# `layout.route_prefix_mismatch`

Route group prefix does not match its file name.

Area 1, [Project layout and modules](../topics/project-layout-and-modules.md); not declinable; the next step is usually the agent's.

```jadpo
routes Todos {
    prefix: /tasks
}
```

```text
error: Prefix `/tasks` doesn't match `todos.jadpo`
 --> domains/planning/routes/todos.jadpo:2:13
  |
2 |     prefix: /tasks
  |             ^^^^^^ gives `tasks.jadpo`
  reason: A route group's file is named after its prefix's fixed segments joined with `_`, so a URL leads to one file: `/tasks` lives in `tasks.jadpo`.
  next: Change the prefix to match `todos.jadpo`, or rename the file `tasks.jadpo` and the group `Tasks` (agent)
  rule: layout.route_prefix_mismatch
  help: https://jadpo.dev/docs/errors/layout.route_prefix_mismatch

check failed: 1 error, 2 files
```