diff --git a/internal/export/export.go b/internal/export/export.go
index 69a31d7f9..24fd1da87 100644
--- a/internal/export/export.go
+++ b/internal/export/export.go
@@ -244,18 +244,18 @@ func inGeneratedRange(line int, ranges []lint.LineRange) bool {
 // because such PIs sit inside a pair's body range and are skipped
 // here.
 func stripDirectives(f *lint.File, directives []directiveStrip) []byte {
-	stripLines := map[int]bool{}
-	bodyLines := map[int]bool{}
+	stripLines := map[int]struct{}{}
+	bodyLines := map[int]struct{}{}
 
 	for _, d := range directives {
 		pairs, _ := gensection.FindMarkerPairs(f, d.name, d.ruleID, d.ruleName)
 		for _, p := range pairs {
 			for line := p.StartLine; line < p.ContentFrom; line++ {
-				stripLines[line] = true
+				stripLines[line] = struct{}{}
 			}
-			stripLines[p.EndLine] = true
+			stripLines[p.EndLine] = struct{}{}
 			for line := p.ContentFrom; line <= p.ContentTo; line++ {
-				bodyLines[line] = true
+				bodyLines[line] = struct{}{}
 			}
 		}
 	}
@@ -276,7 +276,7 @@ func stripDirectives(f *lint.File, directives []directiveStrip) []byte {
 			continue
 		}
 		for line := startLine; line <= endLine; line++ {
-			stripLines[line] = true
+			stripLines[line] = struct{}{}
 		}
 	}
 
@@ -316,20 +316,20 @@ func piLineRange(pi *piparser.ProcessingInstruction, f *lint.File) (int, int) {
 	return start, f.LineOfOffset(pi.ClosureLine.Start)
 }
 
-func overlapsAny(from, to int, set map[int]bool) bool {
+func overlapsAny(from, to int, set map[int]struct{}) bool {
 	for line := from; line <= to; line++ {
-		if set[line] {
+		if _, ok := set[line]; ok {
 			return true
 		}
 	}
 	return false
 }
 
-func emitLines(srcLines [][]byte, strip map[int]bool) []byte {
+func emitLines(srcLines [][]byte, strip map[int]struct{}) []byte {
 	var b bytes.Buffer
 	for i, line := range srcLines {
 		lineNum := i + 1
-		if strip[lineNum] {
+		if _, ok := strip[lineNum]; ok {
 			continue
 		}
 		b.Write(line)
diff --git a/internal/index/locate.go b/internal/index/locate.go
index ff114efed..4b62fe54e 100644
--- a/internal/index/locate.go
+++ b/internal/index/locate.go
@@ -462,9 +462,11 @@ func listItemValue(line string) (string, bool) {
 // Returns "" when none precedes the item.
 func enclosingListKey(lines [][]byte, line int) string {
 	for i := line - 2; i >= 0; i-- {
-		m := piArgRE.FindStringSubmatch(string(lines[i]))
-		if len(m) >= 3 && strings.TrimSpace(m[2]) == "" {
-			return m[1]
+		// FindSubmatch accepts []byte directly, avoiding a string allocation
+		// per scanned line when the caller passes bytes.
+		m := piArgRE.FindSubmatch(lines[i])
+		if len(m) >= 3 && len(m[2]) == 0 {
+			return string(m[1])
 		}
 		// A populated `key: value` line or another list item does not
 		// open a list block for our item; keep scanning past list items
diff --git a/internal/index/locate_test.go b/internal/index/locate_test.go
index f0c610f77..71355bcdb 100644
--- a/internal/index/locate_test.go
+++ b/internal/index/locate_test.go
@@ -248,3 +248,15 @@ func TestLocateFrontMatterKindsListItemWithDifferentValues(t *testing.T) {
 	assert.Equal(t, "kinds", res.FrontMatterKey)
 	assert.Equal(t, "reference", res.FrontMatterValue)
 }
+
+func TestEnclosingListKey_FindsParentKey(t *testing.T) {
+	lines := [][]byte{
+		[]byte("inputs:"),
+		[]byte("  - alpha"),
+		[]byte("  - beta"),
+		[]byte("  - gamma"),
+	}
+	// Line 4 (1-based) is "gamma"; the enclosing key is "inputs".
+	got := enclosingListKey(lines, 4)
+	assert.Equal(t, "inputs", got)
+}
diff --git a/internal/lsp/rename.go b/internal/lsp/rename.go
index 3d40fb29d..e2a232565 100644
--- a/internal/lsp/rename.go
+++ b/internal/lsp/rename.go
@@ -80,7 +80,8 @@ func isValidRefDefLine(source []byte, line int) bool {
 	if bodyLine < 1 {
 		return false
 	}
-	return rename.ValidRefDefBodyLines(body)[bodyLine]
+	_, ok := rename.ValidRefDefBodyLines(body)[bodyLine]
+	return ok
 }
 
 // headingPrepareRange builds the rename range for an ATX or setext
diff --git a/internal/rename/rename.go b/internal/rename/rename.go
index 61ab96423..332d011ea 100644
--- a/internal/rename/rename.go
+++ b/internal/rename/rename.go
@@ -91,10 +91,10 @@ func LinkRef(source []byte, oldLabel, newName string) ([]Edit, error) {
 // reference definition goldmark accepted (not a code-block
 // look-alike). The LSP prepare-rename gate consults it so the rename
 // UI never surfaces on a `[label]: url`-shaped code sample.
-func ValidRefDefBodyLines(body []byte) map[int]bool {
-	out := map[int]bool{}
+func ValidRefDefBodyLines(body []byte) map[int]struct{} {
+	out := map[int]struct{}{}
 	for _, m := range validRefDefMatches(body) {
-		out[m.bodyLine] = true
+		out[m.bodyLine] = struct{}{}
 	}
 	return out
 }
@@ -169,7 +169,7 @@ func validRefDefMatches(body []byte) []validRefDefMatch {
 	var out []validRefDefMatch
 	for _, m := range index.RefDefRegexpMatches(body) {
 		bodyLine := lineOfBodyOffset(body, m[2])
-		if consumed[bodyLine] {
+		if _, ok := consumed[bodyLine]; ok {
 			continue
 		}
 		raw := body[m[2]:m[3]]
@@ -190,8 +190,8 @@ func validRefDefMatches(body []byte) []validRefDefMatch {
 // is by definition not a def. The Document root and
 // LinkReferenceDefinition nodes are skipped: the former spans the
 // whole buffer, the latter IS the line a real def lives on.
-func contentBlockLines(root ast.Node, body []byte) map[int]bool {
-	out := map[int]bool{}
+func contentBlockLines(root ast.Node, body []byte) map[int]struct{} {
+	out := map[int]struct{}{}
 	_ = ast.Walk(root, func(n ast.Node, entering bool) (ast.WalkStatus, error) {
 		if !entering {
 			return ast.WalkContinue, nil
@@ -206,7 +206,7 @@ func contentBlockLines(root ast.Node, body []byte) map[int]bool {
 		ls := n.Lines()
 		for i := 0; i < ls.Len(); i++ {
 			seg := ls.At(i)
-			out[lineOfBodyOffset(body, seg.Start)] = true
+			out[lineOfBodyOffset(body, seg.Start)] = struct{}{}
 		}
 		return ast.WalkContinue, nil
 	})
diff --git a/internal/rename/rename_test.go b/internal/rename/rename_test.go
index 0f4e5b71e..5cb0103fe 100644
--- a/internal/rename/rename_test.go
+++ b/internal/rename/rename_test.go
@@ -88,9 +88,12 @@ func TestLinkRef_WithFrontMatterLineOffset(t *testing.T) {
 
 func TestValidRefDefBodyLines(t *testing.T) {
 	body := []byte("para\n\n[a]: u\n\n```\n[b]: v\n```\n")
+	// ValidRefDefBodyLines returns map[int]struct{} — presence means valid def.
 	got := ValidRefDefBodyLines(body)
-	assert.True(t, got[3], "real def on body line 3")
-	assert.False(t, got[6], "fenced def-shaped line is not a def")
+	_, ok3 := got[3]
+	assert.True(t, ok3, "real def on body line 3")
+	_, ok6 := got[6]
+	assert.False(t, ok6, "fenced def-shaped line is not a def")
 }
 
 func TestBodyAndFMOffset(t *testing.T) {
diff --git a/internal/rules/concisenessscoring/rule.go b/internal/rules/concisenessscoring/rule.go
index e439988d5..68e638c4f 100644
--- a/internal/rules/concisenessscoring/rule.go
+++ b/internal/rules/concisenessscoring/rule.go
@@ -97,17 +97,15 @@ func (r *Rule) Check(f *lint.File) []lint.Diagnostic {
 		}
 
 		line := astutil.ParagraphLine(para, f)
-		message := fmt.Sprintf(
-			"conciseness score too low (%.2f < %.2f); target >= %.2f",
-			result.Conciseness, r.MinScore, r.MinScore,
-		)
 		examples := formatExamples(result.Cues)
+		var cuesSuffix string
 		if examples != "" {
-			message += fmt.Sprintf(
-				"; reduce verbose cues (e.g., %s)",
-				examples,
-			)
+			cuesSuffix = "; reduce verbose cues (e.g., " + examples + ")"
 		}
+		message := fmt.Sprintf(
+			"conciseness score too low (%.2f < %.2f); target >= %.2f%s",
+			result.Conciseness, r.MinScore, r.MinScore, cuesSuffix,
+		)
 
 		diags = append(diags, lint.Diagnostic{
 			File:     f.Path,
diff --git a/internal/rules/concisenessscoring/rule_test.go b/internal/rules/concisenessscoring/rule_test.go
index 4f9f13545..74e728a07 100644
--- a/internal/rules/concisenessscoring/rule_test.go
+++ b/internal/rules/concisenessscoring/rule_test.go
@@ -296,3 +296,53 @@ func TestNewScorer_Success(t *testing.T) {
 	require.NoError(t, err)
 	assert.NotNil(t, s)
 }
+
+func TestCheck_MessageNoConcatenationWhenExamplesPresent(t *testing.T) {
+	// When verbose cues are found, the diagnostic message must include
+	// the cue examples in a single fmt.Sprintf rather than via `message +=`
+	// concatenation. This test verifies the combined message format so the
+	// implementation cannot silently drop the cue text.
+	src := []byte(verboseParagraph() + "\n")
+	f, err := lint.NewFile("test.md", src)
+	require.NoError(t, err)
+
+	threshold := modelConciseness(t)
+	r := &Rule{MinScore: threshold, MinWords: 20}
+	diags := r.Check(f)
+	if len(diags) == 0 {
+		t.Skip("model threshold did not trigger on fixture")
+	}
+	msg := diags[0].Message
+	// The message must contain both the score summary and the cue guidance.
+	assert.Contains(t, msg, "conciseness score too low")
+	assert.Contains(t, msg, "target >=")
+	// verboseParagraph always triggers cue detection; both must be present.
+	assert.Contains(t, msg, "reduce verbose cues")
+	assert.Contains(t, msg, "e.g.,", "message with cues must include formatted examples")
+}
+
+func TestCheck_NoCuesMessage(t *testing.T) {
+	// Exercises the if examples == "" branch: a paragraph that scores as
+	// verbose but produces no cue phrases yields the base message only.
+	noCuePara := "When the configuration is set, the setting is used by the " +
+		"configuration. The configuration uses the setting and the setting " +
+		"configures the configuration."
+	s, err := NewScorer()
+	require.NoError(t, err)
+	scored := s.Score(noCuePara)
+	if len(scored.Cues) > 0 {
+		t.Skip("scorer detected cues in fixture; model may have drifted")
+	}
+
+	src := []byte(noCuePara + "\n")
+	f, err := lint.NewFile("test.md", src)
+	require.NoError(t, err)
+
+	r := &Rule{MinScore: scored.Conciseness + 0.10, MinWords: 1}
+	diags := r.Check(f)
+	require.Len(t, diags, 1, "expected diagnostic for low-scoring no-cue paragraph")
+	msg := diags[0].Message
+	assert.Contains(t, msg, "conciseness score too low")
+	assert.Contains(t, msg, "target >=")
+	assert.NotContains(t, msg, "reduce verbose cues", "no cues detected, so no cue guidance")
+}
diff --git a/internal/secreview/render.go b/internal/secreview/render.go
index df8b365c0..3e4e9094d 100644
--- a/internal/secreview/render.go
+++ b/internal/secreview/render.go
@@ -7,6 +7,7 @@ import (
 	"os"
 	"path/filepath"
 	"sort"
+	"strconv"
 	"time"
 )
 
@@ -112,9 +113,9 @@ func locStr(loc *Location) string {
 		s = "?"
 	}
 	if loc.StartLine != 0 {
-		s += fmt.Sprintf(":%d", loc.StartLine)
+		s += ":" + strconv.Itoa(loc.StartLine)
 		if loc.EndLine != 0 && loc.EndLine != loc.StartLine {
-			s += fmt.Sprintf("-%d", loc.EndLine)
+			s += "-" + strconv.Itoa(loc.EndLine)
 		}
 	}
 	return s