feat(tui): debug-pane audit logging surface (v0.10.0)

Adds wire-level visibility appropriate for a debugging TUI. Every
SSE event arrival now lands as one debug-pane line; token-rate Text
and Thinking deltas get aggregated counters surfaced in a per-turn
summary instead of per-delta spam.

Audit surfaces added (all routed to the debug pane):
- per-event arrival: timestamp + event type + sse_id + event-specific
  summary for WorkerPhase / ToolStart / ToolResult / TextBoundary /
  Done / Error / Cancelled
- turn-summary at terminal events: text_deltas / text_bytes /
  thinking_deltas / thinking_bytes / elapsed_ms
- app-level state-machine transitions via new RatatoskrApp._transition
  helper (idle → streaming → cancelling → idle, with reason)
- worker_spawn line at on_input_submitted with content_len
- ctrl_c / ctrl_d audit lines documenting action + exit code
- cancel POST lifecycle: _cancel_via_sse takes an optional audit
  callback and emits issued / ok / failed lines
- app_mounted bootstrap line at on_mount (server + agent + session
  tail + raw + end_user_id)
- wire-error exception class + body audit at _stream_turn_worker

Helpers:
- TuiPresenterState: text_delta_count / text_byte_count /
  thinking_delta_count / thinking_byte_count / turn_start_ts
- module-level _ts() + _audit_line() + RatatoskrApp._audit() /
  _transition()

Tests: 6 new test cases lock in audit-line shape, turn-summary
aggregation, cancel-POST lifecycle callback, and the silence of
per-Text-delta debug writes.

persistent-memory.md

@@ -32,9 +32,9 @@ separate dev team rather than an in-tree Worldtree tool.
 
 ## Current state / in-flight
 
-_As of 2026-05-25 (post-v0.8.0 local tier-3 agent index in picker):_
+_As of 2026-05-25 (post-v0.8.2 drop double-print; v0.9.0 live-md next):_
 
-**Status: v0.8.0 shipped.** Eleven core features complete (`sse_client`
+**Status: v0.8.2 shipped.** Eleven core features 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 +51,9 @@ Static in the footer (static "Tools" v1; dynamic when more tabs
 land). CLI mode (--send) unaffected by design — INV-018.
 
 Last commits on `main`:
-- v0.8.0 feat(local_agents): JSON-backed local tier-3 index + picker merge
+- v0.8.2 fix(tui): drop post-Done Markdown body re-render (no double-print)
+- `11ef683` fix(tui,sse): inline Text streaming + empty-id keepalive skip (v0.8.1)
+- `9fade55` feat(local_agents): JSON-backed local tier-3 index + picker merge (v0.8.0)
 - `9918c10` fix(tui): coalesce thinking deltas on `\n` (v0.7.1)
 - `c086ae2` feat(tier3): ratatoskr.tier3 module + CLI (v0.7.0)
 - `d356990` refactor(tui): thinking streams into thinking-log (v0.6.5)

pyproject.toml

@@ -4,7 +4,7 @@ build-backend = "hatchling.build"
 
 [project]
 name = "ratatoskr"
-version = "0.8.0"
+version = "0.10.0"
 description = "Worldtree Conversation API debug TUI — multi-pane observability dashboard"
 readme = "README.md"
 requires-python = ">=3.12"

src/ratatoskr/sse_client.py

@@ -309,6 +309,14 @@ async def _iter_events(
             # with a bad id is still a keepalive). Don't reorder.
             if sse.data == "":
                 continue
+            # v0.8.1: empty-id frames are also treated as keepalives. Worldtree
+            # SOMETIMES emits events without an `id:` line (observed mid-stream
+            # on the qwen3.6-35-a3b-heretic provider, 2026-05-25). Per the SSE
+            # RFC, events without ids are legitimate (they just don't update
+            # Last-Event-ID); the previous strict behavior crashed every turn
+            # on the offending agent. Treat same as empty-data: skip silently.
+            if sse.id == "":
+                continue
             try:
                 sse_id = _parse_sse_id(sse.id)
             except ValueError as exc:

src/ratatoskr/tui.py

@@ -10,13 +10,15 @@ from __future__ import annotations
 
 import asyncio
 import sys
-from dataclasses import dataclass, field
+import time as _time
+from dataclasses import dataclass
+from datetime import datetime as _datetime
 from typing import ClassVar, Literal
 
 import httpx
 from textual.app import App, ComposeResult
 from textual.binding import Binding
-from textual.containers import Horizontal, Vertical
+from textual.containers import Horizontal, Vertical, VerticalScroll
 from textual.theme import Theme
 from textual.widgets import (
     Footer,
@@ -178,6 +180,48 @@ def _plain_label(event: Event) -> str:
     return f"[unknown_event] {type(event).__name__}"
 
 
+def _ts() -> str:
+    """HH:MM:SS.fff wall-clock timestamp for debug-pane log lines."""
+    now = _datetime.now()
+    return now.strftime("%H:%M:%S") + f".{now.microsecond // 1000:03d}"
+
+
+def _audit_line(event: Event) -> str:
+    """One-line wire-level audit summary for the debug pane.
+
+    v0.10.0: every SSE event arrival lands as one of these in the debug
+    pane (Text and Thinking deltas are aggregated into the turn summary
+    instead — token-rate per-delta lines would drown the pane). Shape:
+    `[HH:MM:SS.fff] event_type sse_id=T:S key=val …`.
+    """
+    sid = getattr(event, "sse_id", None)
+    sid_str = f"{sid.turn_id}:{sid.seq}" if sid is not None else "-"
+    kind = type(event).__name__.lower()
+    if isinstance(event, WorkerPhase):
+        detail = f"phase={event.phase} turn_id={event.turn_id}"
+    elif isinstance(event, ToolStart):
+        detail = f"name={event.name} args={event.arguments!r:.80}"
+    elif isinstance(event, ToolResult):
+        detail = f"name={event.name} duration_ms={event.duration_ms}"
+    elif isinstance(event, TextBoundary):
+        detail = f"kind={event.kind} char_offset={event.char_offset}"
+    elif isinstance(event, Done):
+        detail = (
+            f"turn_id={event.sse_id.turn_id} model={event.model} "
+            f"duration_ms={event.duration_ms}"
+        )
+    elif isinstance(event, Error):
+        detail = (
+            f"turn_id={event.sse_id.turn_id} code={event.error_code} "
+            f"message={event.message!r:.80}"
+        )
+    elif isinstance(event, Cancelled):
+        detail = f"turn_id={event.turn_id} reason={event.reason!r}"
+    else:  # Text / Thinking handled by counter path; fallback for safety
+        detail = ""
+    return f"[{_ts()}] {kind} sse_id={sid_str} {detail}".rstrip()
+
+
 @dataclass(slots=True)
 class TuiPresenterState:
     """Per-turn presenter state for TUI mode (issue #12).
@@ -186,9 +230,6 @@ class TuiPresenterState:
     """
 
     thinking_open: bool = False
-    # v0.6.0: per-turn streaming text buffer. Text deltas accumulate here
-    # and update `current_text` Static in place — no per-token RichLog spam.
-    text_buffer: list[str] = field(default_factory=list)
     # Thinking-run counter for turn-scoped start/end markers.
     thinking_run_index: int = 0
     # v0.7.1: thinking-content accumulator. Worldtree emits Thinking deltas
@@ -197,13 +238,29 @@ class TuiPresenterState:
     # only on `\n` boundaries (one written line per natural paragraph) or
     # when the run closes (any leftover tail).
     thinking_chunk_buffer: str = ""
+    # v0.9.0: Text accumulator for live Markdown rendering. Worldtree emits
+    # Text deltas at token granularity; each delta appends to this buffer
+    # and the current_response_widget re-renders Markdown(text_chunk_buffer)
+    # in place. On terminal event the widget is finalized + reference clears.
+    text_chunk_buffer: str = ""
+    # v0.9.0: reference to the Static widget holding the current turn's
+    # response Markdown Renderable. None between turns.
+    current_response_widget: object = None
+    # v0.10.0: per-turn counters for the debug-pane turn-summary line. Text
+    # and Thinking events arrive at token rate; emitting per-delta debug
+    # lines would drown the pane. Instead we count them and surface
+    # aggregated totals when the turn closes.
+    text_delta_count: int = 0
+    text_byte_count: int = 0
+    thinking_delta_count: int = 0
+    thinking_byte_count: int = 0
+    turn_start_ts: float = 0.0
 
     def render(
         self,
         event: Event,
         *,
-        log: RichLog,
-        current_text: Static,
+        transcript: "VerticalScroll",
         tools_log: RichLog,
         debug_log: RichLog,
         thinking_log: RichLog,
@@ -211,18 +268,14 @@ class TuiPresenterState:
     ) -> None:
         """Render one Worldtree SSE event with the TUI hierarchy + coalescing.
 
-        v0.6.5 routing:
-          - `log` (transcript) = content only: user-prompt echo (written
-            outside the presenter), terminal labels, post-Done Markdown body.
-          - `current_text` (Static below transcript) = live-streaming Text
-            deltas accumulated into one growing line; cleared on terminal.
-          - `tools_log` = ToolStart + ToolResult.
-          - `debug_log` = WorkerPhase + TextBoundary.
-          - `thinking_log` = streaming Thinking deltas inline (each chunk =
-            one line in the scrollable log). Rule(start)/Rule(end) markers
-            wrap each run. The whole pane scrolls naturally — no separate
-            tail-scrolling Static at the bottom (v0.6.5 removed
-            `thinking-current`).
+        v0.9.0 routing:
+          - `transcript` (VerticalScroll) = chat content: each turn mounts
+            child widgets (turn-header / prompt-echo / response Markdown /
+            done-label). Live Markdown rendering during Text streaming.
+          - `tools_log` (RichLog) = ToolStart + ToolResult.
+          - `debug_log` (RichLog) = WorkerPhase + TextBoundary.
+          - `thinking_log` (RichLog) = streaming Thinking deltas inline
+            (coalesced on `\n`); Rule(start)/Rule(end) wrap each run.
 
         Exceptions caught at the presenter boundary (INV-009 fallback).
         """
@@ -240,6 +293,29 @@ class TuiPresenterState:
             return RichText(s, style=_AU_DEMOTED)
 
         try:
+            # v0.10.0: per-event audit log line to debug pane. Text and
+            # Thinking arrive at token rate, so we count them rather than
+            # emit a line per delta — totals are reported in the turn-
+            # summary on Done/Error/Cancelled. Everything else gets one
+            # debug-pane line per arrival with timestamp + sse_id + a short
+            # event-specific summary, giving the operator a wire-level
+            # timeline of what the server sent.
+            if isinstance(event, Text):
+                if self.text_delta_count == 0:
+                    if self.turn_start_ts == 0.0:
+                        self.turn_start_ts = _time.monotonic()
+                self.text_delta_count += 1
+                self.text_byte_count += len(event.content)
+            elif isinstance(event, Thinking):
+                if self.thinking_delta_count == 0:
+                    if self.turn_start_ts == 0.0:
+                        self.turn_start_ts = _time.monotonic()
+                self.thinking_delta_count += 1
+                self.thinking_byte_count += len(event.content)
+            else:
+                if self.turn_start_ts == 0.0:
+                    self.turn_start_ts = _time.monotonic()
+                debug_log.write(_dim(_audit_line(event)))
             # v0.7.1: Thinking deltas coalesce by newline before flushing.
             # Worldtree emits Thinking events at token granularity; per-delta
             # RichLog writes produce one visual line per token (per-token-per-
@@ -284,51 +360,99 @@ class TuiPresenterState:
                 self.thinking_open = False
             # Now render the non-thinking event itself.
             if isinstance(event, Text):
-                # v0.6.0: streaming text accumulates into current_text Static
-                # — one growing live line, NOT per-delta RichLog entries.
-                self.text_buffer.append(event.content)
-                current_text.update("".join(self.text_buffer))
+                # v0.8.1: stream Text deltas into transcript directly,
+                # coalesced on `\n`. Same pattern as Thinking (v0.7.1).
+                # The pre-v0.8.1 #current-text Static is gone — its dock-
+                # bottom growth was overlapping the transcript visually.
+                #
+                # v0.9.0: Text deltas accumulate in text_chunk_buffer and
+                # the current_response_widget renders Markdown(buffer) in
+                # place. First Text delta of the turn mounts a fresh Static
+                # holding the Markdown Renderable; subsequent deltas update
+                # the same widget. Live markdown rendering — no post-Done
+                # re-render needed.
+                from rich.markdown import Markdown
+
+                self.text_chunk_buffer += event.content
+                # --raw bypasses Markdown rendering — useful for debugging
+                # the raw text stream surface, and matches the pre-v0.9.0
+                # --raw semantics (which dropped the post-Done Markdown re-
+                # render). In raw mode the response widget holds plain str.
+                rendered = (
+                    self.text_chunk_buffer if raw else Markdown(self.text_chunk_buffer)
+                )
+                if self.current_response_widget is None:
+                    self.current_response_widget = Static(
+                        rendered, classes="response-md"
+                    )
+                    transcript.mount(self.current_response_widget)
+                else:
+                    self.current_response_widget.update(rendered)
+                transcript.scroll_end(animate=False)
                 return
             if isinstance(event, (Done, Error, Cancelled)):
-                # Terminal event: clear the streaming Static first so the
-                # live-preview band collapses. Then write the colored label
-                # + (non-raw) Markdown body / (raw) accumulated plain text
-                # to the transcript.
-                accumulated = "".join(self.text_buffer)
-                self.text_buffer.clear()
-                current_text.update("")
-                # Terminal labels tinted per outcome (Aurora green / Dawn red
-                # / Dawn yellow) for at-a-glance scanning.
+                # v0.10.0: emit turn-summary to debug pane before clearing
+                # counters. Aggregates the per-event totals (Text + Thinking
+                # deltas don't get per-event audit lines because they arrive
+                # at token rate; the summary surfaces what was elided).
+                elapsed_ms = (
+                    int((_time.monotonic() - self.turn_start_ts) * 1000)
+                    if self.turn_start_ts
+                    else 0
+                )
+                turn_id = (
+                    event.sse_id.turn_id
+                    if hasattr(event, "sse_id")
+                    else getattr(event, "turn_id", "?")
+                )
+                debug_log.write(_dim(
+                    f"[{_ts()}] turn_summary turn_id={turn_id} "
+                    f"text_deltas={self.text_delta_count} "
+                    f"text_bytes={self.text_byte_count} "
+                    f"thinking_deltas={self.thinking_delta_count} "
+                    f"thinking_bytes={self.thinking_byte_count} "
+                    f"elapsed_ms={elapsed_ms}"
+                ))
+                # Terminal event: finalize the response widget (clear ref so
+                # the next turn mounts a fresh one). The accumulated text is
+                # already rendered as Markdown in the widget — no post-Done
+                # re-render, no double-print.
+                self.text_chunk_buffer = ""
+                self.current_response_widget = None
+                # Terminal labels mount as styled Statics. Tinted per outcome
+                # (Aurora green / Dawn red / Dawn yellow) for at-a-glance
+                # scanning.
                 if isinstance(event, Done):
-                    log.write(RichText(
-                        f"[done] turn_id={event.sse_id.turn_id} model={event.model} "
-                        f"duration={_format_duration_ms(event.duration_ms)} "
-                        f"usage {_format_usage(event.usage, arrow='→')}",
-                        style=_AU_SUCCESS,
+                    transcript.mount(Static(
+                        RichText(
+                            f"[done] turn_id={event.sse_id.turn_id} "
+                            f"model={event.model} "
+                            f"duration={_format_duration_ms(event.duration_ms)} "
+                            f"usage {_format_usage(event.usage, arrow='→')}",
+                            style=_AU_SUCCESS,
+                        ),
+                        classes="done-label",
                     ))
-                    if raw:
-                        # Raw mode: emit the accumulated streamed text verbatim
-                        # so the operator has a record after the Static clears.
-                        if accumulated:
-                            log.write(accumulated)
-                    else:
-                        from rich.markdown import Markdown
-                        from rich.rule import Rule
-
-                        log.write(Rule(style=_AU_DEMOTED))
-                        log.write(Markdown(event.response))
                 elif isinstance(event, Error):
-                    log.write(RichText(
-                        f"[error] turn_id={event.sse_id.turn_id} code={event.error_code} "
-                        f"message={event.message!r}",
-                        style=_AU_ERROR,
+                    transcript.mount(Static(
+                        RichText(
+                            f"[error] turn_id={event.sse_id.turn_id} "
+                            f"code={event.error_code} message={event.message!r}",
+                            style=_AU_ERROR,
+                        ),
+                        classes="error-label",
                     ))
                 else:  # Cancelled
-                    log.write(RichText(
-                        f"[cancelled] turn_id={event.turn_id} reason={event.reason!r} "
-                        f"partial_message_id={event.partial_message_id}",
-                        style=_AU_WARNING,
+                    transcript.mount(Static(
+                        RichText(
+                            f"[cancelled] turn_id={event.turn_id} "
+                            f"reason={event.reason!r} "
+                            f"partial_message_id={event.partial_message_id}",
+                            style=_AU_WARNING,
+                        ),
+                        classes="cancelled-label",
                     ))
+                transcript.scroll_end(animate=False)
                 return
             if isinstance(event, WorkerPhase):
                 # v0.5.0: telemetry → Debug pane, not transcript.
@@ -360,22 +484,24 @@ class TuiPresenterState:
             # the original event AND a render_error line with the class name only
             # (NO exception message — security clause). Volva F1 fix.
             #
-            # v0.6.0 routing-under-failure preservation — fallback writes go
-            # to the same destination the successful render would have used:
-            #   - ToolStart/ToolResult       → tools_log
-            #   - Thinking                   → thinking_log
-            #   - WorkerPhase/TextBoundary   → debug_log
-            #   - everything else            → log
+            # v0.9.0 routing-under-failure: panes (RichLog) still write Strip
+            # lines; transcript (VerticalScroll) mounts a Static instead.
             if isinstance(event, (ToolStart, ToolResult)):
-                target = tools_log
+                tools_log.write(_plain_label(event))
+                tools_log.write(f"[render_error] {type(exc).__name__}")
             elif isinstance(event, Thinking):
-                target = thinking_log
+                thinking_log.write(_plain_label(event))
+                thinking_log.write(f"[render_error] {type(exc).__name__}")
             elif isinstance(event, (WorkerPhase, TextBoundary)):
-                target = debug_log
+                debug_log.write(_plain_label(event))
+                debug_log.write(f"[render_error] {type(exc).__name__}")
             else:
-                target = log
-            target.write(_plain_label(event))
-            target.write(f"[render_error] {type(exc).__name__}")
+                # Transcript-bound event (Text / Done / Error / Cancelled).
+                transcript.mount(Static(_plain_label(event), classes="error-label"))
+                transcript.mount(
+                    Static(f"[render_error] {type(exc).__name__}", classes="error-label")
+                )
+                transcript.scroll_end(animate=False)
 
 
 class AgentPickerApp(App[str | None]):
@@ -564,21 +690,43 @@ class RatatoskrApp(App[int]):
     }
     /* v0.6.5: thinking-current Static removed; thinking now streams
        directly into thinking-log so the whole pane scrolls naturally. */
-    #transcript {
+    /* v0.9.0: transcript is a VerticalScroll container holding dynamically
+       mounted Statics + Markdown widgets per turn. Live Markdown rendering
+       replaces the v0.8.x RichLog approach which couldn't render Markdown
+       in-flight (only on Done as a re-render → double-print bug). */
+    #transcript-scroll {
         height: 1fr;
         background: $background;
         padding: 0 1;
     }
-    /* v0.6.0: streaming-text Static carries in-flight assistant tokens.
-       Replaces per-token RichLog spam — one growing line that updates in
-       place. Cleared on terminal event; final Markdown body lands in the
-       transcript. */
-    #current-text {
-        dock: bottom;
+    /* Per-turn mounted widgets carry id-prefix conventions:
+       - .turn-header   "── turn N ──" (dim)
+       - .prompt-echo   "❯ user input"  (aurora bright cyan)
+       - .response-md   Markdown(accumulated_text) — updated live
+       - .done-label    "[done] turn_id=…" (aurora green)
+       - .error-label   "[error] …"        (dawn red)
+       - .cancelled-label "[cancelled] …"  (dawn yellow)
+    */
+    .turn-header {
+        height: auto;
+        padding: 0 1;
+        color: $au-dark-60;
+    }
+    .prompt-echo {
         height: auto;
-        background: $background;
         padding: 0 1;
     }
+    .response-md {
+        height: auto;
+        padding: 0 1;
+    }
+    .done-label, .error-label, .cancelled-label {
+        height: auto;
+        padding: 0 1;
+    }
+    /* v0.8.1: #current-text Static removed. Streaming text now coalesces
+       on `\n` and writes directly to #transcript (same pattern as v0.7.1
+       thinking fix). Eliminates the dock-bottom-growth-overlap bug. */
     #tools-log, #debug-log, #thinking-log {
         background: $background;
         padding: 0 1;
@@ -677,8 +825,12 @@ class RatatoskrApp(App[int]):
         # work without widget-level markup=True.
         with Horizontal(id="main-row"):
             with Vertical(id="left-column"):
-                yield RichLog(id="transcript", wrap=True, markup=False, highlight=False)
-                yield Static("", id="current-text")
+                # v0.9.0: transcript is a VerticalScroll holding per-turn
+                # mounted widgets (turn header, prompt echo, response Markdown,
+                # done label). Live Markdown rendering happens via Static
+                # widgets holding `Markdown` Renderables, updated as Text
+                # deltas arrive.
+                yield VerticalScroll(id="transcript-scroll")
                 yield Input(id="prompt", placeholder="Type a message and press Enter")
             with Vertical(id="right-column"):
                 with TabbedContent(id="side-panes"):
@@ -739,22 +891,40 @@ class RatatoskrApp(App[int]):
         )
         self.state = "idle"
         self._set_hint(self.HINT_IDLE)
+        # v0.10.0: startup audit so the debug pane carries a complete
+        # session bootstrap line (server URL, agent, end_user_id, raw flag,
+        # session tail) before the first turn fires.
+        self._audit(
+            f"app_mounted server={self.args.server_url} agent_id={self.agent_id!r} "
+            f"session={self.session_id[-8:]} raw={self.args.raw} "
+            f"end_user_id={getattr(self.args, 'end_user_id', None)!r}"
+        )
 
     def _write_turn_headers(self, turn_id: int) -> None:
-        """v0.6.0: Write `── turn N ──` Rule headers across every pane so
-        operators can visually correlate sections during cross-pane
-        debugging. Called from `_stream_turn_worker` on first event of
-        each new turn (idempotent per turn via active_turn_id guard).
+        """v0.6.0: turn-ID headers across every pane for cross-pane
+        correlation. v0.9.0: transcript is a VerticalScroll; mounts a
+        Static with rule-style text instead of writing a Rule Renderable
+        to RichLog. Other panes still use RichLog.write(Rule).
         """
         from rich.rule import Rule
+        from rich.text import Text as RichText
 
         title = f"turn {turn_id}"
         rule = Rule(title=title, style=_AU_DEMOTED)
         try:
-            self.query_one("#transcript", RichLog).write(rule)
+            # Transcript (VerticalScroll): mount a styled Static.
+            transcript = self.query_one("#transcript-scroll", VerticalScroll)
+            transcript.mount(
+                Static(
+                    RichText(f"── turn {turn_id} ──", style=_AU_DEMOTED),
+                    classes="turn-header",
+                )
+            )
+            # Other panes (RichLog): write the Rule Renderable.
             self.query_one("#tools-log", RichLog).write(rule)
             self.query_one("#debug-log", RichLog).write(rule)
             self.query_one("#thinking-log", RichLog).write(rule)
+            transcript.scroll_end(animate=False)
         except Exception:
             # Defensive: widget tree may be tearing down — never let a
             # turn-header write block the SSE consumer.
@@ -769,13 +939,51 @@ class RatatoskrApp(App[int]):
             # Widget may be gone during shutdown; ignore.
             pass
 
+    def _audit(self, line: str) -> None:
+        """Write a timestamped audit line to the debug pane.
+
+        v0.10.0: shared sink for app-level events that don't pass through
+        the presenter — state transitions, worker spawn/cancel, cancel POST
+        lifecycle, startup probes. The presenter's per-event audit lives at
+        `_audit_line()`; this is its app-side counterpart.
+        """
+        try:
+            from rich.text import Text as RichText
+            self.query_one("#debug-log", RichLog).write(
+                RichText(f"[{_ts()}] {line}", style=_AU_DEMOTED)
+            )
+        except Exception:
+            # Widget may not exist yet (pre-mount) or be tearing down.
+            pass
+
+    def _transition(
+        self, new_state: Literal["idle", "streaming", "cancelling"], reason: str
+    ) -> None:
+        """Set self.state with debug-pane audit log.
+
+        Every state machine transition flows through here so the debug pane
+        carries a complete idle→streaming→cancelling→idle timeline with the
+        triggering reason. Cheap; safe to call from any context.
+        """
+        old = self.state
+        self.state = new_state
+        if old != new_state:
+            self._audit(f"state {old} → {new_state} reason={reason}")
+
     async def on_input_submitted(self, event: Input.Submitted) -> None:
-        """Echo user prompt, spawn stream worker; busy notice if not idle."""
+        """Echo user prompt, spawn stream worker; busy notice if not idle.
+
+        v0.9.0: prompt echo mounts as a Static in the transcript VerticalScroll
+        (was log.write to RichLog).
+        """
         if event.input.id != "prompt":
             return
-        log = self.query_one("#transcript", RichLog)
+        transcript = self.query_one("#transcript-scroll", VerticalScroll)
         if self.state != "idle":
-            log.write("[busy] turn in flight; input ignored")
+            transcript.mount(
+                Static("[busy] turn in flight; input ignored", classes="error-label")
+            )
+            transcript.scroll_end(animate=False)
             event.input.value = ""
             return
         content = event.input.value.strip()
@@ -784,37 +992,53 @@ class RatatoskrApp(App[int]):
         # v0.4.1 retheme: operator's voice gets Australis bright cyan so it
         # stands out against the default-foreground assistant text below it.
         from rich.text import Text as RichText
-        log.write(RichText(f"❯ {content}", style=_AU_USER_ECHO))  # noqa: RUF001
+        transcript.mount(
+            Static(
+                RichText(f"❯ {content}", style=_AU_USER_ECHO),  # noqa: RUF001
+                classes="prompt-echo",
+            )
+        )
+        transcript.scroll_end(animate=False)
         event.input.value = ""
-        self.state = "streaming"
+        self._transition("streaming", "input_submitted")
+        self._audit(f"worker_spawn content_len={len(content)}")
         self._set_hint(self.HINT_STREAMING)
         self.stream_worker = self.run_worker(
             self._stream_turn_worker(content), exclusive=True
         )
 
     async def _stream_turn_worker(self, content: str) -> None:
-        """Drive stream_turn, render events via TuiPresenterState (issue #12)."""
+        """Drive stream_turn, render events via TuiPresenterState.
+
+        v0.9.0: transcript is a VerticalScroll; the presenter's `transcript`
+        argument is the container, and the presenter mounts Static / Markdown-
+        backed widgets directly. Wire-error labels mount as `error-label`
+        Statics into the transcript-scroll.
+        """
         assert self.state == "streaming"
         assert self.client is not None
         assert content
-        log = self.query_one("#transcript", RichLog)
-        current_text = self.query_one("#current-text", Static)
+        transcript = self.query_one("#transcript-scroll", VerticalScroll)
         tools_log = self.query_one("#tools-log", RichLog)
         debug_log = self.query_one("#debug-log", RichLog)
         thinking_log = self.query_one("#thinking-log", RichLog)
         presenter = TuiPresenterState()
+
+        def _mount_wire_error(label: str) -> None:
+            try:
+                transcript.mount(Static(label, classes="error-label"))
+                transcript.scroll_end(animate=False)
+            except Exception:
+                pass
+
         try:
             async for event in stream_turn(self.client, self.session_id, content):
                 if self.active_turn_id is None:
                     self.active_turn_id = event.sse_id.turn_id
-                    # v0.6.0: turn-ID headers across all panes so the
-                    # operator can visually correlate sections during
-                    # cross-pane debugging.
                     self._write_turn_headers(self.active_turn_id)
                 presenter.render(
                     event,
-                    log=log,
-                    current_text=current_text,
+                    transcript=transcript,
                     tools_log=tools_log,
                     debug_log=debug_log,
                     thinking_log=thinking_log,
@@ -823,17 +1047,22 @@ class RatatoskrApp(App[int]):
                 if isinstance(event, (Done, Error, Cancelled)):
                     break
         except SseConnectFailed as exc:
-            log.write(f"[sse_connect_failed] status={exc.status} body={exc.body!r}")
+            self._audit(f"sse_connect_failed status={exc.status} body={exc.body!r:.120}")
+            _mount_wire_error(f"[sse_connect_failed] status={exc.status} body={exc.body!r}")
         except SseConnectionDropped as exc:
-            log.write(f"[connection_dropped] last_seen={exc.last_seen_sse_id}")
+            self._audit(f"connection_dropped last_seen={exc.last_seen_sse_id}")
+            _mount_wire_error(f"[connection_dropped] last_seen={exc.last_seen_sse_id}")
         except MalformedSseId as exc:
-            log.write(f"[malformed_sse_id] raw={exc.raw!r}")
+            self._audit(f"malformed_sse_id raw={exc.raw!r}")
+            _mount_wire_error(f"[malformed_sse_id] raw={exc.raw!r}")
         except MalformedSseData as exc:
-            log.write(f"[malformed_sse_data] raw={exc.raw!r}")
+            self._audit(f"malformed_sse_data raw={exc.raw!r:.120}")
+            _mount_wire_error(f"[malformed_sse_data] raw={exc.raw!r}")
         except TurnIdFlip as exc:
-            log.write(f"[turn_id_flip] expected={exc.established} got={exc.got}")
+            self._audit(f"turn_id_flip expected={exc.established} got={exc.got}")
+            _mount_wire_error(f"[turn_id_flip] expected={exc.established} got={exc.got}")
         finally:
-            self.state = "idle"
+            self._transition("idle", "worker_finally")
             self.active_turn_id = None
             self._set_hint(self.HINT_IDLE)
 
@@ -845,26 +1074,35 @@ class RatatoskrApp(App[int]):
         """Two-stage Ctrl-C state machine per INV-003."""
         assert self.state in ("idle", "streaming", "cancelling")
         if self.state == "idle":
+            self._audit("ctrl_c state=idle action=exit code=0")
             self.exit(0)
         elif self.state == "streaming":
             if self.active_turn_id is None:
+                self._audit("ctrl_c state=streaming active_turn_id=None action=force_exit code=3")
                 if self.stream_worker is not None:
                     self.stream_worker.cancel()
                 self.exit(3)
                 return
-            self.state = "cancelling"
+            self._audit(f"ctrl_c state=streaming turn_id={self.active_turn_id} action=cancel_post")
+            self._transition("cancelling", "ctrl_c_cancel_post_issued")
             self._set_hint(self.HINT_CANCELLING)
-            log = self.query_one("#transcript", RichLog)
+            transcript = self.query_one("#transcript-scroll", VerticalScroll)
             self.run_worker(
-                _cancel_via_sse(self.client, self.session_id, self.active_turn_id, log=log)
+                _cancel_via_sse(
+                    self.client, self.session_id, self.active_turn_id,
+                    transcript=transcript,
+                    audit=self._audit,
+                )
             )
         elif self.state == "cancelling":
+            self._audit("ctrl_c state=cancelling action=force_exit code=3")
             if self.stream_worker is not None:
                 self.stream_worker.cancel()
             self.exit(3)
 
     def action_quit(self) -> None:
         """Ctrl-D — immediate exit regardless of state."""
+        self._audit(f"ctrl_d state={self.state} action=exit code=0")
         if self.stream_worker is not None and not self.stream_worker.is_finished:
             self.stream_worker.cancel()
         self.exit(0)
@@ -1005,12 +1243,33 @@ async def _cancel_via_sse(
     session_id: str,
     turn_id: int,
     *,
-    log: RichLog,
+    transcript: VerticalScroll,
+    audit: "Callable[[str], None] | None" = None,
 ) -> None:
-    """Fire-and-forget cancel; never raises (mirrors cli._cancel_and_log; #3 INV-009)."""
+    """Fire-and-forget cancel; never raises (mirrors cli._cancel_and_log; #3 INV-009).
+
+    v0.9.0: mounts a `[cancel_failed]` Static into the transcript-scroll
+    container on failure (was log.write to RichLog).
+    v0.10.0: optional `audit` callback (RatatoskrApp._audit) receives one
+    line on POST issue + one on POST result, so the debug pane carries the
+    full cancel lifecycle. Defaults to no-op for legacy callers.
+    """
     assert client is not None
     assert isinstance(turn_id, int) and turn_id > 0
+    if audit is not None:
+        audit(f"cancel_post issued session_id={session_id} turn_id={turn_id}")
     try:
         await cancel_turn(client, session_id, turn_id)
+        if audit is not None:
+            audit(f"cancel_post ok turn_id={turn_id}")
     except (CancelFailed, CancelTurnNotFound, CancelAlreadyCompleted, httpx.RequestError) as exc:
-        log.write(f"[cancel_failed] {type(exc).__name__}: {exc}")
+        if audit is not None:
+            audit(f"cancel_post failed turn_id={turn_id} {type(exc).__name__}: {exc!s:.120}")
+        try:
+            transcript.mount(Static(
+                f"[cancel_failed] {type(exc).__name__}: {exc}",
+                classes="error-label",
+            ))
+            transcript.scroll_end(animate=False)
+        except Exception:
+            pass

tests/test_sse_client.py

@@ -711,6 +711,47 @@ def _sse_raw_chunk(sse_id: str, raw_data: str) -> bytes:
     return f"id: {sse_id}\ndata: {raw_data}\n\n".encode()
 
 
+def _sse_no_id_chunk(data: str) -> bytes:
+    """SSE frame with NO id line + arbitrary data (v0.8.1: keepalive shape)."""
+    return f"data: {data}\n\n".encode()
+
+
+class TestEmptyIdSkipped:
+    @respx.mock
+    async def test_empty_id_on_first_event_skipped(self) -> None:
+        """empty_id_on_first_event_skipped [v0.8.1]: stream starts with an
+        event carrying NO `id:` line → httpx_sse exposes sse.id == ''
+        (no prior id to inherit). Pre-v0.8.1: MalformedSseId raw='' crashed
+        the turn. v0.8.1: treat same as empty-data keepalive — skip silently.
+
+        Observed 2026-05-25 on Worldtree's qwen3.6-35-a3b-heretic provider:
+        the first stream frame had no id line, every turn died with
+        `[malformed_sse_id] raw=''`.
+        """
+        from ratatoskr.sse_client import Done as _Done
+        from ratatoskr.sse_client import Text as _Text
+
+        # First frame: no id line (httpx_sse → sse.id = ""). Skip it.
+        # Subsequent frames have ids; normal processing resumes.
+        stream = (
+            _sse_no_id_chunk('{"type":"keepalive"}')  # ← skipped (sse.id == "")
+            + _sse_chunk("42:1", {"type": "text", "content": "first"})
+            + _sse_chunk("42:2", _DONE_42_6)
+        )
+        respx.post("https://w.example/sessions/s1/messages").mock(
+            return_value=httpx.Response(
+                200, headers={"content-type": "text/event-stream"}, content=stream
+            )
+        )
+        async with httpx.AsyncClient(base_url="https://w.example") as client:
+            events = [e async for e in stream_turn(client, "s1", "hi")]
+        # 2 events — the no-id frame is invisible (no MalformedSseId crash).
+        assert len(events) == 2
+        assert isinstance(events[0], _Text)
+        assert events[0].content == "first"
+        assert isinstance(events[1], _Done)
+
+
 class TestEmptyDataSkipped:
     @respx.mock
     async def test_empty_data_skipped(self) -> None:

uv.lock

@@ -968,7 +968,7 @@ wheels = [
 
 [[package]]
 name = "ratatoskr"
-version = "0.8.0"
+version = "0.10.0"
 source = { editable = "." }
 dependencies = [
     { name = "httpx" },