diff --git a/.claude/CLAUDE.md b/.claude/CLAUDE.md
index 40ef29d..aede858 100644
--- a/.claude/CLAUDE.md
+++ b/.claude/CLAUDE.md
@@ -27,7 +27,7 @@ cargo test
 ## Key Design Decisions
 
 - Follows hyperpolymath ABI-FFI standard (Idris2 ABI, Zig FFI)
-- MPL-2.0 license
+- MPL-2.0 license (code) + CC-BY-SA-4.0 (docs); full texts in LICENSES/
 - RSR (Rhodium Standard Repository) template
 - Author: Jonathan D.A. Jewell <j.d.a.jewell@open.ac.uk>
 
diff --git a/.github/workflows/rhodibot.yml b/.github/workflows/rhodibot.yml
index a82f178..1f45960 100644
--- a/.github/workflows/rhodibot.yml
+++ b/.github/workflows/rhodibot.yml
@@ -4,7 +4,7 @@
 # Reads root-hygiene rules and auto-fixes what it can:
 #   - Delete banned files (AI.djot, duplicate CONTRIBUTING.adoc, stale snapshots)
 #   - Rename misnamed files (AI.a2ml → 0-AI-MANIFEST.a2ml)
-#   - Fix SPDX headers (AGPL → PMPL in dotfiles)
+#   - Fix SPDX headers (AGPL → MPL-2.0 in dotfiles)
 #   - Create missing required files (SECURITY.md, CONTRIBUTING.md)
 #   - Report unfixable issues as PR comments
 #
@@ -87,7 +87,7 @@ jobs:
           for dotfile in .gitignore .gitattributes .editorconfig; do
             if [ -f "$dotfile" ] && grep -q "AGPL-3.0" "$dotfile" 2>/dev/null; then
               sed -i 's/AGPL-3.0-or-later/MPL-2.0/g; s/AGPL-3.0/MPL-2.0/g' "$dotfile"
-              FIXES="$FIXES\n- Fixed SPDX header in \`$dotfile\` (AGPL → PMPL)"
+              FIXES="$FIXES\n- Fixed SPDX header in \`$dotfile\` (AGPL → MPL-2.0)"
               CHANGED=true
             fi
           done
diff --git a/.gitignore b/.gitignore
index 73f5db0..ae57802 100644
--- a/.gitignore
+++ b/.gitignore
@@ -104,3 +104,8 @@ sync_report*.txt
 # Hypatia scan cache (local-only)
 .hypatia/
 target/
+
+# Idris2 build artefacts
+**/build/
+*.ttc
+*.ttm
diff --git a/.machine_readable/compliance/reuse/dep5 b/.machine_readable/compliance/reuse/dep5
index 49aaed6..bead9ed 100644
--- a/.machine_readable/compliance/reuse/dep5
+++ b/.machine_readable/compliance/reuse/dep5
@@ -52,3 +52,10 @@ License: MPL-2.0
 Files: cliff.toml
 Copyright: {{CURRENT_YEAR}} {{AUTHOR}} ({{OWNER}}) <{{AUTHOR_EMAIL}}>
 License: MPL-2.0
+
+# Documentation prose is CC-BY-SA-4.0 (code/config is MPL-2.0).
+# Last-match-wins in the Debian copyright format, so this overrides the
+# `Files: *` default above for prose docs.
+Files: *.adoc *.md docs/* docs/**/*
+Copyright: {{CURRENT_YEAR}} {{AUTHOR}} ({{OWNER}}) <{{AUTHOR_EMAIL}}>
+License: CC-BY-SA-4.0
diff --git a/.machine_readable/contractiles/must/Mustfile.a2ml b/.machine_readable/contractiles/must/Mustfile.a2ml
index 615f5d0..22df24a 100644
--- a/.machine_readable/contractiles/must/Mustfile.a2ml
+++ b/.machine_readable/contractiles/must/Mustfile.a2ml
@@ -57,7 +57,7 @@ These are hard requirements — CI fails if any check fails.
 - severity: warning
 
 ### no-agpl
-- description: No AGPL-3.0 references (superseded by PMPL)
+- description: No AGPL-3.0 references (superseded by MPL-2.0)
 - run: "! grep -r 'AGPL-3.0' .gitignore .gitattributes .editorconfig 2>/dev/null | head -1 | grep -q ."
 - severity: critical
 
diff --git a/.machine_readable/contractiles/trust/Trustfile.a2ml b/.machine_readable/contractiles/trust/Trustfile.a2ml
index 59b95cf..4547ba3 100644
--- a/.machine_readable/contractiles/trust/Trustfile.a2ml
+++ b/.machine_readable/contractiles/trust/Trustfile.a2ml
@@ -33,8 +33,8 @@ is traceable.
 - severity: warning
 
 ### license-content
-- description: LICENSE contains PMPL identifier
-- run: grep -q 'PMPL' LICENSE
+- description: LICENSE contains MPL-2.0 identifier
+- run: grep -q 'MPL-2.0' LICENSE
 - severity: warning
 
 ### ci-pipeline-present
diff --git a/Cargo.toml b/Cargo.toml
index b1e012a..774aeb4 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -5,7 +5,7 @@ version = "0.1.0"
 edition = "2024"
 authors = ["Jonathan D.A. Jewell <j.d.a.jewell@open.ac.uk>"]
 description = "Generate high-performance C libraries from high-level descriptions using Nim metaprogramming"
-license-file = "LICENSE"
+license = "MPL-2.0"
 repository = "https://github.com/hyperpolymath/nimiser"
 keywords = ["nim", "metaprogramming", "code-generation", "c-libraries"]
 categories = ["command-line-utilities", "development-tools"]
diff --git a/LICENSE b/LICENSE
index 14e2f77..2a8b960 100644
--- a/LICENSE
+++ b/LICENSE
@@ -1,3 +1,5 @@
+SPDX-License-Identifier: MPL-2.0
+
 Mozilla Public License Version 2.0
 ==================================
 
diff --git a/QUICKSTART-MAINTAINER.adoc b/QUICKSTART-MAINTAINER.adoc
index 4a971d6..3f130d4 100644
--- a/QUICKSTART-MAINTAINER.adoc
+++ b/QUICKSTART-MAINTAINER.adoc
@@ -106,7 +106,7 @@ Or via OPSM: `opsm update {{PACKAGE_NAME}}`
 
 == Security Notes
 
-* License: MPL-2.0 (Palimpsest License)
+* License: MPL-2.0 (code) / CC-BY-SA-4.0 (docs)
 * All dependencies SHA-pinned
 * `panic-attacker` scan results: link:INSTALL-SECURITY-REPORT.adoc[]
 * OpenSSF Scorecard: see badge in README
diff --git a/contractiles/trust/Trustfile.a2ml b/contractiles/trust/Trustfile.a2ml
index 30782f6..6bc8fd2 100644
--- a/contractiles/trust/Trustfile.a2ml
+++ b/contractiles/trust/Trustfile.a2ml
@@ -16,7 +16,7 @@ Maximal trust by default — LLM may read, build, test, lint, format.
 
 ### license-content
 - description: LICENSE contains expected SPDX identifier
-- run: grep -q 'SPDX\|License\|MIT\|Apache\|PMPL\|MPL' LICENSE
+- run: grep -q 'SPDX\|MPL-2.0' LICENSE
 - severity: critical
 
 ### no-secrets-committed
diff --git a/docs/RSR_OUTLINE.adoc b/docs/RSR_OUTLINE.adoc
index 014b21c..8faf3bb 100644
--- a/docs/RSR_OUTLINE.adoc
+++ b/docs/RSR_OUTLINE.adoc
@@ -1,6 +1,6 @@
 = RSR Template Repository
 
-image:[Palimpsest-MPL-1.0,link="https://github.com/hyperpolymath/palimpsest-license"] image:[Palimpsest,link="https://github.com/hyperpolymath/palimpsest-license"]
+image:https://img.shields.io/badge/license-MPL--2.0-blue[MPL-2.0,link="LICENSES/MPL-2.0.txt"] image:https://img.shields.io/badge/docs-CC--BY--SA--4.0-blue[CC-BY-SA-4.0,link="LICENSES/CC-BY-SA-4.0.txt"]
 :toc:
 :sectnums:
 
@@ -78,7 +78,7 @@ just validate-rsr
 |Container build (Wolfi base, Podman)
 
 |`LICENSE`
-|MPL-2.0 (Palimpsest MPL)
+|MPL-2.0 (code) / CC-BY-SA-4.0 (docs)
 
 |`EXHIBIT-A-ETHICAL-USE.txt`
 |Ethical use guidelines (LICENSE Exhibit A)
diff --git a/docs/STATE-VISUALIZER.adoc b/docs/STATE-VISUALIZER.adoc
index 2af3297..4be8d44 100644
--- a/docs/STATE-VISUALIZER.adoc
+++ b/docs/STATE-VISUALIZER.adoc
@@ -87,7 +87,7 @@ CONTAINER ECOSYSTEM (Phase 2)
 
 REPO INFRASTRUCTURE
   .machine_readable/                ██████████ 100%    STATE/META/ECOSYSTEM active
-  Governance & License              ██████████ 100%    PMPL & Ethical use verified
+  Governance & License              ██████████ 100%    MPL-2.0 & Ethical use verified
   Development Shells (Nix/Guix)     ██████████ 100%    Reproducible env stable
 
 ─────────────────────────────────────────────────────────────────────────────
diff --git a/src/interface/abi/Foreign.idr b/src/interface/abi/Nimiser/ABI/Foreign.idr
similarity index 96%
rename from src/interface/abi/Foreign.idr
rename to src/interface/abi/Nimiser/ABI/Foreign.idr
index 4c12639..5caa83c 100644
--- a/src/interface/abi/Foreign.idr
+++ b/src/interface/abi/Nimiser/ABI/Foreign.idr
@@ -50,6 +50,15 @@ export
 free : Handle -> IO ()
 free h = primIO (prim__free (handlePtr h))
 
+--------------------------------------------------------------------------------
+-- String Marshalling (declared early; used by the generation wrappers below)
+--------------------------------------------------------------------------------
+
+||| Convert C string to Idris String
+export
+%foreign "support:idris2_getString, libidris2_support"
+prim__getString : Bits64 -> String
+
 --------------------------------------------------------------------------------
 -- Nim Compilation Pipeline
 --------------------------------------------------------------------------------
@@ -102,7 +111,9 @@ genTemplate h tmpl = do
                    (if tmpl.exported then 1 else 0))
   if ptr == 0
     then pure (Left TemplateError)
-    else pure (Right (prim__getString ptr))
+    else do
+      let str = prim__getString ptr
+      pure (Right str)
 
 ||| Generate Nim macro code from a macro definition
 ||| Returns a C string containing generated Nim source, or null on error.
@@ -121,17 +132,14 @@ genMacro h mac = do
                    (if mac.generatesExport then 1 else 0))
   if ptr == 0
     then pure (Left MacroError)
-    else pure (Right (prim__getString ptr))
+    else do
+      let str = prim__getString ptr
+      pure (Right str)
 
 --------------------------------------------------------------------------------
 -- String Operations
 --------------------------------------------------------------------------------
 
-||| Convert C string to Idris String
-export
-%foreign "support:idris2_getString, libidris2_support"
-prim__getString : Bits64 -> String
-
 ||| Free C string allocated by the Nim library
 export
 %foreign "C:nimiser_free_string, libnimiser"
diff --git a/src/interface/abi/Layout.idr b/src/interface/abi/Nimiser/ABI/Layout.idr
similarity index 73%
rename from src/interface/abi/Layout.idr
rename to src/interface/abi/Nimiser/ABI/Layout.idr
index 7044587..ac68b85 100644
--- a/src/interface/abi/Layout.idr
+++ b/src/interface/abi/Nimiser/ABI/Layout.idr
@@ -20,6 +20,8 @@ module Nimiser.ABI.Layout
 import Nimiser.ABI.Types
 import Data.Vect
 import Data.So
+import Data.Nat
+import Decidable.Equality
 
 %default total
 
@@ -33,24 +35,38 @@ paddingFor : (offset : Nat) -> (alignment : Nat) -> Nat
 paddingFor offset alignment =
   if offset `mod` alignment == 0
     then 0
-    else alignment - (offset `mod` alignment)
+    else minus alignment (offset `mod` alignment)
 
 ||| Proof that alignment divides aligned size
 public export
 data Divides : Nat -> Nat -> Type where
   DivideBy : (k : Nat) -> {n : Nat} -> {m : Nat} -> (m = k * n) -> Divides n m
 
+||| Sound decision procedure: does n divide m?
+||| For n = S j, compute q = div m (S j) and check m == q * (S j).
+||| Division does not reduce definitionally, so the equality is checked, not
+||| asserted.
+public export
+decDivides : (n : Nat) -> (m : Nat) -> Maybe (Divides n m)
+decDivides Z _ = Nothing
+decDivides (S j) m =
+  let q = div m (S j) in
+  case decEq m (q * (S j)) of
+    Yes prf => Just (DivideBy q prf)
+    No _ => Nothing
+
 ||| Round up to next alignment boundary
 public export
 alignUp : (size : Nat) -> (alignment : Nat) -> Nat
 alignUp size alignment =
   size + paddingFor size alignment
 
-||| Proof that alignUp produces aligned result
+||| Decide whether alignUp produced an aligned result for a given alignment.
+||| (Division does not reduce definitionally, so this is decided rather than
+||| proven by `Refl`; a universally-quantified `Refl` proof would be unsound.)
 public export
-alignUpCorrect : (size : Nat) -> (align : Nat) -> (align > 0) -> Divides align (alignUp size align)
-alignUpCorrect size align prf =
-  DivideBy ((size + paddingFor size align) `div` align) Refl
+alignUpCorrect : (size : Nat) -> (align : Nat) -> Maybe (Divides align (alignUp size align))
+alignUpCorrect size align = decDivides align (alignUp size align)
 
 --------------------------------------------------------------------------------
 -- Struct Field Layout
@@ -82,7 +98,7 @@ record StructLayout where
 
 ||| Calculate total struct size with padding
 public export
-calcStructSize : Vect n Field -> Nat -> Nat
+calcStructSize : Vect k Field -> Nat -> Nat
 calcStructSize [] align = 0
 calcStructSize (f :: fs) align =
   let lastOffset = foldl (\acc, field => nextFieldOffset field) f.offset fs
@@ -91,23 +107,28 @@ calcStructSize (f :: fs) align =
 
 ||| Proof that field offsets are correctly aligned
 public export
-data FieldsAligned : Vect n Field -> Type where
+data FieldsAligned : Vect k Field -> Type where
   NoFields : FieldsAligned []
   ConsField :
     (f : Field) ->
-    (rest : Vect n Field) ->
+    (rest : Vect k Field) ->
     Divides f.alignment f.offset ->
     FieldsAligned rest ->
     FieldsAligned (f :: rest)
 
 ||| Verify a struct layout is valid
 public export
-verifyLayout : (fields : Vect n Field) -> (align : Nat) -> Either String StructLayout
+verifyLayout : (fields : Vect k Field) -> (align : Nat) -> Either String StructLayout
 verifyLayout fields align =
-  let size = calcStructSize fields align
-   in case decSo (size >= sum (map (\f => f.size) fields)) of
-        Yes prf => Right (MkStructLayout fields size align)
-        No _ => Left "Invalid struct size"
+  let size = calcStructSize fields align in
+  case choose (size >= sum (map (\f => f.size) fields)) of
+    Right _ => Left "Invalid struct size"
+    Left sizeOk =>
+      case decDivides align size of
+        Nothing => Left "Total size is not a multiple of the alignment"
+        Just alignProof =>
+          Right (MkStructLayout fields size align
+                   {sizeCorrect = sizeOk} {aligned = alignProof})
 
 --------------------------------------------------------------------------------
 -- Nim Object Layout Rules
@@ -148,7 +169,7 @@ nimFieldAlign p ty = min (nimFieldSize p ty) (ptrSize p `div` 8)
 ||| Convert a NimObject to a StructLayout using exportc rules
 ||| (C-compatible: declaration order, natural alignment, trailing padding)
 public export
-nimObjectToLayout : Platform -> NimObject -> Either String StructLayout
+nimObjectToLayout : Platform -> NimObjectDef -> Either String StructLayout
 nimObjectToLayout p obj =
   let fields = computeFields p 0 obj.fields
    in verifyLayout (fromList fields) (maxAlign p obj.fields)
@@ -200,10 +221,25 @@ data CABICompliant : StructLayout -> Type where
     FieldsAligned layout.fields ->
     CABICompliant layout
 
+||| Decide whether every field's offset is aligned to its alignment.
+public export
+decFieldsAligned : (fields : Vect k Field) -> Maybe (FieldsAligned fields)
+decFieldsAligned [] = Just NoFields
+decFieldsAligned (f :: fs) =
+  case decDivides f.alignment f.offset of
+    Nothing => Nothing
+    Just dv =>
+      case decFieldsAligned fs of
+        Nothing => Nothing
+        Just rest => Just (ConsField f fs dv rest)
+
 ||| Check if layout follows C ABI
 public export
 checkCABI : (layout : StructLayout) -> Either String (CABICompliant layout)
-checkCABI layout = Right (CABIOk layout ?fieldsAlignedProof)
+checkCABI layout =
+  case decFieldsAligned layout.fields of
+    Just prf => Right (CABIOk layout prf)
+    Nothing => Left "Struct fields are not correctly aligned for C ABI"
 
 --------------------------------------------------------------------------------
 -- Nim-Specific Layout Examples
@@ -224,6 +260,8 @@ nimBufferLayout =
     ]
     16  -- Total size: 16 bytes
     8   -- Alignment: 8 bytes (pointer)
+    {sizeCorrect = Oh}
+    {aligned = DivideBy 2 Refl}
 
 ||| Example: Nim object with default alignment
 ||| type NimResult {.exportc: "nimiser_result".} = object
@@ -239,16 +277,25 @@ nimResultLayout =
     ]
     16  -- Total size: 16 bytes
     8   -- Alignment: 8 bytes
+    {sizeCorrect = Oh}
+    {aligned = DivideBy 2 Refl}
 
 ||| Proof that buffer layout is valid
 export
-nimBufferLayoutValid : CABICompliant nimBufferLayout
-nimBufferLayoutValid = CABIOk nimBufferLayout ?bufferFieldsAligned
+nimBufferLayoutValid : CABICompliant Layout.nimBufferLayout
+nimBufferLayoutValid =
+  CABIOk nimBufferLayout
+    (ConsField _ _ (DivideBy 0 Refl)
+      (ConsField _ _ (DivideBy 2 Refl)
+        (ConsField _ _ (DivideBy 3 Refl) NoFields)))
 
 ||| Proof that result layout is valid
 export
-nimResultLayoutValid : CABICompliant nimResultLayout
-nimResultLayoutValid = CABIOk nimResultLayout ?resultFieldsAligned
+nimResultLayoutValid : CABICompliant Layout.nimResultLayout
+nimResultLayoutValid =
+  CABIOk nimResultLayout
+    (ConsField _ _ (DivideBy 0 Refl)
+      (ConsField _ _ (DivideBy 1 Refl) NoFields))
 
 --------------------------------------------------------------------------------
 -- Offset Calculation
@@ -262,7 +309,11 @@ fieldOffset layout name =
     Just idx => Just (finToNat idx ** index idx layout.fields)
     Nothing => Nothing
 
-||| Proof that field offset is within struct bounds
+||| Decide whether a field's offset is within struct bounds.
+||| In general a field may exceed the struct, so the result is a Maybe witness.
 public export
-offsetInBounds : (layout : StructLayout) -> (f : Field) -> So (f.offset + f.size <= layout.totalSize)
-offsetInBounds layout f = ?offsetInBoundsProof
+offsetInBounds : (layout : StructLayout) -> (f : Field) -> Maybe (So (f.offset + f.size <= layout.totalSize))
+offsetInBounds layout f =
+  case choose (f.offset + f.size <= layout.totalSize) of
+    Left ok => Just ok
+    Right _ => Nothing
diff --git a/src/interface/abi/Nimiser/ABI/Proofs.idr b/src/interface/abi/Nimiser/ABI/Proofs.idr
new file mode 100644
index 0000000..8667f60
--- /dev/null
+++ b/src/interface/abi/Nimiser/ABI/Proofs.idr
@@ -0,0 +1,63 @@
+-- SPDX-License-Identifier: MPL-2.0
+-- Copyright (c) 2026 Jonathan D.A. Jewell (hyperpolymath) <j.d.a.jewell@open.ac.uk>
+--
+||| Machine-checked theorems for the Nimiser ABI.
+|||
+||| Each concrete `StructLayout` value is proven `CABICompliant` by building
+||| the `FieldsAligned` witness directly (one `DivideBy` per field, where the
+||| field offset equals `k * alignment`). Multiplication reduces during
+||| typechecking; division does not — so these witnesses are built by hand
+||| rather than via `decFieldsAligned`.
+
+module Nimiser.ABI.Proofs
+
+import Nimiser.ABI.Types
+import Nimiser.ABI.Layout
+import Data.Vect
+
+%default total
+
+--------------------------------------------------------------------------------
+-- C-ABI compliance of the concrete struct layouts
+--------------------------------------------------------------------------------
+
+||| The `nimiser_buffer` layout is C-ABI compliant.
+||| Fields: data @0 align 8 (0 = 0*8), len @8 align 4 (8 = 2*4),
+||| cap @12 align 4 (12 = 3*4).
+export
+nimBufferCompliant : CABICompliant Layout.nimBufferLayout
+nimBufferCompliant =
+  CABIOk nimBufferLayout
+    (ConsField _ _ (DivideBy 0 Refl)
+      (ConsField _ _ (DivideBy 2 Refl)
+        (ConsField _ _ (DivideBy 3 Refl) NoFields)))
+
+||| The `nimiser_result` layout is C-ABI compliant.
+||| Fields: code @0 align 4 (0 = 0*4), message @8 align 8 (8 = 1*8).
+export
+nimResultCompliant : CABICompliant Layout.nimResultLayout
+nimResultCompliant =
+  CABIOk nimResultLayout
+    (ConsField _ _ (DivideBy 0 Refl)
+      (ConsField _ _ (DivideBy 1 Refl) NoFields))
+
+--------------------------------------------------------------------------------
+-- Result-code encoding facts
+--------------------------------------------------------------------------------
+
+||| The success result encodes to the C integer 0.
+export
+okIsZero : resultToInt Ok = 0
+okIsZero = Refl
+
+||| The null-pointer result encodes to the C integer 4 (a nontrivial, distinct
+||| code in the middle of the enumeration).
+export
+nullPointerIsFour : resultToInt NullPointer = 4
+nullPointerIsFour = Refl
+
+||| The result encoding is injective on the two error codes we pin here:
+||| distinct constructors map to distinct integers, witnessed structurally.
+export
+okDistinctFromError : Not (resultToInt Ok = resultToInt Error)
+okDistinctFromError = \case Refl impossible
diff --git a/src/interface/abi/Types.idr b/src/interface/abi/Nimiser/ABI/Types.idr
similarity index 77%
rename from src/interface/abi/Types.idr
rename to src/interface/abi/Nimiser/ABI/Types.idr
index 2e8d3d6..866c5c2 100644
--- a/src/interface/abi/Types.idr
+++ b/src/interface/abi/Nimiser/ABI/Types.idr
@@ -16,6 +16,7 @@ module Nimiser.ABI.Types
 import Data.Bits
 import Data.So
 import Data.Vect
+import Decidable.Equality
 
 %default total
 
@@ -31,10 +32,7 @@ data Platform = Linux | Windows | MacOS | BSD | WASM
 ||| This will be set during compilation based on target
 public export
 thisPlatform : Platform
-thisPlatform =
-  %runElab do
-    -- Platform detection logic
-    pure Linux  -- Default, override with compiler flags
+thisPlatform = Linux  -- Default, override with compiler flags
 
 --------------------------------------------------------------------------------
 -- Nim Metaprogramming Types
@@ -205,7 +203,62 @@ DecEq Result where
   decEq CompilationFailed CompilationFailed = Yes Refl
   decEq TemplateError TemplateError = Yes Refl
   decEq MacroError MacroError = Yes Refl
-  decEq _ _ = No absurd
+  decEq Ok Error = No (\case Refl impossible)
+  decEq Ok InvalidParam = No (\case Refl impossible)
+  decEq Ok OutOfMemory = No (\case Refl impossible)
+  decEq Ok NullPointer = No (\case Refl impossible)
+  decEq Ok CompilationFailed = No (\case Refl impossible)
+  decEq Ok TemplateError = No (\case Refl impossible)
+  decEq Ok MacroError = No (\case Refl impossible)
+  decEq Error Ok = No (\case Refl impossible)
+  decEq Error InvalidParam = No (\case Refl impossible)
+  decEq Error OutOfMemory = No (\case Refl impossible)
+  decEq Error NullPointer = No (\case Refl impossible)
+  decEq Error CompilationFailed = No (\case Refl impossible)
+  decEq Error TemplateError = No (\case Refl impossible)
+  decEq Error MacroError = No (\case Refl impossible)
+  decEq InvalidParam Ok = No (\case Refl impossible)
+  decEq InvalidParam Error = No (\case Refl impossible)
+  decEq InvalidParam OutOfMemory = No (\case Refl impossible)
+  decEq InvalidParam NullPointer = No (\case Refl impossible)
+  decEq InvalidParam CompilationFailed = No (\case Refl impossible)
+  decEq InvalidParam TemplateError = No (\case Refl impossible)
+  decEq InvalidParam MacroError = No (\case Refl impossible)
+  decEq OutOfMemory Ok = No (\case Refl impossible)
+  decEq OutOfMemory Error = No (\case Refl impossible)
+  decEq OutOfMemory InvalidParam = No (\case Refl impossible)
+  decEq OutOfMemory NullPointer = No (\case Refl impossible)
+  decEq OutOfMemory CompilationFailed = No (\case Refl impossible)
+  decEq OutOfMemory TemplateError = No (\case Refl impossible)
+  decEq OutOfMemory MacroError = No (\case Refl impossible)
+  decEq NullPointer Ok = No (\case Refl impossible)
+  decEq NullPointer Error = No (\case Refl impossible)
+  decEq NullPointer InvalidParam = No (\case Refl impossible)
+  decEq NullPointer OutOfMemory = No (\case Refl impossible)
+  decEq NullPointer CompilationFailed = No (\case Refl impossible)
+  decEq NullPointer TemplateError = No (\case Refl impossible)
+  decEq NullPointer MacroError = No (\case Refl impossible)
+  decEq CompilationFailed Ok = No (\case Refl impossible)
+  decEq CompilationFailed Error = No (\case Refl impossible)
+  decEq CompilationFailed InvalidParam = No (\case Refl impossible)
+  decEq CompilationFailed OutOfMemory = No (\case Refl impossible)
+  decEq CompilationFailed NullPointer = No (\case Refl impossible)
+  decEq CompilationFailed TemplateError = No (\case Refl impossible)
+  decEq CompilationFailed MacroError = No (\case Refl impossible)
+  decEq TemplateError Ok = No (\case Refl impossible)
+  decEq TemplateError Error = No (\case Refl impossible)
+  decEq TemplateError InvalidParam = No (\case Refl impossible)
+  decEq TemplateError OutOfMemory = No (\case Refl impossible)
+  decEq TemplateError NullPointer = No (\case Refl impossible)
+  decEq TemplateError CompilationFailed = No (\case Refl impossible)
+  decEq TemplateError MacroError = No (\case Refl impossible)
+  decEq MacroError Ok = No (\case Refl impossible)
+  decEq MacroError Error = No (\case Refl impossible)
+  decEq MacroError InvalidParam = No (\case Refl impossible)
+  decEq MacroError OutOfMemory = No (\case Refl impossible)
+  decEq MacroError NullPointer = No (\case Refl impossible)
+  decEq MacroError CompilationFailed = No (\case Refl impossible)
+  decEq MacroError TemplateError = No (\case Refl impossible)
 
 --------------------------------------------------------------------------------
 -- Opaque Handles
@@ -221,8 +274,10 @@ data Handle : Type where
 ||| Returns Nothing if pointer is null
 public export
 createHandle : Bits64 -> Maybe Handle
-createHandle 0 = Nothing
-createHandle ptr = Just (MkHandle ptr)
+createHandle ptr =
+  case choose (ptr /= 0) of
+    Left ok => Just (MkHandle ptr {nonNull = ok})
+    Right _ => Nothing
 
 ||| Extract pointer value from handle
 public export
@@ -245,8 +300,8 @@ record NimField where
 
 ||| A Nim object definition that will be exported as a C struct
 public export
-record NimObject where
-  constructor MkNimObject
+record NimObjectDef where
+  constructor MkNimObjectDef
   objectName : String
   fields : List NimField
   isPacked : Bool         -- {.packed.} on the whole object
@@ -284,10 +339,15 @@ ptrSize MacOS = 64
 ptrSize BSD = 64
 ptrSize WASM = 32
 
-||| Pointer type for platform
+||| Pointer-sized integer type for a platform.
+||| 64-bit platforms use Bits64; WASM (32-bit) uses Bits32.
 public export
 CPtr : Platform -> Type -> Type
-CPtr p _ = Bits (ptrSize p)
+CPtr Linux   _ = Bits64
+CPtr Windows _ = Bits64
+CPtr MacOS   _ = Bits64
+CPtr BSD     _ = Bits64
+CPtr WASM    _ = Bits32
 
 --------------------------------------------------------------------------------
 -- Memory Layout Proofs
@@ -306,8 +366,8 @@ data HasAlignment : Type -> Nat -> Type where
 ||| Size of C types (platform-specific)
 public export
 cSizeOf : (p : Platform) -> (t : Type) -> Nat
-cSizeOf p (CInt _) = 4
-cSizeOf p (CSize _) = if ptrSize p == 64 then 8 else 4
+cSizeOf p Bits8 = 1
+cSizeOf p Bits16 = 2
 cSizeOf p Bits32 = 4
 cSizeOf p Bits64 = 8
 cSizeOf p Double = 8
@@ -316,8 +376,8 @@ cSizeOf p _ = ptrSize p `div` 8
 ||| Alignment of C types (platform-specific)
 public export
 cAlignOf : (p : Platform) -> (t : Type) -> Nat
-cAlignOf p (CInt _) = 4
-cAlignOf p (CSize _) = if ptrSize p == 64 then 8 else 4
+cAlignOf p Bits8 = 1
+cAlignOf p Bits16 = 2
 cAlignOf p Bits32 = 4
 cAlignOf p Bits64 = 8
 cAlignOf p Double = 8
diff --git a/src/interface/abi/nimiser-abi.ipkg b/src/interface/abi/nimiser-abi.ipkg
new file mode 100644
index 0000000..3cdafb1
--- /dev/null
+++ b/src/interface/abi/nimiser-abi.ipkg
@@ -0,0 +1,4 @@
+-- SPDX-License-Identifier: MPL-2.0
+package nimiser-abi
+sourcedir = "."
+modules = Nimiser.ABI.Types, Nimiser.ABI.Layout, Nimiser.ABI.Foreign, Nimiser.ABI.Proofs