# Crucible consumer contract

How the artifact repos (`sow-module`, `sow-topdata`, `sow-assets-manifest`)
locate and invoke a Crucible builder. The goal: **no local-machine assumptions**
(Phase 5 exit criterion). A consumer either finds a Crucible binary or fails
closed — it never fakes an artifact.

## Resolution order (single-token command)

Each consumer wrapper resolves its builder to one executable token, in order:

1. **Explicit override** — `$SOW_MODULE_BUILD` / `$SOW_TOPDATA_BUILD` /
   `$CRUCIBLE` (a path or name), if set and executable. Back-compat with the
   pre-Crucible skeletons.
2. **Standalone Crucible binary** — `crucible-module` / `crucible-topdata` /
   `crucible-hak` / `crucible-depot` on `PATH`.
3. **Legacy name** — `sow-module-build` / `sow-topdata-build` on `PATH`
   (pre-D11; kept so nothing breaks during cutover).

If none resolve, the wrapper exits non-zero with a Phase 5 message. The
`crucible` dispatcher (`crucible module …`) is for humans and CI introspection;
wrappers prefer the single-token `crucible-<name>` shim so `"$builder" args`
quoting stays correct.

## Parity contract — wrappers are not authoritative for build inputs

A consumer build wrapper may only:

1. **validate** — a pre-build gate that does not change output;
2. **publish** — a post-build step on a separate artifact;
3. **resolve the crucible binary** — the bootstrap above.

A wrapper MUST NOT fetch, resolve, generate, or stage any input Crucible reads to
produce the artifact. If Crucible needs an input, Crucible acquires it. This makes
the "no local-machine assumptions" + "same inputs → identical output" rules
explicit: local `crucible <build>` and CI `crucible <build>` against the same
committed config must produce identical bytes, with no CI-only pre-steps.

Builders read every input from the project tree. No NWN install is required. A
builder that one day needs NWN game data auto-detects the install (the NWN home
and Steam path are reliably discoverable), with an optional explicit override for
non-standard layouts — never a required hand-set env.

## In CI

Builds run the Crucible **binary** — from the `crucible.sh` / `crucible.ps1`
bootstrap (anonymous download) or, for Nix users, from the flake devshell pinned
by `flake.lock`. CI runs the _same_ `crucible <build>` as local dev, inside the
nix devshell (binary-cache fast). No build container, no token, no CI-only
pre-steps.

The `registry.westgate.pw/deployment/crucible:<sha>` image is **retired**
(2026-07-17): nothing consumed it, `prod.yml` no longer reserves a slot for
it, and CI no longer builds or publishes it. Binaries, wrappers, and the Nix
input are the only supported ways to run Crucible.

## Determinism

Same inputs → identical output bytes. Consumers may checksum artifacts across
runs; non-determinism is a builder bug.