path/filepath"
 	"runtime"
+	"slices"
 	"strings"
 	"sync"
 	"time"
@@ -249,10 +250,8 @@ func (cb *ContextBuilder) sourceFilesChangedLocked() bool {
 	}
 
 	// Check tracked source files (bootstrap + memory).
-	for _, p := range cb.sourcePaths() {
-		if cb.fileChangedSince(p) {
-			return true
-		}
+	if slices.ContainsFunc(cb.sourcePaths(), cb.fileChangedSince) {
+		return true
 	}
 
 	// --- Skills directory (handled separately from sourcePaths) ---
diff --git a/pkg/agent/context_cache_test.go b/pkg/agent/context_cache_test.go
index ba70d4c0d5..0905e8a46a 100644
--- a/pkg/agent/context_cache_test.go
+++ b/pkg/agent/context_cache_test.go
@@ -404,11 +404,11 @@ func TestConcurrentBuildSystemPromptWithCache(t *testing.T) {
 	var wg sync.WaitGroup
 	errs := make(chan string, goroutines*iterations)
 
-	for g := 0; g < goroutines; g++ {
+	for g := range goroutines {
 		wg.Add(1)
 		go func(id int) {
 			defer wg.Done()
-			for i := 0; i < iterations; i++ {
+			for i := range iterations {
 				result := cb.BuildSystemPromptWithCache()
 				if result == "" {
 					errs <- "empty prompt returned"
diff --git a/pkg/agent/loop_test.go b/pkg/agent/loop_test.go
index 6dfc7ef3e3..2a23c889c8 100644
--- a/pkg/agent/loop_test.go
+++ b/pkg/agent/loop_test.go
@@ -5,6 +5,7 @@ import (
 	"fmt"
 	"os"
 	"path/filepath"
+	"slices"
 	"testing"
 	"time"
 
@@ -187,13 +188,7 @@ func TestToolRegistry_ToolRegistration(t *testing.T) {
 	toolsList := toolsInfo["names"].([]string)
 
 	// Check that our custom tool name is in the list
-	found := false
-	for _, name := range toolsList {
-		if name == "mock_custom" {
-			found = true
-			break
-		}
-	}
+	found := slices.Contains(toolsList, "mock_custom")
 	if !found {
 		t.Error("Expected custom tool to be registered")
 	}
@@ -262,13 +257,7 @@ func TestToolRegistry_GetDefinitions(t *testing.T) {
 	toolsList := toolsInfo["names"].([]string)
 
 	// Check that our custom tool name is in the list
-	found := false
-	for _, name := range toolsList {
-		if name == "mock_custom" {
-			found = true
-			break
-		}
-	}
+	found := slices.Contains(toolsList, "mock_custom")
 	if !found {
 		t.Error("Expected custom tool to be registered")
 	}
diff --git a/pkg/agent/memory.go b/pkg/agent/memory.go
index 87a687479d..01e682f3b8 100644
--- a/pkg/agent/memory.go
+++ b/pkg/agent/memory.go
@@ -111,7 +111,7 @@ func (ms *MemoryStore) GetRecentDailyNotes(days int) string {
 	var sb strings.Builder
 	first := true
 
-	for i := 0; i < days; i++ {
+	for i := range days {
 		date := time.Now().AddDate(0, 0, -i)
 		dateStr := date.Format("20060102") // YYYYMMDD
 		monthDir := dateStr[:6]            // YYYYMM
diff --git a/pkg/bus/bus_test.go b/pkg/bus/bus_test.go
index a50586df1a..e07b8c7fea 100644
--- a/pkg/bus/bus_test.go
+++ b/pkg/bus/bus_test.go
@@ -67,7 +67,7 @@ func TestPublishInbound_ContextCancel(t *testing.T) {
 
 	// Fill the buffer
 	ctx := context.Background()
-	for i := 0; i < defaultBusBufferSize; i++ {
+	for i := range defaultBusBufferSize {
 		if err := mb.PublishInbound(ctx, InboundMessage{Content: "fill"}); err != nil {
 			t.Fatalf("fill failed at %d: %v", i, err)
 		}
@@ -154,7 +154,7 @@ func TestConcurrentPublishClose(t *testing.T) {
 	wg.Add(numGoroutines + 1)
 
 	// Spawn many goroutines trying to publish
-	for i := 0; i < numGoroutines; i++ {
+	for range numGoroutines {
 		go func() {
 			defer wg.Done()
 			// Use a short timeout context so we don't block forever after close
@@ -194,7 +194,7 @@ func TestPublishInbound_FullBuffer(t *testing.T) {
 	ctx := context.Background()
 
 	// Fill the buffer
-	for i := 0; i < defaultBusBufferSize; i++ {
+	for i := range defaultBusBufferSize {
 		if err := mb.PublishInbound(ctx, InboundMessage{Content: "fill"}); err != nil {
 			t.Fatalf("fill failed at %d: %v", i, err)
 		}
diff --git a/pkg/channels/manager_test.go b/pkg/channels/manager_test.go
index 6b9f151c3f..f09ecfe2fc 100644
--- a/pkg/channels/manager_test.go
+++ b/pkg/channels/manager_test.go
@@ -274,13 +274,12 @@ func TestWorkerRateLimiter(t *testing.T) {
 		limiter: rate.NewLimiter(2, 1),
 	}
 
-	ctx, cancel := context.WithCancel(context.Background())
-	defer cancel()
+	ctx := t.Context()
 
 	go m.runWorker(ctx, "test", w)
 
 	// Enqueue 4 messages
-	for i := 0; i < 4; i++ {
+	for i := range 4 {
 		w.queue <- bus.OutboundMessage{Channel: "test", ChatID: "1", Content: fmt.Sprintf("msg%d", i)}
 	}
 
@@ -352,8 +351,7 @@ func TestRunWorker_MessageSplitting(t *testing.T) {
 		limiter: rate.NewLimiter(rate.Inf, 1),
 	}
 
-	ctx, cancel := context.WithCancel(context.Background())
-	defer cancel()
+	ctx := t.Context()
 
 	go m.runWorker(ctx, "test", w)
 
@@ -576,7 +574,7 @@ func TestRecordPlaceholder_ConcurrentSafe(t *testing.T) {
 	m := newTestManager()
 
 	var wg sync.WaitGroup
-	for i := 0; i < 100; i++ {
+	for i := range 100 {
 		wg.Add(1)
 		go func(i int) {
 			defer wg.Done()
@@ -591,7 +589,7 @@ func TestRecordTypingStop_ConcurrentSafe(t *testing.T) {
 	m := newTestManager()
 
 	var wg sync.WaitGroup
-	for i := 0; i < 100; i++ {
+	for i := range 100 {
 		wg.Add(1)
 		go func(i int) {
 			defer wg.Done()
@@ -834,7 +832,7 @@ func TestLazyWorkerCreation(t *testing.T) {
 func TestBuildMediaScope_FastIDUniqueness(t *testing.T) {
 	seen := make(map[string]bool)
 
-	for i := 0; i < 1000; i++ {
+	for range 1000 {
 		scope := BuildMediaScope("test", "chat1", "")
 		if seen[scope] {
 			t.Fatalf("duplicate scope generated: %s", scope)
diff --git a/pkg/channels/onebot/onebot.go b/pkg/channels/onebot/onebot.go
index 89cba4ae03..62a9eb34a0 100644
--- a/pkg/channels/onebot/onebot.go
+++ b/pkg/channels/onebot/onebot.go
@@ -337,10 +337,7 @@ func (c *OneBotChannel) sendAPIRequest(action string, params any, timeout time.D
 }
 
 func (c *OneBotChannel) reconnectLoop() {
-	interval := time.Duration(c.config.ReconnectInterval) * time.Second
-	if interval < 5*time.Second {
-		interval = 5 * time.Second
-	}
+	interval := max(time.Duration(c.config.ReconnectInterval)*time.Second, 5*time.Second)
 
 	for {
 		select {
diff --git a/pkg/channels/pico/pico.go b/pkg/channels/pico/pico.go
index 2ae82d8da4..8d8b62a672 100644
--- a/pkg/channels/pico/pico.go
+++ b/pkg/channels/pico/pico.go
@@ -292,8 +292,8 @@ func (c *PicoChannel) authenticate(r *http.Request) bool {
 
 	// Check Authorization header
 	auth := r.Header.Get("Authorization")
-	if strings.HasPrefix(auth, "Bearer ") {
-		if strings.TrimPrefix(auth, "Bearer ") == token {
+	if after, ok := strings.CutPrefix(auth, "Bearer "); ok {
+		if after == token {
 			return true
 		}
 	}
diff --git a/pkg/channels/split.go b/pkg/channels/split.go
index 1c951a31f6..bb26c6d8fc 100644
--- a/pkg/channels/split.go
+++ b/pkg/channels/split.go
@@ -23,10 +23,7 @@ func SplitMessage(content string, maxLen int) []string {
 	var messages []string
 
 	// Dynamic buffer: 10% of maxLen, but at least 50 chars if possible
-	codeBlockBuffer := maxLen / 10
-	if codeBlockBuffer < 50 {
-		codeBlockBuffer = 50
-	}
+	codeBlockBuffer := max(maxLen/10, 50)
 	if codeBlockBuffer > maxLen/2 {
 		codeBlockBuffer = maxLen / 2
 	}
@@ -40,10 +37,7 @@ func SplitMessage(content string, maxLen int) []string {
 		}
 
 		// Effective split point: maxLen minus buffer, to leave room for code blocks
-		effectiveLimit := maxLen - codeBlockBuffer
-		if effectiveLimit < maxLen/2 {
-			effectiveLimit = maxLen / 2
-		}
+		effectiveLimit := max(maxLen-codeBlockBuffer, maxLen/2)
 
 		end := start + effectiveLimit
 
@@ -85,10 +79,9 @@ func SplitMessage(content string, maxLen int) []string {
 					// If we have a reasonable amount of content after the header, split inside
 					if msgEnd > headerEndIdx+20 {
 						// Find a better split point closer to maxLen
-						innerLimit := start + maxLen - 5 // Leave room for "\n```"
-						if innerLimit > totalLen {
-							innerLimit = totalLen
-						}
+						innerLimit := min(
+							// Leave room for "\n```"
+							start+maxLen-5, totalLen)
 						betterEnd := findLastNewlineInRange(runes, start, innerLimit, 200)
 						if betterEnd > headerEndIdx {
 							msgEnd = betterEnd
@@ -117,10 +110,7 @@ func SplitMessage(content string, maxLen int) []string {
 						if unclosedIdx-start > 20 {
 							msgEnd = unclosedIdx
 						} else {
-							splitAt := start + maxLen - 5
-							if splitAt > totalLen {
-								splitAt = totalLen
-							}
+							splitAt := min(start+maxLen-5, totalLen)
 							chunk := strings.TrimRight(string(runes[start:splitAt]), " \t\n\r") + "\n```"
 							messages = append(messages, chunk)
 							remaining := strings.TrimSpace(header + "\n" + string(runes[splitAt:totalLen]))
@@ -196,10 +186,7 @@ func findNewlineFrom(runes []rune, from int) int {
 // findLastNewlineInRange finds the last newline within the last searchWindow runes
 // of the range runes[start:end]. Returns the absolute index or start-1 (indicating not found).
 func findLastNewlineInRange(runes []rune, start, end, searchWindow int) int {
-	searchStart := end - searchWindow
-	if searchStart < start {
-		searchStart = start
-	}
+	searchStart := max(end-searchWindow, start)
 	for i := end - 1; i >= searchStart; i-- {
 		if runes[i] == '\n' {
 			return i
@@ -211,10 +198,7 @@ func findLastNewlineInRange(runes []rune, start, end, searchWindow int) int {
 // findLastSpaceInRange finds the last space/tab within the last searchWindow runes
 // of the range runes[start:end]. Returns the absolute index or start-1 (indicating not found).
 func findLastSpaceInRange(runes []rune, start, end, searchWindow int) int {
-	searchStart := end - searchWindow
-	if searchStart < start {
-		searchStart = start
-	}
+	searchStart := max(end-searchWindow, start)
 	for i := end - 1; i >= searchStart; i-- {
 		if runes[i] == ' ' || runes[i] == '\t' {
 			return i
diff --git a/pkg/channels/wecom/app_test.go b/pkg/channels/wecom/app_test.go
index 5420949de7..0d15e955b4 100644
--- a/pkg/channels/wecom/app_test.go
+++ b/pkg/channels/wecom/app_test.go
@@ -43,7 +43,7 @@ func encryptTestMessageApp(message, aesKey string) (string, error) {
 
 	// Prepare message: random(16) + msg_len(4) + msg + corp_id
 	random := make([]byte, 0, 16)
-	for i := 0; i < 16; i++ {
+	for i := range 16 {
 		random = append(random, byte(i+1))
 	}
 
diff --git a/pkg/channels/wecom/bot_test.go b/pkg/channels/wecom/bot_test.go
index 328b145c2d..97b503ce86 100644
--- a/pkg/channels/wecom/bot_test.go
+++ b/pkg/channels/wecom/bot_test.go
@@ -42,7 +42,7 @@ func encryptTestMessage(message, aesKey string) (string, error) {
 
 	// Prepare message: random(16) + msg_len(4) + msg + receiveid
 	random := make([]byte, 0, 16)
-	for i := 0; i < 16; i++ {
+	for i := range 16 {
 		random = append(random, byte(i))
 	}
 
diff --git a/pkg/channels/wecom/common.go b/pkg/channels/wecom/common.go
index 3c1629577a..39a27d04c4 100644
--- a/pkg/channels/wecom/common.go
+++ b/pkg/channels/wecom/common.go
@@ -125,7 +125,7 @@ func pkcs7Unpad(data []byte) ([]byte, error) {
 		return nil, fmt.Errorf("padding size larger than data")
 	}
 	// Verify all padding bytes
-	for i := 0; i < padding; i++ {
+	for i := range padding {
 		if data[len(data)-1-i] != byte(padding) {
 			return nil, fmt.Errorf("invalid padding byte at position %d", i)
 		}
diff --git a/pkg/config/model_config_test.go b/pkg/config/model_config_test.go
index 084f50a82f..da6e506f84 100644
--- a/pkg/config/model_config_test.go
+++ b/pkg/config/model_config_test.go
@@ -64,7 +64,7 @@ func TestGetModelConfig_RoundRobin(t *testing.T) {
 
 	// Test round-robin distribution
 	results := make(map[string]int)
-	for i := 0; i < 30; i++ {
+	for range 30 {
 		result, err := cfg.GetModelConfig("lb-model")
 		if err != nil {
 			t.Fatalf("GetModelConfig() error = %v", err)
@@ -94,17 +94,15 @@ func TestGetModelConfig_Concurrent(t *testing.T) {
 	var wg sync.WaitGroup
 	errors := make(chan error, goroutines*iterations)
 
-	for i := 0; i < goroutines; i++ {
-		wg.Add(1)
-		go func() {
-			defer wg.Done()
-			for j := 0; j < iterations; j++ {
+	for range goroutines {
+		wg.Go(func() {
+			for range iterations {
 				_, err := cfg.GetModelConfig("concurrent-model")
 				if err != nil {
 					errors <- err
 				}
 			}
-		}()
+		})
 	}
 
 	wg.Wait()
diff --git a/pkg/health/server.go b/pkg/health/server.go
index de1ff60feb..5609ebdf69 100644
--- a/pkg/health/server.go
+++ b/pkg/health/server.go
@@ -4,6 +4,7 @@ import (
 	"context"
 	"encoding/json"
 	"fmt"
+	"maps"
 	"net/http"
 	"sync"
 	"time"
@@ -122,9 +123,7 @@ func (s *Server) readyHandler(w http.ResponseWriter, r *http.Request) {
 	s.mu.RLock()
 	ready := s.ready
 	checks := make(map[string]Check)
-	for k, v := range s.checks {
-		checks[k] = v
-	}
+	maps.Copy(checks, s.checks)
 	s.mu.RUnlock()
 
 	if !ready {
diff --git a/pkg/media/store_test.go b/pkg/media/store_test.go
index 989f90d7c7..1dcfdf350a 100644
--- a/pkg/media/store_test.go
+++ b/pkg/media/store_test.go
@@ -49,7 +49,7 @@ func TestReleaseAll(t *testing.T) {
 
 	paths := make([]string, 3)
 	refs := make([]string, 3)
-	for i := 0; i < 3; i++ {
+	for i := range 3 {
 		paths[i] = createTempFile(t, dir, strings.Repeat("a", i+1)+".jpg")
 		var err error
 		refs[i], err = store.Store(paths[i], MediaMeta{Source: "test"}, "scope1")
@@ -228,12 +228,12 @@ func TestConcurrentSafety(t *testing.T) {
 	var wg sync.WaitGroup
 	wg.Add(goroutines)
 
-	for g := 0; g < goroutines; g++ {
+	for g := range goroutines {
 		go func(gIdx int) {
 			defer wg.Done()
 			scope := strings.Repeat("s", gIdx+1)
 
-			for i := 0; i < filesPerGoroutine; i++ {
+			for i := range filesPerGoroutine {
 				path := createTempFile(t, dir, strings.Repeat("f", gIdx*filesPerGoroutine+i+1)+".tmp")
 				ref, err := store.Store(path, MediaMeta{Source: "test"}, scope)
 				if err != nil {
@@ -448,11 +448,11 @@ func TestConcurrentCleanupSafety(t *testing.T) {
 	wg.Add(workers * 4)
 
 	// Store workers
-	for w := 0; w < workers; w++ {
+	for w := range workers {
 		go func(wIdx int) {
 			defer wg.Done()
 			scope := fmt.Sprintf("scope-%d", wIdx)
-			for i := 0; i < ops; i++ {
+			for i := range ops {
 				p := createTempFile(t, dir, fmt.Sprintf("w%d-f%d.tmp", wIdx, i))
 				store.Store(p, MediaMeta{Source: "test"}, scope)
 			}
@@ -460,30 +460,30 @@ func TestConcurrentCleanupSafety(t *testing.T) {
 	}
 
 	// Resolve workers
-	for w := 0; w < workers; w++ {
+	for range workers {
 		go func() {
 			defer wg.Done()
-			for i := 0; i < ops; i++ {
+			for range ops {
 				store.Resolve("media://nonexistent")
 			}
 		}()
 	}
 
 	// ReleaseAll workers
-	for w := 0; w < workers; w++ {
+	for w := range workers {
 		go func(wIdx int) {
 			defer wg.Done()
-			for i := 0; i < ops; i++ {
+			for range ops {
 				store.ReleaseAll(fmt.Sprintf("scope-%d", wIdx))
 			}
 		}(w)
 	}
 
 	// CleanExpired workers
-	for w := 0; w < workers; w++ {
+	for range workers {
 		go func() {
 			defer wg.Done()
-			for i := 0; i < ops; i++ {
+			for range ops {
 				store.CleanExpired()
 			}
 		}()
diff --git a/pkg/providers/anthropic/provider.go b/pkg/providers/anthropic/provider.go
index 9162174c99..1bb15f771f 100644
--- a/pkg/providers/anthropic/provider.go
+++ b/pkg/providers/anthropic/provider.go
@@ -212,14 +212,14 @@ func translateTools(tools []ToolDefinition) []anthropic.ToolUnionParam {
 }
 
 func parseResponse(resp *anthropic.Message) *LLMResponse {
-	var content string
+	var content strings.Builder
 	var toolCalls []ToolCall
 
 	for _, block := range resp.Content {
 		switch block.Type {
 		case "text":
 			tb := block.AsText()
-			content += tb.Text
+			content.WriteString(tb.Text)
 		case "tool_use":
 			tu := block.AsToolUse()
 			var args map[string]any
@@ -246,7 +246,7 @@ func parseResponse(resp *anthropic.Message) *LLMResponse {
 	}
 
 	return &LLMResponse{
-		Content:      content,
+		Content:      content.String(),
 		ToolCalls:    toolCalls,
 		FinishReason: finishReason,
 		Usage: &UsageInfo{
@@ -264,8 +264,8 @@ func normalizeBaseURL(apiBase string) string {
 	}
 
 	base = strings.TrimRight(base, "/")
-	if strings.HasSuffix(base, "/v1") {
-		base = strings.TrimSuffix(base, "/v1")
+	if before, ok := strings.CutSuffix(base, "/v1"); ok {
+		base = before
 	}
 	if base == "" {
 		return defaultBaseURL
diff --git a/pkg/providers/codex_provider.go b/pkg/providers/codex_provider.go
index dcc740ba44..47618300af 100644
--- a/pkg/providers/codex_provider.go
+++ b/pkg/providers/codex_provider.go
@@ -163,8 +163,8 @@ func resolveCodexModel(model string) (string, string) {
 		return codexDefaultModel, "empty model"
 	}
 
-	if strings.HasPrefix(m, "openai/") {
-		m = strings.TrimPrefix(m, "openai/")
+	if after, ok := strings.CutPrefix(m, "openai/"); ok {
+		m = after
 	} else if strings.Contains(m, "/") {
 		return codexDefaultModel, "non-openai model namespace"
 	}
diff --git a/pkg/providers/cooldown_test.go b/pkg/providers/cooldown_test.go
index 47f43ad5c9..b517e7feba 100644
--- a/pkg/providers/cooldown_test.go
+++ b/pkg/providers/cooldown_test.go
@@ -138,7 +138,7 @@ func TestCooldown_FailureWindowReset(t *testing.T) {
 	ct, current := newTestTracker(now)
 
 	// 4 errors → 1h cooldown
-	for i := 0; i < 4; i++ {
+	for range 4 {
 		ct.MarkFailure("openai", FailoverRateLimit)
 		*current = current.Add(2 * time.Second) // small advance between errors
 	}
@@ -230,7 +230,7 @@ func TestCooldown_ConcurrentAccess(t *testing.T) {
 	ct := NewCooldownTracker()
 	var wg sync.WaitGroup
 
-	for i := 0; i < 100; i++ {
+	for range 100 {
 		wg.Add(3)
 		go func() {
 			defer wg.Done()
diff --git a/pkg/providers/openai_compat/provider.go b/pkg/providers/openai_compat/provider.go
index 5dab9b03ee..d922ed5f7a 100644
--- a/pkg/providers/openai_compat/provider.go
+++ b/pkg/providers/openai_compat/provider.go
@@ -312,8 +312,8 @@ func stripSystemParts(messages []Message) []openaiMessage {
 }
 
 func normalizeModel(model, apiBase string) string {
-	idx := strings.Index(model, "/")
-	if idx == -1 {
+	before, after, ok := strings.Cut(model, "/")
+	if !ok {
 		return model
 	}
 
@@ -321,10 +321,10 @@ func normalizeModel(model, apiBase string) string {
 		return model
 	}
 
-	prefix := strings.ToLower(model[:idx])
+	prefix := strings.ToLower(before)
 	switch prefix {
 	case "moonshot", "nvidia", "groq", "ollama", "deepseek", "google", "openrouter", "zhipu", "mistral":
-		return model[idx+1:]
+		return after
 	default:
 		return model
 	}
diff --git a/pkg/routing/agent_id_test.go b/pkg/routing/agent_id_test.go
index 050fe06451..f9a65c9692 100644
--- a/pkg/routing/agent_id_test.go
+++ b/pkg/routing/agent_id_test.go
@@ -1,6 +1,9 @@
 package routing
 
-import "testing"
+import (
+	"strings"
+	"testing"
+)
 
 func TestNormalizeAgentID_Empty(t *testing.T) {
 	if got := NormalizeAgentID(""); got != DefaultAgentID {
@@ -57,11 +60,11 @@ func TestNormalizeAgentID_AllInvalid(t *testing.T) {
 }
 
 func TestNormalizeAgentID_TruncatesAt64(t *testing.T) {
-	long := ""
-	for i := 0; i < 100; i++ {
-		long += "a"
+	var long strings.Builder
+	for range 100 {
+		long.WriteString("a")
 	}
-	got := NormalizeAgentID(long)
+	got := NormalizeAgentID(long.String())
 	if len(got) > MaxAgentIDLength {
 		t.Errorf("length = %d, want <= %d", len(got), MaxAgentIDLength)
 	}
diff --git a/pkg/skills/loader.go b/pkg/skills/loader.go
index 67d3e70e01..fcbcf934b2 100644
--- a/pkg/skills/loader.go
+++ b/pkg/skills/loader.go
@@ -240,7 +240,7 @@ func (sl *SkillsLoader) parseSimpleYAML(content string) map[string]string {
 	normalized := strings.ReplaceAll(content, "\r\n", "\n")
 	normalized = strings.ReplaceAll(normalized, "\r", "\n")
 
-	for _, line := range strings.Split(normalized, "\n") {
+	for line := range strings.SplitSeq(normalized, "\n") {
 		line = strings.TrimSpace(line)
 		if line == "" || strings.HasPrefix(line, "#") {
 			continue
diff --git a/pkg/skills/search_cache.go b/pkg/skills/search_cache.go
index 5d7d2797ed..1686e3f98c 100644
--- a/pkg/skills/search_cache.go
+++ b/pkg/skills/search_cache.go
@@ -1,7 +1,7 @@
 package skills
 
 import (
-	"sort"
+	"slices"
 	"strings"
 	"sync"
 	"time"
@@ -183,7 +183,7 @@ func buildTrigrams(s string) []uint32 {
 	}
 
 	// Sort and Deduplication
-	sort.Slice(trigrams, func(i, j int) bool { return trigrams[i] < trigrams[j] })
+	slices.Sort(trigrams)
 	n := 1
 	for i := 1; i < len(trigrams); i++ {
 		if trigrams[i] != trigrams[i-1] {
diff --git a/pkg/skills/search_cache_test.go b/pkg/skills/search_cache_test.go
index 816bdfb937..6bbb0e6ebd 100644
--- a/pkg/skills/search_cache_test.go
+++ b/pkg/skills/search_cache_test.go
@@ -153,7 +153,7 @@ func TestSearchCacheConcurrency(t *testing.T) {
 
 	// Concurrent writes
 	go func() {
-		for i := 0; i < 100; i++ {
+		for i := range 100 {
 			cache.Put("query-write-"+string(rune('a'+i%26)), []SearchResult{{Slug: "x"}})
 		}
 		done <- struct{}{}
@@ -161,7 +161,7 @@ func TestSearchCacheConcurrency(t *testing.T) {
 
 	// Concurrent reads
 	go func() {
-		for i := 0; i < 100; i++ {
+		for range 100 {
 			cache.Get("query-write-a")
 		}
 		done <- struct{}{}
diff --git a/pkg/state/state_test.go b/pkg/state/state_test.go
index f717a5bb4a..70117ad61c 100644
--- a/pkg/state/state_test.go
+++ b/pkg/state/state_test.go
@@ -135,7 +135,7 @@ func TestConcurrentAccess(t *testing.T) {
 
 	// Test concurrent writes
 	done := make(chan bool, 10)
-	for i := 0; i < 10; i++ {
+	for i := range 10 {
 		go func(idx int) {
 			channel := fmt.Sprintf("channel-%d", idx)
 			sm.SetLastChannel(channel)
@@ -144,7 +144,7 @@ func TestConcurrentAccess(t *testing.T) {
 	}
 
 	// Wait for all goroutines to complete
-	for i := 0; i < 10; i++ {
+	for range 10 {
 		<-done
 	}
 
diff --git a/pkg/tools/cron.go b/pkg/tools/cron.go
index 52f9146225..0afd51f2de 100644
--- a/pkg/tools/cron.go
+++ b/pkg/tools/cron.go
@@ -3,6 +3,7 @@ package tools
 import (
 	"context"
 	"fmt"
+	"strings"
 	"sync"
 	"time"
 
@@ -218,7 +219,8 @@ func (t *CronTool) listJobs() *ToolResult {
 		return SilentResult("No scheduled jobs")
 	}
 
-	result := "Scheduled jobs:\n"
+	var result strings.Builder
+	result.WriteString("Scheduled jobs:\n")
 	for _, j := range jobs {
 		var scheduleInfo string
 		if j.Schedule.Kind == "every" && j.Schedule.EveryMS != nil {
@@ -230,10 +232,10 @@ func (t *CronTool) listJobs() *ToolResult {
 		} else {
 			scheduleInfo = "unknown"
 		}
-		result += fmt.Sprintf("- %s (id: %s, %s)\n", j.Name, j.ID, scheduleInfo)
+		result.WriteString(fmt.Sprintf("- %s (id: %s, %s)\n", j.Name, j.ID, scheduleInfo))
 	}
 
-	return SilentResult(result)
+	return SilentResult(result.String())
 }
 
 func (t *CronTool) removeJob(args map[string]any) *ToolResult {
diff --git a/pkg/tools/registry_test.go b/pkg/tools/registry_test.go
index 8ae13b20c8..8fe88ca789 100644
--- a/pkg/tools/registry_test.go
+++ b/pkg/tools/registry_test.go
@@ -329,7 +329,7 @@ func TestToolRegistry_ConcurrentAccess(t *testing.T) {
 	r := NewToolRegistry()
 	var wg sync.WaitGroup
 
-	for i := 0; i < 50; i++ {
+	for i := range 50 {
 		wg.Add(1)
 		go func(n int) {
 			defer wg.Done()
diff --git a/pkg/tools/web.go b/pkg/tools/web.go
index 8ba2a723aa..de0c991ff0 100644
--- a/pkg/tools/web.go
+++ b/pkg/tools/web.go
@@ -285,7 +285,7 @@ func (p *DuckDuckGoSearchProvider) extractResults(html string, count int, query
 
 	maxItems := min(len(matches), count)
 
-	for i := 0; i < maxItems; i++ {
+	for i := range maxItems {
 		urlStr := matches[i][1]
 		title := stripTags(matches[i][2])
 		title = strings.TrimSpace(title)
@@ -293,9 +293,9 @@ func (p *DuckDuckGoSearchProvider) extractResults(html string, count int, query
 		// URL decoding if needed
 		if strings.Contains(urlStr, "uddg=") {
 			if u, err := url.QueryUnescape(urlStr); err == nil {
-				idx := strings.Index(u, "uddg=")
-				if idx != -1 {
-					urlStr = u[idx+5:]
+				_, after, ok := strings.Cut(u, "uddg=")
+				if ok {
+					urlStr = after
 				}
 			}
 		}