The short answer
Hand over work that sits behind a clear interface and has tests around it. A new developer can be productive on a service they can run, test and change without understanding the whole system. They cannot be productive inside a large application where every change touches shared code nobody has tested.
If your system is the second kind, the highest-value first task for an augmented developer is often adding test coverage around the area you want to change next.
What makes backend work handover-friendly
- A defined interface, whether that is an API, a queue or a module boundary
- Tests that describe what the code should do, not just that it runs
- The ability to run that part in isolation locally
- Data access patterns that are visible rather than scattered
- Something that fails loudly when it goes wrong
None of these is specific to augmentation. They are what makes a codebase changeable at all. Bringing someone new in exposes which parts have them and which do not.
Picking the first workstream
| Candidate | Suitability | Why |
|---|---|---|
| A new service or endpoint | High | Clear boundary, limited blast radius |
| Integration with a third party | High | Self-contained, well-defined success |
| Background job or scheduled task | Good | Isolated, testable |
| Performance work on a known bottleneck | Good | Measurable, scoped |
| Refactoring shared core code | Low | Needs deep context, high conflict risk |
| Anything on the critical path this sprint | Low | No room for the ramp-up |
Avoid the merge conflict trap
Two developers changing the same files is the fastest way to lose the benefit of a second pair of hands. Review, rebase and conflict resolution consume the extra capacity.
Divide by area of the system rather than by ticket where you can. If the work genuinely overlaps, sequence it instead of running it in parallel, and accept that this bounds how many people help.
Database changes need a rule
Schema changes are where augmented developers most often cause trouble, not through carelessness but because the implications are invisible from the code.
- All schema changes go through migrations in version control, never by hand.
- Someone who knows the data model reviews every migration.
- Migrations run forward only, with a tested path for rolling back a deploy.
- Any change to a large table is discussed before it is written.
- Nobody runs anything against production directly.
The check before you start
Ask whether a competent developer who has never seen your system could run the part you want changed, make a small change, and know from the tests whether they broke something.
If yes, augmentation will work. If no, that is the first piece of work, and it benefits your permanent team just as much.