diff --git a/clients/terminal/render.py b/clients/terminal/render.py
index 27637e2..8fb00b4 100644
--- a/clients/terminal/render.py
+++ b/clients/terminal/render.py
@@ -49,6 +49,15 @@
                 self._thinking_buffer.clear()
             return
 
+        if msg_type == "turn_thinking":
+            if self.show_thinking:
+                thinking = msg.get("thinking", "") or ""
+                prefix = "(subagent) " if msg.get("is_subagent") else ""
+                self._print(f"\n{prefix}[thinking]", color="bright_black")
+                self._print(thinking, color="bright_black")
+                self._print(f"{prefix}[/thinking]", color="bright_black")
+            return
+
         if msg_type == "stream_delta":
             self._print(msg.get("delta", ""), nl=False)
             return
diff --git a/clients/terminal/tui/chat_model.py b/clients/terminal/tui/chat_model.py
index 9c94c80..80539d2 100644
--- a/clients/terminal/tui/chat_model.py
+++ b/clients/terminal/tui/chat_model.py
@@ -64,6 +64,18 @@
             self._current_thinking = None
             return None
 
+        if msg_type == "turn_thinking":
+            # A complete thinking block from a (sub-agent) non-streaming turn.
+            # Stored as a thinking_block with an is_subagent flag so the renderer
+            # can style/indent it as nested sub-agent reasoning.
+            item = ChatItem(
+                kind="thinking_block",
+                content=msg.get("thinking", "") or "",
+                meta={"is_subagent": bool(msg.get("is_subagent", False))},
+            )
+            self.items.append(item)
+            return item
+
         if msg_type == "stream_delta":
             if self._current_assistant is None:
                 self._current_assistant = ChatItem(kind="assistant_message", content="")
diff --git a/clients/terminal/tui/renderers/__init__.py b/clients/terminal/tui/renderers/__init__.py
index 5a5f774..7bc1203 100644
--- a/clients/terminal/tui/renderers/__init__.py
+++ b/clients/terminal/tui/renderers/__init__.py
@@ -4,7 +4,7 @@
 
 from .base import ContentRenderer
 from .registry import RendererRegistry
-from . import message, tool, thinking, error, markdown_content, plain, diff, artifact, status, planning
+from . import message, tool, thinking, error, markdown_content, plain, diff, artifact, status, planning, subagent
 
 
 def default_registry() -> RendererRegistry:
@@ -13,6 +13,9 @@
     reg.register(message.UserMessageRenderer())
     reg.register(message.AssistantMessageRenderer())
     reg.register(thinking.ThinkingRenderer())
+    # spawn_agent cards must be checked before the generic tool renderers.
+    reg.register(subagent.SpawnAgentStartedRenderer())
+    reg.register(subagent.SpawnAgentResultRenderer())
     reg.register(tool.ToolStartedRenderer())
     reg.register(tool.ToolResultRenderer())
     reg.register(error.ErrorRenderer())
diff --git a/clients/terminal/tui/renderers/planning.py b/clients/terminal/tui/renderers/planning.py
index 5a9333a..d0d850a 100644
--- a/clients/terminal/tui/renderers/planning.py
+++ b/clients/terminal/tui/renderers/planning.py
@@ -5,6 +5,7 @@
 from rich.box import ROUNDED
 from rich.console import RenderableType
 from rich.markdown import Markdown
+from rich.padding import Padding
 from rich.panel import Panel
 from rich.text import Text
 
@@ -19,7 +20,8 @@
 
     Non-subagent planning is a transient indicator that rolls through phases
     (Analysis → Execution plan → Plan review) in one line; subagent planning is
-    shown dimmed so it does not bleed into the parent turn's indicator.
+    shown dimmed and indented so it reads as nested inside the spawn_agent card
+    and does not bleed into the parent turn's indicator.
     """
 
     def accepts(self, msg: dict) -> bool:
@@ -31,7 +33,10 @@
         is_subagent = bool(msg.get("is_subagent", False))
         prefix = "(subagent) " if is_subagent else ""
         color = theme.text_dim if is_subagent else theme.info
-        return Text(f"{prefix}⚙ Planning · {label}", style=color.hex)
+        line = Text(f"{prefix}⚙ Planning · {label}", style=color.hex)
+        if is_subagent:
+            return Padding(line, (0, 0, 0, 2))
+        return line
 
 
 class PlanReadyRenderer(ContentRenderer):
@@ -56,10 +61,13 @@
         )
         title = "subagent plan" if is_subagent else "Plan"
         border = theme.text_dim if is_subagent else theme.accent
-        return Panel(
+        panel = Panel(
             body,
             title=title,
             title_align="left",
             border_style=border.hex,
             box=ROUNDED,
-        )
\ No newline at end of file
+        )
+        if is_subagent:
+            return Padding(panel, (0, 0, 0, 2))
+        return panel
\ No newline at end of file
diff --git a/clients/terminal/tui/renderers/subagent.py b/clients/terminal/tui/renderers/subagent.py
new file mode 100644
index 0000000..c4b3502
--- /dev/null
+++ b/clients/terminal/tui/renderers/subagent.py
@@ -0,0 +1,72 @@
+"""Renderers for the spawn_agent tool (sub-agent delegation cards)."""
+
+from __future__ import annotations
+
+from rich.box import ROUNDED
+from rich.console import RenderableType
+from rich.panel import Panel
+from rich.text import Text
+
+from clients.terminal.tui.themes import get_active_theme
+
+from .base import ContentRenderer
+
+_SPAWN_TOOL = "spawn_agent"
+
+
+def _truncate(text: str, limit: int) -> str:
+    text = (text or "").strip()
+    if len(text) <= limit:
+        return text
+    return text[:limit].rstrip() + " …"
+
+
+class SpawnAgentStartedRenderer(ContentRenderer):
+    """Render the start of a spawn_agent call as a distinct sub-agent card."""
+
+    def accepts(self, msg: dict) -> bool:
+        return msg.get("type") == "tool_started" and msg.get("tool") == _SPAWN_TOOL
+
+    def render(self, msg: dict) -> RenderableType:
+        theme = get_active_theme()
+        args = msg.get("args") or {}
+        profile_id = args.get("profile_id") or "default"
+        task = args.get("task") or ""
+        briefing = args.get("briefing") or ""
+
+        title = f"↘ subagent · {profile_id}"
+        body = Text(_truncate(task, 240), style=theme.text.hex)
+        if briefing:
+            body.append("\n", style=theme.text_dim.hex)
+            body.append(f"briefing: {_truncate(briefing, 160)}", style=theme.text_dim.hex)
+        return Panel(
+            body,
+            title=title,
+            title_align="left",
+            border_style=theme.secondary.hex,
+            box=ROUNDED,
+        )
+
+
+class SpawnAgentResultRenderer(ContentRenderer):
+    """Render the result of a spawn_agent call as a distinct sub-agent card."""
+
+    def accepts(self, msg: dict) -> bool:
+        return msg.get("type") == "tool_call" and msg.get("tool") == _SPAWN_TOOL
+
+    def render(self, msg: dict) -> RenderableType:
+        theme = get_active_theme()
+        args = msg.get("args") or {}
+        profile_id = args.get("profile_id") or "default"
+        success = msg.get("success", True)
+        result = msg.get("result")
+        color = theme.tool_success if success else theme.tool_error
+        title = f"↙ subagent · {profile_id} {'✓' if success else '✗'}"
+        body = Text(_truncate(str(result) if result is not None else "", 600), style=theme.text_dim.hex)
+        return Panel(
+            body,
+            title=title,
+            title_align="left",
+            border_style=color.hex,
+            box=ROUNDED,
+        )
\ No newline at end of file
diff --git a/clients/terminal/tui/renderers/thinking.py b/clients/terminal/tui/renderers/thinking.py
index 93e05e4..76ee3aa 100644
--- a/clients/terminal/tui/renderers/thinking.py
+++ b/clients/terminal/tui/renderers/thinking.py
@@ -2,8 +2,9 @@
 
 from __future__ import annotations
 
-from rich.console import RenderableType
 from rich.box import ROUNDED
+from rich.console import RenderableType
+from rich.padding import Padding
 from rich.panel import Panel
 from rich.text import Text
 
@@ -13,7 +14,12 @@
 
 
 class ThinkingRenderer(ContentRenderer):
-    """Render a complete thinking block."""
+    """Render a complete thinking block.
+
+    Sub-agent thinking (``is_subagent=True``) is rendered with a dim border, a
+    ``subagent thinking`` title, and a left indent so it reads as nested inside
+    the parent spawn_agent card rather than as a top-level turn event.
+    """
 
     def accepts(self, msg: dict) -> bool:
         return msg.get("type") == "thinking_block"
@@ -21,10 +27,20 @@
     def render(self, msg: dict) -> RenderableType:
         theme = get_active_theme()
         text = msg.get("content", "")
+        is_subagent = bool(msg.get("is_subagent", False))
+        if is_subagent:
+            panel = Panel(
+                Text(text, style=theme.text_dim.hex),
+                title="subagent thinking",
+                title_align="left",
+                border_style=theme.text_dim.hex,
+                box=ROUNDED,
+            )
+            return Padding(panel, (0, 0, 0, 2))
         return Panel(
             Text(text, style=theme.text_dim.hex),
             title="thinking",
             title_align="left",
             border_style=theme.thinking.hex,
             box=ROUNDED,
-        )
+        )
\ No newline at end of file
diff --git a/clients/terminal/tui/renderers/tool.py b/clients/terminal/tui/renderers/tool.py
index e1e4a82..16bffe2 100644
--- a/clients/terminal/tui/renderers/tool.py
+++ b/clients/terminal/tui/renderers/tool.py
@@ -7,6 +7,7 @@
 from rich.console import RenderableType
 from rich.json import JSON as RichJSON
 from rich.box import ROUNDED
+from rich.padding import Padding
 from rich.panel import Panel
 from rich.text import Text
 
@@ -16,7 +17,11 @@
 
 
 class ToolStartedRenderer(ContentRenderer):
-    """Render a tool call start marker."""
+    """Render a tool call start marker.
+
+    Sub-agent tool calls (``is_subagent=True``) are indented to read as nested
+    inside the parent spawn_agent card.
+    """
 
     def accepts(self, msg: dict) -> bool:
         return msg.get("type") == "tool_started"
@@ -33,17 +38,24 @@
                 body = Text(str(args), style=theme.text_dim.hex)
         else:
             body = Text("")
-        return Panel(
+        panel = Panel(
             body,
             title=title,
             title_align="left",
             border_style=theme.tool_border.hex,
             box=ROUNDED,
         )
+        if bool(msg.get("is_subagent", False)):
+            return Padding(panel, (0, 0, 0, 2))
+        return panel
 
 
 class ToolResultRenderer(ContentRenderer):
-    """Render a tool call result."""
+    """Render a tool call result.
+
+    Sub-agent tool results (``is_subagent=True``) are indented to read as nested
+    inside the parent spawn_agent card.
+    """
 
     def accepts(self, msg: dict) -> bool:
         return msg.get("type") == "tool_call"
@@ -56,10 +68,13 @@
         color = theme.tool_success if success else theme.tool_error
         title = f"← {tool} {'✓' if success else '✗'}"
         body = Text(str(result) if result is not None else "", style=theme.text_dim.hex)
-        return Panel(
+        panel = Panel(
             body,
             title=title,
             title_align="left",
             border_style=color.hex,
             box=ROUNDED,
         )
+        if bool(msg.get("is_subagent", False)):
+            return Padding(panel, (0, 0, 0, 2))
+        return panel
diff --git a/clients/terminal/tui/widgets/chat_panel.py b/clients/terminal/tui/widgets/chat_panel.py
index 9d332ef..f4b9b0a 100644
--- a/clients/terminal/tui/widgets/chat_panel.py
+++ b/clients/terminal/tui/widgets/chat_panel.py
@@ -68,7 +68,13 @@
                 )
             elif item.kind == "thinking_block":
                 renderables.append(
-                    self._registry.render({"type": "thinking_block", "content": item.content})
+                    self._registry.render(
+                        {
+                            "type": "thinking_block",
+                            "content": item.content,
+                            "is_subagent": item.meta.get("is_subagent", False),
+                        }
+                    )
                 )
             elif item.kind == "tool_started":
                 renderables.append(self._registry.render({"type": "tool_started", **item.meta}))
diff --git a/tests/clients/test_planning_renderers.py b/tests/clients/test_planning_renderers.py
index 141a7da..80d09a2 100644
--- a/tests/clients/test_planning_renderers.py
+++ b/tests/clients/test_planning_renderers.py
@@ -2,8 +2,6 @@
 
 from __future__ import annotations
 
-import io
-
 from rich.console import Console
 
 from clients.terminal.tui.renderers.planning import PlanningStatusRenderer, PlanReadyRenderer
@@ -52,5 +50,5 @@
     set_active_theme("gnexus-dark")
     renderer = PlanReadyRenderer()
     msg = {"type": "plan_ready", "plan": "## Plan\n**Steps:**\n1. x\n", "is_subagent": True}
-    panel = renderer.render(msg)
-    assert panel.title == "subagent plan"
\ No newline at end of file
+    out = _render_text(renderer.render(msg))
+    assert "subagent plan" in out
\ No newline at end of file
diff --git a/tests/clients/test_subagent_renderers.py b/tests/clients/test_subagent_renderers.py
new file mode 100644
index 0000000..b5b58fa
--- /dev/null
+++ b/tests/clients/test_subagent_renderers.py
@@ -0,0 +1,110 @@
+"""Tests for sub-agent card renderers (spawn_agent + nested styling)."""
+
+from __future__ import annotations
+
+from rich.console import Console
+
+from clients.terminal.tui.renderers.planning import PlanningStatusRenderer, PlanReadyRenderer
+from clients.terminal.tui.renderers.subagent import (
+    SpawnAgentStartedRenderer,
+    SpawnAgentResultRenderer,
+)
+from clients.terminal.tui.renderers.thinking import ThinkingRenderer
+from clients.terminal.tui.renderers.tool import ToolStartedRenderer, ToolResultRenderer
+from clients.terminal.tui.themes import set_active_theme
+
+
+def _render_text(renderable) -> str:
+    console = Console(record=True, width=80, force_terminal=True, color_system=None)
+    console.print(renderable)
+    return console.export_text()
+
+
+def test_spawn_started_card_shows_profile_and_task() -> None:
+    set_active_theme("gnexus-dark")
+    renderer = SpawnAgentStartedRenderer()
+    msg = {
+        "type": "tool_started",
+        "tool": "spawn_agent",
+        "args": {"task": "audit the auth flow", "profile_id": "developer"},
+        "is_subagent": False,
+    }
+    assert renderer.accepts(msg)
+    panel = renderer.render(msg)
+    assert "subagent" in str(panel.title)
+    assert "developer" in str(panel.title)
+    assert "audit the auth flow" in _render_text(panel)
+
+
+def test_spawn_started_does_not_accept_other_tools() -> None:
+    renderer = SpawnAgentStartedRenderer()
+    assert not renderer.accepts({"type": "tool_started", "tool": "filesystem", "args": {}})
+
+
+def test_spawn_result_card_shows_status() -> None:
+    set_active_theme("gnexus-dark")
+    renderer = SpawnAgentResultRenderer()
+    msg = {
+        "type": "tool_call",
+        "tool": "spawn_agent",
+        "args": {"profile_id": "developer"},
+        "result": "auth flow is fine",
+        "success": True,
+        "is_subagent": False,
+    }
+    assert renderer.accepts(msg)
+    panel = renderer.render(msg)
+    title = str(panel.title)
+    assert "developer" in title
+    assert "✓" in title
+    assert "auth flow is fine" in _render_text(panel)
+
+
+def test_subagent_thinking_is_indented_and_labeled() -> None:
+    set_active_theme("gnexus-dark")
+    renderer = ThinkingRenderer()
+    msg = {"type": "thinking_block", "content": "hmm nested", "is_subagent": True}
+    out = _render_text(renderer.render(msg))
+    assert "subagent thinking" in out
+    assert "hmm nested" in out
+    # Indented: the content lines start with spaces.
+    assert any(line.startswith("  ") for line in out.splitlines())
+
+
+def test_subagent_planning_status_is_indented() -> None:
+    set_active_theme("gnexus-dark")
+    renderer = PlanningStatusRenderer()
+    msg = {"type": "planning_status", "phase": 1, "label": "Analysis", "is_subagent": True}
+    out = _render_text(renderer.render(msg))
+    assert "(subagent)" in out
+    assert any(line.startswith("  ") for line in out.splitlines())
+
+
+def test_subagent_plan_card_is_indented() -> None:
+    set_active_theme("gnexus-dark")
+    renderer = PlanReadyRenderer()
+    msg = {"type": "plan_ready", "plan": "## Plan\n**Steps:**\n1. x\n", "is_subagent": True}
+    out = _render_text(renderer.render(msg))
+    assert "subagent plan" in out
+    assert any(line.startswith("  ") for line in out.splitlines())
+
+
+def test_subagent_tool_card_is_indented() -> None:
+    set_active_theme("gnexus-dark")
+    started = ToolStartedRenderer().render(
+        {"type": "tool_started", "tool": "filesystem", "args": {}, "is_subagent": True}
+    )
+    result = ToolResultRenderer().render(
+        {"type": "tool_call", "tool": "filesystem", "result": "ok", "success": True, "is_subagent": True}
+    )
+    assert any(line.startswith("  ") for line in _render_text(started).splitlines())
+    assert any(line.startswith("  ") for line in _render_text(result).splitlines())
+
+
+def test_non_subagent_tool_card_not_indented() -> None:
+    set_active_theme("gnexus-dark")
+    started = ToolStartedRenderer().render(
+        {"type": "tool_started", "tool": "filesystem", "args": {}, "is_subagent": False}
+    )
+    # A top-level card has border lines starting at column 0 (e.g. "╭──").
+    assert any(line.startswith("╭") for line in _render_text(started).splitlines())
\ No newline at end of file
diff --git a/tests/clients/test_tui_app.py b/tests/clients/test_tui_app.py
index fa924f9..f37e971 100644
--- a/tests/clients/test_tui_app.py
+++ b/tests/clients/test_tui_app.py
@@ -268,6 +268,22 @@
 
 
 @pytest.mark.anyio
+async def test_turn_thinking_creates_subagent_thinking_block() -> None:
+    """turn_thinking events become thinking_block items flagged is_subagent."""
+    async with NaviCodeTui(new_session=True).run_test() as pilot:
+        await pilot.pause()
+        chat = pilot.app.query_one("ChatPanel")
+        chat.handle_ws_event(
+            {"type": "turn_thinking", "thinking": "let me consider…", "is_subagent": True}
+        )
+        await pilot.pause()
+        blocks = [it for it in chat._model.items if it.kind == "thinking_block"]
+        assert len(blocks) == 1
+        assert blocks[0].content == "let me consider…"
+        assert blocks[0].meta["is_subagent"] is True
+
+
+@pytest.mark.anyio
 async def test_unknown_slash_command_shows_error() -> None:
     """Unknown slash command produces an error item in chat."""
     async with NaviCodeTui(new_session=True).run_test() as pilot: