diff --git a/docs/roadmap/remediation.md b/docs/roadmap/remediation.md
index 1c63b68..869bc72 100644
--- a/docs/roadmap/remediation.md
+++ b/docs/roadmap/remediation.md
@@ -219,6 +219,8 @@ selection rules and native comparison status.
 
 ## R6 — P3: Render Stage IDs as Data in Markdown
 
+**Status:** Completed. Markdown escapes stage labels as literal cell text. Tests cover Markdown syntax, a pipe next to a backslash, and exact YAML IDs. A rendered table check confirmed the label stays in one cell.
+
 **Category**
 
 Incomplete output escaping in Stage 13.
diff --git a/internal/core/reporting/markdown.go b/internal/core/reporting/markdown.go
index 7cb715a..c716631 100644
--- a/internal/core/reporting/markdown.go
+++ b/internal/core/reporting/markdown.go
@@ -48,11 +48,11 @@ func Markdown(snapshot Snapshot, secrets ...string) []byte {
 
 	fmt.Fprintln(&b, "## Work-unit errors")
 	fmt.Fprintln(&b)
-	writeMatrix(&b, snapshot, safe, false)
+	writeMatrix(&b, snapshot, r, false)
 	fmt.Fprintln(&b)
 	fmt.Fprintln(&b, "## Recoveries")
 	fmt.Fprintln(&b)
-	writeMatrix(&b, snapshot, safe, true)
+	writeMatrix(&b, snapshot, r, true)
 	fmt.Fprintln(&b)
 	fmt.Fprintln(&b, "Legend: `—` = not started; `n*` = interrupted with n recorded errors or recoveries. Completed error cells are 0 or 1.")
 	fmt.Fprintln(&b)
@@ -71,7 +71,7 @@ func showCount(value *int) string {
 	return fmt.Sprint(*value)
 }
 
-func writeMatrix(b *strings.Builder, snapshot Snapshot, safe func(string) string, recovery bool) {
+func writeMatrix(b *strings.Builder, snapshot Snapshot, redactor redaction.Redactor, recovery bool) {
 	if len(snapshot.StageNames) == 0 || len(snapshot.WorkUnits) == 0 {
 		fmt.Fprintln(b, "No work units.")
 		return
@@ -79,7 +79,7 @@ func writeMatrix(b *strings.Builder, snapshot Snapshot, safe func(string) string
 	columns := snapshot.StageNames
 	fmt.Fprint(b, "| Chunk |")
 	for _, name := range columns {
-		fmt.Fprintf(b, " %s |", safe(name))
+		fmt.Fprintf(b, " %s |", stageCellEscaper.Replace(html.EscapeString(redactor.String(name))))
 	}
 	fmt.Fprint(b, "\n| --- |")
 	for range columns {
@@ -120,6 +120,14 @@ func writeMatrix(b *strings.Builder, snapshot Snapshot, safe func(string) string
 	}
 }
 
+// Encode input backslashes so they cannot interfere with Markdown escapes.
+var stageCellEscaper = strings.NewReplacer(
+	"\r\n", "<br>", "\r", "<br>", "\n", "<br>",
+	"\\", "&#92;", "|", "\\|", "`", "\\`",
+	"[", "\\[", "]", "\\]", "*", "\\*", "_", "\\_", "~", "\\~",
+	"://", "&#58;//", "www.", "www&#46;", "@", "&#64;",
+)
+
 func writeReasons(b *strings.Builder, title string, counts map[string]int, safe func(string) string) {
 	fmt.Fprintf(b, "### %s\n\n", title)
 	if len(counts) == 0 {
diff --git a/internal/core/reporting/markdown_test.go b/internal/core/reporting/markdown_test.go
index 64b14ac..a0fcb2e 100644
--- a/internal/core/reporting/markdown_test.go
+++ b/internal/core/reporting/markdown_test.go
@@ -33,11 +33,11 @@ func TestMarkdownFixedLayoutAndCounts(t *testing.T) {
 	// Compare only complete table rows, preserving order and states while leaving
 	// prose and spacing outside the fixed matrices free to change.
 	wantRows := []string{
-		"| Chunk | grammar_1 | grammar_2 |",
+		"| Chunk | grammar\\_1 | grammar\\_2 |",
 		"| --- | ---: | ---: |",
 		"| Chunk 1 (segments 1–2) | 1 | 0* |",
 		"| Chunk 2 (segments 3–4) | 0 | — |",
-		"| Chunk | grammar_1 | grammar_2 |",
+		"| Chunk | grammar\\_1 | grammar\\_2 |",
 		"| --- | ---: | ---: |",
 		"| Chunk 1 (segments 1–2) | 1 | 2* |",
 		"| Chunk 2 (segments 3–4) | 0 | — |",
@@ -93,11 +93,35 @@ func TestMarkdownNoWorkAndEscapedStageLabel(t *testing.T) {
 		t.Fatal(text)
 	}
 	text = string(Markdown(Snapshot{RunID: "r", StageNames: []string{"bad|label`\nsecret"}, WorkUnits: []WorkUnit{{StageIndex: 0, ChunkIndex: 0, State: "completed"}}}, "secret"))
-	if !strings.Contains(text, "bad\\|label\\`<br>[REDACTED]") {
+	if !strings.Contains(text, "bad\\|label\\`<br>\\[REDACTED\\]") {
 		t.Fatal(text)
 	}
 }
 
+func TestStageIDIsLiteralInMarkdownAndExactInYAML(t *testing.T) {
+	id := `[party](https://example.invalid/) *bold* _emphasis_ ~~strike~~ \| <tag>`
+	snapshot := Snapshot{
+		StageNames: []string{StageLabel(0, "grammar", &id), StageLabel(1, "grammar", nil)},
+		WorkUnits:  []WorkUnit{{StageIndex: 0, ChunkIndex: 0, State: "completed", ErrorCount: 1}},
+		Errors:     []ErrorRecord{{Scope: "work_unit", StageID: &id}},
+	}
+	header := `| Chunk | 1: grammar (\[party\](https&#58;//example.invalid/) \*bold\* \_emphasis\_ \~\~strike\~\~ &#92;\| &lt;tag&gt;) | 2: grammar |`
+	if rows := markdownTableRows(string(Markdown(snapshot))); len(rows) == 0 || rows[0] != header {
+		t.Fatalf("stage labels did not stay in their cells: %v", rows)
+	}
+	data, err := YAML(snapshot.ErrorsDocument())
+	if err != nil {
+		t.Fatal(err)
+	}
+	var decoded struct{ Errors []ErrorRecord }
+	if err := yaml.Unmarshal(data, &decoded); err != nil {
+		t.Fatal(err)
+	}
+	if len(decoded.Errors) != 1 || decoded.Errors[0].StageID == nil || *decoded.Errors[0].StageID != id {
+		t.Fatalf("stage ID changed in YAML: %s", data)
+	}
+}
+
 func markdownTableRows(text string) []string {
 	var rows []string
 	for _, line := range strings.Split(text, "\n") {