Intro to Agentic AI

From Chatting to Doing

NERSC Agentic AI Hackathon

Pengfei Ding
Data Science Engagement Group

Feb 5th, 2026

What Is Agentic AI

High Level

What Is Agentic AI

Agentic AI is an approach where AI systems don’t just answer questions; they plan, take actions, and iterate toward a goal.

Instead of a single prompt-response, an agent can:

  • Understand a task or objective
  • Break it into steps
  • Use tools or data sources
  • Check results and adjust

This shifts AI from “chatting” to “doing,” while keeping humans in control.

Use Cases

Where Agents Shine

Use Cases

Where agentic AI shines is in multi-step, tool-using workflows:

  • Research assistants that gather, compare, and summarize sources
  • Customer support bots that diagnose issues and run internal checks
  • Dev copilots that run tests, read logs, and apply fixes
  • Data analysis agents that query databases, build charts, and explain results
  • IT / DevOps helpers that inspect systems, open tickets, and update dashboards
  • Personal productivity workflows (email drafting, planning, knowledge retrieval)

Building Blocks

Overview

Building Blocks (Overview)

Agentic AI systems typically combine these blocks:

  • LLM: The reasoning and language engine
  • User Interface: Where users interact and guide tasks
  • Tools: Functions the AI can call (web search, code execution, APIs)
  • Memory / Knowledge: Context beyond the chat (documents, databases)
  • Orchestration: Logic that manages steps, retries, and safety checks

Chatbot-Style Agent

Core Components

LLM Options

Commercial cloud:

  • OpenAI (GPT-4/5 via API, Codex)
  • Anthropic (Claude)
  • Google (Gemini)

On-prem / locally hosted:

  • Ollama (easy local model hosting)
  • vLLM (high-throughput model serving)
  • LM Studio, llama.cpp (local inference)

User Interface

Where the agent “lives” for users:

  • Web UI: LibreChat, Open WebUI
  • Client apps: Claude, Cursor
  • CLI tools: Aider, Codex CLI

Integrated Tools (Inside the UI)

Tools allow the chatbot to act:

  • Web search
  • Running bash commands
  • Fetching data from APIs
  • Querying internal systems
  • File operations and code edits

Beyond Basic Chat

RAG, MCP, and Skills

VectorDB + Embeddings (RAG) — Concepts (I)

RAG (Retrieval-Augmented Generation) adds external knowledge to a chatbot by retrieving relevant documents and feeding them into the prompt.

What is an embedding?

  • A numeric vector that represents the meaning of text
  • Similar meanings end up close together in a high-dimensional space
  • Example: “How do I reset my password?” and “Forgot my password” are near each other
  • Typical dimensions range from a few hundred to several thousand values
  • Embeddings are produced by a model trained to place semantically related text nearby

VectorDB + Embeddings (RAG) — Concepts (II)

What is a VectorDB?

  • Stores embeddings and supports fast similarity search
  • Optimized for “find the closest vectors” rather than exact keyword match
  • Examples: ChromaDB, FAISS, Weaviate
  • Uses vector indexes such as HNSW, IVF, or PQ to scale to millions of items

VectorDB + Embeddings (RAG) — How It Works (I)

Similarity search in vector space

  • Convert the user query into an embedding
  • Compare that embedding to stored vectors using a distance metric
    • Cosine similarity (angle between vectors)
    • Euclidean distance
    • Dot product
  • Return the closest matches as “retrieved context”

VectorDB + Embeddings (RAG) — How It Works (II)

Pipeline summary

  1. Chunk documents
  2. Embed chunks
  3. Store in VectorDB
  4. Embed user query
  5. Retrieve top-k chunks
  6. Generate answer grounded in retrieved text

MCP Servers — What and Why

MCP (Model Context Protocol) is a standard way to expose tools, data sources, and workflows to LLMs.

Why MCP matters

  • Decouples tool logic from the chatbot UI
  • Makes tools reusable across multiple agents and clients
  • Enables consistent tool schemas and permissions

MCP Servers — JSON-RPC

JSON-RPC in a nutshell

  • A lightweight protocol where a client sends a JSON request:
    • method: the function name
    • params: input arguments
    • id: request identifier
  • The server returns JSON with result or error

MCP vs OpenAPI + Example

MCP server vs OpenAPI-compliant API server

  • OpenAPI:
    • REST-style endpoints
    • Designed for human-written integrations
    • Strong for CRUD and public APIs
  • MCP:
    • JSON-RPC methods
    • Designed for LLM tool invocation
    • Emphasizes tool discovery, schemas, and safety boundaries
  • MCP tool schemas are optimized for LLM function-calling patterns
  • OpenAPI focuses on HTTP resources and verbs; MCP focuses on callable tools

Minimal MCP tool definition (example)

{
  "name": "search_docs",
  "description": "Search internal docs and return top matches.",
  "inputSchema": {
    "type": "object",
    "properties": {
      "query": { "type": "string" },
      "top_k": { "type": "integer", "default": 5 }
    },
    "required": ["query"]
  }
}

Agents and Agent Skills — An Example (I)

Scenario: “Run a data quality check and summarize findings.”

Agent behavior:

  1. Read instructions
  2. Call a tool (skill) to run a Python script
  3. Parse results
  4. Summarize in plain language

Agents and Agent Skills — An Example (II)

Skill: dq_check

  • Implements a predefined Python script
  • Allows different modes via options
  • Returns structured output for the agent to interpret
  • Uses exit codes to indicate success or failure

Agent Skill Design With Options (I)

Example skill interface (conceptual)

python dq_check.py  --input data.csv \
  --mode full --threshold 0.98 --report json

Options explained

  • --mode quick: basic missing-value scan
  • --mode full: includes schema, duplicates, and distribution checks
  • --threshold 0.98: minimum acceptable completeness ratio
  • --report json|md|html: output format for downstream use
  • --sample: limit rows for faster checks on large files

Agent Skill Design With Options (II)

Why this matters

  • The agent can select the right mode based on user intent
  • Skills are reusable across projects
  • Structured outputs make agent reasoning safer and more consistent
  • Well-designed options reduce hallucination by constraining behavior

Closing Thought

Capability + Control

Closing Thought

Agentic AI is about capability + control:

  • Capability comes from tools, memory, and orchestration
  • Control comes from clear boundaries, permissions, and human oversight

When done well, it turns a chatbot into a reliable collaborator.