diff --git a/src/app.rs b/src/app.rs
index ada3396..6309a05 100644
--- a/src/app.rs
+++ b/src/app.rs
@@ -359,12 +359,12 @@ impl App {
             }
             AppEvent::RebuildSucceeded { summary } => {
                 self.modal = None;
-                self.note_system(format!("[ok] rebuild — {summary}"));
+                self.note_system(crate::t!("project.rebuild_ok", summary = summary));
                 Vec::new()
             }
             AppEvent::RebuildFailed { error } => {
                 self.modal = None;
-                self.note_error(format!("rebuild failed: {error}"));
+                self.note_error(crate::t!("project.rebuild_failed", error = error));
                 Vec::new()
             }
             AppEvent::LoadPickerReady { entries } => {
@@ -394,7 +394,10 @@ impl App {
                 is_temp,
                 history_entries,
             } => {
-                self.note_system(format!("[ok] now editing: {display_name}"));
+                self.note_system(crate::t!(
+                    "project.switched_ok",
+                    display_name = display_name
+                ));
                 self.project_name = Some(display_name);
                 self.project_is_temp = is_temp;
                 self.tables.clear();
@@ -403,20 +406,25 @@ impl App {
                 Vec::new()
             }
             AppEvent::ProjectSwitchFailed { error } => {
-                self.note_error(format!("project switch failed: {error}"));
+                self.note_error(crate::t!("project.switch_failed", error = error));
                 Vec::new()
             }
             AppEvent::ExportSucceeded { path } => {
-                self.note_system(format!("[ok] export — wrote {}", path.display()));
+                self.note_system(crate::t!(
+                    "project.export_ok",
+                    path = path.display()
+                ));
                 Vec::new()
             }
             AppEvent::ExportFailed { error } => {
-                self.note_error(format!("export failed: {error}"));
+                self.note_error(crate::t!("project.export_failed", error = error));
                 Vec::new()
             }
             AppEvent::ReplayCompleted { path, count } => {
-                self.note_system(format!(
-                    "[ok] replay {path} — {count} command(s) run"
+                self.note_system(crate::t!(
+                    "replay.completed",
+                    path = path,
+                    count = count
                 ));
                 Vec::new()
             }
@@ -433,13 +441,23 @@ impl App {
                 // it, mirroring how the interactive `running: …`
                 // path renders source-line context above an error.
                 if line_number == 0 {
-                    self.note_error(format!("replay {path} failed: {error}"));
+                    self.note_error(crate::t!(
+                        "replay.failed_open",
+                        path = path,
+                        error = error
+                    ));
                 } else {
-                    self.note_error(format!(
-                        "replay {path} failed at line {line_number}: {error}"
+                    self.note_error(crate::t!(
+                        "replay.failed_at_line",
+                        path = path,
+                        line_number = line_number,
+                        error = error
                     ));
                     if !command.is_empty() {
-                        self.note_error(format!("  > {command}"));
+                        self.note_error(crate::t!(
+                            "replay.command_echo",
+                            command = command
+                        ));
                     }
                 }
                 Vec::new()
@@ -705,7 +723,7 @@ impl App {
             other if other.starts_with("export ") => {
                 let target = other["export ".len()..].trim();
                 if target.is_empty() {
-                    self.note_error("usage: export [<path>]");
+                    self.note_error(crate::t!("project.export_usage"));
                     return Vec::new();
                 }
                 return vec![Action::Export {
@@ -800,17 +818,33 @@ impl App {
                     let prefix = "running: ";
                     let trimmed_offset = leading_trim_offset(input);
                     let pad = prefix.chars().count() + trimmed_offset + position;
-                    self.note_error(format!("{}^", " ".repeat(pad)));
+                    self.note_error(crate::t!(
+                        "parse.caret",
+                        padding = " ".repeat(pad)
+                    ));
                 }
-                self.note_error(format!("parse error: {}", parse_error_message(&err)));
+                self.note_error(crate::t!(
+                    "parse.error",
+                    detail = parse_error_message(&err)
+                ));
                 Vec::new()
             }
         }
     }
 
+    /// Emit the standard `[ok] <verb> <subject>` header used by
+    /// every successful DSL command. Routes through the i18n
+    /// catalog (ADR-0019 §9 sweep).
+    fn note_ok_summary(&mut self, command: &Command) {
+        self.note_system(crate::t!(
+            "ok.summary",
+            verb = command.verb(),
+            subject = command.display_subject()
+        ));
+    }
+
     fn handle_dsl_success(&mut self, command: &Command, description: Option<TableDescription>) {
-        let summary = format!("[ok] {} {}", command.verb(), command.display_subject());
-        self.note_system(summary);
+        self.note_ok_summary(command);
         if let Some(desc) = description.as_ref() {
             for line in crate::output_render::render_structure(desc) {
                 self.note_system(line);
@@ -820,32 +854,23 @@ impl App {
     }
 
     fn handle_dsl_query_success(&mut self, command: &Command, data: &DataResult) {
-        let summary = format!("[ok] {} {}", command.verb(), command.display_subject());
-        self.note_system(summary);
+        self.note_ok_summary(command);
         for line in crate::output_render::render_data_table(data) {
             self.note_system(line);
         }
     }
 
     fn handle_dsl_insert_success(&mut self, command: &Command, result: &InsertResult) {
-        self.note_system(format!(
-            "[ok] {} {}",
-            command.verb(),
-            command.display_subject()
-        ));
-        self.note_system(format!("  {} row(s) inserted", result.rows_affected));
+        self.note_ok_summary(command);
+        self.note_system(crate::t!("ok.rows_inserted", count = result.rows_affected));
         for line in crate::output_render::render_data_table(&result.data) {
             self.note_system(line);
         }
     }
 
     fn handle_dsl_update_success(&mut self, command: &Command, result: &UpdateResult) {
-        self.note_system(format!(
-            "[ok] {} {}",
-            command.verb(),
-            command.display_subject()
-        ));
-        self.note_system(format!("  {} row(s) updated", result.rows_affected));
+        self.note_ok_summary(command);
+        self.note_system(crate::t!("ok.rows_updated", count = result.rows_affected));
         for line in crate::output_render::render_data_table(&result.data) {
             self.note_system(line);
         }
@@ -856,8 +881,7 @@ impl App {
         command: &Command,
         result: AddColumnResult,
     ) {
-        let summary = format!("[ok] {} {}", command.verb(), command.display_subject());
-        self.note_system(summary);
+        self.note_ok_summary(command);
         // ADR-0018 §9: emit auto-fill note(s) before the
         // structure render, so the pedagogical "the tool did
         // this for you" line is in the user's eye-line next to
@@ -876,8 +900,7 @@ impl App {
         command: &Command,
         result: ChangeColumnTypeResult,
     ) {
-        let summary = format!("[ok] {} {}", command.verb(), command.display_subject());
-        self.note_system(summary);
+        self.note_ok_summary(command);
         if let Some(note) = result.client_side {
             // ADR-0017 §6 + ADR-0018 §9: pedagogical hook
             // telling the learner "the tool did this for you;
@@ -888,19 +911,15 @@ impl App {
             // emitted in order (ADR-0018 §9 explicit rule).
             if note.transformed > 0 {
                 let line = if note.lossy > 0 {
-                    format!(
-                        "[client-side] {n} row(s) transformed; {l} of those discarded \
-                         information (lossy). In raw SQL this would need an explicit \
-                         `CAST` or application-level code.",
-                        n = note.transformed,
-                        l = note.lossy
+                    crate::t!(
+                        "client_side.transformed_lossy",
+                        count = note.transformed,
+                        lossy = note.lossy
                     )
                 } else {
-                    format!(
-                        "[client-side] {n} row(s) were transformed before being stored. \
-                         In raw SQL this would need an explicit `CAST` or \
-                         application-level code.",
-                        n = note.transformed
+                    crate::t!(
+                        "client_side.transformed",
+                        count = note.transformed
                     )
                 };
                 self.note_system(line);
@@ -911,10 +930,10 @@ impl App {
                     Some(crate::db::AutoFillKind::ShortId) => "shortid",
                     None => "auto-generated",
                 };
-                self.note_system(format!(
-                    "[client-side] {m} null cell(s) given auto-generated {kind} values. \
-                     In raw SQL this would need an explicit UPDATE to populate.",
-                    m = note.auto_filled,
+                self.note_system(crate::t!(
+                    "client_side.auto_fill_transition",
+                    count = note.auto_filled,
+                    kind = kind
                 ));
             }
         }
@@ -925,12 +944,8 @@ impl App {
     }
 
     fn handle_dsl_delete_success(&mut self, command: &Command, result: &DeleteResult) {
-        self.note_system(format!(
-            "[ok] {} {}",
-            command.verb(),
-            command.display_subject()
-        ));
-        self.note_system(format!("  {} row(s) deleted", result.rows_affected));
+        self.note_ok_summary(command);
+        self.note_system(crate::t!("ok.rows_deleted", count = result.rows_affected));
         for effect in &result.cascade {
             self.note_system(render_cascade_effect(effect));
         }
@@ -1065,7 +1080,7 @@ impl App {
     fn handle_import_command(&mut self, rest: &str) -> Vec<Action> {
         let rest = rest.trim();
         if rest.is_empty() {
-            self.note_error("usage: import <zip-path> [as <target>]");
+            self.note_error(crate::t!("project.import_usage"));
             return Vec::new();
         }
         // `submit()` trims trailing whitespace from the raw
@@ -1074,7 +1089,7 @@ impl App {
         // than silently treating "as" as part of the zip
         // path.
         if rest == "as" || rest.ends_with(" as") {
-            self.note_error("import: empty target after `as`");
+            self.note_error(crate::t!("project.import_empty_target"));
             return Vec::new();
         }
         let (zip_path, as_target) = match rest.split_once(" as ") {
@@ -1082,13 +1097,13 @@ impl App {
             None => (rest, None),
         };
         if zip_path.is_empty() {
-            self.note_error("usage: import <zip-path> [as <target>]");
+            self.note_error(crate::t!("project.import_usage"));
             return Vec::new();
         }
         if let Some(t) = as_target.as_deref()
             && t.is_empty()
         {
-            self.note_error("import: empty target after `as`");
+            self.note_error(crate::t!("project.import_empty_target"));
             return Vec::new();
         }
         vec![Action::Import {
@@ -1419,19 +1434,17 @@ impl App {
                     crate::friendly::Verbosity::Short => "short",
                     crate::friendly::Verbosity::Verbose => "verbose",
                 };
-                self.note_system(format!("messages: {current}"));
+                self.note_system(crate::t!("messages.show", current = current));
             }
             "short" => {
                 self.messages_verbosity = crate::friendly::Verbosity::Short;
-                self.note_system("messages: short");
+                self.note_system(crate::t!("messages.set_short"));
             }
             "verbose" => {
                 self.messages_verbosity = crate::friendly::Verbosity::Verbose;
-                self.note_system("messages: verbose");
+                self.note_system(crate::t!("messages.set_verbose"));
             }
-            other => self.note_error(format!(
-                "unknown messages mode '{other}' (expected 'short' or 'verbose')"
-            )),
+            other => self.note_error(crate::t!("messages.unknown", value = other)),
         }
     }
 
@@ -1440,16 +1453,14 @@ impl App {
         match arg {
             "simple" => {
                 self.mode = Mode::Simple;
-                self.note_system("mode: simple");
+                self.note_system(crate::t!("mode.set_simple"));
             }
             "advanced" => {
                 self.mode = Mode::Advanced;
-                self.note_system("mode: advanced");
+                self.note_system(crate::t!("mode.set_advanced"));
             }
-            "" => self.note_error("usage: mode simple | mode advanced"),
-            other => self.note_error(format!(
-                "unknown mode '{other}' (expected 'simple' or 'advanced')"
-            )),
+            "" => self.note_error(crate::t!("mode.usage")),
+            other => self.note_error(crate::t!("mode.unknown", value = other)),
         }
     }
 
@@ -1514,7 +1525,7 @@ impl App {
 fn parse_error_message(err: &ParseError) -> String {
     match err {
         ParseError::Invalid { message, .. } => message.clone(),
-        ParseError::Empty => "empty input".to_string(),
+        ParseError::Empty => crate::t!("parse.empty"),
     }
 }
 
diff --git a/src/db.rs b/src/db.rs
index f7d9753..e0a4a17 100644
--- a/src/db.rs
+++ b/src/db.rs
@@ -1810,16 +1810,12 @@ fn generate_shortid_batch(
 /// on a non-empty table per ADR-0018 §9.
 fn format_auto_fill_add_note(ty: Type, row_count: usize) -> String {
     match ty {
-        Type::Serial => format!(
-            "[client-side] {row_count} row(s) given auto-generated serial \
-             values 1..{row_count}. In raw SQL this would need an explicit \
-             UPDATE to populate."
-        ),
-        Type::ShortId => format!(
-            "[client-side] {row_count} row(s) given auto-generated shortid \
-             values. In raw SQL this would need an explicit UPDATE to \
-             populate."
-        ),
+        Type::Serial => {
+            crate::t!("client_side.auto_fill_add_serial", count = row_count)
+        }
+        Type::ShortId => {
+            crate::t!("client_side.auto_fill_add_shortid", count = row_count)
+        }
         _ => unreachable!("called only for serial/shortid"),
     }
 }
diff --git a/src/friendly/keys.rs b/src/friendly/keys.rs
index e8eee79..a9000ed 100644
--- a/src/friendly/keys.rs
+++ b/src/friendly/keys.rs
@@ -118,6 +118,50 @@ pub const KEYS_AND_PLACEHOLDERS: &[(&str, &[&str])] = &[
         "error.type_mismatch.update.hint",
         &["table", "column", "expected_type"],
     ),
+    // ---- Parse error rendering ----
+    ("parse.caret", &["padding"]),
+    ("parse.empty", &[]),
+    ("parse.error", &["detail"]),
+    // ---- Project lifecycle event notes ----
+    ("project.export_failed", &["error"]),
+    ("project.export_ok", &["path"]),
+    ("project.export_usage", &[]),
+    ("project.import_empty_target", &[]),
+    ("project.import_usage", &[]),
+    ("project.rebuild_failed", &["error"]),
+    ("project.rebuild_ok", &["summary"]),
+    ("project.switch_failed", &["error"]),
+    ("project.switched_ok", &["display_name"]),
+    // ---- mode / messages banners ----
+    ("messages.set_short", &[]),
+    ("messages.set_verbose", &[]),
+    ("messages.show", &["current"]),
+    ("messages.unknown", &["value"]),
+    ("mode.set_advanced", &[]),
+    ("mode.set_simple", &[]),
+    ("mode.show_advanced", &[]),
+    ("mode.show_simple", &[]),
+    ("mode.unknown", &["value"]),
+    ("mode.usage", &[]),
+    // ---- DSL command success summaries (ADR-0019 §9 sweep) ----
+    ("ok.rows_deleted", &["count"]),
+    ("ok.rows_inserted", &["count"]),
+    ("ok.rows_updated", &["count"]),
+    ("ok.summary", &["verb", "subject"]),
+    // ---- Client-side success notes (ADR-0017 §6, ADR-0018 §9) ----
+    ("client_side.auto_fill_add_serial", &["count"]),
+    ("client_side.auto_fill_add_shortid", &["count"]),
+    ("client_side.auto_fill_transition", &["count", "kind"]),
+    ("client_side.transformed", &["count"]),
+    ("client_side.transformed_lossy", &["count", "lossy"]),
+    // ---- Replay command surfaces (ADR-0019 §9 sweep) ----
+    ("replay.command_echo", &["command"]),
+    ("replay.completed", &["path", "count"]),
+    ("replay.error_could_not_open", &["path", "detail"]),
+    ("replay.error_nested", &[]),
+    ("replay.error_parse", &["detail"]),
+    ("replay.failed_at_line", &["path", "line_number", "error"]),
+    ("replay.failed_open", &["path", "error"]),
     // ---- UNIQUE violations (anchor: "already has the value") ----
     (
         "error.unique.insert.headline",
diff --git a/src/friendly/strings/en-US.yaml b/src/friendly/strings/en-US.yaml
index 111fbec..7c0dda7 100644
--- a/src/friendly/strings/en-US.yaml
+++ b/src/friendly/strings/en-US.yaml
@@ -151,3 +151,102 @@ error:
       headline: "INSERT requires at least one column value."
     empty_update:
       headline: "UPDATE requires at least one assignment."
+
+# ---- DSL parse error rendering --------------------------------------
+parse:
+  # Wrapper around chumsky's structural error message. The
+  # caret pointer (visualising the failure column) is printed
+  # on its own preceding line via `parse.caret`.
+  error: "parse error: {detail}"
+  # Caret pointer showing where in the input the parser
+  # failed. `{padding}` is the leading whitespace; the
+  # template appends `^` so the rendered line places the
+  # marker under the offending character.
+  caret: "{padding}^"
+  # Default for the `ParseError::Empty` variant — surfaces as
+  # `{detail}` inside the wrapper.
+  empty: "empty input"
+
+# ---- Project lifecycle event notes -----------------------------------
+project:
+  rebuild_ok: "[ok] rebuild — {summary}"
+  rebuild_failed: "rebuild failed: {error}"
+  switched_ok: "[ok] now editing: {display_name}"
+  switch_failed: "project switch failed: {error}"
+  export_ok: "[ok] export — wrote {path}"
+  export_failed: "export failed: {error}"
+  # Usage / argument-parsing errors for app-level commands.
+  export_usage: "usage: export [<path>]"
+  import_usage: "usage: import <zip-path> [as <target>]"
+  import_empty_target: "import: empty target after `as`"
+
+# ---- mode / messages banners (app-level commands) -------------------
+mode:
+  set_simple: "mode: simple"
+  set_advanced: "mode: advanced"
+  show_simple: "mode: simple"
+  show_advanced: "mode: advanced"
+  usage: "usage: mode simple | mode advanced"
+  unknown: "unknown mode '{value}' (expected 'simple' or 'advanced')"
+
+messages:
+  show: "messages: {current}"
+  set_short: "messages: short"
+  set_verbose: "messages: verbose"
+  unknown: "unknown messages mode '{value}' (expected 'short' or 'verbose')"
+
+# ---- DSL command success summaries (ADR-0019 §9 sweep) --------------
+ok:
+  # Generic `[ok] <verb> <subject>` header used for every
+  # successful DSL command. Verbs come from `Command::verb()`
+  # (already English keywords); subjects are the table /
+  # relationship endpoints derived in `Command::display_subject()`.
+  summary: "[ok] {verb} {subject}"
+  # Per-operation row-count footers shown beneath the summary.
+  rows_inserted: "  {count} row(s) inserted"
+  rows_updated: "  {count} row(s) updated"
+  rows_deleted: "  {count} row(s) deleted"
+
+# ---- Client-side success notes (ADR-0017 §6, ADR-0018 §9) ------------
+client_side:
+  # Per-cell transformation notice when `change column ...` rewrote
+  # at least one stored value (storage-class change or non-identity
+  # mapping). `lossy` variant fires under --force-conversion when
+  # information was discarded.
+  transformed: |-
+    [client-side] {count} row(s) were transformed before being stored. In raw SQL this would need an explicit `CAST` or application-level code.
+  transformed_lossy: |-
+    [client-side] {count} row(s) transformed; {lossy} of those discarded information (lossy). In raw SQL this would need an explicit `CAST` or application-level code.
+  # Auto-fill notice when null cells were populated by the
+  # serial/shortid auto-generation contract (change column path).
+  auto_fill_transition: |-
+    [client-side] {count} null cell(s) given auto-generated {kind} values. In raw SQL this would need an explicit UPDATE to populate.
+  # Auto-fill notice for `add column T: x (serial)` on a
+  # non-empty table — values run 1..N.
+  auto_fill_add_serial: |-
+    [client-side] {count} row(s) given auto-generated serial values 1..{count}. In raw SQL this would need an explicit UPDATE to populate.
+  # Auto-fill notice for `add column T: x (shortid)` on a
+  # non-empty table.
+  auto_fill_add_shortid: |-
+    [client-side] {count} row(s) given auto-generated shortid values. In raw SQL this would need an explicit UPDATE to populate.
+
+# ---- Replay command surfaces (ADR-0019 §9 sweep) ---------------------
+replay:
+  # Success summary printed when `replay <path>` completes
+  # without per-line failure.
+  completed: "[ok] replay {path} — {count} command(s) run"
+  # File-open failure (line_number == 0 from the runtime).
+  failed_open: "replay {path} failed: {error}"
+  # Per-line failure header. The command echo is on a
+  # follow-up `command_echo` line so the renderer can format
+  # them as separate output rows.
+  failed_at_line: "replay {path} failed at line {line_number}: {error}"
+  # Indented echo of the offending command line, shown after
+  # `failed_at_line` when the runtime supplied the source.
+  command_echo: "  > {command}"
+  # Errors the runtime constructs inside ReplayFailed.error
+  # before forwarding to App. Carried as plain text so they
+  # compose with `failed_at_line`'s `{error}` placeholder.
+  error_could_not_open: "could not open `{path}`: {detail}"
+  error_parse: "parse error: {detail}"
+  error_nested: "nested `replay` is not allowed inside a replay file"
diff --git a/src/runtime.rs b/src/runtime.rs
index 2bdcfa3..8bf9f89 100644
--- a/src/runtime.rs
+++ b/src/runtime.rs
@@ -1355,7 +1355,11 @@ pub async fn run_replay(
                 path: path.to_string(),
                 line_number: 0,
                 command: String::new(),
-                error: format!("could not open `{}`: {e}", resolved.display()),
+                error: crate::t!(
+                    "replay.error_could_not_open",
+                    path = resolved.display(),
+                    detail = e
+                ),
             });
             return events;
         }
@@ -1378,7 +1382,7 @@ pub async fn run_replay(
                     path: path.to_string(),
                     line_number,
                     command: trimmed.to_string(),
-                    error: format!("parse error: {e}"),
+                    error: crate::t!("replay.error_parse", detail = e),
                 });
                 return events;
             }
@@ -1394,7 +1398,7 @@ pub async fn run_replay(
                 path: path.to_string(),
                 line_number,
                 command: trimmed.to_string(),
-                error: "nested `replay` is not allowed inside a replay file".to_string(),
+                error: crate::t!("replay.error_nested"),
             });
             return events;
         }