core/agent+cli: reasoning deltas, /stream and /verbose

Decode and stream reasoning_content as ReasoningDeltaEvent; keep it on
assistant messages. CLI shows dim reasoning, toggles stream/verbose, and
prints full tool results when verbose.

CLAUDE.md

@@ -57,7 +57,7 @@ Async SQLAlchemy + aiosqlite. `MemoryStore`: schema init (+ lightweight SQLite `
 - **`run_chat_loop`**: multi-round tool loop; default **streaming** text deltas + stream tool-call merge; parallel tools; tool-result char budget; soft context compact on request (**API-calibrated** after first usage when available); cooperative cancel points; optional `on_limit`.
 - **`ChatAgent`**: optional `MemoryStore` (user message persisted immediately; assistant/tools on success); `stream`; system prompt; `retry()` when history ends with a user message (failed/cancelled turn or orphan after resume).
 - **`/compact`**: soft-compact tool dumps → model summary (no tools) → **new** session seeded with summary message.
-- Events: text_delta, assistant_message, tool_call/result, max_rounds, **error** (`retryable`/`source`), **cancelled** (`reason`), **usage** (`TokenUsage`).
+- Events: text_delta, **reasoning_delta**, assistant_message, tool_call/result, max_rounds, **error** (`retryable`/`source`), **cancelled** (`reason`), **usage** (`TokenUsage`).
 - Usage: API `usage` from completions (stream with `include_usage`); **char≈token fallback** (~4 chars/token) when omitted; **context size** = last request ``prompt_tokens`` (API preferred); `last_turn_usage` / `session_usage` are **billed sums** (tool rounds re-send history); CLI end-of-turn + `/status`.
 - Config ``[agent]``: `system_prompt`, `max_tool_result_chars`, `parallel_tools`, `confirm_destructive`, `path_denylist`, `max_context_tokens` (default 200k est. tokens).
 
@@ -84,7 +84,7 @@ Shared interactive I/O: `ask` / `choose` / `form` / `confirm` with pluggable bac
 Click app + readline REPL. Entry: `plyngent` / `python -m plyngent`.
 
 - **`plyngent chat`**: provider/model selection (flags or interactive), SQLite sessions via config `[database]` (file DB under user data if unset/`:memory:`), sessions bound to workspace dir; resumes **most recently updated** session for cwd/`--workspace` by default (`--new` / `--session`).
-- Slash: `/history`, `/sessions` (newest first), `/resume [id]`, `/compact`, `/status` (incl. context char estimate), `/rounds`, `/retry`, …
+- Slash: `/history`, `/sessions` (newest first), `/resume [id]`, `/compact`, `/status` (incl. context char estimate), `/rounds`, `/stream`, `/verbose`, `/retry`, …
 - Explicit `/resume` or `--session` from another workspace prompts: **keep** session path, **update** binding to current, or **abort**.
 - Failed/cancelled turns: user message kept in DB; partial assistant/tool rolled back; Ctrl+C cancels in-flight turn; **TTY confirms** off-loop; auto-retry 10s/20s/30s then `/retry` (no duplicate user message).
 - **`plyngent providers`**: list config providers.

src/plyngent/agent/__init__.py

@@ -7,6 +7,7 @@ from .events import AssistantMessageEvent as AssistantMessageEvent
 from .events import CancelledEvent as CancelledEvent
 from .events import ErrorEvent as ErrorEvent
 from .events import MaxRoundsEvent as MaxRoundsEvent
+from .events import ReasoningDeltaEvent as ReasoningDeltaEvent
 from .events import TextDeltaEvent as TextDeltaEvent
 from .events import ToolCallEvent as ToolCallEvent
 from .events import ToolResultEvent as ToolResultEvent

src/plyngent/agent/events.py

@@ -13,6 +13,10 @@ class TextDeltaEvent(Struct, tag_field="type", tag="text_delta"):
     content: str
 
 
+class ReasoningDeltaEvent(Struct, tag_field="type", tag="reasoning_delta"):
+    content: str
+
+
 class AssistantMessageEvent(Struct, tag_field="type", tag="assistant_message"):
     message: AssistantChatMessage
 
@@ -51,6 +55,7 @@ class UsageEvent(Struct, tag_field="type", tag="usage"):
 
 type AgentEvent = (
     TextDeltaEvent
+    | ReasoningDeltaEvent
     | AssistantMessageEvent
     | ToolCallEvent
     | ToolResultEvent

src/plyngent/agent/loop.py

@@ -31,6 +31,7 @@ from .events import (
     AssistantMessageEvent,
     ErrorEvent,
     MaxRoundsEvent,
+    ReasoningDeltaEvent,
     TextDeltaEvent,
     ToolCallEvent,
     ToolResultEvent,
@@ -122,6 +123,9 @@ async def _non_stream_round(
         msg = "chat completion response contained no choices"
         raise RuntimeError(msg)
     assistant = response.choices[0].message
+    reasoning = assistant.reasoning_content
+    if isinstance(reasoning, str) and reasoning:
+        yield ReasoningDeltaEvent(content=reasoning)
     if isinstance(assistant.content, str) and assistant.content:
         yield TextDeltaEvent(content=assistant.content)
     yield AssistantMessageEvent(message=assistant)
@@ -147,6 +151,7 @@ async def _stream_round(
     )
     stream = await client.chat_completions(stream_param, stream=True)
     content_parts: list[str] = []
+    reasoning_parts: list[str] = []
     tool_deltas: list[StreamToolCallDelta] = []
     last_api_usage: object = UNSET
 
@@ -158,6 +163,9 @@ async def _stream_round(
             continue
         choice = chunk.choices[0]
         delta = choice.delta
+        if isinstance(delta.reasoning_content, str) and delta.reasoning_content:
+            reasoning_parts.append(delta.reasoning_content)
+            yield ReasoningDeltaEvent(content=delta.reasoning_content)
         if isinstance(delta.content, str) and delta.content:
             content_parts.append(delta.content)
             yield TextDeltaEvent(content=delta.content)
@@ -165,6 +173,7 @@ async def _stream_round(
             tool_deltas.extend(delta.tool_calls)
 
     full_content = "".join(content_parts)
+    full_reasoning = "".join(reasoning_parts)
     tool_calls: list[AnyAssistantToolCall] | Unset = UNSET
     if tool_deltas:
         calls = merge_stream_tool_calls(tool_deltas)
@@ -174,6 +183,7 @@ async def _stream_round(
     assistant = AssistantChatMessage(
         content=full_content or None,
         tool_calls=tool_calls,
+        reasoning_content=full_reasoning or UNSET,
     )
     yield AssistantMessageEvent(message=assistant)
     yield UsageEvent(

src/plyngent/cli/display.py

@@ -1,5 +1,6 @@
 from __future__ import annotations
 
+from contextvars import ContextVar
 from typing import TYPE_CHECKING
 
 import click
@@ -8,6 +9,7 @@ from plyngent.agent import (
     CancelledEvent,
     ErrorEvent,
     MaxRoundsEvent,
+    ReasoningDeltaEvent,
     TextDeltaEvent,
     ToolCallEvent,
     ToolResultEvent,
@@ -23,6 +25,18 @@ if TYPE_CHECKING:
 _TOOL_RESULT_PREVIEW = 120
 _TOOL_ARGS_PREVIEW = 80
 
+# Process/session display flag for tool result dumps (set from ReplState / slash).
+_verbose_tool_results: ContextVar[bool] = ContextVar("verbose_tool_results", default=False)
+
+
+def set_verbose_tool_results(enabled: bool) -> None:  # noqa: FBT001
+    """Set whether tool results print in full (True) or as a short preview."""
+    _ = _verbose_tool_results.set(enabled)
+
+
+def get_verbose_tool_results() -> bool:
+    return _verbose_tool_results.get()
+
 
 def _preview(text: str, limit: int) -> str:
     if len(text) <= limit:
@@ -41,11 +55,25 @@ def _echo_stream(text: str) -> None:
         pass
 
 
-async def render_events(events: AsyncIterator[AgentEvent]) -> None:  # noqa: C901, PLR0912
+async def render_events(  # noqa: C901, PLR0912, PLR0915
+    events: AsyncIterator[AgentEvent],
+    *,
+    verbose: bool | None = None,
+) -> None:
     """Print agent events to the terminal (text deltas stream as they arrive)."""
+    show_full = get_verbose_tool_results() if verbose is None else verbose
+    printed_reasoning = False
     printed_text = False
     async for event in events:
-        if isinstance(event, TextDeltaEvent):
+        if isinstance(event, ReasoningDeltaEvent):
+            if not printed_reasoning:
+                click.echo()
+                click.secho("reasoning: ", fg="bright_black", nl=False)
+                printed_reasoning = True
+            _echo_stream(event.content)
+        elif isinstance(event, TextDeltaEvent):
+            if printed_reasoning and not printed_text:
+                click.echo()
             if not printed_text:
                 click.echo()
                 click.secho("assistant: ", fg="cyan", nl=False)
@@ -59,7 +87,11 @@ async def render_events(events: AsyncIterator[AgentEvent]) -> None:  # noqa: C90
             else:
                 click.secho(f"\n[tool] custom id={call.id}", fg="yellow")
         elif isinstance(event, ToolResultEvent):
-            preview = _preview(event.message.content, _TOOL_RESULT_PREVIEW)
+            content = event.message.content
+            if show_full:
+                click.secho(f"[tool ok]\n{content}", fg="magenta")
+            else:
+                preview = _preview(content, _TOOL_RESULT_PREVIEW)
                 # Single-line summary; full result stays in the message history for the model.
                 one_line = preview.replace("\n", " ")
                 click.secho(f"[tool ok] {one_line}", fg="magenta")
@@ -89,6 +121,6 @@ async def render_events(events: AsyncIterator[AgentEvent]) -> None:  # noqa: C90
         else:
             # AssistantMessageEvent — text already shown via TextDeltaEvent.
             _ = event
-    if printed_text:
+    if printed_text or printed_reasoning:
         click.echo()
     click.echo()

src/plyngent/cli/readline_setup.py

@@ -28,12 +28,14 @@ SLASH_COMMANDS: tuple[str, ...] = (
     "/provider",
     "/model",
     "/tools",
+    "/stream",
+    "/verbose",
     "/rounds",
     "/retry",
     "/status",
 )
 
-_TOOLS_ARGS: tuple[str, ...] = ("on", "off")
+_ON_OFF_ARGS: tuple[str, ...] = ("on", "off")
 
 
 def history_path() -> Path:
@@ -74,8 +76,8 @@ def _argument_options(state: ReplState, command: str, text: str) -> list[str]:
         return filter_prefix(text, sorted(state.config.providers.keys()))
     if command == "/model":
         return filter_prefix(text, sorted(state.provider.models.keys()))
-    if command == "/tools":
+    if command in {"/tools", "/stream", "/verbose"}:
-        return filter_prefix(text, list(_TOOLS_ARGS))
+        return filter_prefix(text, list(_ON_OFF_ARGS))
     if command == "/resume":
         return []
     return []

src/plyngent/cli/repl.py

@@ -35,6 +35,8 @@ Commands:
   /provider [name]   Show or switch provider
   /model [id]        Show or switch model
   /tools [on|off]    Show or toggle tools
+  /stream [on|off]   Show or toggle streaming model output
+  /verbose [on|off]  Show or toggle full tool-result dumps
   /rounds [n]        Show or set max tool-loop rounds
   /retry             Re-run incomplete last user turn (DB/orphan user; no retype)
   /status            Show session/provider/tools/rounds status
@@ -43,8 +45,9 @@ User messages are saved immediately. On API errors or Ctrl+C, partial
 assistant/tool output is discarded but the user message stays (so /retry
 works after resume, not only via readline history). Auto-retry: 10s/20s/30s.
 
-Tab completes slash commands and some arguments (provider, model, tools).
+Tab completes slash commands and some arguments (provider, model, tools,
-Use --session ID or /resume to continue a prior chat after restart.
+stream, verbose). Use --session ID or /resume to continue a prior chat
+after restart.
 """
 
 type SlashHandler = Callable[[], None | Awaitable[None]]
@@ -74,7 +77,9 @@ def _cmd_status(state: ReplState) -> None:
         f"session={state.session_id}  messages={len(state.agent.messages)}  "
         f"pending_retry={pending_disp}\n"
         f"tools={'on' if state.tools_enabled else 'off'}  "
-        f"rounds={state.max_rounds}  stream={'on' if state.agent.stream else 'off'}\n"
+        f"rounds={state.max_rounds}  "
+        f"stream={'on' if state.agent.stream else 'off'}  "
+        f"verbose={'on' if state.verbose else 'off'}\n"
         f"context_tokens={ctx_tilde}{ctx_tokens}/{ctx_budget} ({ctx_tag})  "
         f"context_chars={ctx_chars}  "
         f"tool_result_max={state.agent.max_tool_result_chars}\n"
@@ -185,6 +190,40 @@ def _cmd_tools(state: ReplState, arg: str) -> None:
     click.echo(f"tools={'on' if state.tools_enabled else 'off'}")
 
 
+def _cmd_stream(state: ReplState, arg: str) -> None:
+    token = arg.strip().lower()
+    if not token:
+        click.echo(f"stream={'on' if state.agent.stream else 'off'}")
+        return
+    if token in {"on", "1", "true", "yes"}:
+        enabled = True
+    elif token in {"off", "0", "false", "no"}:
+        enabled = False
+    else:
+        click.echo("usage: /stream [on|off]")
+        return
+    state.stream_enabled = enabled
+    state.agent.stream = enabled
+    click.echo(f"stream={'on' if enabled else 'off'}")
+
+
+def _cmd_verbose(state: ReplState, arg: str) -> None:
+    token = arg.strip().lower()
+    if not token:
+        click.echo(f"verbose={'on' if state.verbose else 'off'}")
+        return
+    if token in {"on", "1", "true", "yes"}:
+        enabled = True
+    elif token in {"off", "0", "false", "no"}:
+        enabled = False
+    else:
+        click.echo("usage: /verbose [on|off]")
+        return
+    state.verbose = enabled
+    state.sync_display_flags()
+    click.echo(f"verbose={'on' if enabled else 'off'}")
+
+
 def _cmd_rounds(state: ReplState, arg: str) -> None:
     token = arg.strip()
     if not token:
@@ -287,6 +326,8 @@ async def _dispatch_slash(state: ReplState, command: str, arg: str) -> bool:
         "provider": lambda: _cmd_provider(state, arg),
         "model": lambda: _cmd_model(state, arg),
         "tools": lambda: _cmd_tools(state, arg),
+        "stream": lambda: _cmd_stream(state, arg),
+        "verbose": lambda: _cmd_verbose(state, arg),
         "rounds": lambda: _cmd_rounds(state, arg),
         "retry": lambda: _cmd_retry(state),
         "status": lambda: _cmd_status(state),
@@ -323,6 +364,7 @@ async def run_repl(state: ReplState) -> None:
         f"session={state.session_id}  tools={'on' if state.tools_enabled else 'off'}  "
         f"rounds={state.max_rounds}  messages={len(state.agent.messages)}  "
         f"stream={'on' if state.agent.stream else 'off'}  "
+        f"verbose={'on' if state.verbose else 'off'}"
     )
     click.echo("Type /help for commands. Empty line is ignored.")
 

src/plyngent/cli/state.py

@@ -29,6 +29,8 @@ class ReplState:
     model: str
     tools_enabled: bool
     max_rounds: int = DEFAULT_MAX_ROUNDS
+    stream_enabled: bool = True
+    verbose: bool = False
     client: ChatClient = field(init=False)
     agent: ChatAgent = field(init=False)
     session_id: int | None = None
@@ -38,6 +40,12 @@ class ReplState:
         self.client = cast("ChatClient", cast("object", create_client(self.provider)))
         self.workspace = Path(self.workspace).expanduser().resolve()
         self.agent = self._make_agent()
+        self.sync_display_flags()
+
+    def sync_display_flags(self) -> None:
+        from plyngent.cli.display import set_verbose_tool_results
+
+        set_verbose_tool_results(self.verbose)
 
     def _workspace_key(self) -> str:
         key = normalize_workspace(self.workspace)
@@ -74,7 +82,7 @@ class ReplState:
             session_id=self.session_id,
             max_rounds=self.max_rounds,
             on_limit=prompt_continue_limit_async,
-            stream=True,
+            stream=self.stream_enabled,
             system_prompt=system_prompt,
             max_tool_result_chars=agent_cfg.max_tool_result_chars,
             parallel_tools=agent_cfg.parallel_tools,
@@ -84,9 +92,13 @@ class ReplState:
     def rebuild_client(self) -> None:
         """Recreate client and agent after provider/model/tools change."""
         messages = list(self.agent.messages)
+        # Preserve live stream toggle if agent already exists.
+        if hasattr(self, "agent"):
+            self.stream_enabled = self.agent.stream
         self.client = cast("ChatClient", cast("object", create_client(self.provider)))
         self.agent = self._make_agent()
         self.agent.messages = messages
+        self.sync_display_flags()
 
     def _set_workspace(self, path: Path) -> None:
         """Update REPL + tool workspace root."""

src/plyngent/lmproto/deepseek/openai_compat/model.py

@@ -20,8 +20,8 @@ type DeepSeekReasoningEffort = ReasoningEffort | Literal["max"]
 
 
 class AssistantChatMessage(BaseAssistantChatMessage):
+    # reasoning_content lives on the base assistant message (OpenAI-compat).
     prefix: bool | Unset = UNSET
-    reasoning_content: str | Unset = UNSET
 
 
 class ToolChatMessage(BaseToolChatMessage):

src/plyngent/lmproto/openai_compatible/model.py

@@ -72,6 +72,8 @@ class AssistantChatMessage(Struct, tag_field="role", tag="assistant"):
     audio: IDObject | Unset = UNSET
     refusal: str | Unset = UNSET
     tool_calls: list[AnyAssistantToolCall] | Unset = UNSET
+    # OpenAI-compat / DeepSeek thinking streams (omitted when unset).
+    reasoning_content: str | Unset = UNSET
 
 
 class ToolChatMessage(ChatMessage, tag_field="role", tag="tool"):
@@ -235,6 +237,7 @@ class StreamToolCallDelta(Struct):
 class DeltaMessage(Struct):
     role: RoleAssistant | Unset = UNSET
     content: str | Unset = UNSET
+    reasoning_content: str | Unset = UNSET
     tool_calls: list[StreamToolCallDelta] | Unset = UNSET
 
 

tests/test_agent/test_loop.py

@@ -9,6 +9,7 @@ from plyngent.agent import (
     AssistantMessageEvent,
     ChatAgent,
     MaxRoundsEvent,
+    ReasoningDeltaEvent,
     TextDeltaEvent,
     ToolCallEvent,
     ToolRegistry,
@@ -338,6 +339,78 @@ async def test_stream_yields_deltas_incrementally() -> None:
     assert messages[-1].content == "ab"
 
 
+async def test_stream_yields_reasoning_deltas() -> None:
+    class ReasoningClient:
+        @overload
+        async def chat_completions(
+            self, param: ChatCompletionsParam, *, stream: Literal[False] = False
+        ) -> ChatCompletionResponse: ...
+
+        @overload
+        async def chat_completions(
+            self, param: ChatCompletionsParam, *, stream: Literal[True]
+        ) -> AsyncIterator[ChatCompletionChunk]: ...
+
+        async def chat_completions(
+            self, param: ChatCompletionsParam, *, stream: bool = False
+        ) -> ChatCompletionResponse | AsyncIterator[ChatCompletionChunk]:
+            del param
+            if not stream:
+                return _response(AssistantChatMessage(content="ans", reasoning_content="think"))
+
+            async def chunks() -> AsyncIterator[ChatCompletionChunk]:
+                for part in ("th", "ink"):
+                    yield ChatCompletionChunk(
+                        id="1",
+                        object="chat.completion.chunk",
+                        created=0,
+                        model="t",
+                        choices=[
+                            ChunkChoice(
+                                index=0,
+                                delta=DeltaMessage(reasoning_content=part),
+                                finish_reason=None,
+                            )
+                        ],
+                    )
+                yield ChatCompletionChunk(
+                    id="1",
+                    object="chat.completion.chunk",
+                    created=0,
+                    model="t",
+                    choices=[
+                        ChunkChoice(
+                            index=0,
+                            delta=DeltaMessage(content="ans"),
+                            finish_reason="stop",
+                        )
+                    ],
+                )
+
+            return chunks()
+
+    messages: list[AnyChatMessage] = [UserChatMessage(content="hi")]
+    events = [e async for e in run_chat_loop(ReasoningClient(), messages, model="m", stream=True)]
+    reasoning = [e for e in events if isinstance(e, ReasoningDeltaEvent)]
+    assert [r.content for r in reasoning] == ["th", "ink"]
+    deltas = [e for e in events if isinstance(e, TextDeltaEvent)]
+    assert [d.content for d in deltas] == ["ans"]
+    assert isinstance(messages[-1], AssistantChatMessage)
+    assert messages[-1].content == "ans"
+    assert messages[-1].reasoning_content == "think"
+
+
+async def test_non_stream_yields_reasoning() -> None:
+    client = ScriptedClient([_response(AssistantChatMessage(content="ok", reasoning_content="plan"))])
+    messages: list[AnyChatMessage] = [UserChatMessage(content="hi")]
+    events = [e async for e in run_chat_loop(client, messages, model="m", stream=False)]
+    reasoning = [e for e in events if isinstance(e, ReasoningDeltaEvent)]
+    assert len(reasoning) == 1
+    assert reasoning[0].content == "plan"
+    assert isinstance(messages[-1], AssistantChatMessage)
+    assert messages[-1].reasoning_content == "plan"
+
+
 async def test_run_chat_loop_with_tools() -> None:
     @tool
     def add(a: int, b: int) -> int:

tests/test_cli/test_display.py

@@ -0,0 +1,51 @@
+from __future__ import annotations
+
+from typing import TYPE_CHECKING
+
+from plyngent.agent import ReasoningDeltaEvent, TextDeltaEvent, ToolResultEvent
+from plyngent.cli.display import render_events, set_verbose_tool_results
+from plyngent.lmproto.openai_compatible.model import ToolChatMessage
+
+if TYPE_CHECKING:
+    from collections.abc import AsyncIterator
+
+    import pytest
+
+    from plyngent.agent import AgentEvent
+
+
+async def _aiter(events: list[AgentEvent]) -> AsyncIterator[AgentEvent]:
+    for event in events:
+        yield event
+
+
+async def test_render_reasoning_and_text(capsys: pytest.CaptureFixture[str]) -> None:
+    await render_events(
+        _aiter(
+            [
+                ReasoningDeltaEvent(content="think"),
+                TextDeltaEvent(content="hello"),
+            ]
+        )
+    )
+    out = capsys.readouterr().out
+    assert "reasoning: " in out
+    assert "think" in out
+    assert "assistant: " in out
+    assert "hello" in out
+
+
+async def test_tool_result_preview_vs_verbose(capsys: pytest.CaptureFixture[str]) -> None:
+    long = "x" * 200
+    msg = ToolChatMessage(content=long, tool_call_id="1")
+    set_verbose_tool_results(False)
+    await render_events(_aiter([ToolResultEvent(message=msg)]))
+    out = capsys.readouterr().out
+    assert "…" in out
+    assert long not in out
+
+    set_verbose_tool_results(True)
+    await render_events(_aiter([ToolResultEvent(message=msg)]), verbose=True)
+    out2 = capsys.readouterr().out
+    assert long in out2
+    set_verbose_tool_results(False)

tests/test_cli/test_readline_setup.py

@@ -77,6 +77,8 @@ def test_completer_commands(tmp_path: object, monkeypatch: object) -> None:
         found.append(item)
         index += 1
     assert "/help" in found
+    assert "/stream" in SLASH_COMMANDS
+    assert "/verbose" in SLASH_COMMANDS
     assert set(found) <= set(SLASH_COMMANDS)
 
 

tests/test_cli/test_repl_commands.py

@@ -116,6 +116,27 @@ async def test_tools_toggle(state: ReplState) -> None:
     assert state.tools_enabled is False
 
 
+async def test_stream_toggle(state: ReplState) -> None:
+    assert state.agent.stream is True
+    assert await handle_slash(state, "/stream off") is True
+    assert state.agent.stream is False
+    assert state.stream_enabled is False
+    assert await handle_slash(state, "/stream on") is True
+    assert state.agent.stream is True
+
+
+async def test_verbose_toggle(state: ReplState) -> None:
+    from plyngent.cli.display import get_verbose_tool_results
+
+    assert state.verbose is False
+    assert await handle_slash(state, "/verbose on") is True
+    assert state.verbose is True
+    assert get_verbose_tool_results() is True
+    assert await handle_slash(state, "/verbose off") is True
+    assert state.verbose is False
+    assert get_verbose_tool_results() is False
+
+
 async def test_resume(state: ReplState) -> None:
     sid = state.session_id
     assert sid is not None