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Skills / Product-design

Hooked Model

The Hook is an experience designed to connect the user's problem to the company's solution with enough frequency to form a habit.

The Hooked Model is Nir Eyal's four-phase framework for building habit-forming products: Trigger, Action, Variable Reward, and Investment. Each pass through the cycle strengthens the user's automatic behavior until the product becomes part of their routine. Designed for product managers, founders, and UX designers who want to build genuine retention — not just re-engagement campaigns.

By Nir Eyal · Free
Specimen 01 · Live diagnosisHooked Model
Input

“It's a B2B SaaS tool for engineers — a code review platform. We get good activation but terrible retention after 30 days. Users try it, then stop…”

Diagnosis
I'll walk your product through all four phases of the Hook cycle and build out a Hook Canvas for you.
Full transcript ↓
Calibrated referenceagent-skills.ai
The gap

Design products users return to automatically — without paid re-engagement

The Hooked Model is a strictly sequenced four-phase loop. The Trigger phase distinguishes external triggers (notifications, icons, word-of-mouth) from internal triggers — the emotional states (boredom, loneliness, anxiety) that the product ultimately comes to relieve. The Action phase applies Fogg's Behavior Model (Behavior = Motivation × Ability × Trigger) to strip the user's behavior to its minimum viable form, reducing friction across six simplicity factors. The Variable Reward phase, grounded in Skinnerian operant conditioning, sustains craving through unpredictable payoffs across three types: Rewards of the Tribe (social validation), Rewards of the Hunt (search and discovery), and Rewards of the Self (mastery and completion). The Investment phase has users deposit time, data, content, or social capital — loading the next trigger and storing value that makes the product more useful with every cycle. Supporting tools include the Habit Zone matrix (frequency vs. perceived utility), the Manipulation Matrix (a 2×2 ethical check), and the 5 Whys technique for uncovering the true internal trigger.

The problem

Most products struggle with retention not because of poor features, but because they never become habits — users try them once and drift away. Teams spend enormous budgets on re-engagement ads and push notifications when the real problem is that the product never connected to an internal trigger or invested users enough to make returning feel automatic. Without a deliberate Hook cycle, engagement is always rented.

The solution

Walk any product through the four-phase Hook cycle and emerge with a concrete Hook Canvas: a mapped internal trigger, a friction-minimized action, a designed variable reward, and investment mechanisms that load the next trigger — turning one-time users into returning ones by design.

You bring
  • A product, feature, or concept you want to make habit-forming
  • Your target user and the emotional state or pain point they experience
  • Your current onboarding or engagement flow (even roughly described)
  • Any ethical concerns or constraints you want to factor into the design
You get
  • A completed Hook Canvas mapping all four phases to your specific product
  • A 5 Whys internal trigger chain revealing the real emotional driver your product addresses
  • A friction audit scoring your Action phase against Fogg's six simplicity factors with specific reduction recommendations
  • A Manipulation Matrix assessment confirming whether your habit-forming design is ethical and sustainable
In action

Watch the methodology work.

Three specimens from a single real session: the same situation, unaided and calibrated, the full transcript, and the skill answering live in the channel where the work happens.

Fig.01The same situation, two ways
Specimens A · B
Specimen AVague
Unaided

“Your analytics show 60% of new users complete their first code review, but 30-day retention is under 15%. The team has tried weekly digest emails, Slack reminders, and a mobile app — but users still drift. Every sprint, growth proposes another re-engagement campaign. Nobody on the team can articulate why users would open the product on their own.”

×Vague — nothing concrete to act on.
Specimen BCalibrated
With Hooked Model

“After running the Hook cycle, you've identified that engineers' internal trigger is fear of being a bottleneck — not task completion. The Action phase is redesigned so engineers see their open reviews in under three seconds. A Tribe reward layer now surfaces team-visible acknowledgment when a review unblocks a PR. The Investment phase prompts engineers to follow teammates immediately after their first review, loading the next social-anxiety trigger automatically. Thirty-day retention climbs because the cycle closes — and your growth team stops paying for re-engagement that the product now handles itself.”

Specific, grounded, and ends with one clear next step.
Fig.02A real session, unedited
In-app · assistant
Hooked ModelClaude
Hooked Model
I'll walk your product through all four phases of the Hook cycle and build out a Hook Canvas for you. Before we start: what's the product or feature you want to make habit-forming, and who's the user you're designing for?
It's a B2B SaaS tool for engineers — a code review platform. We get good activation but terrible retention after 30 days. Users try it, then stop coming back.
That's a classic Hook gap — users activated but the cycle never closed. Let's start with the Trigger phase, because this is almost certainly where your retention problem begins. You're relying on external triggers (email reminders, Slack pings) but the product hasn't yet latched onto an internal trigger — an emotional state the engineer experiences that the product comes to relieve. Let me run a quick 5 Whys with you. Why does an engineer open your platform in the first place?
To review a pull request that someone assigned to them.
Good. Why do they feel compelled to do that review — what's the feeling if they don't? Is it guilt about blocking a teammate? Fear of being seen as a bottleneck? Anxiety about missing a bug that ships to prod? Keep going one level deeper — what's the emotional state underneath the assigned task?
Probably... fear of being the bottleneck. Nobody wants to be the person slowing down the team.
That's your internal trigger: fear of being a bottleneck — a specific social anxiety about professional standing. That's much more powerful than 'assigned PR.' Now your product needs to relieve that feeling, not just complete a task. This reshapes both your Action phase (the first behavior should be impossibly fast — show engineers their open reviews the instant they land) and your Variable Reward (this is a Rewards of the Tribe product: social standing, team approval, the visible signal that they're unblocking people). Are you surfacing any social metrics today — reviews completed, teammates unblocked, PRs shipped?
No, it's pretty utilitarian — just the PR queue. No social layer at all.
That's your retention gap in one sentence. The internal trigger is social anxiety, the reward type should be Tribe — but you're delivering a task list with no social signal. Let me build out the full Hook Canvas now. For the Investment phase, I'll also show you how to load the next trigger: the platform should prompt engineers to set notification preferences or follow specific teammates immediately after their first review is acknowledged — storing social capital that makes the next return feel obligatory rather than optional.
This makes so much sense. We've been thinking about retention as a notification problem but it's actually a reward design problem.
Reply to Hooked Model
What the skill is doing
01Hook Canvas Generation
02Internal Trigger Mapping (5 Whys)
03Action Phase Friction Audit
Fig.03The same skill, in the channel you already use
WhatsApp · live
9:41
HMHooked Modeltyping…
Messages are end-to-end encrypted. No one outside of this chat can read them.
Today
It's a B2B SaaS tool for engineers — a code review platform. We get good activation but terrible retention after 30 days. Users try it, then stop comi…9:14✓✓
I'll walk your product through all four phases of the Hook cycle and build out a Hook Canvas for you.9:14
Before we start: what's the product or feature you want to make habit-forming, and who's the user you're designing for?9:15
Message

The same skill, where the work happens.

No new app to learn. The methodology runs over the WhatsApp Business API, so the answer lands as a reply in the thread you’re already in — same rigour, zero context-switch.

Reads the situation, names the pattern, returns one concrete next move.
Delivered in seconds, inside a conversation that already exists.
Specimen · WhatsApp Business API · live
Capabilities

What it does, specifically.

Each capability is a distinct move drawn straight from the source methodology — not a generic assistant guessing.

CapabilityC-01

Hook Canvas Generation

Produces a structured four-phase analysis document covering Trigger, Action, Variable Reward, and Investment for a specific product. Each phase is populated with product-specific language, not generic advice. The canvas serves as both a design tool and a communication artifact for product teams.

Based on Eyal's Hook Canvas worksheet, which applies the same four-phase diagnostic to any product regardless of domain, as demonstrated through case studies of Instagram, Pinterest, Slack, and Twitter in 'Hooked.'
CapabilityC-02

Internal Trigger Mapping (5 Whys)

Uses a structured 5 Whys chain to move from a product's surface use case to the underlying emotional state driving behavior. The output names the specific internal trigger — boredom, fear of missing out, anxiety, loneliness — that the product is positioned to relieve.

Eyal adapts Toyota's 5 Whys technique specifically to identify internal triggers, arguing that 'the ultimate goal of a habit-forming product is to solve the user's pain by creating an association so that the user identifies the product as the source of relief.'
CapabilityC-03

Action Phase Friction Audit

Evaluates the user's core action against Fogg's six simplicity factors — time, money, physical effort, brain cycles, social deviance, and non-routine — and identifies which factors are creating unnecessary friction. Produces ranked reduction recommendations specific to the product's context.

Eyal integrates B.J. Fogg's Behavior Model (B = MAT) directly into the Action phase, stating that designers must 'identify what is making it difficult for the user to accomplish the intended action' across each simplicity dimension.
CapabilityC-04

Variable Reward Design

Identifies which of the three reward types — Tribe (social validation), Hunt (search and discovery), Self (mastery and completion) — is primary for a product, and diagnoses whether the reward is sufficiently variable to sustain craving. Recommends specific design patterns to introduce variability without eliminating user autonomy.

Based on Eyal's typology of variable rewards derived from Skinnerian operant conditioning research, with emphasis on his finding that rewards must preserve the user's sense of agency to avoid reactance and disengagement.
CapabilityC-05

Manipulation Matrix Ethics Review

Applies Eyal's 2×2 Manipulation Matrix — asking whether the designer uses the product themselves and whether the product materially improves users' lives — to classify the proposed design as Facilitator, Peddler, Entertainer, or Dealer. Surfaces specific dark-pattern risks and recommends ethical alternatives.

Eyal's Manipulation Matrix is a built-in ethical framework in 'Hooked,' designed to give product teams a structured way to audit habit-forming features before shipping and to avoid engineering compulsive use that harms users.
Tested

Graded before it shipped.

Every skill is scored against independent scenarios for methodology fidelity before it goes live — not vibes, a rubric.

What it produces
OutputD-01

Hook Canvas

A completed four-phase document mapping Trigger, Action, Variable Reward, and Investment for your product — with internal trigger named, action stripped to minimum viable form, reward type identified and variabilized, and investment mechanisms that preload the next cycle.

OutputD-02

Internal Trigger Chain

A 5 Whys drill-down diagram tracing from the stated product use case to the underlying emotional state — the real internal trigger your product is positioned to relieve. Includes implication for messaging and onboarding copy.

OutputD-03

Friction Audit Report

A scored assessment of your current Action phase against Fogg's six simplicity factors, with each factor rated and specific friction-reduction changes ranked by expected impact on conversion and habit formation.

OutputD-04

Manipulation Matrix Assessment

A 2×2 quadrant placement for your product's habit-forming design — Facilitator, Peddler, Entertainer, or Dealer — with specific ethical risk flags and recommended design modifications to stay in the Facilitator quadrant.

The source

Grounded in the original work.

Every answer traces back to a real source and the practitioner who wrote it — not a secondhand summary. Here is the source of record.

Source authorA-01

Nir Eyal

Nir Eyal is a behavioral design author and lecturer at the Stanford Graduate School of Business, where he has taught product psychology and consumer behavior. His 2014 book 'Hooked: How to Build Habit-Forming Products' became a foundational text in the product industry, adopted in curricula at Y Combinator, Stanford d.school, and MBA programs worldwide. His work synthesizes behavioral economics, B.J. Fogg's behavior model, and Skinnerian psychology into a single, actionable product design framework.

Status · Inspired by Nir Eyal’s work — not yet claimed. Are you Nir Eyal?
Primary sourceS-01

Hooked: How to Build Habit-Forming Products

by Nir Eyal

Stanford GSB lecturer; author of 'Hooked' (2014) and 'Indistractable' (2019); framework taught at Y Combinator and Stanford d.school.

Read the original ↗
Citationnirandfar.com
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At launchI want to run my product through the full Hook cycle and build a Hook Canvas. It's [describe your product] and the core user is [describe user]. We have an activation problem / retention problem / engagement problem — can we start with the Trigger phase and work through all four stages?