diff --git a/docs/contracts/issues/13.contract.md b/docs/contracts/issues/13.contract.md
index b2ae491..a357fbe 100644
--- a/docs/contracts/issues/13.contract.md
+++ b/docs/contracts/issues/13.contract.md
@@ -154,10 +154,12 @@ New `Static(id="pane-name")` widget alongside the existing `identity` + `hint` w
 
 - **INV-013**: Layout is `Horizontal` two-column. Left column width = 2fr; right column width = 1fr.
 - **INV-014**: `ToolStart` / `ToolResult` events route to `tools_log` (Tools pane), never to `log` (transcript).
-- **INV-015**: Every other event type (`Text`, `Thinking`, `WorkerPhase`, `TextBoundary`, `Done`, `Error`, `Cancelled`) keeps its issue-#12 routing target (`log` for chronological entries; `thinking_widget` for live deltas).
-- **INV-016**: Input retains keyboard focus across `Ctrl+1` tab switch.
-- **INV-017**: `thinking-current` Static docks to the top of the **left column**, not the whole App — TabbedContent's vertical extent on the right is independent of thinking-runs starting/stopping.
+- **INV-015** *(amended v0.5.0)*: The transcript (`log`) is **content-only** — receives `Text`, `Done` (label + Markdown body + Rule), `Error`, `Cancelled`, and the user-prompt echo (`❯ <content>`). **All telemetry events (`Thinking` closed runs, `WorkerPhase`, `TextBoundary`) route to `debug_log` (Debug pane), NOT `log`.** Live thinking deltas continue to update `thinking_widget` per-delta. The pre-v0.5.0 shape (telemetry mixed into transcript) is retired under the project's no-backwards-compat rule.
+- **INV-016**: Input retains keyboard focus across `Ctrl+1` / `Ctrl+2` tab switches.
+- **INV-017** *(amended v0.5.0)*: `thinking-current` Static docks to the top of the **right column** (above `TabbedContent`), not the left column. Live thinking visibility persists across tab switches. v0.5.0 moves it from left → right so the left column is genuinely content-only.
 - **INV-018**: CLI mode (`ratatoskr.cli._amain`) is unaffected. CLI keeps inline `· tool_start: …` / `· tool_result: …` rendering on stderr per issue #12 INV-005.
+- **INV-019** *(new v0.5.0)*: Two TabPanes in the right column: `Tools` (id `tools-tab`, contains `#tools-log`) + `Debug` (id `debug-tab`, contains `#debug-log`). Ctrl+1 activates Tools; Ctrl+2 activates Debug. `pane-name` Static reflects the active tab name dynamically.
+- **INV-020** *(new v0.5.0)*: Render-exception fallback (INV-009) preserves routing per event class: `ToolStart` / `ToolResult` fallback writes to `tools_log`; `WorkerPhase` / `Thinking` / `TextBoundary` fallback writes to `debug_log`; everything else falls back to `log`.
 
 ## TESTS (additions / changes to test_tui.py)
 
@@ -185,21 +187,28 @@ Existing tests that need adjustment (NOT rewrite):
 
 All error routing from issues #4 / #6 / #7 / #12 stays verbatim. The tools_log routing change is internal to the presenter; error paths (`SseConnectFailed`, `SseConnectionDropped`, `MalformedSseId`, `MalformedSseData`, `TurnIdFlip`) all write their labeled lines to `log` (the main transcript). Reason: errors are turn-terminal and need to be visible in the operator's primary attention surface; routing them to the Tools pane would hide them behind a tab switch.
 
-## Layout-spec snapshot (after this issue lands)
+## Layout-spec snapshot (after v0.5.0)
 
 ```
 +────────────────────────────────+──────────────────────+
-| · thinking-current             |  ┌─ Tools ─────────┐ |
-|                                |  │ · tool_start:.. │ |
-|  ❯ user-typed line             |  │ · tool_result.. │ |
-|  assistant streaming text...   |  │                 │ |
-|  [done] turn_id=… duration=…   |  │                 │ |
-|                                |  │                 │ |
-|                                |  │                 │ |
-|  [prompt: type and press Enter]|  └─────────────────┘ |
+|  ❯ user-typed line             | · thinking-current   |
+|  assistant streaming text...   |  ┌Tools─┬─Debug─────┐|
+|  [done] turn_id=… duration=…   |  │ · tool_start:..  │|
+|  …markdown render…             |  │ · tool_result..  │|
+|                                |  │                  │|
+|                                |  │                  │|
+|                                |  │                  │|
+|  [prompt: type and press Enter]|  └──────────────────┘|
 +────────────────────────────────+──────────────────────+
 | agent · …sess_id  Tools  Ctrl-C twice to exit         |
 +───────────────────────────────────────────────────────+
 ```
 
-(Width split 2fr:1fr; tab strip is Textual-default.)
+Left column is content-only (transcript + prompt). Right column hosts the
+live `thinking-current` Static at top + `TabbedContent` cycling between
+`Tools` (tool events) and `Debug` (thinking closed runs + worker_phase +
+text_boundary).
+
+(Width split 2fr:1fr; tab strip is Textual-default; Header/Footer
+backgrounds explicitly set to `$surface` to override the Textual default
+`$primary`-blue tinting.)
diff --git a/persistent-memory.md b/persistent-memory.md
index 7fe26e5..18609ae 100644
--- a/persistent-memory.md
+++ b/persistent-memory.md
@@ -32,9 +32,9 @@ separate dev team rather than an in-tree Worldtree tool.
 
 ## Current state / in-flight
 
-_As of 2026-05-24 (post-v0.4.1 Australis theme retheme):_
+_As of 2026-05-24 (post-v0.5.0 content-only main pane + Debug tab):_
 
-**Status: v0.4.1 shipped.** Nine core issues complete (`sse_client`
+**Status: v0.5.0 shipped.** Nine core issues complete (`sse_client`
 #1, `sessions` #2, `cli` #3, `tui` #4, `--end-user-id` #5, TUI
 startup error visibility #6, presenter contract semantics amendment
 #12, startup agent picker #8, §5 layout reshape + Tools pane #13)
@@ -51,7 +51,8 @@ Static in the footer (static "Tools" v1; dynamic when more tabs
 land). CLI mode (--send) unaffected by design — INV-018.
 
 Last commits on `main`:
-- v0.4.1 style(tui): apply Australis theme to TUI chrome + widgets
+- v0.5.0 refactor(tui): content-only main pane + Debug tab + chrome dark
+- `2756f5f` style(tui): apply Australis theme to TUI chrome + widgets (v0.4.1)
 - `24e4371` feat(tui): issue #13 — §5 layout reshape + Tools pane (v0.4.0)
 - `d30be12` feat(sessions,cli,tui): issue #8 — startup agent picker (v0.3.0)
 - `c85f6bd` fix(tui): anchor layout via dock so Input never moves (v0.2.1)
diff --git a/pyproject.toml b/pyproject.toml
index fed6dd1..5c68931 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -4,7 +4,7 @@ build-backend = "hatchling.build"
 
 [project]
 name = "ratatoskr"
-version = "0.4.1"
+version = "0.5.0"
 description = "Worldtree Conversation API debug TUI — multi-pane observability dashboard"
 readme = "README.md"
 requires-python = ">=3.12"
diff --git a/src/ratatoskr/tui.py b/src/ratatoskr/tui.py
index a2577d5..88c9bc3 100644
--- a/src/ratatoskr/tui.py
+++ b/src/ratatoskr/tui.py
@@ -186,16 +186,17 @@ class TuiPresenterState:
         log: RichLog,
         thinking_widget: Static,
         tools_log: RichLog,
+        debug_log: RichLog,
         raw: bool,
     ) -> None:
         """Render one Worldtree SSE event with the TUI hierarchy + coalescing.
 
-        Two-views-of-thinking decoupling: per-delta updates go to
-        `thinking_widget`; one closed entry per run goes to `log`.
-
-        Issue #13: `ToolStart` / `ToolResult` events route to `tools_log`
-        (the Tools pane in the right column) instead of `log`. Every other
-        event keeps its issue-#12 routing.
+        v0.5.0 routing: main `log` (transcript) is CONTENT-ONLY — Text,
+        terminal labels ([done] / [error] / [cancelled]), and the
+        post-Done Markdown render. All telemetry (Thinking closed runs,
+        WorkerPhase, TextBoundary) routes to `debug_log` (Debug tab); all
+        tool activity (ToolStart, ToolResult) routes to `tools_log` (Tools
+        tab). Live thinking deltas continue to update `thinking_widget`.
 
         Exceptions are caught at the presenter boundary (INV-009 fallback).
         """
@@ -229,10 +230,12 @@ class TuiPresenterState:
                 display_text = ("…" + acc[-200:]) if len(acc) > 200 else acc
                 thinking_widget.update(display_text)
                 return
-            # Non-thinking event: close any open thinking run (one RichLog entry).
+            # Non-thinking event: close any open thinking run.
+            # v0.5.0: closed thinking runs land in debug_log (Debug pane), not
+            # transcript — keeps the main pane content-only.
             if self.thinking_open:
                 full_thinking = "".join(self.thinking_buffer)
-                log.write(_dim(f"· thinking: {full_thinking}"))
+                debug_log.write(_dim(f"· thinking: {full_thinking}"))
                 self.thinking_buffer.clear()
                 self.thinking_open = False
                 thinking_widget.update("")
@@ -272,7 +275,8 @@ class TuiPresenterState:
                 thinking_widget.display = False
                 return
             if isinstance(event, WorkerPhase):
-                log.write(_dim(
+                # v0.5.0: telemetry → Debug pane, not transcript.
+                debug_log.write(_dim(
                     f"· worker_phase: phase={event.phase} turn_id={event.turn_id}"
                 ))
                 return
@@ -290,7 +294,8 @@ class TuiPresenterState:
                 ))
                 return
             if isinstance(event, TextBoundary):
-                log.write(_dim(
+                # v0.5.0: telemetry → Debug pane, not transcript.
+                debug_log.write(_dim(
                     f"· text_boundary: kind={event.kind} char_offset={event.char_offset}"
                 ))
                 return
@@ -299,10 +304,17 @@ class TuiPresenterState:
             # the original event AND a render_error line with the class name only
             # (NO exception message — security clause). Volva F1 fix.
             #
-            # Issue #13: routing-under-failure preservation — ToolStart/ToolResult
-            # fallback writes go to tools_log (the routed destination per
-            # INV-014), not the transcript. Every other event falls back to log.
-            target = tools_log if isinstance(event, (ToolStart, ToolResult)) else log
+            # v0.5.0: routing-under-failure preservation — fallback writes go
+            # to the same destination the successful render would have used:
+            #   - ToolStart/ToolResult       → tools_log
+            #   - WorkerPhase/Thinking/TextBoundary → debug_log
+            #   - everything else (Text/Done/Error/Cancelled) → log
+            if isinstance(event, (ToolStart, ToolResult)):
+                target = tools_log
+            elif isinstance(event, (WorkerPhase, Thinking, TextBoundary)):
+                target = debug_log
+            else:
+                target = log
             target.write(_plain_label(event))
             target.write(f"[render_error] {type(exc).__name__}")
 
@@ -380,20 +392,32 @@ class AgentPickerApp(App[str | None]):
 class RatatoskrApp(App[int]):
     """Textual TUI shell — single chat pane."""
 
-    # Issue #13: Horizontal two-column layout per design-brief §5.
-    # Left column (2fr) is the chat surface; right column (1fr) is the
-    # TabbedContent housing side panes. v1 has only the Tools tab.
+    # Issue #13 + v0.5.0 follow-up: Horizontal two-column layout per
+    # design-brief §5. Left column (2fr) is the **content-only** chat
+    # surface — assistant text, user prompt echo, [done]/[error]/[cancelled]
+    # terminal labels, post-Done markdown render. Right column (1fr) houses
+    # ALL telemetry: live thinking preview docked above TabbedContent;
+    # tab strip carries Tools (ToolStart/ToolResult) + Debug (Thinking
+    # closed runs + WorkerPhase + TextBoundary).
     #
-    # Dock rules narrow to per-container scope so thinking-current toggling
-    # in the left column doesn't reflow the right column's TabbedContent.
-    # The v0.2.1 layout-stability property is preserved within the left
-    # column by docking thinking-current top + prompt bottom of that column.
+    # v0.5.0 routing change: thinking-current Static moved from left column
+    # to right column header so the left column is genuinely content-only;
+    # closed thinking runs go to debug-log instead of transcript.
     #
-    # v0.4.1: Australis theme — Aurora blue/cyan primary, Ice background,
-    # Sea darks for chrome separators. Widget colors use theme variables
-    # ($primary/$accent/$au-dark-60/$au-bright-cyan/etc.) so a future theme
-    # swap rebinds them centrally.
+    # v0.5.0 chrome fix: Header/Footer backgrounds explicitly set to $surface
+    # (Sea bright-black #373b46) overriding Textual's default $primary-blue
+    # tinting. TabbedContent active-tab tinting also softened.
+    #
+    # Australis theme variables ($primary/$accent/$au-dark-60/$au-bright-cyan/
+    # etc.) carry colors so a future theme swap rebinds centrally.
     DEFAULT_CSS = """
+    Header {
+        background: $surface;
+        color: $au-bright-blue;
+    }
+    Footer {
+        background: $surface;
+    }
     #main-row {
         height: 1fr;
     }
@@ -408,14 +432,18 @@ class RatatoskrApp(App[int]):
         dock: top;
         height: auto;
         color: $au-dark-60;
+        padding: 0 1;
     }
     #transcript {
         height: 1fr;
         background: $background;
     }
-    #tools-log {
+    #tools-log, #debug-log {
         background: $background;
     }
+    #side-panes Tabs {
+        background: $surface;
+    }
     #prompt {
         dock: bottom;
         border: tall $panel;
@@ -446,10 +474,10 @@ class RatatoskrApp(App[int]):
     BINDINGS: ClassVar[list[Binding]] = [
         Binding("ctrl+c", "interrupt", "Cancel / Exit", priority=True),
         Binding("ctrl+d", "quit", "Exit immediately", priority=True),
-        # Issue #13: §5 keybinding family Ctrl+1..5 jumps between side panes
-        # without losing Input focus (INV-016). v1 only has Tools; Ctrl+2..5
-        # land as Persona/AdminEvents/BifrostState/ServerLog panes ship.
+        # §5 keybinding family Ctrl+1..5 jumps between side panes
+        # without losing Input focus (INV-016).
         Binding("ctrl+1", "focus_tools", "Tools tab", priority=False),
+        Binding("ctrl+2", "focus_debug", "Debug tab", priority=False),
     ]
 
     HINT_IDLE = "Ctrl-C twice to exit"
@@ -478,9 +506,9 @@ class RatatoskrApp(App[int]):
 
     def compose(self) -> ComposeResult:
         yield Header()
-        # Issue #13: Horizontal two-column layout. Left column = chat surface
-        # (thinking-current docked top, transcript fills middle, prompt docked
-        # bottom). Right column = TabbedContent for side panes (v1: Tools only).
+        # v0.5.0 layout: left column is content-only (transcript + prompt).
+        # Right column houses ALL telemetry — thinking-current live preview
+        # docked above the TabbedContent; tabs cycle Tools / Debug.
         # markup=False on RichLog so labeled lines like "[cancel_failed] ..."
         # render verbatim; Rich would otherwise interpret bracket spans as
         # style markup. The post-Done markdown render uses Markdown() directly
@@ -488,17 +516,21 @@ class RatatoskrApp(App[int]):
         # widget-level markup=True.
         with Horizontal(id="main-row"):
             with Vertical(id="left-column"):
-                yield Static("", id="thinking-current")
                 yield RichLog(id="transcript", wrap=True, markup=False, highlight=False)
                 yield Input(id="prompt", placeholder="Type a message and press Enter")
             with Vertical(id="right-column"):
+                yield Static("", id="thinking-current")
                 with TabbedContent(id="side-panes"):
                     with TabPane("Tools", id="tools-tab"):
                         yield RichLog(
                             id="tools-log", wrap=True, markup=False, highlight=False
                         )
+                    with TabPane("Debug", id="debug-tab"):
+                        yield RichLog(
+                            id="debug-log", wrap=True, markup=False, highlight=False
+                        )
         # INV-002 + INV-003: visible identity + hint widgets (Footer-area).
-        # INV (issue #13): pane-name widget displays current side-pane name.
+        # pane-name widget displays current side-pane name.
         yield Static("", id="identity")
         yield Static("Tools", id="pane-name")
         yield Static(self.HINT_IDLE, id="hint")
@@ -559,8 +591,9 @@ class RatatoskrApp(App[int]):
         assert content
         log = self.query_one("#transcript", RichLog)
         thinking_widget = self.query_one("#thinking-current", Static)
-        # Issue #13: tools_log routes ToolStart/ToolResult into the Tools pane.
+        # v0.5.0: separate panes for tools vs telemetry; transcript is content only.
         tools_log = self.query_one("#tools-log", RichLog)
+        debug_log = self.query_one("#debug-log", RichLog)
         presenter = TuiPresenterState()
         try:
             async for event in stream_turn(self.client, self.session_id, content):
@@ -571,6 +604,7 @@ class RatatoskrApp(App[int]):
                     log=log,
                     thinking_widget=thinking_widget,
                     tools_log=tools_log,
+                    debug_log=debug_log,
                     raw=self.args.raw,
                 )
                 if isinstance(event, (Done, Error, Cancelled)):
@@ -631,6 +665,12 @@ class RatatoskrApp(App[int]):
         — `test_ctrl_1_preserves_input_focus` is the regression guard.
         """
         self.query_one("#side-panes", TabbedContent).active = "tools-tab"
+        self.query_one("#pane-name", Static).update("Tools")
+
+    def action_focus_debug(self) -> None:
+        """v0.5.0: Ctrl+2 activates the Debug tab. INV-016 preserves Input focus."""
+        self.query_one("#side-panes", TabbedContent).active = "debug-tab"
+        self.query_one("#pane-name", Static).update("Debug")
 
 
 def run_tui(args: ParsedArgs) -> int:
diff --git a/tests/test_tui.py b/tests/test_tui.py
index a724c04..9be2a6f 100644
--- a/tests/test_tui.py
+++ b/tests/test_tui.py
@@ -126,6 +126,7 @@ class TestTuiPresenterState:
             log=log,
             thinking_widget=widget,
             tools_log=MagicMock(),
+            debug_log=MagicMock(),
             raw=False,
         )
         state.render(
@@ -133,6 +134,7 @@ class TestTuiPresenterState:
             log=log,
             thinking_widget=widget,
             tools_log=MagicMock(),
+            debug_log=MagicMock(),
             raw=False,
         )
         state.render(
@@ -140,6 +142,7 @@ class TestTuiPresenterState:
             log=log,
             thinking_widget=widget,
             tools_log=MagicMock(),
+            debug_log=MagicMock(),
             raw=False,
         )
         # Widget updated 3 times — once per delta — with cumulative content
@@ -151,13 +154,15 @@ class TestTuiPresenterState:
         # No RichLog write yet — closure hasn't fired
         assert log.write.call_count == 0
 
-    def test_thinking_closes_one_richlog_entry(self) -> None:
-        """thinking_closes_one_richlog_entry [happy]: 2x Thinking + WorkerPhase →
-        RichLog has ONE closed thinking entry + one worker_phase entry; widget cleared+hidden.
+    def test_thinking_closes_one_debuglog_entry(self) -> None:
+        """thinking_closes_one_debuglog_entry [happy, v0.5.0]: 2x Thinking + WorkerPhase →
+        debug_log has ONE closed thinking entry + one worker_phase entry; widget cleared+hidden;
+        transcript (log) untouched.
         """
         from ratatoskr.tui import TuiPresenterState
 
         log = MagicMock()
+        debug_log = MagicMock()
         widget = MagicMock()
         state = TuiPresenterState()
         state.render(
@@ -165,6 +170,7 @@ class TestTuiPresenterState:
             log=log,
             thinking_widget=widget,
             tools_log=MagicMock(),
+            debug_log=debug_log,
             raw=False,
         )
         state.render(
@@ -172,6 +178,7 @@ class TestTuiPresenterState:
             log=log,
             thinking_widget=widget,
             tools_log=MagicMock(),
+            debug_log=debug_log,
             raw=False,
         )
         state.render(
@@ -179,14 +186,16 @@ class TestTuiPresenterState:
             log=log,
             thinking_widget=widget,
             tools_log=MagicMock(),
+            debug_log=debug_log,
             raw=False,
         )
-        # Closure wrote "· thinking: ab"; then worker_phase wrote "· worker_phase: ..."
-        assert log.write.call_count == 2
+        # v0.5.0: closure + worker_phase write to debug_log; transcript untouched.
+        assert debug_log.write.call_count == 2
+        assert not log.write.called
         # First write = closed thinking entry containing the full accumulated text
-        assert "· thinking: ab" in log.write.call_args_list[0][0][0]
-        # Second write = worker_phase with demotion prefix
-        assert "· worker_phase:" in log.write.call_args_list[1][0][0]
+        assert "· thinking: ab" in _text_of(debug_log.write.call_args_list[0][0][0])
+        # Second write = worker_phase with demotion prefix (also in debug_log)
+        assert "· worker_phase:" in _text_of(debug_log.write.call_args_list[1][0][0])
         # Widget cleared + hidden
         widget.update.assert_called_with("")
         assert widget.display is False
@@ -205,6 +214,7 @@ class TestTuiPresenterState:
             log=log,
             thinking_widget=widget,
             tools_log=MagicMock(),
+            debug_log=MagicMock(),
             raw=False,
         )
         last_update = widget.update.call_args_list[-1][0][0]
@@ -228,6 +238,7 @@ class TestTuiPresenterState:
             log=log,
             thinking_widget=widget,
             tools_log=MagicMock(),
+            debug_log=MagicMock(),
             raw=False,
         )
         assert widget.display is True
@@ -237,17 +248,20 @@ class TestTuiPresenterState:
             log=log,
             thinking_widget=widget,
             tools_log=MagicMock(),
+            debug_log=MagicMock(),
             raw=False,
         )
         assert widget.display is False
 
-    def test_multiple_thinking_runs_each_get_richlog_entry(self) -> None:
-        """multiple_thinking_runs_each_get_richlog_entry [scenario]:
-        Thinking → Text → Thinking → Done → TWO closed thinking RichLog entries.
+    def test_multiple_thinking_runs_each_get_debuglog_entry(self) -> None:
+        """multiple_thinking_runs_each_get_debuglog_entry [scenario, v0.5.0]:
+        Thinking → Text → Thinking → Done → TWO closed thinking entries in debug_log
+        (transcript receives only the Text + Done content).
         """
         from ratatoskr.tui import TuiPresenterState
 
         log = MagicMock()
+        debug_log = MagicMock()
         widget = MagicMock()
         state = TuiPresenterState()
         state.render(
@@ -255,6 +269,7 @@ class TestTuiPresenterState:
             log=log,
             thinking_widget=widget,
             tools_log=MagicMock(),
+            debug_log=debug_log,
             raw=False,
         )
         state.render(
@@ -262,6 +277,7 @@ class TestTuiPresenterState:
             log=log,
             thinking_widget=widget,
             tools_log=MagicMock(),
+            debug_log=debug_log,
             raw=False,
         )
         state.render(
@@ -269,46 +285,62 @@ class TestTuiPresenterState:
             log=log,
             thinking_widget=widget,
             tools_log=MagicMock(),
+            debug_log=debug_log,
             raw=False,
         )
         # Close the second run with a Done.
         state.render(
-            _make_tui_done(), log=log, thinking_widget=widget, tools_log=MagicMock(), raw=True
+            _make_tui_done(),
+            log=log,
+            thinking_widget=widget,
+            tools_log=MagicMock(),
+            debug_log=debug_log,
+            raw=True,
         )
-        # Count closed thinking entries — now dim RichText; plain text starts with "· thinking:".
-        thinking_entries = [_text_of(call[0][0]) for call in log.write.call_args_list]
+        # v0.5.0: closed thinking entries land in debug_log, NOT log.
+        thinking_entries = [_text_of(call[0][0]) for call in debug_log.write.call_args_list]
         thinking_entries = [t for t in thinking_entries if t.startswith("· thinking:")]
         assert len(thinking_entries) == 2
         assert "first" in thinking_entries[0]
         assert "second" in thinking_entries[1]
+        # transcript receives: "hi" (Text) + "[done] ..." (terminal label) only.
+        log_writes = [_text_of(c[0][0]) for c in log.write.call_args_list]
+        assert "hi" in log_writes
+        assert any(w.startswith("[done]") for w in log_writes if isinstance(w, str))
 
     def test_render_exception_fallback(self) -> None:
-        """render_exception_fallback [adversarial]:
-        widget.update raises → RichLog gets BOTH a plain-labeled fallback line for
-        the original event AND a `[render_error] <ExceptionClassName>` line
-        (NO exception message per INV-009 security clause); state does NOT propagate.
+        """render_exception_fallback [adversarial, v0.5.0]:
+        widget.update raises → debug_log gets BOTH a plain-labeled fallback line
+        for the original Thinking event AND a `[render_error] <ExceptionClassName>`
+        line (NO exception message per INV-009 security clause). transcript
+        receives nothing — routing preservation under failure (debug-shaped
+        event falls back to debug_log).
         """
         from ratatoskr.tui import TuiPresenterState
 
         log = MagicMock()
+        debug_log = MagicMock()
         widget = MagicMock()
         widget.update.side_effect = AttributeError("widget gone (msg should NOT leak)")
         state = TuiPresenterState()
-        # Should not raise; should write a fallback labeled line + a [render_error] line.
         state.render(
             Thinking(sse_id=SID, content="x"),
             log=log,
             thinking_widget=widget,
             tools_log=MagicMock(),
+            debug_log=debug_log,
             raw=False,
         )
-        writes = [call[0][0] for call in log.write.call_args_list if isinstance(call[0][0], str)]
-        # POST-007: plain-label fallback for the original Thinking event (pre-amendment shape).
+        writes = [c[0][0] for c in debug_log.write.call_args_list if isinstance(c[0][0], str)]
+        # POST-007: plain-label fallback for the original Thinking event.
         assert any(w.startswith("[thinking]") for w in writes), writes
         # POST-007: render_error line with class name ONLY.
         assert any(w == "[render_error] AttributeError" for w in writes), writes
         # Critical: exception message MUST NOT appear in any write (INV-009 security).
         assert not any("widget gone" in w for w in writes), writes
+        # v0.5.0 routing preservation: transcript receives NOTHING on a
+        # debug-shaped event's failure path.
+        assert not log.write.called
 
     def test_state_reset_per_worker(self) -> None:
         """state_reset_per_worker [trace]: fresh TuiPresenterState() starts no thinking open."""
@@ -320,6 +352,7 @@ class TestTuiPresenterState:
             log=MagicMock(),
             thinking_widget=MagicMock(),
             tools_log=MagicMock(),
+            debug_log=MagicMock(),
             raw=False,
         )
         s2 = TuiPresenterState()
@@ -327,12 +360,14 @@ class TestTuiPresenterState:
         assert s2.thinking_open is False
 
     def test_cancelled_mid_thinking_closes(self) -> None:
-        """cancelled_mid_thinking_closes [scenario]:
-        Thinking, Cancelled → ONE closed thinking entry + a [cancelled] entry; widget hidden.
+        """cancelled_mid_thinking_closes [scenario, v0.5.0]:
+        Thinking, Cancelled → ONE closed thinking entry in debug_log + a
+        [cancelled] entry in transcript; widget hidden.
         """
         from ratatoskr.tui import TuiPresenterState
 
         log = MagicMock()
+        debug_log = MagicMock()
         widget = MagicMock()
         state = TuiPresenterState()
         state.render(
@@ -340,6 +375,7 @@ class TestTuiPresenterState:
             log=log,
             thinking_widget=widget,
             tools_log=MagicMock(),
+            debug_log=debug_log,
             raw=False,
         )
         state.render(
@@ -349,12 +385,14 @@ class TestTuiPresenterState:
             log=log,
             thinking_widget=widget,
             tools_log=MagicMock(),
+            debug_log=debug_log,
             raw=False,
         )
-        # Closed thinking entries are now dim RichText; terminal labels are plain str.
-        writes = [_text_of(c[0][0]) for c in log.write.call_args_list]
-        assert any(w.startswith("· thinking: partial") for w in writes)
-        assert any(w.startswith("[cancelled]") for w in writes)
+        # v0.5.0: closed thinking entry lands in debug_log; terminal [cancelled] in transcript.
+        debug_writes = [_text_of(c[0][0]) for c in debug_log.write.call_args_list]
+        log_writes = [_text_of(c[0][0]) for c in log.write.call_args_list]
+        assert any(w.startswith("· thinking: partial") for w in debug_writes)
+        assert any(w.startswith("[cancelled]") for w in log_writes)
         assert widget.display is False
 
     def test_done_renders_markdown_after_label(self) -> None:
@@ -374,10 +412,16 @@ class TestTuiPresenterState:
             log=log,
             thinking_widget=widget,
             tools_log=MagicMock(),
+            debug_log=MagicMock(),
             raw=False,
         )
         state.render(
-            _make_tui_done(), log=log, thinking_widget=widget, tools_log=MagicMock(), raw=False
+            _make_tui_done(),
+            log=log,
+            thinking_widget=widget,
+            tools_log=MagicMock(),
+            debug_log=MagicMock(),
+            raw=False,
         )
         writes = [c[0][0] for c in log.write.call_args_list]
         # Text stream wrote "hi" with no prefix.
@@ -403,33 +447,44 @@ class TestTuiPresenterState:
             log=log,
             thinking_widget=widget,
             tools_log=MagicMock(),
+            debug_log=MagicMock(),
             raw=True,
         )
         state.render(
-            _make_tui_done(), log=log, thinking_widget=widget, tools_log=MagicMock(), raw=True
+            _make_tui_done(),
+            log=log,
+            thinking_widget=widget,
+            tools_log=MagicMock(),
+            debug_log=MagicMock(),
+            raw=True,
         )
         writes = [c[0][0] for c in log.write.call_args_list]
         assert not any(isinstance(w, Rule) for w in writes)
         assert not any(isinstance(w, Markdown) for w in writes)
 
-    def test_worker_phase_demoted(self) -> None:
-        """worker_phase_demoted [trace]: WorkerPhase → RichLog "· worker_phase:" prefix
-        rendered with dim Rich style (INV-003: dim style + `· ` prefix in TUI).
+    def test_worker_phase_demoted_to_debug_log(self) -> None:
+        """worker_phase_demoted_to_debug_log [trace, v0.5.0]: WorkerPhase → debug_log
+        "· worker_phase:" prefix rendered with Australis dark-60 Rich style.
+        Transcript receives nothing.
         """
         from rich.text import Text as RichText
 
         from ratatoskr.tui import TuiPresenterState
 
         log = MagicMock()
+        debug_log = MagicMock()
         state = TuiPresenterState()
         state.render(
             WorkerPhase(sse_id=SID, phase="streaming", turn_id=42),
             log=log,
             thinking_widget=MagicMock(),
             tools_log=MagicMock(),
+            debug_log=debug_log,
             raw=False,
         )
-        renderable = log.write.call_args[0][0]
+        # v0.5.0: WorkerPhase routes to debug_log, NOT transcript.
+        assert not log.write.called
+        renderable = debug_log.write.call_args[0][0]
         # INV-003: must be a styled Rich Text renderable, not a plain str.
         # v0.4.1 retheme: style is now Australis Sea dark-60 ("#86929d") instead
         # of the terminal-dim filter "dim". Assert non-empty styling either way.
@@ -458,7 +513,14 @@ class TestTuiPresenterState:
             widget.display = True  # pre-set to non-default to detect the clear
             state = TuiPresenterState()
             # thinking_open is False (state just constructed).
-            state.render(terminal, log=log, thinking_widget=widget, tools_log=MagicMock(), raw=True)
+            state.render(
+                terminal,
+                log=log,
+                thinking_widget=widget,
+                tools_log=MagicMock(),
+                debug_log=MagicMock(),
+                raw=True,
+            )
             # Belt-and-braces: widget cleared + hidden on EVERY terminal event.
             widget.update.assert_called_with("")
             assert widget.display is False, type(terminal).__name__
@@ -480,6 +542,7 @@ class TestTuiPresenterState:
             log=log,
             thinking_widget=MagicMock(),
             tools_log=tools_log,
+            debug_log=MagicMock(),
             raw=False,
         )
         # INV-014: write went to tools_log
@@ -500,6 +563,7 @@ class TestTuiPresenterState:
             log=log,
             thinking_widget=MagicMock(),
             tools_log=tools_log,
+            debug_log=MagicMock(),
             raw=False,
         )
         assert tools_log.write.called
@@ -518,6 +582,7 @@ class TestTuiPresenterState:
             log=log,
             thinking_widget=MagicMock(),
             tools_log=tools_log,
+            debug_log=MagicMock(),
             raw=False,
         )
         assert log.write.called
@@ -536,6 +601,7 @@ class TestTuiPresenterState:
             log=log,
             thinking_widget=MagicMock(),
             tools_log=MagicMock(),
+            debug_log=MagicMock(),
             raw=False,
         )
         line = log.write.call_args[0][0]
@@ -553,6 +619,7 @@ class TestTuiPresenterState:
             log=log,
             thinking_widget=MagicMock(),
             tools_log=MagicMock(),
+            debug_log=MagicMock(),
             raw=True,
         )
         done_line = next(
@@ -580,6 +647,7 @@ class TestTuiPresenterState:
             log=log,
             thinking_widget=MagicMock(),
             tools_log=MagicMock(),
+            debug_log=MagicMock(),
             raw=True,
         )
         done_line = next(
@@ -738,8 +806,12 @@ class TestLayoutShape:
             row = app.query_one("#main-row", Horizontal)
             assert row is not None
 
-    async def test_left_column_has_transcript_and_prompt(self) -> None:
-        """left_column_has_transcript_and_prompt: left column = transcript + prompt + thinking."""
+    async def test_left_column_content_only(self) -> None:
+        """left_column_content_only [v0.5.0]: left column = transcript + prompt ONLY.
+
+        thinking-current Static moved to right column so the left column is
+        genuinely content-only (transcript + prompt input).
+        """
         from textual.containers import Vertical
         from textual.widgets import Input, RichLog, Static
 
@@ -747,14 +819,15 @@ class TestLayoutShape:
         async with app.run_test() as pilot:
             await pilot.pause()
             left = app.query_one("#left-column", Vertical)
-            assert left is not None
+            right = app.query_one("#right-column", Vertical)
             transcript = app.query_one("#transcript", RichLog)
             prompt = app.query_one("#prompt", Input)
             thinking = app.query_one("#thinking-current", Static)
-            # Widgets are inside the left column (descendant check)
             assert transcript in left.walk_children()
             assert prompt in left.walk_children()
-            assert thinking in left.walk_children()
+            # v0.5.0: thinking-current is now under the right column, NOT left.
+            assert thinking not in left.walk_children()
+            assert thinking in right.walk_children()
 
     async def test_right_column_has_tabbed_content_with_tools_tab(self) -> None:
         """right_column_has_tabbed_content_with_tools_tab: #side-panes + TabPane#tools-tab."""
@@ -819,6 +892,47 @@ class TestLayoutShape:
                 f"INV-016: Input focus must survive Ctrl+1 tab switch; got focused={app.focused}"
             )
 
+    async def test_debug_tab_exists(self) -> None:
+        """debug_tab_exists [v0.5.0]: right column has Debug TabPane + #debug-log RichLog."""
+        from textual.widgets import RichLog, TabPane
+
+        app = _resolved_app(_args_new(), session_id="s-new12345", agent_id="mimir")
+        async with app.run_test() as pilot:
+            await pilot.pause()
+            debug_tab = app.query_one("#debug-tab", TabPane)
+            debug_log = app.query_one("#debug-log", RichLog)
+            assert debug_log in debug_tab.walk_children()
+
+    async def test_ctrl_2_activates_debug_tab(self) -> None:
+        """ctrl_2_activates_debug_tab [v0.5.0]: Ctrl+2 → TabbedContent.active == 'debug-tab'."""
+        from textual.widgets import TabbedContent
+
+        app = _resolved_app(_args_new(), session_id="s-new12345", agent_id="mimir")
+        async with app.run_test() as pilot:
+            await pilot.pause()
+            await pilot.press("ctrl+2")
+            await pilot.pause()
+            assert app.query_one("#side-panes", TabbedContent).active == "debug-tab"
+
+    async def test_pane_name_updates_on_tab_switch(self) -> None:
+        """pane_name_updates_on_tab_switch [v0.5.0]: pane-name reflects active tab.
+
+        Two tabs now (Tools / Debug); pane-name updates from "Tools" to "Debug"
+        and back as the operator switches via Ctrl+1 / Ctrl+2.
+        """
+        from textual.widgets import Static
+
+        app = _resolved_app(_args_new(), session_id="s-new12345", agent_id="mimir")
+        async with app.run_test() as pilot:
+            await pilot.pause()
+            pane_name = app.query_one("#pane-name", Static)
+            await pilot.press("ctrl+2")
+            await pilot.pause()
+            assert str(pane_name.render()) == "Debug"
+            await pilot.press("ctrl+1")
+            await pilot.pause()
+            assert str(pane_name.render()) == "Tools"
+
 
 import asyncio  # noqa: E402
 
diff --git a/uv.lock b/uv.lock
index 9639cdc..64da077 100644
--- a/uv.lock
+++ b/uv.lock
@@ -968,7 +968,7 @@ wheels = [
 
 [[package]]
 name = "ratatoskr"
-version = "0.4.1"
+version = "0.5.0"
 source = { editable = "." }
 dependencies = [
     { name = "httpx" },