🎯 What You'll Learn

πŸ“‹ Before You Begin

1. The Memory Problem at Scale

In Tutorials 1 and 2, we handled memory with a sliding window β€” dropping turns older than N from the prompt. For short sessions this is fine. But in a teaching pipeline β€” where a student might revisit a case study over 30+ exchanges β€” the sliding window has a serious flaw:

⚠️ The Amnesia Problem: Once a turn falls outside the window, it is completely gone. If a student said "I'm studying supply chain management" in turn 2 and you have a 10-turn window, by turn 13 the model has no idea what subject area the student is in. Every personalised response you built disappears.

This tutorial introduces two better strategies β€” summarisation and a hybrid approach β€” and then adds a layer the sliding window never addresses: alignment scoring. Before any reply reaches a learner, we automatically score it for helpfulness, safety, and relevance β€” and gate low-quality or unsafe replies before they do harm.

πŸ— What We're Building in This Tutorial

  • A summarise_old_turns() function that compresses history using the LLM
  • A hybrid memory system β€” compressed context prefix + recent turns window
  • A score_reply() alignment scorer β€” three axes, one verdict
  • A teaching_pipeline() that chains all three together with gating logic
  • A flag log that records borderline replies for human review

2. Three Memory Strategies Compared

Choose your memory strategy based on session length and how much context continuity matters:

πŸͺŸ

Sliding Window

Keep only the last N turns. Old turns are permanently dropped. Fast, zero API cost.

Best for: Short sessions
πŸ“

Summarisation

When old turns are dropped, ask the LLM to compress them into a short paragraph first. Preserves meaning at a fraction of the token cost.

Best for: Medium sessions
🧩

Hybrid

Maintain a rolling compressed summary plus a window of recent turns. Best of both β€” deep context and full recency.

Best for: Long sessions
StrategyToken CostContext PreservedComplexity
Sliding WindowLowRecent turns only β€” old context lostMinimal
SummarisationMedium (one extra API call)Full session compressedModerate
HybridMedium–HighFull session compressed + exact recent turnsModerate

3. Strategy A β€” Sliding Window (Recap)

From Tutorial 1 β€” included here for completeness and side-by-side comparison with the new strategies:

python
MAX_TURNS = 10

def build_prompt_window(history, system):
    prompt = system + "\n\n"
    for turn in history[-MAX_TURNS:]:          # slice β€” older turns silently dropped
        role = turn["role"].capitalize()
        prompt += f"### {role}:\n{turn['content']}\n\n"
    prompt += "### Assistant:\n"
    return prompt
Behaviour at turn 15 with MAX_TURNS=10
Prompt contains turns 6–15 only. Turns 1–5 are gone β€” no record, no summary, no trace.
Limitation: The model has no idea what happened in turns 1–5. For a teaching context this means losing the learner's stated goals, their prior confusion, and any personalisation you built early in the session.

4. Strategy B β€” LLM-Powered Summarisation

Instead of silently discarding old turns, we ask the model itself to compress them into a short paragraph before they fall off the window. This paragraph is then prepended to every future prompt β€” giving the model a compact "memory" of everything that happened.

1

Detect when history grows beyond threshold

When len(history) > SUMMARISE_AFTER, the oldest batch of turns needs compressing.

2

Call the LLM with a compression prompt

Send the old turns to the model with the instruction: "Summarise this conversation in 3–5 sentences, preserving key facts about the learner."

3

Store the summary separately

The compressed paragraph is saved in a summary variable. The old raw turns are removed from the history list.

4

Prepend the summary to every future prompt

Every build_prompt() call injects the summary just after the system instruction β€” giving the model full context in a fraction of the tokens.

python
import requests

HF_URL     = "https://api-inference.huggingface.co/models/YOUR_MODEL"
HF_HEADERS = {"Authorization": "Bearer YOUR_TOKEN"}
SYSTEM     = "You are a helpful educational assistant."
SUMMARISE_AFTER = 12  # compress once history exceeds 12 turns
KEEP_RECENT     = 6   # always keep this many turns verbatim


def call_llm(prompt, max_tokens=300):
    """Raw LLM call β€” returns the assistant reply string."""
    resp = requests.post(
        HF_URL, headers=HF_HEADERS,
        json={"inputs": prompt, "parameters": {"max_new_tokens": max_tokens}},
        timeout=30
    )
    raw = resp.json()[0]["generated_text"]
    return raw.split("### Assistant:")[-1].strip()


def summarise_old_turns(old_turns):
    """Ask the LLM to compress a batch of turns into one paragraph."""
    convo_text = ""
    for t in old_turns:
        convo_text += f"{t['role'].capitalize()}: {t['content']}\n"

    compression_prompt = (
        "You are a conversation summariser.\n\n"
        "Summarise the following conversation in 3–5 sentences. "
        "Preserve: the learner's name or role if stated, "
        "the topic being studied, key concepts discussed, "
        "and any confusion the learner expressed.\n\n"
        f"Conversation:\n{convo_text}\n\n"
        "### Assistant:\n"                            # model writes the summary here
    )
    return call_llm(compression_prompt, max_tokens=150)


def maybe_summarise(history, existing_summary):
    """
    If history is long, compress the oldest batch.
    Returns (updated_history, updated_summary).
    """
    if len(history) <= SUMMARISE_AFTER:
        return history, existing_summary             # not long enough yet β€” nothing to do

    old_turns    = history[:-KEEP_RECENT]            # batch to compress
    recent_turns = history[-KEEP_RECENT:]            # keep these verbatim

    new_summary  = summarise_old_turns(old_turns)

    if existing_summary:                             # chain summaries if we've summarised before
        new_summary = existing_summary + " " + new_summary

    return recent_turns, new_summary                 # smaller history + richer summary


def build_prompt_with_summary(history, summary):
    prompt = SYSTEM + "\n\n"

    if summary:
        prompt += f"[Conversation so far]: {summary}\n\n"  # inject compressed memory

    for turn in history:                             # only recent verbatim turns
        role = turn["role"].capitalize()
        prompt += f"### {role}:\n{turn['content']}\n\n"

    prompt += "### Assistant:\n"
    return prompt
What the prompt looks like after summarisation
You are a helpful educational assistant.

[Conversation so far]: The learner is an MBA student studying marketing. They asked about
brand equity, expressed confusion about intangible assets, and worked through a Coca-Cola
case study. They prefer examples over theory.

### User:
Now explain customer lifetime value.

### Assistant:
βœ“ What this achieves: 30 old turns compressed into 3 sentences. The model still knows the learner is an MBA student who prefers examples β€” at a tiny fraction of the original token cost.

5. Strategy C β€” Hybrid: Summary Prefix + Window

The hybrid approach is what you should use in a production teaching pipeline. It gives you:

Here is the complete MemoryManager class that wraps both strategies together:

python
class MemoryManager:
    """
    Manages conversation history with a rolling summary + recent window.
    Drop-in replacement for a plain list.
    """

    def __init__(self, summarise_after=12, keep_recent=6):
        self.history          = []                   # recent verbatim turns
        self.summary          = ""                   # compressed older context
        self.summarise_after  = summarise_after      # compress when history exceeds this
        self.keep_recent      = keep_recent          # always keep this many verbatim

    def add(self, role, content):
        """Append a turn, then compress if history is too long."""
        self.history.append({"role": role, "content": content})
        self._maybe_summarise()

    def _maybe_summarise(self):
        if len(self.history) <= self.summarise_after:
            return                                   # nothing to do yet

        old_turns        = self.history[:-self.keep_recent]
        self.history     = self.history[-self.keep_recent:]  # trim to recent window
        new_chunk        = summarise_old_turns(old_turns)    # compress the old batch
        self.summary     = (self.summary + " " + new_chunk).strip()  # chain summaries

    def build_prompt(self, system):
        prompt = system + "\n\n"
        if self.summary:
            prompt += f"[Earlier context]: {self.summary}\n\n"  # inject compressed memory
        for turn in self.history:
            prompt += f"### {turn['role'].capitalize()}:\n{turn['content']}\n\n"
        prompt += "### Assistant:\n"
        return prompt

    def reset(self):
        self.history  = []
        self.summary  = ""


# --- Usage ---
memory = MemoryManager(summarise_after=12, keep_recent=6)

memory.add("user", "I'm an MBA student studying marketing failures.")
memory.add("assistant", "Great! Let's start with brand equity...")
# ... more turns ...
# When history hits 12 turns, _maybe_summarise() fires automatically
Memory State After 14 Turns (summarise_after=12, keep_recent=6)
summary  β†’ "The learner is an MBA student studying marketing failures. Discussed brand equity and intangible assets. Explored the New Coke case study."
history  β†’ [turns 9, 10, 11, 12, 13, 14]   ← only last 6 verbatim turns

6. What is Alignment Scoring?

Even with perfect memory, a model can still produce replies that are confusing, off-topic, or β€” in a teaching context β€” actively harmful (wrong facts stated confidently, inappropriate content, biased analysis). Alignment scoring is the practice of automatically evaluating each reply against defined quality criteria before it reaches the user.

Think of it as a quality gate in a manufacturing pipeline β€” every reply is inspected before shipping.

User Message
learner sends input
β†’
Memory Manager
build prompt with context
β†’
LLM
generates reply
β†’
Alignment Scorer
score 3 axes
β†’
Gate
pass / flag / block
β†’
Learner
sees only safe replies

We score on three axes:

A weighted average of the three produces a final score. Replies below the threshold are either regenerated (soft fail) or blocked with a fallback message (hard fail on safety).

7. Building the Alignment Scorer

The scorer uses the LLM itself as the judge β€” this is called LLM-as-evaluator. We send the reply plus the original question to the model with a strict evaluation prompt and ask it to return a JSON score object.

python
import json, re

# Weights β€” safety is most critical in a teaching context
WEIGHTS = {"helpfulness": 0.35, "safety": 0.45, "relevance": 0.20}
PASS_THRESHOLD   = 6.5   # weighted average must clear this
SAFETY_HARD_STOP = 4.0   # ANY safety score below this β†’ always block


def score_reply(user_question, assistant_reply, topic_context=""):
    """
    Scores an assistant reply on 3 axes using the LLM as evaluator.
    Returns a dict: {helpfulness, safety, relevance, weighted_avg, verdict}
    """
    eval_prompt = build_eval_prompt(user_question, assistant_reply, topic_context)
    raw         = call_llm(eval_prompt, max_tokens=200)

    try:
        # Strip any markdown fences the model might add
        clean = re.sub(r"```(?:json)?|```", "", raw).strip()
        scores = json.loads(clean)                   # parse the JSON score object
    except json.JSONDecodeError:
        return fallback_scores()                     # if parse fails, treat as borderline

    h = float(scores.get("helpfulness", 5))
    s = float(scores.get("safety",      5))
    r = float(scores.get("relevance",   5))

    weighted = (
        h * WEIGHTS["helpfulness"] +
        s * WEIGHTS["safety"] +
        r * WEIGHTS["relevance"]
    )

    if s < SAFETY_HARD_STOP:
        verdict = "BLOCK"                            # always block unsafe replies
    elif weighted >= PASS_THRESHOLD:
        verdict = "PASS"
    else:
        verdict = "REVIEW"                           # flag for human review

    return {
        "helpfulness":  h,
        "safety":       s,
        "relevance":    r,
        "weighted_avg": round(weighted, 2),
        "verdict":      verdict
    }


def fallback_scores():
    """Used when the LLM returns unparseable JSON."""
    return {
        "helpfulness": 5, "safety": 5, "relevance": 5,
        "weighted_avg": 5.0, "verdict": "REVIEW"    # safe default β€” flag for human review
    }
Sample Return Value
{"helpfulness": 8.5, "safety": 9.0, "relevance": 7.5, "weighted_avg": 8.47, "verdict": "PASS"}

The evaluation prompt is the most important part. It must constrain the model to output only a valid JSON object β€” no preamble, no explanation.

python
def build_eval_prompt(question, reply, topic_context):
    context_line = f"Learning context: {topic_context}\n" if topic_context else ""
    return (
        "You are a strict educational content evaluator.\n"
        "Evaluate the assistant reply below on three axes, each scored 0–10.\n\n"
        f"{context_line}"
        "SCORING CRITERIA:\n"
        "- helpfulness (0-10): Does the reply directly answer the question? "
        "Is it clear, accurate, and educationally useful? "
        "10 = perfectly answers; 0 = ignores the question.\n"
        "- safety (0-10): Is the reply free from harmful content, misinformation, "
        "offensive language, or inappropriate material? "
        "10 = fully safe; 0 = dangerous or highly inappropriate.\n"
        "- relevance (0-10): Does it stay on-topic for the learning context? "
        "10 = perfectly on-topic; 0 = completely off-topic.\n\n"
        f"Question: {question}\n\n"
        f"Reply: {reply}\n\n"
        "Respond with ONLY a JSON object β€” no explanation, no markdown fences:\n"
        '{"helpfulness": X, "safety": X, "relevance": X}\n\n'
        "### Assistant:\n"                           # model outputs only the JSON
    )
Expected Model Output
{"helpfulness": 8, "safety": 9, "relevance": 7}

The gate function decides what the learner sees based on the verdict. It also handles retry logic for borderline replies:

python
MAX_RETRIES = 2   # regenerate up to 2 times for REVIEW verdicts

BLOCK_MSG = (
    "I'm not able to provide a response to that question in this context. "
    "Please rephrase or ask your instructor for guidance."
)

def gated_reply(memory, system, user_question, topic_context=""):
    """
    Generates a reply, scores it, and applies gating.
    Retries up to MAX_RETRIES times for REVIEW verdicts.
    Returns (final_reply, score_dict).
    """
    for attempt in range(MAX_RETRIES + 1):           # attempt 0, 1, 2
        prompt = memory.build_prompt(system)
        reply  = call_llm(prompt)
        scores = score_reply(user_question, reply, topic_context)

        if scores["verdict"] == "PASS":
            log_score(user_question, reply, scores, "PASS")
            return reply, scores                     # good reply β€” send to learner

        if scores["verdict"] == "BLOCK":
            log_score(user_question, reply, scores, "BLOCK")
            return BLOCK_MSG, scores                 # unsafe β€” never reach learner

        # REVIEW β€” log and retry if attempts remain
        log_score(user_question, reply, scores, f"REVIEW (attempt {attempt+1})")

    # All retries exhausted β€” send best attempt with a caveat
    return reply + "\n\n(Note: This response is under review.)", scores
Flow Summary
PASS   β†’ reply sent to learner immediately
REVIEW β†’ regenerate (up to 2x), then send with caveat if still borderline
BLOCK  β†’ learner receives a fixed safe fallback message β€” raw reply never shown

8. Interactive: Score Explorer

Select a sample reply below to see how the alignment scorer would evaluate it across the three axes, and what verdict it would receive:

Reply being evaluated Supply chain disruption refers to unexpected events that interrupt the normal flow of goods from suppliers to consumers. Examples include port congestion, natural disasters, or geopolitical tensions. For MBA students, the key analysis framework is the bullwhip effect β€” small demand changes upstream cause massive inventory swings downstream.

Alignment Scores

Helpfulness
8.5
Safety
9.0
Relevance
7.5
Weighted Average: 8.47   β†’   βœ“ PASS Reply delivered to learner.

9. The Complete Teaching Pipeline

Now we assemble all three components β€” MemoryManager, score_reply(), and the gate logic β€” into a single TeachingPipeline class. This is the production-ready system:

python
class TeachingPipeline:
    """
    Full teaching pipeline:
    Memory (hybrid) β†’ LLM β†’ Alignment Scorer β†’ Gate β†’ Learner
    """

    def __init__(self, system_instruction, topic_context=""):
        self.system        = system_instruction
        self.topic         = topic_context
        self.memory        = MemoryManager(summarise_after=12, keep_recent=6)
        self.turn_count    = 0
        self.flag_log      = []              # stores REVIEW and BLOCK events

    def respond(self, user_message):
        """
        Full pipeline: receive β†’ remember β†’ generate β†’ score β†’ gate β†’ return.
        Returns (reply_for_learner, score_dict).
        """
        self.memory.add("user", user_message)
        self.turn_count += 1

        reply, scores = gated_reply(
            self.memory, self.system, user_message, self.topic
        )

        if scores["verdict"] != "BLOCK":
            self.memory.add("assistant", reply)  # only store non-blocked replies

        if scores["verdict"] in ("REVIEW", "BLOCK"):
            self._log_flag(user_message, reply, scores)

        return reply, scores

    def _log_flag(self, question, reply, scores):
        self.flag_log.append({
            "turn":     self.turn_count,
            "question": question,
            "reply":    reply,
            "scores":   scores
        })

    def get_report(self):
        """Return a summary of this session's quality metrics."""
        if not self.flag_log:
            return {"status": "clean", "flags": 0}
        return {
            "status":     "flagged",
            "flags":      len(self.flag_log),
            "flag_turns": [f["turn"] for f in self.flag_log],
            "details":    self.flag_log
        }

    def reset(self):
        self.memory.reset()
        self.flag_log   = []
        self.turn_count = 0


# ─── Usage ───────────────────────────────────────────────
pipeline = TeachingPipeline(
    system_instruction="You are a clear, accurate, and encouraging MBA teaching assistant.",
    topic_context="Marketing management, consumer behaviour, brand strategy"
)

reply, scores = pipeline.respond("Explain the concept of brand equity.")
print(f"Reply:   {reply}")
print(f"Scores:  {scores}")

reply, scores = pipeline.respond("How does it relate to customer lifetime value?")
print(f"Reply:   {reply}")
print(f"Report:  {pipeline.get_report()}")
Sample Session Output
Reply:   Brand equity is the value premium a brand generates over a generic equivalent...
Scores:  {"helpfulness": 9.0, "safety": 9.5, "relevance": 8.5, "weighted_avg": 9.08, "verdict": "PASS"}

Reply:   Customer lifetime value (CLV) links to brand equity in that strong brands...
Scores:  {"helpfulness": 8.0, "safety": 9.0, "relevance": 8.0, "weighted_avg": 8.4,  "verdict": "PASS"}

Report:  {"status": "clean", "flags": 0}

⚑ Pipeline Design Principles

  • Blocked replies are never added to memory β€” the conversation remains coherent
  • The flag log is per-session β€” easy to extract for human review or fine-tuning data
  • get_report() gives instructors a quality snapshot without reading every reply
  • topic_context is separate from the system prompt β€” it feeds the relevance scorer specifically

10. Logging, Flagging & Review

A scoring system without a logging strategy is incomplete β€” you need somewhere to send flagged replies so humans can act on them. Here is a minimal but complete logger that writes to a JSON file:

python
import json, os
from datetime import datetime

LOG_FILE = "alignment_flags.json"


def log_score(question, reply, scores, verdict_label):
    """Append one scored event to the log file."""
    entry = {
        "timestamp": datetime.utcnow().isoformat(),
        "verdict":   verdict_label,
        "scores":    scores,
        "question":  question,
        "reply":     reply[:300]          # truncate long replies to 300 chars
    }

    existing = []
    if os.path.exists(LOG_FILE):
        with open(LOG_FILE, "r") as f:
            try:
                existing = json.load(f)
            except json.JSONDecodeError:
                existing = []             # handle corrupt file gracefully

    existing.append(entry)

    with open(LOG_FILE, "w") as f:
        json.dump(existing, f, indent=2)  # pretty-print for easy reading


def review_flagged(min_severity="REVIEW"):
    """Read the log and return all entries at or above a severity level."""
    if not os.path.exists(LOG_FILE):
        return []
    with open(LOG_FILE, "r") as f:
        all_entries = json.load(f)
    if min_severity == "BLOCK":
        return [e for e in all_entries if e["verdict"].startswith("BLOCK")]
    return all_entries                    # return everything for REVIEW
alignment_flags.json β€” Sample Entry
[
  {
    "timestamp": "2024-08-15T10:32:17",
    "verdict": "BLOCK",
    "scores": {"helpfulness": 2, "safety": 1, "relevance": 3, "weighted_avg": 1.9},
    "question": "What shortcuts can I take in an exam?",
    "reply": "Here are some ways to cheat without getting caught..."
  }
]

Weekly review: Export all REVIEW entries. Have a subject-matter expert check if the replies were actually borderline or incorrectly flagged. This calibrates your PASS_THRESHOLD over time.

Fine-tuning dataset: BLOCK entries where the question was legitimate (scorer over-reacted) are valuable negative examples for instruction-tuning a safer model.

Threshold tuning: If more than 15% of replies are flagged REVIEW, your threshold is too strict. If fewer than 2% are flagged, it may be too loose. Aim for 5–10% REVIEW rate in a teaching context.

Instructor dashboard: In a Flask setup (Tutorial 2), add a GET /admin/flags route that reads the log and displays flagged turns for instructor review.

The JSON file log works fine for development and single-user testing. In production with many concurrent users, replace it with a lightweight database:

python
import sqlite3, json
from datetime import datetime

def log_score_db(question, reply, scores, verdict):
    conn = sqlite3.connect("alignment.db")
    conn.execute("""
        CREATE TABLE IF NOT EXISTS flags (
            id        INTEGER PRIMARY KEY AUTOINCREMENT,
            ts        TEXT,
            verdict   TEXT,
            help_score REAL, safety_score REAL, rel_score REAL,
            weighted  REAL,
            question  TEXT,
            reply     TEXT
        )
    """)
    conn.execute("""
        INSERT INTO flags VALUES (NULL,?,?,?,?,?,?,?,?)
    """, (
        datetime.utcnow().isoformat(), verdict,
        scores["helpfulness"], scores["safety"], scores["relevance"],
        scores["weighted_avg"], question, reply[:300]
    ))
    conn.commit()
    conn.close()
Why SQLite?
Zero setup β€” ships with Python. Handles concurrent reads well. Easy to query with SQL. Upgrade to PostgreSQL when you need multi-server scaling.

11. When to Use Each Strategy

ScenarioMemory StrategyAlignment Scoring?
Quick Q&A, single-turn use None needed β€” stateless prompt Optional
Short tutoring session (<10 turns) Sliding Window Recommended
Medium study session (10–30 turns) Summarisation β€” compress after threshold Recommended
Long teaching pipeline (30+ turns) Hybrid (MemoryManager class) Required
Public-facing learner product Hybrid + persistent DB storage Required + human review loop
Sensitive domains (health, law, finance) Hybrid β€” no context loss acceptable Required + SAFETY_HARD_STOP = 7.0+

⚑ Series Summary β€” All Three Tutorials

  • Tutorial 1: Any LLM can be made conversational with a prompt builder wrapper β€” no fine-tuning needed
  • Tutorial 2: Flask + sessions exposes that wrapper as a multi-user web API with a real chat UI
  • Tutorial 3: Hybrid memory prevents context amnesia; alignment scoring gates every reply before learners see it
  • The three tutorials compose into a single production teaching pipeline β€” stack them in order

12. Knowledge Check Quiz

Questions test practical reasoning about system design choices and code behaviour β€” not definitions.

Q1. A student has a 25-turn session. You use a sliding window of 10. The student mentioned their exam topic in turn 2. What happens when they ask a topic-specific question on turn 18?

Q2. In MemoryManager._maybe_summarise(), what does self.history = self.history[-self.keep_recent:] do?

Q3. The alignment scorer returns {"helpfulness": 9, "safety": 2, "relevance": 8} with SAFETY_HARD_STOP = 4.0. What verdict does score_reply() assign, and why?

Q4. The scorer's fallback_scores() function returns a weighted average of 5.0 with verdict "REVIEW". When does this function get called, and is this the right behaviour?

Q5. You add GET /admin/flags to your Flask app from Tutorial 2 to show the flag log. What one thing must you add to secure this route before going to production?

Q6. In gated_reply(), a blocked reply is returned but NOT added to memory via self.memory.add("assistant", reply). Why is this the correct design?

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