diff --git a/lib/content/api.sx b/lib/content/api.sx
index d09899b6..6c9535b4 100644
--- a/lib/content/api.sx
+++ b/lib/content/api.sx
@@ -49,8 +49,8 @@
     (if (content/op? ops) (doc-apply doc ops) (doc-apply-all doc ops))))
 
 ;; ── render boundary ──
-;; fmt is "html"/"sx"/"md" (or :html/:sx/:md — keywords evaluate to their name).
-;; "md" needs markdown.sx loaded.
+;; fmt is "html"/"sx"/"md"/"text" (or the matching keyword). "md" needs
+;; markdown.sx loaded; "text" needs text.sx loaded.
 (define
   content/render
   (fn
@@ -60,6 +60,7 @@
       ((= fmt "sx") (asSx doc))
       ((= fmt "md") (asMarkdown doc))
       ((= fmt "markdown") (asMarkdown doc))
+      ((= fmt "text") (asText doc))
       (else (error (str "unknown render format: " fmt))))))
 
 (define content/html asHTML)
diff --git a/lib/content/conformance.sh b/lib/content/conformance.sh
index 3549ad04..a25d508b 100755
--- a/lib/content/conformance.sh
+++ b/lib/content/conformance.sh
@@ -15,7 +15,7 @@ if [ ! -x "$SX_SERVER" ]; then
   fi
 fi
 
-SUITES=(block doc render api meta markdown validate store snapshot crdt crdt-store sync md-import fed)
+SUITES=(block doc render api meta markdown text validate store snapshot crdt crdt-store sync md-import fed)
 
 OUT_JSON="lib/content/scoreboard.json"
 OUT_MD="lib/content/scoreboard.md"
@@ -43,6 +43,7 @@ run_suite() {
 (load "lib/content/render.sx")
 (load "lib/content/api.sx")
 (load "lib/content/meta.sx")
+(load "lib/content/text.sx")
 (load "lib/content/markdown.sx")
 (load "lib/content/validate.sx")
 (load "lib/content/store.sx")
diff --git a/lib/content/scoreboard.json b/lib/content/scoreboard.json
index 1624aad3..167c48e6 100644
--- a/lib/content/scoreboard.json
+++ b/lib/content/scoreboard.json
@@ -6,6 +6,7 @@
     "api": {"pass": 26, "fail": 0},
     "meta": {"pass": 27, "fail": 0},
     "markdown": {"pass": 20, "fail": 0},
+    "text": {"pass": 20, "fail": 0},
     "validate": {"pass": 17, "fail": 0},
     "store": {"pass": 29, "fail": 0},
     "snapshot": {"pass": 20, "fail": 0},
@@ -15,7 +16,7 @@
     "md-import": {"pass": 24, "fail": 0},
     "fed": {"pass": 20, "fail": 0}
   },
-  "total_pass": 365,
+  "total_pass": 385,
   "total_fail": 0,
-  "total": 365
+  "total": 385
 }
diff --git a/lib/content/scoreboard.md b/lib/content/scoreboard.md
index 3d202d4f..2cfaa99d 100644
--- a/lib/content/scoreboard.md
+++ b/lib/content/scoreboard.md
@@ -10,6 +10,7 @@ _Generated by `lib/content/conformance.sh`_
 | api | 26 | 0 | 26 |
 | meta | 27 | 0 | 27 |
 | markdown | 20 | 0 | 20 |
+| text | 20 | 0 | 20 |
 | validate | 17 | 0 | 17 |
 | store | 29 | 0 | 29 |
 | snapshot | 20 | 0 | 20 |
@@ -18,4 +19,4 @@ _Generated by `lib/content/conformance.sh`_
 | sync | 14 | 0 | 14 |
 | md-import | 24 | 0 | 24 |
 | fed | 20 | 0 | 20 |
-| **Total** | **365** | **0** | **365** |
+| **Total** | **385** | **0** | **385** |
diff --git a/lib/content/tests/text.sx b/lib/content/tests/text.sx
new file mode 100644
index 00000000..078292ba
--- /dev/null
+++ b/lib/content/tests/text.sx
@@ -0,0 +1,72 @@
+;; Extension — plain-text render mode + excerpts.
+
+(st-bootstrap-classes!)
+(content/bootstrap!)
+(content-bootstrap-text!)
+
+;; ── per-block ──
+(content-test
+  "heading text"
+  (asText (mk-heading "h" 2 "Title"))
+  "Title")
+(content-test "paragraph text" (asText (mk-text "p" "Body")) "Body")
+(content-test "code text" (asText (mk-code "c" "sx" "(+ 1 2)")) "(+ 1 2)")
+(content-test "quote text" (asText (mk-quote "q" "Ada" "to err")) "to err")
+(content-test
+  "image -> alt"
+  (asText (mk-image "i" "/c.png" "a cat"))
+  "a cat")
+(content-test
+  "embed -> empty"
+  (asText (mk-embed "e" "https://v" "vimeo"))
+  "")
+(content-test "divider -> empty" (asText (mk-divider "d")) "")
+(content-test
+  "list -> joined"
+  (asText (mk-list "l" false (list "a" "b" "c")))
+  "a, b, c")
+(content-test "empty list -> empty" (asText (mk-list "l" false (list))) "")
+
+;; ── document joins non-empty child texts with a space ──
+(define
+  d
+  (doc-append
+    (doc-append
+      (doc-append
+        (doc-append (doc-empty "d") (mk-heading "h" 1 "Title"))
+        (mk-text "p" "Hello world"))
+      (mk-divider "dv"))
+    (mk-list "l" true (list "x" "y"))))
+(content-test "doc text skips empties" (asText d) "Title Hello world x, y")
+(content-test "empty doc text" (asText (doc-empty "e")) "")
+
+;; ── via facade ──
+(content-test "render text" (content/render d "text") (asText d))
+(content-test "render text keyword" (content/render d :text) (asText d))
+(content-test "content/text alias" (content/text d) (asText d))
+(content-test "block-text alias" (block-text (mk-text "p" "x")) "x")
+
+;; ── excerpt ──
+(content-test
+  "excerpt under limit"
+  (content/excerpt d 100)
+  "Title Hello world x, y")
+(content-test "excerpt truncates" (content/excerpt d 5) "Title…")
+(content-test
+  "excerpt exact length"
+  (content/excerpt
+    (doc-append (doc-empty "e") (mk-text "p" "12345"))
+    5)
+  "12345")
+(content-test
+  "excerpt one over"
+  (content/excerpt
+    (doc-append (doc-empty "e") (mk-text "p" "123456"))
+    5)
+  "12345…")
+
+;; ── reflects edits ──
+(content-test
+  "text after update"
+  (asText (doc-update d "p" "text" "Changed"))
+  "Title Changed x, y")
diff --git a/lib/content/text.sx b/lib/content/text.sx
new file mode 100644
index 00000000..aaad1128
--- /dev/null
+++ b/lib/content/text.sx
@@ -0,0 +1,46 @@
+;; content-on-sx — plain-text render mode + excerpts.
+;;
+;; A fourth boundary format via polymorphic dispatch: blocks answer asText,
+;; stripping all markup. Useful for search indexing, meta descriptions and
+;; previews. The document joins non-empty child texts with a single space.
+;;
+;; Requires (loaded by harness): block.sx, doc.sx.
+
+(define
+  content-bootstrap-text!
+  (fn
+    ()
+    (begin
+      (ct-def-method! "CtHeading" "asText" "asText ^ text")
+      (ct-def-method! "CtText" "asText" "asText ^ text")
+      (ct-def-method! "CtCode" "asText" "asText ^ text")
+      (ct-def-method! "CtQuote" "asText" "asText ^ text")
+      (ct-def-method! "CtImage" "asText" "asText ^ alt")
+      (ct-def-method! "CtEmbed" "asText" "asText ^ ''")
+      (ct-def-method! "CtDivider" "asText" "asText ^ ''")
+      (ct-def-method!
+        "CtList"
+        "asText"
+        "asText ^ (items inject: '' into: [:a :x | (a = '' ifTrue: [x] ifFalse: [a , ', ' , x])])")
+      (ct-def-method!
+        "CtDoc"
+        "asText"
+        "asText ^ (blocks inject: '' into: [:a :b | (b asText = '') ifTrue: [a] ifFalse: [(a = '' ifTrue: [b asText] ifFalse: [a , ' ' , b asText])]])")
+      true)))
+
+;; ── SX boundary ──
+(define asText (fn (node) (str (st-send node "asText" (list)))))
+(define content/text asText)
+(define block-text asText)
+
+;; excerpt: first n chars of the plain text, with an ellipsis if truncated.
+(define
+  content/excerpt
+  (fn
+    (doc n)
+    (let
+      ((t (asText doc)))
+      (if
+        (<= (string-length t) n)
+        t
+        (str (substring t 0 n) "…")))))
diff --git a/plans/content-on-sx.md b/plans/content-on-sx.md
index 7833fc6d..b72c083b 100644
--- a/plans/content-on-sx.md
+++ b/plans/content-on-sx.md
@@ -19,7 +19,7 @@ injected adapter, not core.
 
 ## Status (rolling)
 
-`bash lib/content/conformance.sh` → **365/365** (Phases 1–4 COMPLETE + extensions: HTML/SX escaping, Markdown render+import, durable CRDT replication, validation, snapshot cache, doc metadata)
+`bash lib/content/conformance.sh` → **385/385** (Phases 1–4 COMPLETE + 9 extensions: HTML/SX escaping, Markdown render+import, CRDT replication, validation, snapshot cache, doc metadata, plain-text render)
 
 ## Ground rules
 
@@ -84,9 +84,16 @@ lib/content/api.sx ── (content/edit) (content/render) (content/history) ─
 - [x] Markdown import adapter (`md-import.sx`: text → blocks, round-trips export)
 - [x] snapshot cache over replay (`snapshot.sx`: cache-not-primary, transparent)
 - [x] document metadata (`meta.sx`: title/slug/tags + Ghost title plumbing)
+- [x] plain-text render + excerpt (`text.sx`: asText, content/excerpt)
 
 ## Progress log
 
+- 2026-06-07 — Extension: plain-text render + excerpts (`text.sx`). Fourth
+  boundary format via polymorphic `asText` (heading/text/code/quote→text,
+  image→alt, embed/divider→"", list→", "-joined); the document joins non-empty
+  child texts with a space. `content/render doc "text"`, `content/text`,
+  `content/excerpt doc n` (first n chars + "…" if truncated). For previews,
+  meta-descriptions, search indexing. 20 tests; suite 385/385.
 - 2026-06-07 — Extension: document metadata (`meta.sx`). CtDoc gained optional
   title/slug/tags ivars (declared in doc.sx, default nil/empty, no effect on
   block ops). Reads via message dispatch; copy-on-write setters