diff --git a/internal/logging/text.go b/internal/logging/text.go
index 5f88aea..357efb4 100644
--- a/internal/logging/text.go
+++ b/internal/logging/text.go
@@ -2,6 +2,7 @@ package logging
 
 import (
 	"bytes"
+	"encoding/json"
 	"io"
 	"net/url"
 	"regexp"
@@ -116,8 +117,26 @@ func redactForm(body string) (string, bool) {
 	return strings.Join(parts, "&"), true
 }
 
-var textFieldLine = regexp.MustCompile(`^\s*([A-Za-z_][A-Za-z0-9_.-]*)\s*[:=]`)
-var textFieldLabel = regexp.MustCompile(`\b([A-Za-z_][A-Za-z0-9_.-]*)\s*[:=]`)
+// One field lexer for quoted/unquoted labels and diagnostic projections.
+// JSON names are decoded, so escapes cannot bypass the content classifier.
+const textFieldName = `((?:\\?"(?:\\.|[^"\\\r\n])*\\?")|(?:'(?:\\.|[^'\\\r\n])*')|` + "(?:`[^`\\r\\n]*`)" + `|(?:“[^”\r\n]*”)|(?:‘[^’\r\n]*’)|(?:[\p{L}_][\p{L}\p{N}_.-]*))`
+
+var textFieldLine = regexp.MustCompile(`^\s*` + textFieldName + `\s*[:=]`)
+var textFieldLabel = regexp.MustCompile(textFieldName + `\s*[:=]`)
+
+func textFieldKey(token string) (string, bool) {
+	if strings.HasPrefix(token, `\"`) && strings.HasSuffix(token, `\"`) {
+		token = `"` + token[2:len(token)-2] + `"`
+	}
+	if strings.HasPrefix(token, `"`) {
+		var key string
+		if err := json.Unmarshal([]byte(token), &key); err != nil {
+			return "", false
+		}
+		return normalizedField(key), true
+	}
+	return normalizedField(token), true
+}
 
 var diagnosticUUID = regexp.MustCompile(`^(?:call-)?[0-9a-fA-F]{8}-[0-9a-fA-F]{4}-[0-9a-fA-F]{4}-[0-9a-fA-F]{4}-[0-9a-fA-F]{12}$`)
 
@@ -129,7 +148,10 @@ func diagnosticTextLine(line string, contentIndent int) bool {
 	if len(field) == 0 || len(line)-len(strings.TrimLeft(line, " \t")) > contentIndent {
 		return false
 	}
-	key := normalizedField(line[field[2]:field[3]])
+	key, valid := textFieldKey(line[field[2]:field[3]])
+	if !valid {
+		return false
+	}
 	value := strings.TrimSpace(line[field[1]:])
 	switch key {
 	case "taskid", "tenantid", "trunkid", "attempts", "remaining", "retryafter", "count", "elapsedms", "durationms":
@@ -152,11 +174,38 @@ func diagnosticTextLine(line string, contentIndent int) bool {
 	return false
 }
 
+// Complete embedded JSON belongs to structural redaction, not the free-text
+// lexer. Keep its boundaries so quoted keys cannot discard adjacent diagnostics.
+func structuredTextSpans(body string) [][2]int {
+	var spans [][2]int
+	for offset := 0; offset < len(body); {
+		next := strings.IndexAny(body[offset:], "{[")
+		if next < 0 {
+			break
+		}
+		start := offset + next
+		dec := json.NewDecoder(strings.NewReader(body[start:]))
+		var raw json.RawMessage
+		if err := dec.Decode(&raw); err != nil {
+			offset = start + 1
+			continue
+		}
+		end := start + int(dec.InputOffset())
+		spans = append(spans, [2]int{start, end})
+		offset = end
+	}
+	return spans
+}
+
 func redactConversationLines(body string) string {
+	spans := structuredTextSpans(body)
+	offset := 0
 	lines := strings.SplitAfter(body, "\n")
 	hiding := false
 	contentIndent := 0
 	for i, line := range lines {
+		lineOffset := offset
+		offset += len(line)
 		// Content owns its full tail, including unknown fields, speaker names,
 		// nested message metadata and blank paragraphs. Typed diagnostics are a
 		// projection of individual lines, never an inferred end of the dialogue.
@@ -169,8 +218,19 @@ func redactConversationLines(body string) string {
 		// Labels establish ownership wherever they occur in an error chain, not
 		// only at line start. Preserve the preceding actual failure description.
 		for _, span := range textFieldLabel.FindAllStringSubmatchIndex(line, -1) {
-			key := line[span[2]:span[3]]
-			if !sensitive(key) {
+			position := lineOffset + span[0]
+			structured := false
+			for _, region := range spans {
+				if position >= region[0] && position < region[1] {
+					structured = true
+					break
+				}
+			}
+			if structured {
+				continue
+			}
+			key, valid := textFieldKey(line[span[2]:span[3]])
+			if valid && !sensitive(key) {
 				continue
 			}
 			lines[i] = line[:span[0]] + "[REDACTED_FIELD]"
@@ -178,7 +238,9 @@ func redactConversationLines(body string) string {
 				lines[i] += "\n"
 			}
 			// Credentials own only this line; content owns the following paragraphs.
-			hiding = conversationField(key)
+			// Malformed quoted labels have no safely classifiable tail. Keep it
+			// opaque too, rather than silently exposing a failed name decode.
+			hiding = !valid || conversationField(key)
 			contentIndent = len(line) - len(strings.TrimLeft(line, " \t"))
 			break
 		}
diff --git a/internal/logging/text_security_test.go b/internal/logging/text_security_test.go
index 10bab30..0ec2221 100644
--- a/internal/logging/text_security_test.go
+++ b/internal/logging/text_security_test.go
@@ -61,6 +61,29 @@ func TestContentFieldClassificationAndEveryLoggingPathAgree(t *testing.T) {
 	}
 }
 
+func TestQuotedContentLabelsEstablishOwnershipOnEveryLoggingPath(t *testing.T) {
+	for _, label := range []string{`"messages"`, `'conversation'`, "`history`", `“prompt”`, `‘messages’`, `\"messages\"`, `"m\u0065ssages"`, `"m\qssages"`} {
+		value := "upstream failed: " + label + ":\nrole: user\nmessage: private-user-turn\nrole: assistant\nmessage: private-assistant-turn\nstatus=retry_pending\ntask_id=4\nattempts=2"
+		for _, debug := range []bool{false, true} {
+			out := installTestLogger(t, debug)
+			slog.Error("request failed", "error", errors.New(value), "detail", value)
+			slog.Info(value, "stage", "failure_observed")
+			TextBody(t.Context(), "HTTP text observed", []byte(value), "transport", "http")
+			text := out.String()
+			for _, secret := range []string{"private-user-turn", "private-assistant-turn"} {
+				if strings.Contains(text, secret) {
+					t.Fatalf("label %q debug %v leak: %s", label, debug, text)
+				}
+			}
+			for _, keep := range []string{"upstream failed", "status=retry_pending", "task_id=4", "attempts=2"} {
+				if !strings.Contains(text, keep) {
+					t.Fatal("diagnostic lost", text)
+				}
+			}
+		}
+	}
+}
+
 func TestUnknownDialogueFieldsCannotEndContentOwnership(t *testing.T) {
 	for _, dialogue := range []string{
 		"role: user\nmessage: private-user-turn\nrole: assistant\nmessage: private-assistant-turn",