Can an agent write code?
Mostly. An agent writes, tests and ships real features in a codebase it can read, and it does so faster than a person. It cannot decide what to build, and it degrades badly as a system gets large and undocumented.
- Hours back per week
- 16
- Human cost
- €5,000–10,000/mo per developer
- Agent cost
- €100–400/mo
Step by step
A job is never one task. Here is each step, rated on its own — tick the ones you would actually hand over and take the brief with you.
Write a well-specified feature
YESClear spec, existing patterns to follow, tests to satisfy. This works now.
Write tests
YESThorough, including the edge cases people skip. Watch for tests that assert current behaviour rather than correct behaviour.
Fix a reproducible bug
YESGiven a reproduction, it is often faster than the person who wrote the code.
Refactor and migrate
YESMechanical change across hundreds of files. One of the strongest uses.
Debug something intermittent
HALFRace conditions and heisenbugs need patience and instrumentation, and it gives up into plausible guesses.
Design a system
HALFCompetent conventional architecture. It cannot weigh your constraints, team or five-year plan.
- Yours
Decide what to build
NOT YETProduct judgement. Nothing about writing code fast helps if you build the wrong thing.
- Yours
Own production
NOT YETSomeone has to be accountable at 3am, and it cannot be a process.
4/6 steps selected. Build a brief scoped to exactly those, with the guardrails for this job attached.
What still needs you
- What to build
- Architecture decisions with long consequences
- Production accountability
- Code review
How this goes wrong
Volume of unreviewed code. An agent produces plausible code faster than a team can review it, and the result is a codebase nobody understands with tests that assert the bugs.
What it needs access to
- Git repository
- CI
- Test suite
- Issue tracker
- Staging environment
Read access to all of it, write access to as little as possible. Scopes are enforced by the system; instructions are only followed by the agent.
The prompt
A full brief for this job, written the way it should be given: explicit about what to do, and more explicit about what not to.
You are my engineering agent. For each ticket: read the surrounding code first and follow the existing patterns rather than introducing new ones. Write the test before the implementation, and make sure the test fails for the right reason before you make it pass. Keep the diff minimal — no drive-by refactoring, no reformatting. Run the full suite and the linter before opening a PR. In the PR description, state what you changed, what you deliberately did not change, and what you are unsure about. If the ticket is ambiguous, ask instead of guessing. Never merge, never touch production, never modify CI or secrets.
Questions people ask
Will agents replace developers?
They have already replaced a lot of typing and almost none of the judgement. The teams getting real leverage kept their review discipline and pointed agents at well-specified work; the teams that shipped unreviewed agent output are now maintaining code nobody wrote.
What about large legacy codebases?
This is where the verdict would drop to half. Agents do well in codebases with clear patterns and good tests, and struggle in exactly the systems where the work is most expensive.
Want the part that works actually running?
The brief above is the easy half. The other half is connecting it to Git repository and CI, holding it inside the boundaries on this page, and having somewhere the exceptions land where you will actually see them. That is what Ogento does.
Set up a software development agentThis site is made by Ogento. The verdicts are not written to suit them — 32% of the jobs here say do not hand this over wholesale.