buchk · buchk · Jul 22, 2026 · Jul 23, 2026 · Jul 23, 2026 · Jul 23, 2026
diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
@@ -5,30 +5,6 @@ on:
   pull_request:
 
 jobs:
-  build-test-docs:
-    runs-on: ubuntu-latest
-    steps:
-      - uses: actions/checkout@v4
-      - uses: actions/setup-dotnet@v4
-        with:
-          dotnet-version: 10.0.x
-      - uses: actions/setup-python@v5
-        with:
-          python-version: '3.12'
-      - run: dotnet restore TypeFerence.slnx
-      - run: dotnet build TypeFerence.slnx --no-restore --configuration Release
-      - run: dotnet test TypeFerence.slnx --no-build --configuration Release
-      - run: dotnet src/TypeFerence.Cli/bin/Release/net10.0/typeference.dll build examples/helio --target all --out dist-ci-1 --emit-ard --publisher-domain helio.example
-      - run: dotnet src/TypeFerence.Cli/bin/Release/net10.0/typeference.dll build examples/helio --target all --out dist-ci-2 --emit-ard --publisher-domain helio.example
-      - run: diff -qr dist-ci-1 dist-ci-2
-      - run: pip install -r tools/requirements-docs.txt
-      - run: python tools/render_whitepaper.py
-      - run: cp output/pdf/typeference-whitepaper.pdf /tmp/typeference-whitepaper-first.pdf
-      - run: python tools/render_whitepaper.py
-      - run: cmp /tmp/typeference-whitepaper-first.pdf output/pdf/typeference-whitepaper.pdf
-      - run: sudo apt-get update && sudo apt-get install -y poppler-utils
-      - run: pdfinfo output/pdf/typeference-whitepaper.pdf
-
   go-implementation:
     runs-on: ubuntu-latest
     steps:
@@ -44,8 +20,10 @@ jobs:
         working-directory: go
       - run: go test ./...
         working-directory: go
-      - name: Static binary (CGO_ENABLED=0)
-        run: CGO_ENABLED=0 go build -trimpath -ldflags "-s -w" -o /tmp/typeference ./cmd/typeference
+      - name: Static binaries (CGO_ENABLED=0)
+        run: |
+          CGO_ENABLED=0 go build -trimpath -ldflags "-s -w" -o /tmp/typeference ./cmd/typeference
+          CGO_ENABLED=0 go build -trimpath -ldflags "-s -w" -o /tmp/typeference-lsp ./cmd/typeference-lsp
         working-directory: go
       - name: Go binary reproduces committed reference output byte-for-byte
         run: /tmp/typeference diff examples/helio --against dist --emit-ard --publisher-domain helio.example
@@ -56,31 +34,21 @@ jobs:
           GOOS=js GOARCH=wasm go build ./cmd/typeference-wasm
           go run ./cmd/playground-pack -root .. -out /tmp/examples.json
         working-directory: go
-      # NOTE: BETH pack/score is intentionally NOT gating CI yet. The harness is
-      # unproven end to end (no real judged run has been collected), and an
-      # offline pack+score observes nothing — a green scorecard there would be
-      # vacuous (see ADR-0009 and score.go's judged-coverage requirement). Wire
-      # it back in once a real run is exercisable in CI or on the dev machine.
 
-  # Cross-implementation conformance: both compilers run the shared fixture
-  # corpus in conformance/; a digest mismatch on any fixture is a broken
-  # build. See conformance/README.md and ADR-0005.
-  conformance:
+  # Determinism suite: the Go compiler compiles the shared fixture corpus in
+  # conformance/ and must reproduce the committed digests. This is the
+  # single-implementation successor to the cross-implementation suite; the
+  # fixtures and canonicalization rulings (ADR-0004) are unchanged (ADR-0014).
+  determinism:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v4
-      - uses: actions/setup-dotnet@v4
-        with:
-          dotnet-version: 10.0.x
       - uses: actions/setup-go@v5
         with:
           go-version: stable
           cache-dependency-path: go/go.sum
-      - name: Conformance suite (Go implementation)
-        run: go test ./conformance -v
+      - run: go test ./conformance -v
         working-directory: go
-      - name: Conformance suite (C# reference implementation)
-        run: dotnet test TypeFerence.slnx --filter FullyQualifiedName~ConformanceSuiteTests
 
   # The repository-root AGENTS.md and dist-maintainer are build artifacts of
   # agents/maintainer (the self-hosted maintainer definition). Drift between
@@ -98,3 +66,18 @@ jobs:
         working-directory: go
       - name: Root AGENTS.md is the compiled artifact
         run: cmp AGENTS.md dist-maintainer/neutral/typeference-maintainer/AGENTS.md
+
+  docs:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - uses: actions/setup-python@v5
+        with:
+          python-version: '3.12'
+      - run: pip install -r tools/requirements-docs.txt
+      - run: python tools/render_whitepaper.py
+      - run: cp output/pdf/typeference-whitepaper.pdf /tmp/typeference-whitepaper-first.pdf
+      - run: python tools/render_whitepaper.py
+      - run: cmp /tmp/typeference-whitepaper-first.pdf output/pdf/typeference-whitepaper.pdf
+      - run: sudo apt-get update && sudo apt-get install -y poppler-utils
+      - run: pdfinfo output/pdf/typeference-whitepaper.pdf
diff --git a/.github/workflows/release.yml b/.github/workflows/release.yml
@@ -15,20 +15,16 @@ permissions:
   contents: write
 
 jobs:
-  # Nothing ships unless both implementations, the shared conformance suite,
-  # and the self-host drift gate are green at the tagged commit.
+  # Nothing ships unless the test suite, the determinism suite, and the
+  # self-host drift gate are green at the tagged commit.
   verify:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v4
-      - uses: actions/setup-dotnet@v4
-        with:
-          dotnet-version: 10.0.x
       - uses: actions/setup-go@v5
         with:
           go-version: stable
           cache-dependency-path: go/go.sum
-      - run: dotnet test TypeFerence.slnx
       - run: go test ./...
         working-directory: go
       - name: Self-host drift gate

diff --git a/.gitignore b/.gitignore
@@ -11,3 +11,8 @@ __pycache__/
 web/playground/typeference.wasm
 web/playground/wasm_exec.js
 web/playground/examples.json
+
+# Codex remote attachment scratch
+.codex-remote-attachments/
+go/typeference-wasm
+*.wasm
diff --git a/AGENTS.md b/AGENTS.md
@@ -8,15 +8,15 @@ The agent that maintains the TypeFerence repository, defined in TypeFerence's ow
 - Where the specification and an implementation disagree, the specification wins; record the ruling in docs/decisions and cover it with a conformance fixture.
 - Every canonicalization or composition ruling ships with a fixture under conformance/fixtures in the same change.
 - Never silently diverge from the specification; fixing the specification is allowed, silent divergence is not.
-- Any change to code generation must keep the C# and Go implementations byte-identical, verified by the conformance suite before merge.
+- Any change to code generation must reproduce the committed digests, verified by the determinism suite before merge.
 - Never weaken determinism, provenance, or fail-closed behavior to make a change easier.
 - A conformance digest is regenerated only together with the specification change and ADR that justify it; never hand-edit a digest.
 - Repeated builds from identical source must stay byte-identical on every platform.
 - The signature map always resides outside the source root; moving it inside creates a digest/signature cycle and is forbidden.
 - signatureIntent.required fails closed; the unsigned-staging option exists solely to emit payloads for an external signer.
 - TypeFerence imports externally produced signatures; it never signs, never verifies cryptographic validity, and never resolves keys.
 - Trust metadata is declarative; never dereference identity, attestation, or provenance URIs during compilation.
-- Every commit builds and passes both implementations' test suites and the shared conformance suite.
+- Every commit builds and passes the test suite and the determinism suite.
 - Decisions with real tradeoffs are recorded as ADRs in docs/decisions before the change merges.
 - Documentation must be accurate against the code at the commit that includes it; no fabricated adoption, benchmarks, or endorsements.
 - Commit messages are conventional and written for a critical human reader.
@@ -28,5 +28,5 @@ The agent that maintains the TypeFerence repository, defined in TypeFerence's ow
 ## Available skills
 
 - `typeference-maintainer.audit-drift`: Confirms the committed AGENTS.md and maintainer bundle are exact build artifacts of this definition.
-- `typeference-maintainer.verify-conformance`: Runs the shared conformance suite on both implementations and reports any digest disagreement.
+- `typeference-maintainer.verify-conformance`: Runs the determinism suite and reports whether the compiler reproduces the committed digests.
 
diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -9,6 +9,28 @@ versioning. Tool versions (this file) are independent of the typed-resource
 TypeFerence is an experimental reference implementation; pre-1.0 versions make no
 compatibility promises between minor versions.
 
+## [Unreleased]
+
+### Changed
+
+- **Go-only implementation** ([ADR-0014](docs/decisions/0014-go-only-implementation.md)).
+  The C# reference implementation was retired; the Go implementation is now the
+  sole implementation. The specification stays normative in principle. The
+  cross-implementation conformance suite becomes a single-implementation
+  golden-file determinism suite over the same fixtures — the determinism
+  guarantee is unchanged.
+
+### Added
+
+- **`.tfer` source format** and object-model constructs (ADRs 0012–0019):
+  invocation-mode skill variants, user-defined typed context (`contextType`
+  refinement, context held by id, `requiresContextTypes`), tools as extern
+  declarations (`requiresTools`), capability exposure/visibility, and sealing
+  (`sealed`/`required` bindings). All additive and opt-in.
+- **Language server** (`typeference-lsp`): authoring and composition
+  diagnostics, completion, go-to-definition, and document symbols for `.tfer`
+  and `.yaml` sources.
+
 ## [0.0.4] - 2026-07-15
 
 ### Added

diff --git a/Directory.Build.props b/Directory.Build.props
diff --git a/Makefile b/Makefile
@@ -1,41 +1,37 @@
-# TypeFerence build entry points. Requires: Go 1.24+, .NET 10 SDK (reference
-# implementation only). All artifacts are deterministic; run `make conformance`
-# to verify both implementations agree byte-for-byte.
+# TypeFerence build entry points. Requires: Go 1.24+ and nothing else. All
+# artifacts are deterministic; run `make conformance` to verify the compiler
+# reproduces the committed digests byte-for-byte (ADR-0014).
 
 GO ?= go
-DOTNET ?= dotnet
 VERSION ?= dev
 GOFLAGS := -trimpath
 LDFLAGS := -s -w -X main.version=$(VERSION)
 BINDIR := bin
 
-.PHONY: all build build-go build-dotnet test test-go test-dotnet conformance \
+.PHONY: all build build-go build-lsp test test-go conformance \
 	selfhost selfhost-check fmt vet clean release-binaries playground
 
 all: build test
 
-build: build-go build-dotnet
+build: build-go build-lsp
 
 # Single static binary, no runtime dependencies.
 build-go:
 	cd go && CGO_ENABLED=0 $(GO) build $(GOFLAGS) -ldflags "$(LDFLAGS)" -o ../$(BINDIR)/typeference$(shell $(GO) env GOEXE) ./cmd/typeference
 
-build-dotnet:
-	$(DOTNET) build TypeFerence.slnx
+# Language server for .tfer/.yaml authoring diagnostics (internal/lsp).
+build-lsp:
+	cd go && CGO_ENABLED=0 $(GO) build $(GOFLAGS) -ldflags "$(LDFLAGS)" -o ../$(BINDIR)/typeference-lsp$(shell $(GO) env GOEXE) ./cmd/typeference-lsp
 
-test: test-go test-dotnet
+test: test-go
 
 test-go:
 	cd go && $(GO) test ./...
 
-test-dotnet:
-	$(DOTNET) test TypeFerence.slnx
-
-# Cross-implementation conformance: both compilers run the shared fixture
-# corpus; digests must match the manifests and each other.
+# Determinism suite: the compiler compiles the shared fixture corpus and must
+# reproduce the committed digests (ADR-0014).
 conformance:
 	cd go && $(GO) test ./conformance -run TestConformance -v
-	$(DOTNET) test TypeFerence.slnx --filter FullyQualifiedName~ConformanceSuiteTests
 
 # Recompile the self-hosted maintainer definition (agents/maintainer) into its
 # committed artifacts: dist-maintainer and the repository-root AGENTS.md.
@@ -50,7 +46,6 @@ selfhost-check: build-go
 
 fmt:
 	cd go && gofmt -l -w .
-	$(DOTNET) format TypeFerence.slnx
 
 vet:
 	cd go && $(GO) vet ./...

diff --git a/README.md b/README.md
@@ -137,33 +137,22 @@ what "No differences." means. `eval` and `equivalence` are covered in
 [Behavioral evals](#behavioral-evals) below; both default to a dry run that
 never makes a network call.
 
-## Two implementations, one specification
-
-The C# implementation under `src/` is the reference implementation; the Go
-implementation under `go/` is an independent second implementation. Both compile
-identical source to **byte-identical artifacts**, enforced by a shared conformance
-suite ([conformance/](conformance/README.md)) that runs on both implementations in
-CI — expected digests are generated by one implementation and independently
-verified by the other. That suite is what makes the
-[specification](docs/specification.md) real rather than aspirational.
-
-### Reference implementation (C#)
-
-Requires the .NET 10 SDK.
-
-```powershell
-dotnet build TypeFerence.slnx
-dotnet src/TypeFerence.Cli/bin/Debug/net10.0/typeference.dll validate examples/helio
-dotnet src/TypeFerence.Cli/bin/Debug/net10.0/typeference.dll serve dist/neutral
-```
-
-The MCP server (`typeference serve`) is currently implemented in the reference
-implementation only. It exposes tools such as:
-
-- `executive-assistant.prepare-brief`
-- `payments-repo-agent.repository-status`
-
-Calls return a deterministic invocation package for the host agent. TypeFerence does not embed an LLM provider.
+## One implementation, one specification
+
+The Go implementation under `go/` is the reference implementation. The
+[specification](docs/specification.md) stays normative in principle — the
+abstraction is the contract, and anyone may realize it differently — but this
+repository's Go compiler is the one living answer ([ADR-0014](docs/decisions/0014-go-only-implementation.md)).
+Determinism is preserved and made visible by the
+[conformance suite](conformance/README.md): the compiler must reproduce the
+committed digests byte-for-byte.
+
+An earlier C# reference implementation was retired when the project committed to
+being a tool rather than a multi-implementation standard. Determinism — the
+property that makes `diff` and the committed-digest guarantee real — is a property
+of one good compiler and was unaffected; only the second implementation, and the
+cross-implementation half of the conformance suite, went away. TypeFerence embeds
+no LLM provider and holds no deployment state.
 
 ## Self-hosting
 
@@ -220,8 +209,7 @@ TypeFerence does not hold signing keys. An external signer can produce detached
 
 ## Repository map
 
-- `src/` - C# reference implementation: compiler, target adapters, CLI, and MCP runtime.
-- `go/` - independent Go implementation: compiler, target adapters, CLI, and eval harness.
+- `go/` - the Go implementation: compiler, target adapters, CLI, language server (`cmd/typeference-lsp`), and eval harness.
 - `conformance/` - shared cross-implementation conformance fixtures (byte-identity contract).
 - `examples/helio/` - fictional cross-domain organization.
 - `web/playground/` - browser playground: the Go compiler built for `js/wasm`, plus the BETH operator console.
@@ -230,7 +218,6 @@ TypeFerence does not hold signing keys. An external signer can produce detached
 - `docs/specification.md` - normative v3 behavior.
 - `docs/decisions/` - architecture decision records.
 - `docs/whitepaper.md` and `output/pdf/typeference-whitepaper.pdf` - design paper.
-- `tests/` - C# test suite: type system, targets, determinism, conformance runner, MCP integration.
 - `CHANGELOG.md` and `docs/release-checklist.md` - versioning and release process.
 
 ## Design boundaries

diff --git a/TypeFerence.slnx b/TypeFerence.slnx
diff --git a/.../agents/typeference-maintainer.agent.yaml → .../agents/typeference-maintainer.agent.tfer b/.../agents/typeference-maintainer.agent.yaml → .../agents/typeference-maintainer.agent.tfer
@@ -1,3 +1,4 @@
+---
 schemaVersion: 3
 kind: agent
 id: typeference/typeference-maintainer@0.1.0
@@ -12,3 +13,4 @@ slots:
   repositoryMap: context/repository-map.md
 contextFiles:
   - context/repository-map.md
+---
diff --git a/.../capabilities/audit-drift.capability.yaml → .../capabilities/audit-drift.capability.tfer b/.../capabilities/audit-drift.capability.yaml → .../capabilities/audit-drift.capability.tfer
@@ -1,7 +1,9 @@
+---
 schemaVersion: 3
 kind: capability
 id: typeference/capabilities/audit-drift@0.1.0
 displayName: Audit Self-Host Drift
 description: Recompile the maintainer definition and report drift against the committed artifacts.
 inputSchema: '{"type":"object","additionalProperties":false}'
 outputSchema: '{"type":"object","properties":{"clean":{"type":"boolean"},"driftedFiles":{"type":"array","items":{"type":"string"}}},"required":["clean","driftedFiles"]}'
+---
diff --git a/...lities/verify-conformance.capability.yaml → ...lities/verify-conformance.capability.tfer b/...lities/verify-conformance.capability.yaml → ...lities/verify-conformance.capability.tfer
@@ -1,7 +1,9 @@
+---
 schemaVersion: 3
 kind: capability
 id: typeference/capabilities/verify-conformance@0.1.0
 displayName: Verify Conformance
-description: Run both implementations against the shared conformance suite and report agreement.
+description: Run the determinism suite and report whether the compiler reproduces the committed digests.
 inputSchema: '{"type":"object","additionalProperties":false}'
 outputSchema: '{"type":"object","properties":{"passed":{"type":"boolean"},"mismatches":{"type":"array","items":{"type":"string"}}},"required":["passed","mismatches"]}'
+---
diff --git a/agents/maintainer/context/contribution.md b/agents/maintainer/context/contribution.md
@@ -2,9 +2,8 @@
 
 - Work on feature branches; never rewrite published history; never tag or publish a
   release outside the checklist in `docs/release-checklist.md`.
-- Before any commit: `dotnet test TypeFerence.slnx`, `go test ./...` (from `go/`),
-  and the conformance suite (`make conformance`) all pass. A commit that breaks any
-  of them does not land.
+- Before any commit: `go test ./...` (from `go/`) and the determinism suite
+  (`make conformance`) both pass. A commit that breaks either does not land.
 - Design decisions with real tradeoffs — spec semantics, canonical bytes, trust
   model, dependencies — are recorded in `docs/decisions/` as numbered ADRs in the
   same change.