# `Puck.Eval.Step`
[🔗](https://github.com/bradleygolden/puck/blob/v0.2.25/lib/puck/eval/trajectory.ex#L1)

Represents a single LLM call within a trajectory.

Each step captures the input, output, token usage, timing, and metadata
from a `Puck.call/4` invocation.

## Fields

  * `:input` - The content sent to the LLM
  * `:output` - The parsed struct (if `output_schema` was used) or raw content
  * `:tokens` - Token usage map with `:input`, `:output`, and `:total` keys
  * `:duration_ms` - Time taken for this call in milliseconds
  * `:metadata` - Additional metadata from `Puck.Response.metadata`

## Example

    %Step{
      input: "Find John's email",
      output: %LookupContact{name: "John"},
      tokens: %{input: 150, output: 30, total: 180},
      duration_ms: 450,
      metadata: %{model: "claude-sonnet-4-5-20250514"}
    }

# `t`

```elixir
@type t() :: %Puck.Eval.Step{
  duration_ms: non_neg_integer(),
  input: term(),
  metadata: map(),
  output: term(),
  tokens: %{
    input: non_neg_integer(),
    output: non_neg_integer(),
    total: non_neg_integer()
  }
}
```

# `new`

Creates a new Step struct.

## Options

  * `:input` - The content sent to the LLM (required)
  * `:output` - The response content (required)
  * `:tokens` - Token usage map (default: `%{input: 0, output: 0, total: 0}`)
  * `:duration_ms` - Call duration in milliseconds (default: `0`)
  * `:metadata` - Additional metadata (default: `%{}`)

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