Studio: surface the tool-call nudge in the chat UI (#7559)

* Studio: show a Nudging tool calls badge while the tool-call re-prompt runs

* Guard the nudge status ordering assertion against index 0

* Tighten the nudge status comments

* Announce the nudge text instead of the generic spinner label

* Trim the nudge status comments

Collapse the multi-line notes to fewer lines and drop one that restated the assert below it. The blank-before-badge ordering reason and the keep-in-sync contract are preserved.

---------

Co-authored-by: danielhanchen <unslothai@gmail.com>

studio/backend/core/inference/llama_cpp.py

@@ -92,6 +92,7 @@ from utils.subprocess_compat import (
 from utils.process_lifetime import child_popen_kwargs as _child_popen_kwargs
 from core.inference.tool_call_parser import (
     MAX_ACT_REPROMPTS as _MAX_REPROMPTS,
+    NUDGE_TOOL_CALLS_STATUS as _NUDGE_TOOL_CALLS_STATUS,
     REPROMPT_MAX_CHARS as _REPROMPT_MAX_CHARS,
     is_short_intent_without_action as _is_short_intent_without_action,
     reprompt_to_act_message as _reprompt_to_act_message,
@@ -12419,7 +12420,10 @@ class LlamaCppBackend:
                             _it_r = _iter_timings or {}
                             _accumulated_predicted_ms += _it_r.get("predicted_ms", 0)
                             _accumulated_predicted_n += _it_r.get("predicted_n", 0)
+                            # Blank first (the route resets its text cursor only on an
+                            # empty status), then the badge so the retry is not a hang.
                             yield {"type": "status", "text": ""}
+                            yield {"type": "status", "text": _NUDGE_TOOL_CALLS_STATUS}
                             continue
 
                         if _forced_tool_call_pending:

studio/backend/core/inference/safetensors_agentic.py

@@ -35,6 +35,7 @@ from core.inference.tool_call_parser import (
     _strip_mistral_reasoning,
     BUDGET_EXHAUSTED_NUDGE,
     MAX_ACT_REPROMPTS,
+    NUDGE_TOOL_CALLS_STATUS,
     RAG_MAX_SEARCHES_PER_TURN,
     RAG_SEARCH_CAP_NUDGE,
     TOOL_XML_SIGNALS,
@@ -1032,9 +1033,10 @@ def run_safetensors_tool_loop(
                             "content": reprompt_to_act_message(tool_hint),
                         }
                     )
-                    # Empty status clears the badge and resets the route's
+                    # Blank first: it clears the badge and resets the route's per-turn
-                    # per-turn text cursor before the re-prompted turn streams.
+                    # text cursor. The badge then shows the pause is a re-prompt, not a stall.
                     yield {"type": "status", "text": ""}
+                    yield {"type": "status", "text": NUDGE_TOOL_CALLS_STATUS}
                     continue
 
                 # Final answer. If a literal tool marker in prose was buffered but

studio/backend/core/inference/tool_call_parser.py

@@ -183,6 +183,9 @@ INTENT_SIGNAL = re.compile(
 # times since #5620); safetensors and MLX inherit the same cap from here.
 MAX_ACT_REPROMPTS = 3
 REPROMPT_MAX_CHARS = 2000
+# Composer badge while a hidden re-prompted turn regenerates, else the UI looks
+# hung. Matched exactly by the frontend (utils/tool-status.ts); keep in sync.
+NUDGE_TOOL_CALLS_STATUS = "Nudging tool calls"
 
 
 def is_short_intent_without_action(text: str) -> bool:

studio/backend/tests/test_llama_cpp_tool_loop.py

@@ -26,6 +26,7 @@ from core.inference.llama_cpp import (
     _PROVISIONAL_ARGS_MIN_CHARS,
     LlamaCppBackend,
 )
+from core.inference.tool_call_parser import NUDGE_TOOL_CALLS_STATUS
 from state import tool_approvals
 from state.tool_approvals import TOOL_REJECTED_MESSAGE, resolve_tool_decision
 
@@ -1841,6 +1842,140 @@ def test_reprompted_tool_call_still_streams_final_answer(monkeypatch):
     assert len(payloads) == 3
 
 
+def _status_texts(events: list[dict]) -> list[str]:
+    return [event["text"] for event in events if event.get("type") == "status"]
+
+
+_WEB_SEARCH_TOOL = {
+    "type": "function",
+    "function": {
+        "name": "web_search",
+        "description": "Search the web.",
+        "parameters": {
+            "type": "object",
+            "properties": {"query": {"type": "string"}},
+            "required": ["query"],
+        },
+    },
+}
+
+
+def _nudge_then_search_streams() -> list[list[str]]:
+    """Stall, then a re-prompted turn that finally searches, then the answer."""
+
+    return [
+        [_sse({"content": "I will search the web now."}), _done()],
+        [
+            _sse(
+                {
+                    "tool_calls": [
+                        {
+                            "index": 0,
+                            "id": "call_search",
+                            "type": "function",
+                            "function": {
+                                "name": "web_search",
+                                "arguments": json.dumps({"query": "red square"}),
+                            },
+                        }
+                    ]
+                }
+            ),
+            _done(),
+        ],
+        [_sse({"content": "Final answer: the square is red."}), _done()],
+    ]
+
+
+def test_plan_without_action_nudge_is_announced_on_the_status_channel(monkeypatch):
+    """The re-prompted turn is hidden, so without a badge the UI looks frozen."""
+
+    payloads: list[dict] = []
+    backend = _make_backend(monkeypatch, _nudge_then_search_streams(), payloads)
+    monkeypatch.setattr(
+        "core.inference.tools.execute_tool",
+        lambda *_a, **_k: "Search results: red is #f00.",
+    )
+
+    events = list(
+        backend.generate_chat_completion_with_tools(
+            messages = [{"role": "user", "content": "What colour is the square?"}],
+            tools = [_WEB_SEARCH_TOOL],
+            max_tool_iterations = 2,
+        )
+    )
+
+    statuses = _status_texts(events)
+    assert NUDGE_TOOL_CALLS_STATUS in statuses
+    index = statuses.index(NUDGE_TOOL_CALLS_STATUS)
+    # Blank first: the route resets its text cursor only on an empty status.
+    # index > 0 matters: at 0, statuses[-1] wraps to the terminal clear.
+    assert index > 0 and statuses[index - 1] == ""
+    assert statuses[index + 1].startswith("Searching:")
+    assert statuses[-1] == ""
+
+
+def test_plan_without_action_nudge_status_clears_when_the_retry_just_answers(monkeypatch):
+    streams = [
+        [_sse({"content": "I will search the web now."}), _done()],
+        [_sse({"content": "No search needed. Final answer: the square is red."}), _done()],
+    ]
+    payloads: list[dict] = []
+    backend = _make_backend(monkeypatch, streams, payloads)
+
+    events = list(
+        backend.generate_chat_completion_with_tools(
+            messages = [{"role": "user", "content": "What colour is the square?"}],
+            tools = [_WEB_SEARCH_TOOL],
+            max_tool_iterations = 2,
+        )
+    )
+
+    statuses = _status_texts(events)
+    assert NUDGE_TOOL_CALLS_STATUS in statuses
+    assert statuses[-1] == ""
+
+
+def test_direct_answer_never_shows_the_nudge_status(monkeypatch):
+    payloads: list[dict] = []
+    backend = _make_backend(
+        monkeypatch,
+        [[_sse({"content": "The square is red."}), _done()]],
+        payloads,
+    )
+
+    events = list(
+        backend.generate_chat_completion_with_tools(
+            messages = [{"role": "user", "content": "What colour is the square?"}],
+            tools = [_WEB_SEARCH_TOOL],
+            max_tool_iterations = 2,
+        )
+    )
+
+    assert NUDGE_TOOL_CALLS_STATUS not in _status_texts(events)
+
+
+def test_nudge_status_absent_when_nudging_is_disabled(monkeypatch):
+    payloads: list[dict] = []
+    backend = _make_backend(monkeypatch, _nudge_then_search_streams(), payloads)
+    monkeypatch.setattr(
+        "core.inference.tools.execute_tool",
+        lambda *_a, **_k: "Search results: red is #f00.",
+    )
+
+    events = list(
+        backend.generate_chat_completion_with_tools(
+            messages = [{"role": "user", "content": "What colour is the square?"}],
+            tools = [_WEB_SEARCH_TOOL],
+            max_tool_iterations = 2,
+            nudge_tool_calls = False,
+        )
+    )
+
+    assert NUDGE_TOOL_CALLS_STATUS not in _status_texts(events)
+    assert len(payloads) == 1
+
+
 def test_confirm_tool_calls_allow_executes_gguf_tool(monkeypatch):
     streams = [
         _structured_tool_call("python", {"code": "print(1)"}, "call_py"),

studio/backend/tests/test_safetensors_tool_loop.py

@@ -24,6 +24,7 @@ from core.inference.safetensors_agentic import (
     strip_tool_markup_streaming,
 )
 from core.inference.tool_call_parser import (
+    NUDGE_TOOL_CALLS_STATUS,
     RAG_MAX_SEARCHES_PER_TURN,
     has_tool_signal,
     parse_tool_calls_from_text,
@@ -2231,6 +2232,24 @@ def test_reprompt_names_only_active_tools_not_hardcoded():
     assert "python" not in reprompt["content"]
 
 
+def test_reprompt_is_announced_on_the_status_channel():
+    # The re-prompted turn is hidden, so the badge is the only sign of life.
+    # Blank still comes first: the route resets its text cursor only on that.
+    _captured, events = _reprompt_loop(auto_heal_tool_calls = True)
+    statuses = [e["text"] for e in events if e["type"] == "status"]
+    assert NUDGE_TOOL_CALLS_STATUS in statuses
+    index = statuses.index(NUDGE_TOOL_CALLS_STATUS)
+    # index > 0 matters: at 0, statuses[-1] wraps to the terminal clear.
+    assert index > 0 and statuses[index - 1] == ""
+    assert statuses[-1] == ""
+
+
+def test_reprompt_status_absent_without_a_nudge():
+    _captured, events = _reprompt_loop(auto_heal_tool_calls = False)
+    statuses = [e["text"] for e in events if e["type"] == "status"]
+    assert NUDGE_TOOL_CALLS_STATUS not in statuses
+
+
 def test_reprompt_suppressed_when_auto_heal_disabled():
     # With Auto-Heal off the safetensors nudge must stay silent for backend parity
     # with the GGUF loop, so only the single initial generation runs.

studio/frontend/src/components/assistant-ui/thread.tsx

@@ -91,6 +91,7 @@ import {
   useResearchRunStore,
 } from "@/features/chat/stores/research-run-store";
 import { parseExternalModelId } from "@/features/chat/external-providers";
+import { toolStatusKind } from "@/features/chat/utils/tool-status";
 import { McpComposerButton } from "@/features/chat/mcp-composer-button";
 import { getExternalReasoningCapabilities } from "@/features/chat/provider-capabilities";
 import { useRagToolDisabled } from "@/features/chat/hooks/use-rag-tool-disabled";
@@ -2847,15 +2848,28 @@ const ToolStatusDisplay: FC = () => {
   }
   // From the store's start time, so returning to the conversation resumes rather than restarting.
   const elapsed = Math.max(0, Math.floor((now - startedAt) / 1000));
-  const isRunning = toolStatus.startsWith("Running");
+  const kind = toolStatusKind(toolStatus);
-  const StatusIcon = isRunning ? TerminalIcon : GlobeIcon;
+  const isNudging = kind === "nudge";
+  const StatusIcon = kind === "terminal" ? TerminalIcon : GlobeIcon;
   return (
     <div
       data-testid="composer-tool-status"
       className="mb-2 flex w-full flex-row items-center gap-2 px-1.5 pt-0.5 pb-1"
     >
-      <div className="flex animate-pulse items-center gap-2 rounded-full border border-primary/20 bg-primary/5 px-3 py-1.5 text-xs text-primary">
+      <div
-        <StatusIcon className="size-3.5" />
+        className={cn(
+          "flex items-center gap-2 rounded-full border border-primary/20 bg-primary/5 px-3 py-1.5 text-xs text-primary",
+          // The spinner is its own motion cue; pulsing too just fades it mid-spin.
+          !isNudging && "animate-pulse",
+        )}
+      >
+        {isNudging ? (
+          // label, not the default "Loading": the spinner is the badge's only
+          // role="status" region, so its name is what gets announced.
+          <Spinner className="size-3.5" label={toolStatus} />
+        ) : (
+          <StatusIcon className="size-3.5" />
+        )}
         <span>{toolStatus}</span>
         <span className="tabular-nums opacity-60">{elapsed}s</span>
       </div>

studio/frontend/src/features/chat/utils/tool-status.ts

@@ -0,0 +1,15 @@
+// SPDX-License-Identifier: AGPL-3.0-only
+// Copyright 2026-present the Unsloth AI Inc. team. All rights reserved. See /studio/LICENSE.AGPL-3.0
+
+/** Mirrors NUDGE_TOOL_CALLS_STATUS in backend core/inference/tool_call_parser.py; keep in sync. */
+export const NUDGE_TOOL_CALLS_STATUS = "Nudging tool calls";
+
+export type ToolStatusKind = "nudge" | "terminal" | "web";
+
+/** Which glyph the badge shows: exact match for the nudge, "Running" prefix for sandbox tools, globe otherwise. */
+export function toolStatusKind(status: string): ToolStatusKind {
+  if (status === NUDGE_TOOL_CALLS_STATUS) {
+    return "nudge";
+  }
+  return status.startsWith("Running") ? "terminal" : "web";
+}

studio/frontend/tests/tool-status.test.ts

@@ -0,0 +1,45 @@
+// SPDX-License-Identifier: AGPL-3.0-only
+// Copyright 2026-present the Unsloth AI Inc. team. All rights reserved. See /studio/LICENSE.AGPL-3.0
+
+import assert from "node:assert/strict";
+import test from "node:test";
+
+import {
+  NUDGE_TOOL_CALLS_STATUS,
+  toolStatusKind,
+} from "../src/features/chat/utils/tool-status.ts";
+
+test("the nudge status is the exact string the backend sends", () => {
+  // Mirrors tool_call_parser.py, so a reword on either side must break here.
+  assert.equal(NUDGE_TOOL_CALLS_STATUS, "Nudging tool calls");
+  assert.equal(toolStatusKind(NUDGE_TOOL_CALLS_STATUS), "nudge");
+});
+
+test("sandbox tools keep the terminal glyph", () => {
+  for (const status of [
+    "Running Python: print(1)",
+    "Running Python...",
+    "Running: ls -la",
+    "Running command...",
+  ]) {
+    assert.equal(toolStatusKind(status), "terminal", status);
+  }
+});
+
+test("every other status keeps the globe", () => {
+  for (const status of [
+    "Searching: red square",
+    "Reading: unsloth.ai",
+    "Reading page...",
+    "Searching documents: quarterly report",
+    "Calling: get_weather",
+  ]) {
+    assert.equal(toolStatusKind(status), "web", status);
+  }
+});
+
+test("a status that merely mentions nudging is not the nudge itself", () => {
+  // Exact match only: a tool named after the phrase must not steal the spinner.
+  assert.equal(toolStatusKind("Calling: Nudging tool calls"), "web");
+  assert.equal(toolStatusKind("Nudging tool calls again"), "web");
+});