community.general/docs/docsite/directive_desc.yml

become: Boolean that controls if privilege escalation is used or not on Task execution.
become_flags: A string of flag(s) to pass to the privilege escalation program when ``become`` is True.
become_method: Which method of privilege escalation to use. i.e. sudo/su/etc.
become_user: User that you 'become' after using privilege escalation, the remote/login user must have permissions to become this user.
check_mode: A boolean that controls if a task is executed in 'check' mode
connection: Allows you to change the connection plugin used for tasks to execute on the target.
environment: A dictionary that gets converted into environment vars to be provided for the task upon execution.
gather_facts: A boolean that controls if the play will automatically run the 'setup' task to gather facts for the hosts.
hosts: A list of groups, hosts or host pattern that translates into a list of hosts that are the play's target.
ignore_errors: Boolean that allows you to ignore task failures and continue with play. It does not affect connection errors.
name: It's a name, works mostly for documentation, in the case of tasks/handlers it can be an identifier.
remote_user: User used to log into the target via the connection plugin. AKA login user.
no_log: Boolean that controls information disclosure.
run_once: Boolean that will bypass the host loop, forcing the task to execute on the first host available and will also apply any facts to all active hosts.
when: Conditional expression, determines if an iteration of a task is run or not.
strategy: Allows you to choose the connection plugin to use for the play.
tags: Tags applied to the task or included tasks, this allows selecting subsets of tasks from the command line.
vars: Dictionary/map of variables
always_run: DEPRECATED, forces a task to run even in check mode, use check_mode directive instead.
delegate_to: Host to execute task instead of the target (inventory_hostname), connection vars from the delegated host will also be used for the task.
delegate_facts: Boolean that allows you to apply facts to delegated host instead of inventory_hostname.
changed_when: Conditional expression that overrides the task's normal 'changed' status.
failed_when: Conditional expression that overrides the task's normal 'failed' status.