Happy path
The happy path helps to understand how a feature should work when everything goes well. It is usually the first path described in acceptance criteria, use cases, specs, and tests.
The problem arises when the team only designs or tests that path.
Example
For an email change:
- the user is authenticated;
- enters a valid email;
- confirms the change;
- the system updates the data;
- sends a verification to the new email.
That is the happy path. But negative scenarios and edge cases are also needed.
What's missing if there's only a happy path
- Invalid email.
- Email already used by another account.
- User without permissions.
- Expired session.
- Connection error.
- Email service down.
- Empty field.
- Repeated attempts.
- Security rules not met.
Many defects appear precisely outside the ideal path.
Relationship with acceptance criteria
A good set of acceptance criteria includes:
- happy path;
- negative scenarios;
- edge cases;
- business rules;
- preconditions;
- observable outcome.
The happy path is necessary, but not sufficient.
Happy path and AI
AI tends to produce solutions that cover the main flow unless it is explicitly asked for errors, limits, and exceptions. That is why, when writing prompts or specs, it is advisable to clearly request:
- negative scenarios;
- edge cases;
- permissions;
- inconsistent states;
- external errors;
- validations;
- recovery.
Common mistake
Testing only that everything goes well. The happy path shows that the ideal flow can work, but not that the feature is robust. An incomplete story or spec leaves undefined what happens when the data is invalid, permissions are missing, or the system enters an error state.
Resources
🏦 IA aplicada al trabajo ágil [AI Applied to Agile Work, in Spanish]Skill Arena · Scrum Manager
📄 Historias de usuario v.5.0 [User Stories v.5.0, in Spanish]Free download · Scrum Manager · Jan 2026
See also
Want to advance in agility? You can search for calls for courses and exams, or go at your own pace by becoming a member of the Agile Club. This membership includes exclusive resources, e-learning classrooms, and access to Skill Arena: a space to practice and measure your agile skills at your own pace.