diff --git a/.machine_read/ANCHOR.scope-arrest.2026-01-01.scm b/.machine_read/ANCHOR.scope-arrest.2026-01-01.scm
new file mode 100644
index 0000000..643d8b2
--- /dev/null
+++ b/.machine_read/ANCHOR.scope-arrest.2026-01-01.scm
@@ -0,0 +1,50 @@
+;; ANCHOR.scope-arrest.2026-01-01.Jewell.scm  (anvomidav)
+;; SPDX-License-Identifier: MIT OR AGPL-3.0-or-later
+;; SPDX-FileCopyrightText: 2026 hyperpolymath
+;;
+;; This anchor file defines the scope arrest for phase f0.
+;; It freezes the project identity and establishes the conformance baseline.
+
+(define anchor
+  '((schema . "hyperpolymath.anchor/1")
+    (repo . "hyperpolymath/anvomidav")
+    (date . "2026-01-01")
+    (authority . "repo-superintendent")
+    (purpose . ("Scope arrest + make repo unambiguously runnable + freeze identity."))
+    (identity
+      . ((project . "Anvomidav")
+         (kind . "domain-language + CLI toolchain")
+         (domain . "figure-skating choreography")
+         (one-sentence . "A DSL and toolchain for expressing skating choreography and validating rule constraints.")))
+
+    (semantic-anchor
+      . ((policy . "dual")
+         (reference-impl . ("Rust workspace" "CLI is authoritative behavior"))
+         (formal-spec . ("SPEC.core.scm defines syntax/semantics; conformance corpus is binding"))))
+
+    (allowed-implementation-languages
+      . ("Rust")) ;; keep narrow in f0; editors/tooling optional later
+    (forbidden
+      . ("Expanding into unrelated domains"
+         "Adding new backends"
+         "Rewriting as a different project"))
+
+    (golden-path
+      . ((smoke-test-command . "cargo test && cargo run -p anv-cli -- check examples/*")
+         (success-criteria . ("parse+check succeeds on at least 1 example"
+                              "at least 5 invalid examples produce stable diagnostics"))))
+
+    (mandatory-files
+      . ("./.machine_read/LLM_SUPERINTENDENT.scm"
+         "./.machine_read/SPEC.core.scm"
+         "./.machine_read/ROADMAP.f0.scm"
+         "./conformance/"))
+
+    (first-pass-directives
+      . ("Ensure README(s) do not contradict this identity."
+         "If multiple READMEs exist, create one canonical machine README pointer (no prose needed)."
+         "Quarantine tree-sitter/editor integration as optional: it must not block core build."
+         "Add conformance corpus representing core grammar + rule checks."))
+
+    (rsr
+      . ((target-tier . "bronze-now") (upgrade-path . "silver-after-f1")))))
diff --git a/.machine_read/AUTHORITY_STACK.scm b/.machine_read/AUTHORITY_STACK.scm
new file mode 100644
index 0000000..420f08e
--- /dev/null
+++ b/.machine_read/AUTHORITY_STACK.scm
@@ -0,0 +1,47 @@
+;; AUTHORITY_STACK.mustfile-nickel.scm
+;; SPDX-License-Identifier: MIT OR AGPL-3.0-or-later
+;; SPDX-FileCopyrightText: 2026 hyperpolymath
+;;
+;; Shared drop for hyperpolymath repos: defines task routing + config authority.
+
+(define authority-stack
+  '((schema . "hyperpolymath.authority-stack/1")
+    (intent
+      . ("Stop agentic drift and toolchain creep."
+         "Make the repo executable via a single blessed interface."
+         "Prevent the LLM from inventing commands, tools, or files."))
+
+    (operational-authority
+      . ((local-tasks . "just")
+         (deployment-transitions . "must")
+         (config-manifests . "nickel")
+         (container-engine . "podman-first")))
+
+    (hard-rules
+      . ("Makefiles are forbidden."
+         "All operations must be invoked via `just <recipe>` (local) or `must <transition>` (deployment)."
+         "If a recipe/transition does not exist, the correct action is to ADD it (and document it), not to run ad-hoc commands."
+         "Nickel manifests are the single source of truth for config; do not hand-edit generated outputs."
+         "No network-required runtime paths for demos/tests unless explicitly permitted in ANCHOR."))
+
+    (workflow
+      . ((first-run
+           . ("Read ANCHOR*.scm"
+              "Read STATE.scm"
+              "Run: just --list"
+              "Run: just test"
+              "Run: just demo (if defined)"))
+         (adding-new-capability
+           . ("Update SPEC/ROADMAP first"
+              "Add a `just` recipe (and tests) that implements the capability"
+              "Only then edit code"))))
+
+    (tooling-contract
+      . ((mustfile-notes
+           . ("Mustfile is the deployment contract (physical state transitions)."
+              "must is the supervisor/enforcer for must-spec; it routes through just where appropriate."))
+         (nickel-notes
+           . ("Nickel provides validated, type-safe manifests."
+              "Prefer .ncl for machine-truth; render docs from it via your conversion pipeline."))
+         (shell-entrypoints
+           . ("Shell wrappers may exist; all must route to just/must without inventing extra logic."))))))
diff --git a/.machine_read/CANONICAL_README.scm b/.machine_read/CANONICAL_README.scm
new file mode 100644
index 0000000..b2922c8
--- /dev/null
+++ b/.machine_read/CANONICAL_README.scm
@@ -0,0 +1,89 @@
+;; SPDX-License-Identifier: MIT OR AGPL-3.0-or-later
+;; SPDX-FileCopyrightText: 2025-2026 hyperpolymath
+;;
+;; CANONICAL_README.scm - Pointer to Canonical Documentation
+;;
+;; This file establishes the documentation hierarchy for the repository.
+;; Multiple READMEs exist for different purposes; this file clarifies authority.
+
+(define canonical-docs
+  '((schema . "hyperpolymath.canonical-docs/1")
+    (updated . "2026-01-01")
+
+    ;; ==========================================================================
+    ;; PRIMARY DOCUMENTATION
+    ;; ==========================================================================
+    (primary
+      . ((readme
+           . ((path . "./README.adoc")
+              (purpose . "Main project documentation, quick start, syntax examples")
+              (authority . "canonical")))
+         (roadmap
+           . ((path . "./ROADMAP.adoc")
+              (purpose . "Development phases and milestones")
+              (authority . "canonical")))
+         (contributing
+           . ((path . "./CONTRIBUTING.adoc")
+              (purpose . "How to contribute")
+              (authority . "canonical")))
+         (security
+           . ((path . "./SECURITY.md")
+              (purpose . "Security policy and vulnerability reporting")
+              (authority . "canonical")))))
+
+    ;; ==========================================================================
+    ;; MACHINE-READABLE DOCUMENTATION
+    ;; ==========================================================================
+    (machine-readable
+      . ((superintendent
+           . ((path . "./.machine_read/LLM_SUPERINTENDENT.scm")
+              (purpose . "Instructions for AI/LLM agents")))
+         (spec
+           . ((path . "./.machine_read/SPEC.core.scm")
+              (purpose . "Core language specification (binding)")))
+         (roadmap-f0
+           . ((path . "./.machine_read/ROADMAP.f0.scm")
+              (purpose . "Phase f0 scope arrest roadmap")))
+         (state
+           . ((path . "./STATE.scm")
+              (purpose . "Current project state")))))
+
+    ;; ==========================================================================
+    ;; SUPPLEMENTARY DOCUMENTATION (Non-authoritative for Core)
+    ;; ==========================================================================
+    (supplementary
+      . ((academic
+           . ((path . "./docs/academic/README.adoc")
+              (purpose . "Academic papers and formal proofs")
+              (status . "optional")))
+         (implementation
+           . ((path . "./docs/IMPLEMENTATION.adoc")
+              (purpose . "Implementation details")
+              (status . "optional")))))
+
+    ;; ==========================================================================
+    ;; EDITOR/TOOLING DOCUMENTATION (OPTIONAL - Does not affect core)
+    ;; ==========================================================================
+    (optional-tooling
+      . ((neovim
+           . ((path . "./editors/neovim/README.md")
+              (purpose . "Neovim integration")
+              (status . "optional - does not block core build")))
+         (helix
+           . ((path . "./editors/helix/README.md")
+              (purpose . "Helix editor integration")
+              (status . "optional - does not block core build")))
+         (tree-sitter
+           . ((path . "./tree-sitter-anvomidav/")
+              (purpose . "Tree-sitter grammar for syntax highlighting")
+              (status . "optional - does not block core build")))))
+
+    ;; ==========================================================================
+    ;; READING ORDER FOR NEW CONTRIBUTORS
+    ;; ==========================================================================
+    (reading-order
+      . (("README.adoc" . "Start here for project overview")
+         ("ROADMAP.adoc" . "Understand development phases")
+         ("CONTRIBUTING.adoc" . "How to participate")
+         (".machine_read/SPEC.core.scm" . "Language specification")
+         ("crates/anv-cli/src/main.rs" . "CLI entry point")))))
diff --git a/.machine_read/LLM_SUPERINTENDENT.scm b/.machine_read/LLM_SUPERINTENDENT.scm
new file mode 100644
index 0000000..3eeb81d
--- /dev/null
+++ b/.machine_read/LLM_SUPERINTENDENT.scm
@@ -0,0 +1,81 @@
+;; SPDX-License-Identifier: MIT OR AGPL-3.0-or-later
+;; SPDX-FileCopyrightText: 2025-2026 hyperpolymath
+;;
+;; LLM_SUPERINTENDENT.scm - Instructions for AI/LLM agents operating on this repository
+;;
+;; This file provides machine-readable directives for LLM code assistants.
+
+(define superintendent
+  '((schema . "hyperpolymath.superintendent/1")
+    (updated . "2026-01-01")
+
+    ;; Project identity - DO NOT DEVIATE
+    (identity
+      . ((name . "Anvomidav")
+         (kind . "domain-specific language + CLI toolchain")
+         (domain . "figure skating choreography")
+         (one-sentence . "A DSL and toolchain for expressing skating choreography and validating ISU rule constraints.")))
+
+    ;; Implementation constraints
+    (implementation
+      . ((language . "Rust")
+         (workspace . "Cargo.toml defines workspace members")
+         (cli-binary . "anv-cli")
+         (reference-behavior . "CLI output is authoritative")))
+
+    ;; What to protect
+    (invariants
+      . (("Core semantics must match SPEC.core.scm")
+         ("ISU rule validation must pass for valid examples in conformance/valid/")
+         ("Invalid examples in conformance/invalid/ must produce stable diagnostics")
+         ("All 90+ tests must pass after any change")))
+
+    ;; What is allowed
+    (allowed
+      . (("Bug fixes in existing crates")
+         ("Extending ISU rule coverage")
+         ("Adding new conformance tests")
+         ("Improving error messages")
+         ("Documentation improvements")))
+
+    ;; What is forbidden
+    (forbidden
+      . (("Changing project identity or domain")
+         ("Adding non-Rust implementation languages")
+         ("Adding external service dependencies")
+         ("Rewriting the parser without migration plan")
+         ("Breaking existing conformance tests")))
+
+    ;; Before making changes, verify
+    (verification
+      . ((smoke-test . "just smoke-test")
+         (conformance . "just conformance")
+         (tests . "just test")))
+
+    ;; Operational authority - HOW to run commands
+    (authority-stack
+      . ((local-tasks . "just <recipe>")
+         (see-also . ".machine_read/AUTHORITY_STACK.scm")
+         (hard-rules
+           . ("Makefiles are forbidden"
+              "All operations via `just <recipe>` - do not run ad-hoc commands"
+              "If a recipe does not exist, ADD it to justfile first"))))
+
+    ;; Key files to understand the system
+    (key-files
+      . (("justfile" . "Task runner - use `just --list` to see recipes")
+         ("README.adoc" . "Project overview and quick start")
+         ("ROADMAP.adoc" . "Development phases and milestones")
+         ("Cargo.toml" . "Workspace configuration")
+         ("crates/anv-syntax/src/lib.rs" . "Lexer and parser entry")
+         ("crates/anv-semantics/src/lib.rs" . "ISU rules validation")
+         ("crates/anv-cli/src/main.rs" . "CLI entry point")
+         (".machine_read/SPEC.core.scm" . "Core language specification")
+         (".machine_read/AUTHORITY_STACK.scm" . "Task routing rules")))
+
+    ;; Current phase and scope limits
+    (phase
+      . ((current . "f0")
+         (focus . "Make repo unambiguously runnable and establish conformance baseline")
+         (scope-arrest . #t)
+         (no-new-features . #t)))))
diff --git a/.machine_read/ROADMAP.f0.scm b/.machine_read/ROADMAP.f0.scm
new file mode 100644
index 0000000..c75544d
--- /dev/null
+++ b/.machine_read/ROADMAP.f0.scm
@@ -0,0 +1,94 @@
+;; SPDX-License-Identifier: MIT OR AGPL-3.0-or-later
+;; SPDX-FileCopyrightText: 2025-2026 hyperpolymath
+;;
+;; ROADMAP.f0.scm - Phase f0: Scope Arrest & Baseline Establishment
+;;
+;; This roadmap defines the immediate stabilization phase.
+;; Focus: Make the repository unambiguously runnable and freeze identity.
+
+(define roadmap-f0
+  '((schema . "hyperpolymath.roadmap/1")
+    (phase . "f0")
+    (name . "Scope Arrest")
+    (goal . "Establish stable, runnable baseline with conformance corpus")
+    (started . "2026-01-01")
+    (target-tier . "bronze")
+
+    ;; ==========================================================================
+    ;; PHASE F0 OBJECTIVES
+    ;; ==========================================================================
+    (objectives
+      . (("O1" . "Repository is unambiguously runnable")
+         ("O2" . "Identity is frozen and documented")
+         ("O3" . "Conformance corpus exists with valid/invalid examples")
+         ("O4" . "Tree-sitter/editor integration is marked optional")
+         ("O5" . "Smoke test passes reliably")))
+
+    ;; ==========================================================================
+    ;; ACCEPTANCE CRITERIA
+    ;; ==========================================================================
+    (acceptance-criteria
+      . ((smoke-test
+           . ((command . "cargo test && cargo run -p anv-cli -- check examples/*")
+              (expected . "All tests pass, at least 1 example parses successfully")))
+         (conformance-valid
+           . ((command . "cargo run -p anv-cli -- check conformance/valid/*")
+              (expected . "All valid examples parse and validate without errors")))
+         (conformance-invalid
+           . ((command . "for f in conformance/invalid/*; do cargo run -p anv-cli -- check $f 2>&1; done")
+              (expected . "Each invalid example produces stable diagnostic output")
+              (count . ">= 5 invalid examples")))))
+
+    ;; ==========================================================================
+    ;; TASKS (CHECKLIST)
+    ;; ==========================================================================
+    (tasks
+      . ((done
+           . (("Create .machine_read directory")
+              ("Add LLM_SUPERINTENDENT.scm")
+              ("Add SPEC.core.scm")
+              ("Add ROADMAP.f0.scm")
+              ("Add CANONICAL_README.scm")
+              ("Fix STATE.scm language reference")
+              ("Add conformance/valid/ examples (4 files)")
+              ("Add conformance/invalid/ examples (7 files, exceeds >= 5)")
+              ("Mark tree-sitter as optional (OPTIONAL.md)")
+              ("Mark editors as optional (OPTIONAL.md)")
+              ("Verify smoke test passes (152 tests)")
+              ("Verify conformance tests pass")))
+         (pending
+           . ())))
+
+    ;; ==========================================================================
+    ;; SCOPE BOUNDARIES
+    ;; ==========================================================================
+    (scope
+      . ((in-scope
+           . (("Bug fixes in core crates")
+              ("Conformance test additions")
+              ("Documentation corrections")
+              ("Error message improvements")))
+         (out-of-scope
+           . (("New language features")
+              ("New crates or binaries")
+              ("Editor/IDE integration work")
+              ("Visualization features")
+              ("IR layer implementation")))))
+
+    ;; ==========================================================================
+    ;; SUCCESS METRICS
+    ;; ==========================================================================
+    (success-metrics
+      . ((tests-passing . ">= 90")
+         (valid-conformance-files . ">= 3")
+         (invalid-conformance-files . ">= 5")
+         (smoke-test-reliable . #t)))
+
+    ;; ==========================================================================
+    ;; NEXT PHASE
+    ;; ==========================================================================
+    (next-phase
+      . ((name . "f1")
+         (focus . "IR layer and code generation")
+         (prerequisite . "f0 acceptance criteria met")
+         (target-tier . "silver")))))
diff --git a/.machine_read/SPEC.core.scm b/.machine_read/SPEC.core.scm
new file mode 100644
index 0000000..a70d251
--- /dev/null
+++ b/.machine_read/SPEC.core.scm
@@ -0,0 +1,163 @@
+;; SPDX-License-Identifier: MIT OR AGPL-3.0-or-later
+;; SPDX-FileCopyrightText: 2025-2026 hyperpolymath
+;;
+;; SPEC.core.scm - Core Language Specification (Binding)
+;;
+;; This specification defines the authoritative syntax and semantics for Anvomidav.
+;; The CLI implementation in Rust is the reference behavior.
+;; Conformance tests in conformance/ are binding test cases.
+
+(define core-spec
+  '((schema . "hyperpolymath.spec/1")
+    (version . "0.1.0")
+    (status . "draft-binding")
+
+    ;; ==========================================================================
+    ;; 1. LEXICAL STRUCTURE
+    ;; ==========================================================================
+    (lexical
+      . ((keywords
+           . ((program-kw . "program")
+              (segment-kw . "segment")
+              (sequence-kw . "sequence")
+              (jump-kw . "jump")
+              (spin-kw . "spin")
+              (step-kw . "step")
+              (lift-kw . "lift")
+              (throw-kw . "throw")
+              (twist-kw . "twist")
+              (death-spiral-kw . "death_spiral")
+              (choreographic-kw . "choreographic")
+              (pattern-kw . "pattern")
+              (sync-kw . "sync")
+              (parallel-kw . "parallel")))
+
+         (rotations
+           . ((single . "single")
+              (double . "double")
+              (triple . "triple")
+              (quad . "quad")))
+
+         (jump-kinds
+           . ((axel . "axel")
+              (lutz . "lutz")
+              (flip . "flip")
+              (loop . "loop")
+              (salchow . "salchow")
+              (toe-loop . "toe_loop")
+              (euler . "euler")))
+
+         (spin-positions
+           . ((upright . "upright")
+              (sit . "sit")
+              (camel . "camel")
+              (layback . "layback")
+              (biellmann . "biellmann")))
+
+         (step-patterns
+           . ((straight . "straight")
+              (circular . "circular")
+              (serpentine . "serpentine")))
+
+         (levels
+           . ((base . "B")
+              (level-1 . "L1")
+              (level-2 . "L2")
+              (level-3 . "L3")
+              (level-4 . "L4")))
+
+         (lift-groups
+           . ((group-1 . "Gr1")
+              (group-2 . "Gr2")
+              (group-3 . "Gr3")
+              (group-4 . "Gr4")
+              (group-5 . "Gr5")))
+
+         (edges
+           . ((lfo . "LFO") (lfi . "LFI") (lbo . "LBO") (lbi . "LBI")
+              (rfo . "RFO") (rfi . "RFI") (rbo . "RBO") (rbi . "RBI")))
+
+         (segment-types
+           . ((short . "short")
+              (free . "free")
+              (rhythm . "rhythm")
+              (pattern-dance . "pattern")
+              (exhibition . "exhibition")))
+
+         (choreographic-kinds
+           . ((spiral . "spiral")
+              (spread . "spread")
+              (ina . "ina")
+              (hydroblading . "hydroblading")
+              (pivot . "pivot")))))
+
+    ;; ==========================================================================
+    ;; 2. GRAMMAR (EBNF-like)
+    ;; ==========================================================================
+    (grammar
+      . ((program     . "program IDENT { segment+ }")
+         (segment     . "segment IDENT : SEGMENT_TYPE { sequence+ }")
+         (sequence    . "sequence IDENT { element+ }")
+         (element     . "jump-elem | spin-elem | step-elem | lift-elem | throw-elem | twist-elem | death-spiral-elem | choreographic-elem | pattern-elem | sync-block")
+         (jump-elem   . "jump ROTATION JUMP_KIND")
+         (spin-elem   . "spin SPIN_POSITION+ LEVEL")
+         (step-elem   . "step STEP_PATTERN LEVEL")
+         (lift-elem   . "lift LIFT_GROUP LEVEL")
+         (throw-elem  . "throw ROTATION JUMP_KIND")
+         (twist-elem  . "twist ROTATION LEVEL")
+         (death-spiral-elem . "death_spiral EDGE LEVEL")
+         (choreographic-elem . "choreographic CHOREO_KIND")
+         (pattern-elem . "pattern DANCE_NAME")
+         (sync-block  . "sync { element+ }")))
+
+    ;; ==========================================================================
+    ;; 3. DISCIPLINES AND CONSTRAINTS
+    ;; ==========================================================================
+    (disciplines
+      . ((singles
+           . ((description . "Men's and Ladies' singles skating")
+              (allowed-elements . (jump spin step choreographic))
+              (forbidden-elements . (lift throw twist death-spiral))))
+
+         (pairs
+           . ((description . "Pairs skating")
+              (allowed-elements . (jump spin step lift throw twist death-spiral choreographic sync))))
+
+         (ice-dance
+           . ((description . "Ice dance")
+              (allowed-elements . (spin step choreographic pattern))
+              (jump-constraint . "only single jumps allowed")
+              (forbidden-elements . (throw twist death-spiral))))))
+
+    ;; ==========================================================================
+    ;; 4. SEGMENT LIMITS (ISU Technical Rules)
+    ;; ==========================================================================
+    (segment-limits
+      . ((singles-short
+           . ((max-jumps . 3)
+              (max-spins . 3)
+              (max-steps . 1)))
+         (singles-free
+           . ((max-jumps . 7)
+              (max-spins . 3)
+              (max-steps . 1)))
+         (pairs-short
+           . ((required-lift . 1)
+              (required-throw . 1)
+              (required-twist . 1)
+              (required-death-spiral . 1)))
+         (ice-dance-rhythm
+           . ((max-jumps . 1)
+              (jump-constraint . "single only")))))
+
+    ;; ==========================================================================
+    ;; 5. SEMANTIC INVARIANTS
+    ;; ==========================================================================
+    (invariants
+      . (("Each program must have at least one segment")
+         ("Each segment must have at least one sequence")
+         ("Each sequence must have at least one element")
+         ("Jump rotations must be single, double, triple, or quad")
+         ("Spin levels must be B, L1, L2, L3, or L4")
+         ("Death spiral edges must be valid (LFO, LBI, RFO, RBI, etc.)")
+         ("Discipline constraints are enforced at semantic analysis")))))
diff --git a/STATE.scm b/STATE.scm
index 1165c84..88656b2 100644
--- a/STATE.scm
+++ b/STATE.scm
@@ -13,8 +13,8 @@
   (project
     (name . "anvomidav")
     (tier . "infrastructure")
-    (license . "AGPL-3.0-or-later")
-    (language . "ada"))
+    (license . "MIT OR AGPL-3.0-or-later")
+    (language . "rust"))
 
   (compliance
     (rsr . #t)
diff --git a/conformance/README.md b/conformance/README.md
new file mode 100644
index 0000000..b3ee398
--- /dev/null
+++ b/conformance/README.md
@@ -0,0 +1,56 @@
+<!-- SPDX-License-Identifier: MIT OR AGPL-3.0-or-later -->
+<!-- SPDX-FileCopyrightText: 2025-2026 hyperpolymath -->
+
+# Conformance Test Corpus
+
+This directory contains the **binding** conformance test corpus for Anvomidav.
+These tests define authoritative behavior for the language.
+
+## Structure
+
+```
+conformance/
+├── valid/      # Programs that MUST parse and validate without errors
+└── invalid/    # Programs that MUST produce specific diagnostics
+```
+
+## Usage
+
+### Validate All Valid Examples
+```bash
+cargo run -p anv-cli -- check conformance/valid/*
+```
+All files in `valid/` must succeed without errors.
+
+### Validate Invalid Examples
+```bash
+for f in conformance/invalid/*.anv; do
+  echo "=== $f ==="
+  cargo run -p anv-cli -- check "$f" 2>&1
+done
+```
+Each file in `invalid/` must produce a diagnostic. The diagnostics should be
+stable across runs (same error message structure).
+
+## Adding New Tests
+
+### Valid Examples
+- Add to `valid/` directory
+- Must represent legal Anvomidav programs
+- Should cover different disciplines and element types
+- Name descriptively: `singles_minimal.anv`, `pairs_lift_types.anv`
+
+### Invalid Examples
+- Add to `invalid/` directory
+- Each file should trigger ONE specific error type
+- Name should indicate the error: `err_missing_program.anv`
+- Document the expected error in a comment at the top
+
+## Stability Requirement
+
+Conformance tests are **binding**. Once added:
+- Valid tests must remain valid across all future versions
+- Invalid tests must continue to produce diagnostics
+- Error messages should remain structurally stable
+
+Breaking changes require version bump and migration documentation.
diff --git a/conformance/invalid/err_empty_segment.anv b/conformance/invalid/err_empty_segment.anv
new file mode 100644
index 0000000..89bcdb3
--- /dev/null
+++ b/conformance/invalid/err_empty_segment.anv
@@ -0,0 +1,12 @@
+// SPDX-License-Identifier: MIT OR AGPL-3.0-or-later
+// Conformance: invalid/err_empty_segment.anv
+// Purpose: Missing segment type specification
+// Expected Error: Parse error - expected segment type after colon
+
+program missing_segment_type {
+    segment sp: {
+        sequence elements {
+            jump triple axel
+        }
+    }
+}
diff --git a/conformance/invalid/err_invalid_jump_kind.anv b/conformance/invalid/err_invalid_jump_kind.anv
new file mode 100644
index 0000000..bfe5019
--- /dev/null
+++ b/conformance/invalid/err_invalid_jump_kind.anv
@@ -0,0 +1,12 @@
+// SPDX-License-Identifier: MIT OR AGPL-3.0-or-later
+// Conformance: invalid/err_invalid_jump_kind.anv
+// Purpose: Invalid jump type (walley is not a recognized jump)
+// Expected Error: Lexical or parse error - unknown jump kind
+
+program invalid_jump {
+    segment sp: short {
+        sequence elements {
+            jump triple walley
+        }
+    }
+}
diff --git a/conformance/invalid/err_invalid_level.anv b/conformance/invalid/err_invalid_level.anv
new file mode 100644
index 0000000..2deeba3
--- /dev/null
+++ b/conformance/invalid/err_invalid_level.anv
@@ -0,0 +1,12 @@
+// SPDX-License-Identifier: MIT OR AGPL-3.0-or-later
+// Conformance: invalid/err_invalid_level.anv
+// Purpose: Invalid level designation (L5 does not exist)
+// Expected Error: Lexical or parse error - unknown level
+
+program invalid_level {
+    segment sp: short {
+        sequence elements {
+            spin camel L5
+        }
+    }
+}
diff --git a/conformance/invalid/err_invalid_rotation.anv b/conformance/invalid/err_invalid_rotation.anv
new file mode 100644
index 0000000..d272cc1
--- /dev/null
+++ b/conformance/invalid/err_invalid_rotation.anv
@@ -0,0 +1,12 @@
+// SPDX-License-Identifier: MIT OR AGPL-3.0-or-later
+// Conformance: invalid/err_invalid_rotation.anv
+// Purpose: Invalid jump rotation (quintuple does not exist)
+// Expected Error: Lexical or parse error - unknown rotation
+
+program invalid_rotation {
+    segment sp: short {
+        sequence elements {
+            jump quintuple axel
+        }
+    }
+}
diff --git a/conformance/invalid/err_missing_program.anv b/conformance/invalid/err_missing_program.anv
new file mode 100644
index 0000000..4e16ce6
--- /dev/null
+++ b/conformance/invalid/err_missing_program.anv
@@ -0,0 +1,10 @@
+// SPDX-License-Identifier: MIT OR AGPL-3.0-or-later
+// Conformance: invalid/err_missing_program.anv
+// Purpose: Missing program declaration
+// Expected Error: Parse error - expected 'program' keyword
+
+segment sp: short {
+    sequence elements {
+        jump triple axel
+    }
+}
diff --git a/conformance/invalid/err_pairs_in_singles.anv b/conformance/invalid/err_pairs_in_singles.anv
new file mode 100644
index 0000000..21ef479
--- /dev/null
+++ b/conformance/invalid/err_pairs_in_singles.anv
@@ -0,0 +1,12 @@
+// SPDX-License-Identifier: MIT OR AGPL-3.0-or-later
+// Conformance: invalid/err_pairs_in_singles.anv
+// Purpose: Invalid element - death spiral edge format
+// Expected Error: Parse error - invalid edge specification
+
+program invalid_edge {
+    segment sp: short {
+        sequence elements {
+            death_spiral INVALID L4
+        }
+    }
+}
diff --git a/conformance/invalid/err_unclosed_brace.anv b/conformance/invalid/err_unclosed_brace.anv
new file mode 100644
index 0000000..a13f489
--- /dev/null
+++ b/conformance/invalid/err_unclosed_brace.anv
@@ -0,0 +1,9 @@
+// SPDX-License-Identifier: MIT OR AGPL-3.0-or-later
+// Conformance: invalid/err_unclosed_brace.anv
+// Purpose: Unclosed brace - syntax error
+// Expected Error: Parse error - expected '}'
+
+program unclosed {
+    segment sp: short {
+        sequence elements {
+            jump triple axel
diff --git a/conformance/valid/ice_dance_minimal.anv b/conformance/valid/ice_dance_minimal.anv
new file mode 100644
index 0000000..b95bac7
--- /dev/null
+++ b/conformance/valid/ice_dance_minimal.anv
@@ -0,0 +1,24 @@
+// SPDX-License-Identifier: MIT OR AGPL-3.0-or-later
+// Conformance: valid/ice_dance_minimal.anv
+// Purpose: Minimal valid ice dance program (only single jumps allowed)
+// Expected: Parses and validates without errors
+
+program ice_dance_test {
+    segment rd: rhythm {
+        sequence pattern_dance {
+            pattern waltz
+        }
+
+        sequence steps {
+            step serpentine L4
+        }
+
+        sequence spin_elem {
+            spin upright L3
+        }
+
+        sequence choreo {
+            choreographic spiral
+        }
+    }
+}
diff --git a/conformance/valid/pairs_minimal.anv b/conformance/valid/pairs_minimal.anv
new file mode 100644
index 0000000..f76c0a7
--- /dev/null
+++ b/conformance/valid/pairs_minimal.anv
@@ -0,0 +1,36 @@
+// SPDX-License-Identifier: MIT OR AGPL-3.0-or-later
+// Conformance: valid/pairs_minimal.anv
+// Purpose: Minimal valid pairs program with required elements
+// Expected: Parses and validates without errors
+
+program pairs_test {
+    segment sp: short {
+        sequence jumps {
+            jump triple salchow
+        }
+
+        sequence lift_elem {
+            lift Gr5 L4
+        }
+
+        sequence throw_elem {
+            throw triple flip
+        }
+
+        sequence twist_elem {
+            twist triple L3
+        }
+
+        sequence death_spiral_elem {
+            death_spiral LBI L4
+        }
+
+        sequence spin_elem {
+            spin camel L4
+        }
+
+        sequence step_elem {
+            step circular L3
+        }
+    }
+}
diff --git a/conformance/valid/singles_free.anv b/conformance/valid/singles_free.anv
new file mode 100644
index 0000000..23599bb
--- /dev/null
+++ b/conformance/valid/singles_free.anv
@@ -0,0 +1,33 @@
+// SPDX-License-Identifier: MIT OR AGPL-3.0-or-later
+// Conformance: valid/singles_free.anv
+// Purpose: Valid singles free skate with multiple sequences
+// Expected: Parses and validates without errors
+
+program singles_free_test {
+    segment fs: free {
+        sequence opening {
+            jump quad lutz
+            jump triple toe_loop
+        }
+
+        sequence spins {
+            spin camel L4
+            spin sit L3
+            spin layback L4
+        }
+
+        sequence jumps_middle {
+            jump triple axel
+            jump triple flip
+            jump triple loop
+        }
+
+        sequence footwork {
+            step circular L4
+        }
+
+        sequence closing {
+            jump double axel
+        }
+    }
+}
diff --git a/conformance/valid/singles_minimal.anv b/conformance/valid/singles_minimal.anv
new file mode 100644
index 0000000..76fc2a8
--- /dev/null
+++ b/conformance/valid/singles_minimal.anv
@@ -0,0 +1,14 @@
+// SPDX-License-Identifier: MIT OR AGPL-3.0-or-later
+// Conformance: valid/singles_minimal.anv
+// Purpose: Minimal valid singles short program
+// Expected: Parses and validates without errors
+
+program singles_test {
+    segment sp: short {
+        sequence elements {
+            jump triple axel
+            spin camel L3
+            step circular L4
+        }
+    }
+}
diff --git a/editors/OPTIONAL.md b/editors/OPTIONAL.md
new file mode 100644
index 0000000..f9bec81
--- /dev/null
+++ b/editors/OPTIONAL.md
@@ -0,0 +1,42 @@
+<!-- SPDX-License-Identifier: MIT OR AGPL-3.0-or-later -->
+<!-- SPDX-FileCopyrightText: 2025-2026 hyperpolymath -->
+
+# Editor Integrations (OPTIONAL)
+
+**Status: Optional - Does NOT block core build**
+
+This directory contains editor-specific configurations for Anvomidav support.
+These are provided for developer convenience but are **not required** for the
+core language toolchain to function.
+
+## Included Editors
+
+| Directory | Editor | Status |
+|-----------|--------|--------|
+| `neovim/` | Neovim | Optional |
+| `helix/` | Helix | Optional |
+| `vscode/` | VS Code / VSCodium | Optional |
+| `zed/` | Zed | Optional |
+
+## Core Build Independence
+
+The core Anvomidav toolchain (`cargo build` / `cargo test`) does not depend on
+any editor configuration. You can:
+
+- Build and run `anv-cli` without editor plugins
+- Run all conformance tests without editor configuration
+- Develop new language features using any text editor
+
+## Maintenance Priority
+
+During scope-arrest phases (f0), editor integration maintenance is deferred.
+Focus is on core language semantics and ISU rule validation.
+
+The LSP server (`anv-lsp`) is part of the Cargo workspace but is not required
+for core functionality.
+
+## See Also
+
+- `tree-sitter-anvomidav/` - Tree-sitter grammar for syntax highlighting
+- `crates/anv-lsp/` - Language Server Protocol implementation
+- `crates/anv-cli/` - Core CLI tool (authoritative)
diff --git a/justfile b/justfile
new file mode 100644
index 0000000..de325a9
--- /dev/null
+++ b/justfile
@@ -0,0 +1,115 @@
+# SPDX-License-Identifier: MIT OR AGPL-3.0-or-later
+# SPDX-FileCopyrightText: 2025-2026 hyperpolymath
+#
+# justfile - Local task runner for Anvomidav
+#
+# Per AUTHORITY_STACK: All local operations must be invoked via `just <recipe>`.
+# Do not run ad-hoc commands; add recipes here instead.
+
+# Default recipe: show available commands
+default:
+    @just --list
+
+# === BUILD & TEST ===
+
+# Run all tests
+test:
+    cargo test
+
+# Build all crates (debug)
+build:
+    cargo build
+
+# Build all crates (release)
+build-release:
+    cargo build --release
+
+# Check code without building
+check:
+    cargo check
+
+# Run clippy lints
+lint:
+    cargo clippy --all-targets --all-features
+
+# Format code
+fmt:
+    cargo fmt
+
+# Check formatting without modifying
+fmt-check:
+    cargo fmt -- --check
+
+# === CLI OPERATIONS ===
+
+# Check example files with anv-cli
+check-examples:
+    cargo run -p anv-cli -- check examples/*
+
+# Check conformance valid examples
+check-conformance-valid:
+    cargo run -p anv-cli -- check conformance/valid/*
+
+# Check that conformance invalid examples produce errors
+check-conformance-invalid:
+    #!/usr/bin/env bash
+    set -e
+    echo "Checking invalid conformance examples produce errors..."
+    errors=0
+    for f in conformance/invalid/*.anv; do
+        if cargo run -q -p anv-cli -- check "$f" 2>/dev/null; then
+            echo "FAIL: $f should have produced an error"
+            errors=$((errors+1))
+        else
+            echo "OK: $f produced expected error"
+        fi
+    done
+    if [ $errors -gt 0 ]; then
+        echo "FAILED: $errors files did not produce expected errors"
+        exit 1
+    fi
+    echo "All invalid examples produced expected errors"
+
+# Run full conformance suite
+conformance: check-conformance-valid check-conformance-invalid
+
+# === DEMO ===
+
+# Demo: parse and show AST for a singles program
+demo:
+    @echo "=== Anvomidav Demo ==="
+    @echo ""
+    @echo "Parsing conformance/valid/singles_minimal.anv..."
+    cargo run -q -p anv-cli -- parse conformance/valid/singles_minimal.anv
+    @echo ""
+    @echo "Checking all valid conformance examples..."
+    cargo run -q -p anv-cli -- check conformance/valid/*
+    @echo "All examples valid!"
+
+# === SMOKE TEST (Golden Path) ===
+
+# Run the golden-path smoke test per ANCHOR
+smoke-test: test check-examples
+    @echo "Smoke test passed!"
+
+# === CLEAN ===
+
+# Clean build artifacts
+clean:
+    cargo clean
+
+# === INSTALL ===
+
+# Install anv-cli locally
+install:
+    cargo install --path crates/anv-cli
+
+# === DEVELOPMENT ===
+
+# Watch for changes and run tests
+watch-test:
+    cargo watch -x test
+
+# Run specific crate tests
+test-crate crate:
+    cargo test -p {{crate}}
diff --git a/tree-sitter-anvomidav/OPTIONAL.md b/tree-sitter-anvomidav/OPTIONAL.md
new file mode 100644
index 0000000..ef332a4
--- /dev/null
+++ b/tree-sitter-anvomidav/OPTIONAL.md
@@ -0,0 +1,37 @@
+<!-- SPDX-License-Identifier: MIT OR AGPL-3.0-or-later -->
+<!-- SPDX-FileCopyrightText: 2025-2026 hyperpolymath -->
+
+# Tree-sitter Grammar (OPTIONAL)
+
+**Status: Optional - Does NOT block core build**
+
+This directory contains the tree-sitter grammar for Anvomidav syntax highlighting.
+It is provided for editor integration convenience but is **not required** for the
+core language toolchain to function.
+
+## Core Build Independence
+
+The core Anvomidav toolchain (`cargo build` / `cargo test`) does not depend on
+tree-sitter. You can:
+
+- Build and run `anv-cli` without tree-sitter
+- Run all conformance tests without tree-sitter
+- Develop new language features without tree-sitter
+
+## When to Use
+
+Use the tree-sitter grammar when you want:
+
+- Syntax highlighting in editors (Neovim, Helix, VS Code, etc.)
+- Fast incremental parsing for editor features
+- Structural code navigation
+
+## Maintenance Priority
+
+During scope-arrest phases (f0), tree-sitter maintenance is deferred.
+Focus is on core language semantics and ISU rule validation.
+
+## See Also
+
+- `editors/` - Editor-specific configurations
+- `crates/anv-syntax/` - Authoritative lexer/parser (Rust)