feat(agent): add ask_user tool

Made-with: Cursor

nanobot/agent/loop.py

@@ -20,14 +20,15 @@ from nanobot.agent.memory import Consolidator, Dream
 from nanobot.agent.runner import _MAX_INJECTIONS_PER_TURN, AgentRunner, AgentRunSpec
 from nanobot.agent.skills import BUILTIN_SKILLS_DIR
 from nanobot.agent.subagent import SubagentManager
+from nanobot.agent.tools.ask import AskUserTool
 from nanobot.agent.tools.cron import CronTool
 from nanobot.agent.tools.filesystem import EditFileTool, ListDirTool, ReadFileTool, WriteFileTool
 from nanobot.agent.tools.message import MessageTool
 from nanobot.agent.tools.notebook import NotebookEditTool
 from nanobot.agent.tools.registry import ToolRegistry
 from nanobot.agent.tools.search import GlobTool, GrepTool
-from nanobot.agent.tools.shell import ExecTool
 from nanobot.agent.tools.self import MyTool
+from nanobot.agent.tools.shell import ExecTool
 from nanobot.agent.tools.spawn import SpawnTool
 from nanobot.agent.tools.web import WebFetchTool, WebSearchTool
 from nanobot.bus.events import InboundMessage, OutboundMessage
@@ -287,6 +288,7 @@ class AgentLoop:
             self.workspace if (self.restrict_to_workspace or self.exec_config.sandbox) else None
         )
         extra_read = [BUILTIN_SKILLS_DIR] if allowed_dir else None
+        self.tools.register(AskUserTool())
         self.tools.register(
             ReadFileTool(
                 workspace=self.workspace, allowed_dir=allowed_dir, extra_allowed_dirs=extra_read
@@ -407,6 +409,56 @@ class AgentLoop:
             return UNIFIED_SESSION_KEY
         return msg.session_key
 
+    @staticmethod
+    def _tool_call_name(tool_call: dict[str, Any]) -> str:
+        function = tool_call.get("function")
+        if isinstance(function, dict) and isinstance(function.get("name"), str):
+            return function["name"]
+        name = tool_call.get("name")
+        return name if isinstance(name, str) else ""
+
+    @staticmethod
+    def _tool_call_arguments(tool_call: dict[str, Any]) -> dict[str, Any]:
+        function = tool_call.get("function")
+        raw = function.get("arguments") if isinstance(function, dict) else tool_call.get("arguments")
+        if isinstance(raw, dict):
+            return raw
+        if isinstance(raw, str):
+            try:
+                parsed = json.loads(raw)
+            except json.JSONDecodeError:
+                return {}
+            return parsed if isinstance(parsed, dict) else {}
+        return {}
+
+    def _pending_ask_user_id(self, history: list[dict[str, Any]]) -> str | None:
+        pending: dict[str, str] = {}
+        for message in history:
+            if message.get("role") == "assistant":
+                for tool_call in message.get("tool_calls") or []:
+                    if isinstance(tool_call, dict) and isinstance(tool_call.get("id"), str):
+                        pending[tool_call["id"]] = self._tool_call_name(tool_call)
+            elif message.get("role") == "tool":
+                tool_call_id = message.get("tool_call_id")
+                if isinstance(tool_call_id, str):
+                    pending.pop(tool_call_id, None)
+        for tool_call_id, name in reversed(pending.items()):
+            if name == "ask_user":
+                return tool_call_id
+        return None
+
+    def _ask_user_options_from_messages(self, messages: list[dict[str, Any]]) -> list[str]:
+        for message in reversed(messages):
+            if message.get("role") != "assistant":
+                continue
+            for tool_call in reversed(message.get("tool_calls") or []):
+                if not isinstance(tool_call, dict) or self._tool_call_name(tool_call) != "ask_user":
+                    continue
+                options = self._tool_call_arguments(tool_call).get("options")
+                if isinstance(options, list):
+                    return [str(option) for option in options if isinstance(option, str)]
+        return []
+
     async def _run_agent_loop(
         self,
         initial_messages: list[dict],
@@ -799,7 +851,7 @@ class AgentLoop:
                 session_summary=pending,
                 current_role=current_role,
             )
-            final_content, _, all_msgs, _, _ = await self._run_agent_loop(
+            final_content, _, all_msgs, stop_reason, _ = await self._run_agent_loop(
                 messages, session=session, channel=channel, chat_id=chat_id,
                 message_id=msg.metadata.get("message_id"),
                 pending_queue=pending_queue,
@@ -808,10 +860,12 @@ class AgentLoop:
             self._clear_runtime_checkpoint(session)
             self.sessions.save(session)
             self._schedule_background(self.consolidator.maybe_consolidate_by_tokens(session))
+            options = self._ask_user_options_from_messages(all_msgs) if stop_reason == "ask_user" else []
             return OutboundMessage(
                 channel=channel,
                 chat_id=chat_id,
                 content=final_content or "Background task completed.",
+                buttons=[options] if options else [],
             )
 
         # Extract document text from media at the processing boundary so all
@@ -850,14 +904,27 @@ class AgentLoop:
 
         history = session.get_history(max_messages=0)
 
-        initial_messages = self.context.build_messages(
-            history=history,
-            current_message=msg.content,
-            session_summary=pending,
-            media=msg.media if msg.media else None,
-            channel=msg.channel,
-            chat_id=msg.chat_id,
-        )
+        pending_ask_id = self._pending_ask_user_id(history)
+        if pending_ask_id:
+            initial_messages = [
+                {"role": "system", "content": self.context.build_system_prompt(channel=msg.channel)},
+                *history,
+                {
+                    "role": "tool",
+                    "tool_call_id": pending_ask_id,
+                    "name": "ask_user",
+                    "content": msg.content,
+                },
+            ]
+        else:
+            initial_messages = self.context.build_messages(
+                history=history,
+                current_message=msg.content,
+                session_summary=pending,
+                media=msg.media if msg.media else None,
+                channel=msg.channel,
+                chat_id=msg.chat_id,
+            )
 
         async def _bus_progress(
             content: str,
@@ -898,7 +965,7 @@ class AgentLoop:
         user_persisted_early = False
         media_paths = [p for p in (msg.media or []) if isinstance(p, str) and p]
         has_text = isinstance(msg.content, str) and msg.content.strip()
-        if has_text or media_paths:
+        if not pending_ask_id and (has_text or media_paths):
             extra: dict[str, Any] = {"media": list(media_paths)} if media_paths else {}
             text = msg.content if isinstance(msg.content, str) else ""
             session.add_message("user", text, **extra)
@@ -944,6 +1011,11 @@ class AgentLoop:
         logger.info("Response to {}:{}: {}", msg.channel, msg.sender_id, preview)
 
         meta = dict(msg.metadata or {})
+        buttons: list[list[str]] = []
+        if stop_reason == "ask_user":
+            options = self._ask_user_options_from_messages(all_msgs)
+            if options:
+                buttons = [options]
         if on_stream is not None and stop_reason != "error":
             meta["_streamed"] = True
         return OutboundMessage(
@@ -951,6 +1023,7 @@ class AgentLoop:
             chat_id=msg.chat_id,
             content=final_content,
             metadata=meta,
+            buttons=buttons,
         )
 
     def _sanitize_persisted_blocks(

nanobot/agent/runner.py

@@ -3,16 +3,16 @@
 from __future__ import annotations
 
 import asyncio
-from dataclasses import dataclass, field
 import inspect
 import os
+from dataclasses import dataclass, field
 from pathlib import Path
 from typing import Any
 
 from loguru import logger
 
 from nanobot.agent.hook import AgentHook, AgentHookContext
-from nanobot.utils.prompt_templates import render_template
+from nanobot.agent.tools.ask import AskUserInterrupt
 from nanobot.agent.tools.registry import ToolRegistry
 from nanobot.providers.base import LLMProvider, LLMResponse, ToolCallRequest
 from nanobot.utils.helpers import (
@@ -23,6 +23,7 @@ from nanobot.utils.helpers import (
     maybe_persist_tool_result,
     truncate_text,
 )
+from nanobot.utils.prompt_templates import render_template
 from nanobot.utils.runtime import (
     EMPTY_FINAL_RESPONSE_MESSAGE,
     build_finalization_retry_message,
@@ -312,6 +313,8 @@ class AgentRunner:
                 context.tool_events = list(new_events)
                 completed_tool_results: list[dict[str, Any]] = []
                 for tool_call, result in zip(response.tool_calls, results):
+                    if isinstance(fatal_error, AskUserInterrupt) and tool_call.name == "ask_user":
+                        continue
                     tool_message = {
                         "role": "tool",
                         "tool_call_id": tool_call.id,
@@ -326,6 +329,15 @@ class AgentRunner:
                     messages.append(tool_message)
                     completed_tool_results.append(tool_message)
                 if fatal_error is not None:
+                    if isinstance(fatal_error, AskUserInterrupt):
+                        final_content = fatal_error.question
+                        stop_reason = "ask_user"
+                        context.final_content = final_content
+                        context.stop_reason = stop_reason
+                        if hook.wants_streaming():
+                            await hook.on_stream_end(context, resuming=False)
+                        await hook.after_iteration(context)
+                        break
                     error = f"Error: {type(fatal_error).__name__}: {fatal_error}"
                     final_content = error
                     stop_reason = "tool_error"
@@ -656,13 +668,21 @@ class AgentRunner:
         tool_results: list[tuple[Any, dict[str, str], BaseException | None]] = []
         for batch in batches:
             if spec.concurrent_tools and len(batch) > 1:
-                tool_results.extend(await asyncio.gather(*(
+                batch_results = await asyncio.gather(*(
                     self._run_tool(spec, tool_call, external_lookup_counts)
                     for tool_call in batch
-                )))
+                ))
+                tool_results.extend(batch_results)
             else:
+                batch_results = []
                 for tool_call in batch:
-                    tool_results.append(await self._run_tool(spec, tool_call, external_lookup_counts))
+                    result = await self._run_tool(spec, tool_call, external_lookup_counts)
+                    tool_results.append(result)
+                    batch_results.append(result)
+                    if isinstance(result[2], AskUserInterrupt):
+                        break
+            if any(isinstance(error, AskUserInterrupt) for _, _, error in batch_results):
+                break
 
         results: list[Any] = []
         events: list[dict[str, str]] = []
@@ -724,6 +744,9 @@ class AgentRunner:
                 "status": "error",
                 "detail": str(exc),
             }
+            if isinstance(exc, AskUserInterrupt):
+                event["status"] = "waiting"
+                return "", event, exc
             if spec.fail_on_tool_error:
                 return f"Error: {type(exc).__name__}: {exc}", event, exc
             return f"Error: {type(exc).__name__}: {exc}", event, None

nanobot/agent/tools/ask.py

@@ -0,0 +1,50 @@
+"""Tool for pausing a turn until the user answers."""
+
+from typing import Any
+
+from nanobot.agent.tools.base import Tool, tool_parameters
+from nanobot.agent.tools.schema import ArraySchema, StringSchema, tool_parameters_schema
+
+
+class AskUserInterrupt(BaseException):
+    """Internal signal: the runner should stop and wait for user input."""
+
+    def __init__(self, question: str, options: list[str] | None = None) -> None:
+        self.question = question
+        self.options = [str(option) for option in (options or []) if str(option)]
+        super().__init__(question)
+
+
+@tool_parameters(
+    tool_parameters_schema(
+        question=StringSchema(
+            "The question to ask before continuing. Use this only when the task needs the user's answer."
+        ),
+        options=ArraySchema(
+            StringSchema("A possible answer label"),
+            description="Optional choices. The user may still reply with free text.",
+        ),
+        required=["question"],
+    )
+)
+class AskUserTool(Tool):
+    """Ask the user a blocking question."""
+
+    @property
+    def name(self) -> str:
+        return "ask_user"
+
+    @property
+    def description(self) -> str:
+        return (
+            "Pause and ask the user a question when their answer is required to continue. "
+            "Use options for likely answers; the user's reply, typed or selected, is returned as the tool result. "
+            "For non-blocking notifications or buttons, use the message tool instead."
+        )
+
+    @property
+    def exclusive(self) -> bool:
+        return True
+
+    async def execute(self, question: str, options: list[str] | None = None, **_: Any) -> Any:
+        raise AskUserInterrupt(question=question, options=options)

tests/agent/test_ask_user.py

@@ -0,0 +1,158 @@
+import asyncio
+from unittest.mock import MagicMock
+
+import pytest
+
+from nanobot.agent.loop import AgentLoop
+from nanobot.agent.runner import AgentRunner, AgentRunSpec
+from nanobot.agent.tools.ask import AskUserInterrupt, AskUserTool
+from nanobot.agent.tools.base import Tool, tool_parameters
+from nanobot.agent.tools.registry import ToolRegistry
+from nanobot.agent.tools.schema import tool_parameters_schema
+from nanobot.bus.events import InboundMessage
+from nanobot.bus.queue import MessageBus
+from nanobot.providers.base import GenerationSettings, LLMResponse, ToolCallRequest
+
+
+def _make_provider(chat_with_retry):
+    provider = MagicMock()
+    provider.get_default_model.return_value = "test-model"
+    provider.generation = GenerationSettings()
+    provider.chat_with_retry = chat_with_retry
+    return provider
+
+
+def test_ask_user_tool_schema_and_interrupt():
+    tool = AskUserTool()
+    schema = tool.to_schema()["function"]
+
+    assert schema["name"] == "ask_user"
+    assert "question" in schema["parameters"]["required"]
+    assert schema["parameters"]["properties"]["options"]["type"] == "array"
+
+    with pytest.raises(AskUserInterrupt) as exc:
+        asyncio.run(tool.execute("Continue?", options=["Yes", "No"]))
+
+    assert exc.value.question == "Continue?"
+    assert exc.value.options == ["Yes", "No"]
+
+
+@pytest.mark.asyncio
+async def test_runner_pauses_on_ask_user_without_executing_later_tools():
+    @tool_parameters(tool_parameters_schema(required=[]))
+    class LaterTool(Tool):
+        called = False
+
+        @property
+        def name(self) -> str:
+            return "later"
+
+        @property
+        def description(self) -> str:
+            return "Should not run after ask_user pauses the turn."
+
+        async def execute(self, **kwargs):
+            self.called = True
+            return "later result"
+
+    async def chat_with_retry(**kwargs):
+        return LLMResponse(
+            content="",
+            finish_reason="tool_calls",
+            tool_calls=[
+                ToolCallRequest(
+                    id="call_ask",
+                    name="ask_user",
+                    arguments={"question": "Install this package?", "options": ["Yes", "No"]},
+                ),
+                ToolCallRequest(id="call_later", name="later", arguments={}),
+            ],
+        )
+
+    later = LaterTool()
+    tools = ToolRegistry()
+    tools.register(AskUserTool())
+    tools.register(later)
+
+    result = await AgentRunner(_make_provider(chat_with_retry)).run(AgentRunSpec(
+        initial_messages=[{"role": "user", "content": "continue"}],
+        tools=tools,
+        model="test-model",
+        max_iterations=3,
+        max_tool_result_chars=16_000,
+        concurrent_tools=True,
+    ))
+
+    assert result.stop_reason == "ask_user"
+    assert result.final_content == "Install this package?"
+    assert "ask_user" in result.tools_used
+    assert later.called is False
+    assert result.messages[-1]["role"] == "assistant"
+    assert result.messages[-1]["tool_calls"][0]["function"]["name"] == "ask_user"
+    assert not any(message.get("name") == "ask_user" for message in result.messages)
+
+
+@pytest.mark.asyncio
+async def test_ask_user_sends_buttons_and_resumes_with_next_message(tmp_path):
+    seen_messages: list[list[dict]] = []
+
+    async def chat_with_retry(**kwargs):
+        seen_messages.append(kwargs["messages"])
+        if len(seen_messages) == 1:
+            return LLMResponse(
+                content="",
+                finish_reason="tool_calls",
+                tool_calls=[
+                    ToolCallRequest(
+                        id="call_ask",
+                        name="ask_user",
+                        arguments={
+                            "question": "Install the optional package?",
+                            "options": ["Install", "Skip"],
+                        },
+                    )
+                ],
+            )
+        return LLMResponse(content="Skipped install.", usage={})
+
+    loop = AgentLoop(
+        bus=MessageBus(),
+        provider=_make_provider(chat_with_retry),
+        workspace=tmp_path,
+        model="test-model",
+    )
+
+    first = await loop._process_message(
+        InboundMessage(channel="cli", sender_id="user", chat_id="direct", content="set it up")
+    )
+
+    assert first is not None
+    assert first.content == "Install the optional package?"
+    assert first.buttons == [["Install", "Skip"]]
+
+    session = loop.sessions.get_or_create("cli:direct")
+    assert any(message.get("role") == "assistant" and message.get("tool_calls") for message in session.messages)
+    assert not any(message.get("role") == "tool" and message.get("name") == "ask_user" for message in session.messages)
+
+    second = await loop._process_message(
+        InboundMessage(channel="cli", sender_id="user", chat_id="direct", content="Skip")
+    )
+
+    assert second is not None
+    assert second.content == "Skipped install."
+    assert any(
+        message.get("role") == "tool"
+        and message.get("name") == "ask_user"
+        and message.get("content") == "Skip"
+        for message in seen_messages[-1]
+    )
+    assert not any(
+        message.get("role") == "user" and message.get("content") == "Skip"
+        for message in session.messages
+    )
+    assert any(
+        message.get("role") == "tool"
+        and message.get("name") == "ask_user"
+        and message.get("content") == "Skip"
+        for message in session.messages
+    )