Why should a coding agent never merge its own change?
why-an-agent-never-merges-its-own-change.answer
Because the agent that wrote a change checks its own assumptions, not the ticket. An independent reviewer answers the ticket's named criteria against the exact commit and can send it back. niwa never lets the author merge: the check runs on the merged result, and every merge carries its receipt.
The blind spot
The agent that wrote the code also decided what done means. Asked to review itself, it rereads the same reasoning and finds it sound.
Criteria, not an opinion
The reviewer is an agent too, and it will be wrong sometimes. So it answers named criteria instead of giving a general opinion, and you can overrule any verdict from the terminal.
The receipt
Every merge carries its receipt: the criteria, the reviewer and the rounds. The approval is written into the commit, so every merged change traces back to its verdict.
How often it matters
On niwa's own git history, from 29 August to 28 September 2026, 52% of changes were sent back at least once before merging (227 of 437), and 436 of 441 merges carry an approval from a reviewer that wasn't the author.