# `MobDev.OtpTrace.Harness`
[🔗](https://github.com/genericjam/mob_dev/blob/main/lib/mob_dev/otp_trace/harness.ex#L9)

Characterization harness: a curated set of Elixir features exercised
in tight blocks. Designed to be wrapped in `MobDev.OtpTrace.capture/1`
to record the runtime modules touched by typical Elixir code.

## Phases

Run individually or together. Each phase exercises a coherent slice
so the trace can be partitioned into "what does X actually need."

  * `language/0`    — pattern match, comprehension, anonymous fns,
                      struct + protocol dispatch, exception handling
  * `collections/0` — Enum, Stream, List, Map, MapSet, Tuple, Range
  * `strings/0`     — String, Binary, charlist conversion, sigils
  * `processes/0`   — spawn, send/receive, monitor, link
  * `otp/0`         — GenServer, Supervisor, Application boot, Logger
  * `data/0`        — ETS, :persistent_term, Date/Time
  * `errors/0`      — raise, rescue, throw/catch, exit/trap_exit
  * `all/0`         — runs everything sequentially

## What this is NOT

- Not a benchmark — timings are meaningless under trace overhead
- Not exhaustive — covers common Elixir, not every language corner
- Not production-safe — runs `:erlang.trace/3` system-wide

## How modules are defined

Modules used by the harness are defined at compile time of THIS module,
NOT inside the traced functions. That's deliberate: tracing inside a
`defmodule` block captures the entire compiler call graph (~80 modules
of `:elixir_*`, `:erl_lint`, `:sys_core_*`). Production apps don't run
the compiler at runtime, so we exclude that surface from the baseline.

# `all`

# `collections`

# `data`

# `errors`

# `language`

# `otp`

# `processes`

# `strings`

---

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