To test what your smart value returns, use the manual trigger with log action and the result displays in the audit log.

issue

The active issue. Through the dot notation you can access fields like issue type, status and custom fields (details on how you can use these to interact with Jira's api are here)

{{issue.components.name}}
{{issue.created.format("dd/MM/yyyy")}} - this is the date the issue was created
displayed in the format 21/03/2019
{{issue.description}} - the content in the description field
{{issue.project}} - the project this issue is a part of.
{{issue.duedate}} - this is the due date for scheduled issue
{{issue.issuetype.name}} - the name of the type of issue
{{issue.key}} - the issue's unique identifier, comprised the project key and the
issue's number
{{issue.status.name}} - the name of the status the issue is at in its workflow.
{{issue.toUrl}} - use this to display a url
{{issue.CustomField.property}} - some of these are:
  * {{issue.CustomField.id}} - the unique id for the field assigned by Jira. It is
    better to use this than name as it cannot be changed.
  * {{issue.CustomField.name}} - the visible label displayed on the left of the
    field
  * {{issue.CustomField.description}} - the text displayed below the custom field
    viewed in the Simple Search column.
  * {{issue.CustomField.defaultValue}} - the value displayed on first view of the
    field

issues

A list of issues generated by a trigger that runs a JQL search (Incoming Webhook trigger or Scheduled trigger when set to process in bulk). All of the issues found by the trigger are then treated as a single bundle of issues. You could then use this to count the number of issues returned. For example, you might count how many issues have a priority of 'highest' and then send an alert. Or you could count how many issues have the same label, same fixVersion, etc. You can also use this with lists. For more information on when issues is available, see Run a rule against issues in bulk.

{{#issues}}{{key}}{{/}} - the key for each issue
{{issues.size}} - count of the issues

issue.comments

Multiple comments on the active issue (this example is explained in detail in how to use smart values)

{{#issue.comments}}
Comment by: {{author}} at: {{created}}
{{body}}
{{/}}

{{issue.comments.last.body}}
{{issue.comments.first.body}} - the body of the first of many comments
{{issue.comments.size}} - count of comments for the issue

{{#issue.comments}}{{#first}}First:{{author.key}}{{/}}{{body}}{{/}} - prints all of the comments and only prints the first author's key

issue.components

Components of an issue as a list. See accesing multi-value fields

{{issue.components.first.name}}

issue.epic

Added by: This is added any time an issue is added

If this issue is in an Epic, then epic refers to the Epic issue. You can access all fields of the Epic.

{{issue.epic.key}}
{{issue.epic.status.name}}
{{issue.epic.My Custom Field}}

issue.fixVersions

Fix versions of an issue as a list. See accesing multi-value fields.
Properties for versions include: name, description, archived, released, releaseDate

{{issue.fixVersions.first.releaseDate}}

issue.latest

This re-fetches the latest state of the issue from Jira.

{{issue.latest.description}}

issue.parent

If this issue is a sub-task, then parent refers to the parent issue. You can access all fields of the parent.

{{issue.parent.key}}
{{issue.parent.priority.name}}
{{issue.parent.Epic Link}}
{{issue.parent.epic.summary}}

issue.properties

Here you can access any issue property. Properties are frequently used by add-ons and integrations to store values.

{{issue.properties.some.value}}

issue.project

This smart-value allows you to access project specific attributes:

{{issue.project.key}}
{{issue.project.name}}

issue.Request Type

Jira Service Management specific request type object that you can grab information from.

{{issue.Request Type}}
{{issue.Request Type.requestType.name}} - Customer request type
{{issue.Request Type.currentStatus.status}} - Current  status
{{issue.Customer Request Type}} - Customer request type for older Jira instances

The "Request Type" prefix may be
"Customer Request Type" in older instances of Jira. You can check this by navigating to the "Custom fields" page in the
global admin section. There should be a locked field named either "Request Type" or "Customer Request Type" there.

issue.security.name

The text of the security level.

{{issue.security.name}}
{{issue.security.id}}

issue.url

The URL to access the issue. Also provides the customer portal URL for Jira Service Management issues.

{{issue.url}}
{{issue.url.customer}}

issue.versions

Affects version of an issue as a list. See accesing multi-value fields.
Properties for versions include: name, description, archived, released, releaseDate

{{issue.versions.first.releaseDate}}

issue.watchers

You can access the current watchers of an issue.

{{issue.watchers.displayName}}
{{issue.watchers.emailAddress}}

lookupIssues

Returns a list of issues from a JQL search used by the Lookup issues action. Learn more about the Lookup issues action

The properties available for the {{lookupIssues}} smart value are listed in the following section.

Available properties

Examples of using the lookupIssues value

Create a list of the keys of all the issues from the JQL search:

These are the issue keys found by the JQL search {{lookupIssues.key}}.

Iterate through each issue using a loop and print the keys in bullet point form:

These are the issue keys found by the JQL search:
{{#lookupIssues}}
* {{key}}
{{/}}

Sum all of the story points for issues returned from the JQL search:

There are {{lookupIssues.Story Points.sum}} story points remaining.

Retrieve the highest story point value for issues returned from the JQL search:

The highest story point value is {{lookupIssues.Story Points.max}}.

triggerIssue

Added by: The Related Issues Action.

Refers to the original issue when you branch the chain.

{{triggerIssue.description}}

... all fields available to {{issue}} are available here as well.

attachment

• filename {{attachment.filetype}}: the filename of the attachment
• mimeType {{attachment.mimeType}}: the file format of the attachment
• author {{attachment.author}}: the user who added the attachment
  • accountId {{attachment.author.accountId}}: the ID associated with the user name
  • emailAddress {{attachment.author.emailAddress}}: the email address associated with the user name
  • displayName {{attachment.author.displayName}}: the name displayed in your Jira instance
  • active {{attachment.author.active}}: Is the user an active user or has their account been deactivated
  • timeZone {{attachment.author.timeZone}}: what timezone the user is registered being in (this does not change dynamically based upon where the user logs in from, it is the timeZone registered in their user account)
• created {{attachment.created}}: the date and time the attachment was added to the issue
• size {{attachment.size}}: the attachment file size in bytes

baseUrl

Prints the url of the Jira instance

changelog

Added by: Jira Triggers that edit an issue

All the fields that were changed. Each field is a list of changes. You can access useful things like the previous status during a transition

• this is only available for some triggers.
  
  

{{#changelog.summary}}
  {{toString}}
{{/}}
{{#changelog.issuetype}}
  {{fromString}}
{{/}}
// Previous status name
{{#changelog.status}}{{fromString}}{{/}}
// Previous status id (for using in another Edit action
{{#changelog.status}}{{from}}{{/}}

comment

Added by: Jira Triggers that contain a comment. E.g. Issue commented

{{comment.body}}
{{comment.author}}
{{comment.created}}
{{comment.visibility.type}} - comment restriction type, if any e.g. role
{{comment.visibility.value}} - comment restriction label, if any  e.g. Developers 
{{comment.internal}} - for Jira Service Management comments, returns false if the comment is visible to customers.
{{comment.properties}} - Way to access any comment property. Properties are frequently used by add-ons and integrations to store values.
{{comment.properties."sd.public.comment".internal}}

createdIssue

The previous issue created in this rule

{{createdIssue.some field}}

createdIssues

Added by: Clone Issue Action, Create Issue Action, Create Sub-tasks Action

A list of issues that have been created in the rule

{{#createdIssues}}{{key}}{{/}}

eventType

The type of event that triggered the rule such as: jira:issue_updated :issue_commented

{{eventType}}

fieldChange

The changed field value is available anywhere smart values are supported using the {{fieldChange}} substitution. Use {{fieldChange.fromString}} and {{fieldChange.toString}} to access display values and {{fieldChange.from}} and {{fieldChange.to}} to access raw values (for a select field for example).

{{fieldChange}} only contains the first changed value. If multiple values are changed (e.g. when setting multiple Fix Versions) then you can iterate over these using the {{#changelog.fix Version}}{{toString}}{{/changelog.fix Version}} expression.

Jira Service Management’s customer satisfaction

rate

Returns the value of the Jira Service Management’s rate custom field.

{{issue.Satisfaction.rate}}

scale

Returns the value of the Jira Service Management’s scale custom field.

{{issue.Satisfaction.scale}}

rule

{{rule.name}} - Prints out the name of the running rule
{{rule.actor}} - Accesses the rule actor user.

sprint

Added by: Sprint created, started or completed triggers

{{sprint.id}}
{{sprint.name}}
{{sprint.isStarted}}
{{sprint.isClosed}}
{{sprint.startDate}}
{{sprint.endDate}}
{{sprint.completeDate}}
{{sprint.originBoardId}}
{{sprint.goal}}

version

A representation of a release/version in Jira.

{{version.name}}
{{version.id}}
{{version.description}}
{{version.archived}}
{{version.startDate}}
{{version.released}}
{{version.releaseDate}}
{{version.project.key}}
{{issue.versions.first.name}}

webhookData

Added by: Webhook Trigger
This allows access to data that was sent along with the incoming webhook
The body of the Webhook request

{{webhookData.someValue.childValue}}

webhookResponse

Added by: Send web request with "Wait for response" checked
On successful request, you will be able access webhook response data using the following smart values:

{{webhookResponse.status}} - response code e.g. 200
{{webhookResponse.headers}} - headers that can be accessed with dot nation
{{webhookResponse.headers.Content-Type}}
{{webhookResponse.body}} - body that can be accessed with dot nation
{{webhookResponse.body.name}}
{{webhookResponses}} - list of responses made when list operations
{{webhookResponses.last.body}}

Multiple responses can be access via the following fields:

{{webhookResponses.last.someValue.childValue}}
{{#webhookResponses}}
    Data from response: {{someValue.childValue}}
{{/}}

worklog

Added by: Worklogged Trigger
The worklog entry that has just been logged against an issue.

{{worklog.comment}}
{{worklog.started}}
{{worklog.timeSpentSeconds}}
// Cloud only
{{worklog.timeSpent}}
// Visibility is available when the worklog is restricted
{{worklog.visibility}}
{{worklog.visibility.type}}
{{worklog.visibility.value}}

Asset fields

You can access an Asset field's full name, key, or summary through the following smart values:

{{issue.InsightField}}          // returns Some Client Name (ABC-123)
{{issue.InsightField.key}}      // returns ABC-123
{{issue.InsightField.summary}}  // returns Some Client Name

Tempo Account field

You can access a Tempo Account field's properties through the following smart values:

{{issue.TempoAccountField}}       // Provides the name of the account
{{issue.TempoAccountField.id}}    // Provides the ID of the account
{{issue.TempoAccountField.name}}  // Provides the name of the account
{{issue.TempoAccountField.key}}   // Provides the key of the account