| name | gherkin-authoring |
| description | Use when drafting, reviewing, or improving Gherkin, Cucumber scenarios, BDD acceptance criteria, feature examples, Scenario Outlines, Backgrounds, Rules, Doc Strings, Data Tables, tags, or Gherkin embedded in Markdown. |
Gherkin Authoring
Overview
Write Gherkin as executable examples of business behavior. Optimize for domain language, concrete examples, and observable outcomes; keep implementation and UI mechanics inside step definitions.
Scope
Use this for standalone .feature files and Gherkin embedded in Markdown or other prose. When Gherkin is inside a Markdown wrapper, review or rewrite only the Gherkin section unless the user asks for broader document edits. Preserve fences, headings, and surrounding prose. If the input includes Markdown around the Gherkin, return the Markdown wrapper with only the Gherkin block changed.
Workflow
- Identify the Gherkin region: whole
.feature file, fenced gherkin block, indented block, quoted acceptance criteria, or inline scenario text.
- Preserve the surrounding wrapper unless explicitly asked to change it. For Markdown input, return the heading/prose/fence context, not just the fenced Gherkin block.
- Clarify the behavior as examples: initial state, event, observable outcome.
- Choose the smallest structure that expresses the behavior:
Feature, optional Rule, Background, Scenario/Example, or Scenario Outline with Examples.
- Keep scenarios concrete and short, usually 3-5 steps.
- Review syntax and readability before returning: colons, step keywords, duplicate step text, observable outcomes, and table/doc string formatting.
Quick Reference
| Construct | Use for | Syntax note |
|---|
Feature: | One high-level capability per feature document or block | Requires : |
Rule: | Group scenarios under one business rule | Requires : |
Scenario: / Example: | One concrete example | Requires : |
Background: | Short shared context for following scenarios | Requires :; one per Feature or Rule |
Scenario Outline: | Same behavior with varied data | Requires Examples: and <parameter> placeholders |
Examples: | Data rows for an outline | Requires : and a table |
Given | Known state or precondition | No : |
When | Event or action | No : |
Then | Observable outcome | No : |
And / But | Continue the previous step type | No : |
* | Bullet-like step list | Use sparingly for list-style setup |
@tag | Group or filter features/scenarios | Place above the item tagged |
# | Line comment | Line comments only; no block comments |
""" | Doc String | Passed as final step argument |
| ` | ` | Data Table |
Authoring Rules
- Use the language domain experts use. Avoid translating business behavior into UI clicks, HTTP calls, database rows, queues, mocks, or implementation details.
Given puts the system in a known state. Avoid user interaction in Given steps.
When describes one meaningful event.
Then describes an outcome visible to a user or external system. Do not assert hidden database state unless that is the actual external contract.
- Use
And and But to improve flow, not to hide new phases of the scenario.
- Avoid identical step text under different step keywords; Cucumber ignores
Given/When/Then when matching step definitions.
- Use two-space indentation unless preserving existing style.
- Keep
Background short and vivid. If it grows beyond about four lines, use higher-level steps or split by Rule/Feature.
- Use
Scenario Outline only when examples share the same behavior and differ by data.
- Escape
| as \|, newline as \n, and backslash as \\ inside Data Table cells.
Example
Markdown wrapper preserved; only the Gherkin block is authored:
## Acceptance Criteria
```gherkin
Feature: Password reset
Rule: Reset links expire after their allowed lifetime
Scenario: Customer resets their password before the link expires
Given Priya has requested a password reset
And the reset link is still valid
When Priya chooses a new password with the reset link
Then she can sign in with the new password
Scenario: Customer uses an expired reset link
Given Priya has requested a password reset
And the reset link has expired
When Priya tries to choose a new password with the reset link
Then she is told the reset link has expired
And her password is unchanged
```
Common Mistakes
| Mistake | Fix |
|---|
| Complaining about Markdown around a Gherkin block | Preserve the wrapper and work only on the Gherkin section. |
| Returning only a fenced Gherkin block when the input was Markdown | Return the original Markdown wrapper with only the Gherkin content changed. |
Feature Checkout or Scenario: Place order: | Add the missing colon after Feature; remove extra colon from the scenario title. |
Given I click the checkout button | Move interaction to When; describe state in Given. |
Then an order row exists in the database | Prefer an observable result, such as an order confirmation. |
Reusing the same step text for Given and Then | Change the wording so the domain meaning is distinct. |
| Long scripts with many UI actions | Raise the abstraction and keep the scenario to the behavior. |
Large Background sections | Use higher-level context or split scenarios by Rule or Feature. |