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Teaching deck · portfolio edition · 29 Oct 2026

Agentic AI

From software that answers questions,
to software that gets things done.

Before we start

Where you may already encounter AI

Predictive text

suggests a possible next word

Feed ranking

orders items you might find relevant

Fraud detection

flags suspicious payment patterns

Traffic estimates

estimates journey times from signals

Recommendations

suggests something to watch next

Spam filtering

classifies messages using learned signals

One approach: machine learning

Normally, you write the rules

Normal program

if "lottery" in subject:
    mark_as_spam()
if "winner" in subject:
    mark_as_spam()
# ...and 400 more rules
# that spammers work around
# by writing "w1nner"

Learned model

Train a model on emails labelled spam or not spam.

It learns statistical patterns that can help classify new messages. Those predictions can still be wrong.

The one-line version

Machine learning uses examples to learn patterns. AI also includes approaches based on explicit rules.

But notice something

Many models are specialised

Spam model
classifies messages

Face matcher
compares face features

Traffic model
estimates travel time

Fraud model
scores payment risk

A task-specific model does not automatically generalise to unrelated work.

Then something changed

One model.
Many language tasks.

A starting point for language models

Finish this sentence

“The canteen is always ______ during lunch break.”

A language model generates tokens using patterns learned during training and the context it receives. The next token is selected from a probability distribution.

Next-token generation is the starting point, not a complete account of training, reasoning or tool use.

One piece of vocabulary

Tokens

Text is represented as tokens: common character sequences, sometimes whole words or word pieces.

“ tokenization” → token + ization

The split depends on the model and language.

Why you should care

Token counts affect context limits and usage costs. Tools and repeated model calls can add latency and other charges.

But there's a problem

A fictional attendance question

QUESTION

How many attendance days am I short for Data Structures?

ILLUSTRATIVE, UNSUPPORTED ANSWER

You are short by 6 days. As per Academic Regulation R-2021, Clause 8.4, submit a condonation form within 15 days.

Why this answer is unsupported

The needed evidence is missing

No authorised record

A model does not automatically have access to your private attendance record

Knowledge limits

Training has a cutoff. Current information needs an appropriate source or tool

Unsupported detail

A fluent answer or a plausible citation does not establish that a claim is true

Add relevant evidence

Give it the document first

Your question Search docs 3 paragraphs Model Answer this is called RAG, retrieval augmented generation

Retrieve relevant passages and ask for a grounded answer. Check the cited passage: retrieval can miss evidence and does not guarantee correctness.

Same fictional question, with a fictional rulebook

A grounded answer

I don't have your attendance count. In this illustrative rulebook, 75% is required, and below 65% cannot be condoned, so I'd need your actual figure to tell you.

Separate what the source supports from what is still unknown.

In this text-only example

It still only
talks.

Without a connected booking tool

“Book me a lab slot for Thursday”

ILLUSTRATIVE TEXT-ONLY RESPONSE

“Sure! Here's how you can book a lab slot: log in to the portal, go to Lab Booking, select Thursday…”

Helpful. But you still have to do it.

The leap

Give it tools

Without tools

“Here's how you can book a slot…”

It writes.

With tools

→ check_availability("Thu")
→ confirm_booking("Thu", "2 PM")
→ book_slot("Thu", "2 PM")

The system can act within its permissions.

How that actually works

A tool call crosses a system boundary

  • The application defines available tools and their parameters
  • The model can propose a call, such as book_slot("Thu","2 PM")
  • For a custom function, your application validates permission and arguments, then executes it
  • The result returns to the model. Hosted tools execute in the provider’s runtime

A proposed call is not proof that the action was allowed, executed or successful.

And now it has a name

Model + tools + a control loop

In this talk, an agent uses model decisions to choose steps toward a goal. A fixed workflow can also call tools without being agentic.

Where we are

A working model, not a universal taxonomy

1 · Chatbot generates a response 2 · RAG retrieves supporting context 3 · Agent uses tools in a control loop 4 · Agentic plans and adapts within limits today's topic ↗

The real question

What makes it
agentic?

An analogy that works

Two people in your class

The one who follows instructions

“Book the seminar hall for Friday.”

Hall is booked. It's already taken? They come back and tell you it's taken. Task over.

Your class representative

“Book the seminar hall for Friday.”

Taken? Looks for another room on Friday, checks capacity and asks: “AV room 3–5 PM, is that okay?” A different day needs agreement.

Same instruction. One executes. One pursues the goal.

The five ingredients

Five properties to design and test

  • A goal and boundaries, including what the system may change
  • It selects steps, using a model within an application-controlled loop
  • It uses permitted tools, with validated arguments and results
  • It observes and adapts, looks at what happened, changes the plan
  • It needs stopping rules, limits, failure handling and human escalation

The loop that makes it possible

Think → Act → Look → repeat

Think Act Observe Done? not yet, go again yes → answer

Illustrative run · event summary

“Find me a slot to demo my project this week”

Think    Need a free hall, and everyone's free time.
Act      check_hall_availability("this week")
Look     Only Fri 3–5 PM is free.
Think    Now check if the team is free then.
Act      read_calendar(team, "Fri 3–5 PM")
Look     Two members have a lab till 4.
Think    Won't work. Try the AV room instead.
Act      check_hall_availability("AV room")
Look     Free Fri 4–6 PM. Everyone available.
Think    Ask before committing the booking and notification.
Act      confirm_permission("book and notify") → approved
Act      book("AV room","Fri 4-6"); notify(team)
Done     Verify booking receipt and notification result.

The important bit

Nobody told it to try the AV room

It hit a wall, and changed its own plan.

Adaptive planning is useful when it preserves the user’s constraints, requests required approval and checks the outcome.

Common application patterns

Where you'll meet it

Coding agents

Can inspect a repository, propose edits and run tests within granted access; review remains part of the workflow

Deep research

Can search sources, follow leads and draft a report; citations and conclusions still need checking

Support systems

Can inspect a ticket, propose a reply or perform permitted actions; sensitive changes may require approval

Be honest about it

Where it goes wrong

It loops forever

Retries the same failing step, or decides a bad result was good enough

Every step costs

Model calls, tools and retries add cost and latency. One workflow step does not imply one API call

Mistakes compound

A wrong step 2 quietly poisons every step after it

Design limits for steps, time and spend. Validate tool boundaries, define approvals and provide a safe failure path.

The question I want you to ask

How would you know if your agent is any good?

If it worked in your demo three times, you have proved almost nothing.

What to measure

Four things

  • Did it finish the task? Not "did it sound good", did the slot actually get booked
  • Was the path appropriate? Track tool calls, retries and unnecessary actions alongside quality
  • Did it do anything it shouldn't? Wrong booking, wrong email, wrong refund
  • Cost and time per task, the numbers that decide if it ever ships

Define success criteria. Use realistic, edge and failure cases; repeat runs, compare changes and keep held-out cases. A small demo is a starting point.

Build one

One bounded project to start

Rulebook bot

Use an authorised handbook. Retrieve relevant clauses, cite them and test unsupported questions.

Placement prep agent

Use a job description and your notes to draft a study plan. Confirm before adding calendar events.

Mess menu agent

Compare a menu with stated preferences. Add notifications only with explicit permission.

Start with one bounded task and clear tests. Add tools only when the task needs them; more tools do not by themselves make a system agentic.

Further reading · checked 29 Oct 2026

Primary references

A revised teaching edition. The attendance scenario, policies and booking trace are illustrative. Terminology and implementations vary.

The last few years taught computers to answer.

The next few are teaching them to finish the job.

Thank you

Questions

ML = learns patterns from examples LLM = predicts the next token RAG = retrieves supporting context Agent = model + tools + control loop Agentic = adapts within defined limits
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