feat: add comedian agent and datetime tool, update README

Author: danishi

README.md

@@ -50,6 +50,18 @@ requirements.txt     # Python dependencies
    ```
 4. Use a tunneling tool like `ngrok` to expose `http://localhost:8080/slack/events` to Slack during development.
 
+### Optional: Use the ADK Web Development UI
+
+The Agent Development Kit includes a built-in web-based Development UI that you can run locally. It's a powerful tool for testing, debugging, and interacting with your agent during development. It provides a chat interface to send messages to your agent and inspect the results.
+
+1.  **Start the ADK web server:**
+    ```bash
+    adk web
+    ```
+
+2.  **Interact with your agent:**
+    Open the local URL (usually `http://127.0.0.1:8000`) in your browser to use the Development UI.
+
 ## Slack App Configuration
 1. Create a new Slack app at <https://api.slack.com/apps>.
 2. Under **OAuth & Permissions**, add the following Bot Token scopes:

app/__init__.py

@@ -0,0 +1,3 @@
+from .main import root_agent
+
+__all__ = ["root_agent"]

app/agents/comedian.py

@@ -0,0 +1,49 @@
+import os
+from google.adk import Agent
+from google.adk.planners import BuiltInPlanner
+from google.genai import types
+from dotenv import load_dotenv
+
+load_dotenv()
+MODEL_NAME = os.environ.get("MODEL_NAME", "gemini-2.5-flash")
+
+comedian_agent = Agent(
+    model=MODEL_NAME,
+    name="comedian_agent",
+    planner=BuiltInPlanner(
+        thinking_config=types.ThinkingConfig(
+            thinking_budget=512,
+        )
+    ),
+    description=(
+        "Use this agent to generate witty, humorous, and lighthearted responses."
+        "It transforms any input into a comedic remark, pun, or short bit while staying safe and engaging."
+    ),
+    instruction="""
+**Role & Persona**
+You are a professional comedian agent. Your job is to entertain through clever, witty, and humorous remarks. You blend stand-up style comedy, observational humor, and playful exaggeration, while keeping your tone light, engaging, and audience-friendly.
+
+**Guidelines**
+
+* Always aim for humor: jokes, witty comments, playful exaggerations, or puns.
+* Use everyday situations, pop culture, or absurd twists to make responses fun.
+* Keep the humor lighthearted and safe; avoid offensive, harmful, or discriminatory jokes.
+* If asked about serious topics, still bring a humorous spin while respecting the sensitivity of the subject.
+* Feel free to break the “fourth wall” (self-aware humor about being an AI comedian).
+
+**Style**
+
+* Short punchlines and snappy one-liners work best.
+* Occasionally build up a mini “bit” (setup → punchline).
+* Use conversational humor as if you were on stage talking to a live audience.
+
+**Examples**
+
+* User: *Tell me about AI.*
+  Comedian Agent: “AI is like a teenager—knows everything, but still asks you for Wi-Fi.”
+* User: *What’s the weather like?*
+  Comedian Agent: “It’s so hot outside, my ice cream applied for life insurance.”
+* User: *Give me motivation.*
+  Comedian Agent: “Remember: even a broken clock is right twice a day… and that clock still gets more rest than you.”
+""",
+)

app/main.py

@@ -14,7 +14,10 @@
 from google.adk.agents import Agent
 from google.adk.events.event import Event
 from google.adk.runners import InMemoryRunner
-from google.adk.tools import google_search
+# from google.adk.tools import google_search
+
+from .agents.comedian import comedian_agent
+from .tools.get_current_datetime import get_current_datetime
 
 # Environment variables
 load_dotenv()
@@ -98,7 +101,8 @@ async def _populate_session_from_thread(
 root_agent = Agent(
     name="slack_bot_agent",
     model=MODEL_NAME,
-    instruction="""You are acting as a Slack Bot. All your responses must be formatted using Slack-compatible Markdown.
+    instruction="""
+You are acting as a Slack Bot. All your responses must be formatted using Slack-compatible Markdown.
 
 ### Formatting Rules
 - **Headings / emphasis**: Use `*bold*` for section titles or important words.
@@ -109,12 +113,18 @@ async def _populate_session_from_thread(
 - Blockquotes: Use `>` at the beginning of a line.
 
 Always structure your response clearly, using these rules so it renders correctly in Slack.""",
-    tools=[google_search],
+    tools=[
+        get_current_datetime,
+    ],
+    sub_agents=[
+        comedian_agent,
+    ],
 )
 
 runner = InMemoryRunner(agent=root_agent, app_name=APP_NAME)
 session_service = runner.session_service
 
+
 @bolt_app.event("app_mention")
 async def handle_mention(body, say, client, logger, ack):
     # Ack as soon as possible to avoid Slack retries that can cause duplicated responses
@@ -164,6 +174,7 @@ async def handle_mention(body, say, client, logger, ack):
         thread_ts=thread_ts,
     )
 
+
 @fastapi_app.post("/slack/events")
 async def slack_events(req: Request):
     retry_num = req.headers.get("x-slack-retry-num")
@@ -181,6 +192,7 @@ async def slack_events(req: Request):
         return JSONResponse(status_code=403, content={"error": f"{team_id}:workspace_not_allowed"})
     return await handler.handle(req)
 
+
 @fastapi_app.get("/")
 async def root():
     return {"status": "ok"}

app/tools/get_current_datetime.py

@@ -0,0 +1,19 @@
+import datetime
+import pytz
+from google.adk.tools import ToolContext
+
+
+async def get_current_datetime(timezone: str, tool_context: ToolContext):
+    """Gets the current date and time for a given timezone.
+
+    Args:
+        timezone: The timezone to get the current time from. Defaults to "America/Los_Angeles".
+    """
+    if not timezone:
+        timezone = "America/Los_Angeles"
+    try:
+        tz = pytz.timezone(timezone)
+        now = datetime.datetime.now(tz).strftime("%Y-%m-%d %H:%M:%S")
+        return {"current_datetime": now}
+    except pytz.UnknownTimeZoneError:
+        return {"error": f"Unknown timezone: {timezone}"}

requirements.txt

@@ -6,3 +6,4 @@ google-adk>=1.12.0
 httpx>=0.27.0
 python-dotenv>=1.0.0
 aiohttp>=3.9
+pytz