For a while, I've been occasionally updating a list of requirements for a software I would be able to comfortably use to manage my GTD system. So without further ado:
- actions
- actions are always in a context, and some actions are also tied to a project (my primary way to look at lists of actions is by context)
- dates
- start date (i.e. schedule a task to become current at a future date)
- recurring tasks (e.g. every weekday, every Monday, every first Tuesday of the month…)
- due date not important; making the task red once it passed the due date is useless to me; maybe another implementation could make this information useful
- email
- quick way to create an action from an email (otherwise I am more likely to leave emails in my inbox rather than create tasks)
- quickly find email related to an action
- special but important case of a start date: create action from an email that become current at a future date (i.e. "if no answer in 7 days, do this")
- projects
- lists of current projects
- in each project
- next actions for that project
- reference material: notes (typically indented lists), files (PDF, screenshots)
- ability to archive projects
- access
- desktop
- mobile
- Android support (bonus for also working on iOS)
- fast read access to specific "list" (e.g. context, project)
- editing lists from a mobile is not a priority (just having read-only access, while not ideal, would suffice)
- offline on mobile (ideally with background sync so the offline version is used even when online for speed)
- proven stability of the system's cloud-based component
