# `Sigra.Install.Injection`
[🔗](https://github.com/sztheory/sigra/blob/v1.20.0/lib/sigra/install/injection.ex#L1)

Structured injection descriptor for `Sigra.Install.Injector`.

Features return a list of `%Sigra.Install.Injection{}` records from
the `injections/1` callback in `Sigra.Install.Feature`; the walker
passes each to `Sigra.Install.Injector.apply/2`, which owns marker
checking and
anchor resolution so every feature inherits idempotency (GEN-04)
for free.

## Fields

  * `:target` — project-relative path of the file to mutate
    (e.g. `"lib/my_app_web/router.ex"`).
  * `:marker` — idempotency marker comment. If the file already
    contains this string, `Injector.apply/2` is a no-op.
  * `:anchor` — where to insert the content. One of
    `:before_last_end`, `:after_use_block`, `:at_top`, or a custom
    atom routed by `Injector`.
  * `:content` — rendered code block to insert.

Per CONTEXT.md CD-03 the planner may rename these fields; this plan
keeps the draft names (`target`/`marker`/`anchor`/`content`) verbatim
so Wave 3 (`Features.Core` extraction) and Wave 4 (walker refactor)
can reference them without a second rename.

# `anchor`

```elixir
@type anchor() ::
  :before_last_end | :after_use_block | :at_top | :browser_pipeline | atom()
```

# `t`

```elixir
@type t() :: %Sigra.Install.Injection{
  anchor: anchor(),
  content: String.t(),
  marker: String.t(),
  target: Path.t()
}
```

---

*Consult [api-reference.md](api-reference.md) for complete listing*