# `Arcana.Telemetry.Logger`
[🔗](https://github.com/georgeguimaraes/arcana/blob/main/lib/arcana/telemetry/logger.ex#L1)

Ready-to-use telemetry logger for Arcana events.

Logs all Arcana operations with timing information to help identify
performance bottlenecks.

## Usage

Add to your application's `start/2` function:

    def start(_type, _args) do
      Arcana.Telemetry.Logger.attach()

      children = [
        # ...
      ]

      Supervisor.start_link(children, strategy: :one_for_one)
    end

## Example Output

    [info] [Arcana] search completed in 42ms (15 results)
    [info] [Arcana] llm.complete completed in 1.23s [zai:glm-4.7] ok (156 chars) prompt=892chars
    [info] [Arcana] agent.gate completed in 235ms (proceed)
    [info] [Arcana] agent.rewrite completed in 235ms
    [info] [Arcana] llm.complete completed in 2.1s [zai:glm-4.7] ok (45 chars) prompt=1204chars
    [info] [Arcana] agent.expand completed in 2.15s (3 queries)
    [info] [Arcana] agent.search completed in 156ms (25 chunks)
    [info] [Arcana] agent.reason completed in 1.2s (2 iterations)
    [info] [Arcana] agent.rerank completed in 312ms (10/25 kept)
    [info] [Arcana] llm.complete completed in 3.2s [zai:glm-4.7] ok (1892 chars) prompt=4521chars
    [info] [Arcana] agent.answer completed in 3.25s
    [info] [Arcana] ask completed in 6.12s

## Options

You can customize the logger by passing options to `attach/1`:

    Arcana.Telemetry.Logger.attach(
      level: :debug,           # Log level (default: :info)
      handler_id: "my-logger"  # Custom handler ID (default: "arcana-telemetry-logger")
    )

## Detaching

To stop logging, call:

    Arcana.Telemetry.Logger.detach()

# `attach`

Attaches telemetry handlers for logging Arcana events.

## Options

  * `:level` - The log level to use (default: `:info`)
  * `:handler_id` - Custom handler ID (default: `"arcana-telemetry-logger"`)

# `detach`

Detaches the telemetry handlers.

## Options

  * `:handler_id` - The handler ID to detach (default: `"arcana-telemetry-logger"`)

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