diff --git a/datasette/handle_exception.py b/datasette/handle_exception.py
index fc290dbc..e255ddf2 100644
--- a/datasette/handle_exception.py
+++ b/datasette/handle_exception.py
@@ -28,6 +28,7 @@ def handle_exception(datasette, request, exception):
             rich.get_console().print_exception(show_locals=True)
 
         title = None
+        plain_message = None
         if isinstance(exception, Base400):
             status = exception.status
             info = {}
@@ -36,6 +37,7 @@ def handle_exception(datasette, request, exception):
             status = exception.status
             info = exception.error_dict
             message = exception.message
+            plain_message = exception.plain_message
             if exception.message_is_html:
                 message = Markup(message)
             title = exception.title
@@ -50,7 +52,7 @@ def handle_exception(datasette, request, exception):
             add_cors_headers(headers)
         if request.path.split("?")[0].endswith(".json"):
             body = dict(info)
-            body.update(error_body(message, status))
+            body.update(error_body(plain_message or message, status))
             return Response.json(body, status=status, headers=headers)
         info.update(
             {
diff --git a/datasette/views/base.py b/datasette/views/base.py
index a12ae050..88d16753 100644
--- a/datasette/views/base.py
+++ b/datasette/views/base.py
@@ -29,12 +29,15 @@ class DatasetteError(Exception):
         status=500,
         template=None,
         message_is_html=False,
+        plain_message=None,
     ):
         self.message = message
         self.title = title
         self.error_dict = error_dict or {}
         self.status = status
         self.message_is_html = message_is_html
+        # Plain text used for JSON error responses when message is HTML
+        self.plain_message = plain_message
 
 
 class View:
diff --git a/datasette/views/database.py b/datasette/views/database.py
index c9dcfa89..10dc66ae 100644
--- a/datasette/views/database.py
+++ b/datasette/views/database.py
@@ -819,6 +819,10 @@ class QueryView(View):
                     title="SQL Interrupted",
                     status=400,
                     message_is_html=True,
+                    plain_message=(
+                        "SQL query took too long. The time limit is"
+                        " controlled by the sql_time_limit_ms setting."
+                    ),
                 )
             except sqlite3.DatabaseError as ex:
                 query_error = str(ex)
diff --git a/datasette/views/row.py b/datasette/views/row.py
index 2a103180..d9a3deeb 100644
--- a/datasette/views/row.py
+++ b/datasette/views/row.py
@@ -200,6 +200,10 @@ class RowView(BaseView):
                 title="SQL Interrupted",
                 status=400,
                 message_is_html=True,
+                plain_message=(
+                    "SQL query took too long. The time limit is"
+                    " controlled by the sql_time_limit_ms setting."
+                ),
             )
         except (sqlite3.OperationalError, InvalidSql) as e:
             raise DatasetteError(str(e), title="Invalid SQL", status=400)
diff --git a/stable-api-recommendations.md b/stable-api-recommendations.md
index 4da23934..0d817612 100644
--- a/stable-api-recommendations.md
+++ b/stable-api-recommendations.md
@@ -394,9 +394,11 @@ Concerns:
    ✅ Done — now 400 (fixed with §1b).
 4. ~~**Row delete 500** (§1c) — inconsistent with every sibling endpoint.~~
    ✅ Done — now 400.
-5. **The "SQL Interrupted" error embeds an HTML fragment in the JSON `error`
+5. ~~**The "SQL Interrupted" error embeds an HTML fragment in the JSON `error`
    value** (views/database.py:805-820). Error strings in the JSON API should
-   be plain text.
+   be plain text.~~ ✅ **Done** — `DatasetteError` gained a `plain_message`
+   used for JSON responses; the HTML error page keeps the rich version with
+   the SQL textarea. §8 is now fully resolved.
 
 ---
 
diff --git a/tests/test_api.py b/tests/test_api.py
index da0ebc07..9a96f14f 100644
--- a/tests/test_api.py
+++ b/tests/test_api.py
@@ -329,14 +329,8 @@ def test_sql_time_limit(app_client_shorter_time_limit):
     )
     assert 400 == response.status
     expected_message = (
-        "<p>SQL query took too long. The time limit is controlled by the\n"
-        '<a href="https://docs.datasette.io/en/stable/settings.html#sql-time-limit-ms">sql_time_limit_ms</a>\n'
-        "configuration option.</p>\n"
-        '<textarea style="width: 90%">select sleep(0.5)</textarea>\n'
-        "<script>\n"
-        'let ta = document.querySelector("textarea");\n'
-        'ta.style.height = ta.scrollHeight + "px";\n'
-        "</script>"
+        "SQL query took too long. The time limit is"
+        " controlled by the sql_time_limit_ms setting."
     )
     assert response.json == {
         "ok": False,
@@ -356,7 +350,7 @@ async def test_custom_sql_time_limit(ds_client):
         "/fixtures/-/query.json?sql=select+sleep(0.01)&_timelimit=5",
     )
     assert response.status_code == 400
-    assert response.json()["error"].startswith("<p>SQL query took too long.")
+    assert response.json()["error"].startswith("SQL query took too long.")
 
 
 @pytest.mark.asyncio
diff --git a/tests/test_error_shape.py b/tests/test_error_shape.py
index 040e645a..44856b36 100644
--- a/tests/test_error_shape.py
+++ b/tests/test_error_shape.py
@@ -717,3 +717,25 @@ async def test_alter_and_set_column_type_ignore_content_type(ds_error_shape):
         actor={"id": "root"},
     )
     assert sct.status_code == 200, sct.text
+
+
+# SQL Interrupted errors carry plain text in JSON, not an HTML fragment
+
+
+@pytest.mark.asyncio
+async def test_sql_interrupted_json_error_is_plain_text(ds_client):
+    response = await ds_client.get(
+        "/fixtures/-/query.json?sql=select+sleep(0.01)&_timelimit=5"
+    )
+    data = assert_canonical_error(response, 400)
+    assert "<" not in data["error"]
+    assert data["error"].startswith("SQL query took too long.")
+
+
+@pytest.mark.asyncio
+async def test_sql_interrupted_html_page_keeps_rich_error(ds_client):
+    response = await ds_client.get(
+        "/fixtures/-/query?sql=select+sleep(0.01)&_timelimit=5"
+    )
+    assert response.status_code == 400
+    assert "<textarea" in response.text