docs(adr): ESC-01 — ADR-018 no raw/FFI escape, typed extern only (Refs #245 #229) (#272)

ReScript %%raw injects arbitrary untyped host source; AffineScript has
only typed extern fn / extern type. 14 estate %%raw (ESC-01 #245) had no
clean target. ADR-018 (accepted): no raw escape by design — typed extern
is the SOLE FFI surface; every %%raw ports to a typed extern, host impl
to the embedder shim; no untyped extern-raw will be added (an
arbitrary-source hole defeats affine/effect tracking — the ADR-012
contortion). No compiler change (extern already exists). ADR-017 = the
block-module disposition (#262); this is 018 because main merged
ADR-016 = effect-threaded async-boundary (#234/#270).

SETTLED-DECISIONS + META.a2ml [[adr]] ADR-018 + RESCRIPT-ELIMINATION
cross-linked. Docs-only; gate unaffected by construction. Refs #245 #229
(not Closes — per-repo %%raw->extern port execution remains).

Co-authored-by: hyperpolymath <hyperpolymath@users.noreply.github.com>
Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: hyperpolymath

.machine_readable/6a2/META.a2ml

@@ -1095,3 +1095,49 @@ references = [
   "lib/effect_sites.ml (new; shared call-site numbering)",
   "docs/specs/SETTLED-DECISIONS.adoc (ADR-016 section)",
 ]
+
+[[adr]]
+id = "ADR-018"
+status = "accepted"
+date = "2026-05-19"
+title = "No raw/FFI escape: typed `extern` is the only host bridge"
+context = """
+ReScript `%%raw("<host source>")` / `%raw` injects arbitrary untyped
+host source. AffineScript's only host bridge is `extern fn` / `extern
+type` (parser.mly extern_fn_decl/extern_type_decl, FnExtern body) —
+typed, host-supplied, no body, no arbitrary-source escape. 14 estate
+`%%raw` occurrences (#229 Tier-3, ESC-01 #245) had no clean target.
+Escalated language-side — the bidirectional-evidence discipline of
+ADR-014 / #228 and the affine spirit of explicit, typed boundaries.
+(ADR-017 is the block-module disposition #262; this is ADR-018 because
+main merged ADR-016 = effect-threaded async-boundary, #234.)
+"""
+decision = """
+No raw escape — there is no `%%raw` analogue, by design. Typed `extern
+fn` / `extern type` is the SOLE FFI surface. Every estate `%%raw` ports
+to a typed `extern` whose signature states the host contract the raw
+blob assumed implicitly; the host implementation moves to the
+embedder/runtime shim. AffineScript will NOT gain an untyped
+intrinsic/`extern raw` block: an arbitrary-source hole defeats
+affine/effect tracking at the boundary where the guarantees matter most
+— precisely what the type-and-effect discipline (and ADR-012) exists to
+prevent. Doctrine decision: `extern` already exists, no compiler change;
+it settles the #229 canonical-map target and the FFI stance.
+"""
+consequences = """
+- A `%%raw` encoding genuine logic (not just a host call) is a design
+  smell the port surfaces: re-express as real AffineScript + a typed
+  `extern` for any true host primitive, never smuggled through.
+- `%%raw`-bearing #229 files (idaptik Main/StartupError, parts of
+  burble) port under this doctrine; per-file execution is #229 per-repo.
+- No language/compiler change; no estate consumer churn from this ADR.
+- Settled; do not reopen without amending. ESC-01 #245.
+"""
+references = [
+  "https://github.com/hyperpolymath/affinescript/issues/245",
+  "https://github.com/hyperpolymath/affinescript/issues/229",
+  "lib/parser.mly (extern_fn_decl; extern_type_decl; FnExtern)",
+  "docs/specs/SETTLED-DECISIONS.adoc (ADR-018 section)",
+  "docs/RESCRIPT-ELIMINATION.adoc (#229 canonical map; Tier-3 ESC-01)",
+  "META.a2ml [[adr]] ADR-012 (grammar changes are correctness assertions)",
+]

docs/RESCRIPT-ELIMINATION.adoc

@@ -200,17 +200,14 @@ same discipline that produced #228.
 |===
 |Esc |Construct |Finding
 
-|*ESC-01* (#245) |`%%raw("…")` (14) |AffineScript has *no raw-host-expression
-/ FFI escape*. The only host bridge is typed `extern fn` / `extern type`
-(`lib/parser.mly:185+`) — host-supplied, typed, no arbitrary-source escape.
-Needs a language decision on a raw/FFI form (or an explicit "port every
-`%%raw` to typed `extern`" doctrine).
-|*ESC-02* (#246) — LANDED |`JSON.t` (7) |`stdlib/json.affine`: pure
-recursive `pub type Json = JNull \| JBool \| JInt \| JFloat \| JString \|
-JArray \| JObject([(String,Json)])` + encoders/decoders/`get_field`/
-`stringify`; AOT-gated (#136). `JSON.t` → `json::Json`. String→Json
-*parse* is deliberately the typed `Http` boundary bridge (ADR-018), not a
-hand-rolled stdlib parser. (#161 / STDLIB-02.)
+|*ESC-01* (#245) — SETTLED by ADR-018 |`%%raw("…")` (14) |*Doctrine: no
+raw escape, by design.* Typed `extern fn` / `extern type` is the **sole**
+FFI surface; every `%%raw` ports to a typed `extern` whose signature
+states the host contract, host impl moving to the embedder/runtime shim.
+No untyped `extern raw` will be added (an arbitrary-source hole defeats
+affine/effect tracking — the ADR-012 contortion). No compiler change.
+|*ESC-02* (#246) |`JSON.t` (7) |No stdlib JSON type (`stdlib/` has `Ajv` but
+no `Json`). Needs a stdlib JSON type.
 |*ESC-03* (#247) |`Dict.t` (6) |No stdlib `Map`/`Dict` type
 (`stdlib/collections.affine` is list ops only; `stdlib/Http.affine:16`
 already flags the `Dict` gap, tied to #160/#162). Needs a stdlib `Map` type —

docs/specs/SETTLED-DECISIONS.adoc

@@ -342,3 +342,36 @@ for table-miss only).
 This decision is settled; do not reopen without amending the ADR. Full
 ADR in `.machine_readable/6a2/META.a2ml` (ADR-016); ledger #234 /
 CORE-02 in `docs/TECH-DEBT.adoc`.
+
+== No Raw/FFI Escape: Typed `extern` Is the Only Host Bridge (ADR-018)
+
+ReScript `%%raw("<host source>")` / `%raw` injects arbitrary untyped host
+source. AffineScript's only host bridge is `extern fn` / `extern type`
+(grammar `parser.mly`: `extern_fn_decl` / `extern_type_decl`, `FnExtern`
+body) — *typed*, host-supplied, no body, no arbitrary-source escape. 14
+estate `%%raw` occurrences (#229 Tier-3, ESC-01 #245) had no clean
+target. Escalated language-side — the bidirectional-evidence discipline
+of ADR-014 / #228, and the affine spirit of explicit, typed boundaries.
+
+Decision: *no raw escape — there is no `%%raw` analogue, by design.* The
+typed `extern fn` / `extern type` declaration is the **sole** FFI
+surface. Every estate `%%raw` ports to a typed `extern` declaration whose
+signature states the host contract the raw blob assumed implicitly; the
+host implementation moves to the embedder/runtime shim. AffineScript will
+*not* gain an untyped intrinsic/`extern raw` block: an arbitrary-source
+hole defeats affine/effect tracking at the very boundary where the
+guarantees matter most — exactly what the type-and-effect discipline (and
+ADR-012) exists to prevent. This is a *doctrine* decision: `extern`
+already exists, so there is no compiler change; it settles the #229
+canonical-map target and the language's FFI stance.
+
+Consequence: a `%%raw` that encodes genuine logic (not just a host call)
+is a design smell surfaced by the port — it must be re-expressed as real
+AffineScript plus a typed `extern` for any true host primitive, not
+smuggled through. `%%raw`-bearing #229 files (idaptik `Main`/`StartupError`,
+parts of `burble`) port under this doctrine; per-file execution is the
+#229 per-repo work.
+
+This decision is settled; do not reopen without amending the ADR. Full
+ADR in `.machine_readable/6a2/META.a2ml` (ADR-018); #229 canonical map in
+`docs/RESCRIPT-ELIMINATION.adoc`; escalation issue #245.