---
title: "modelcheck-syntax-artifact-header — Mova code model"
description: "Mova code model of tools/modelcheck/src/syntax.rs: components with their labels, obernants and the model text."
url: "https://groupants.elamur.ai/free/en/mova/tools/modelcheck/src/syntax.rs.groupant/artifact-integrity.groupant/artifact-header.groupant/"
---
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# modelcheck-syntax-artifact-header

The groupant beside tools/modelcheck/src/syntax.rs in the Mova repository: what the code computes, what it never does, how to go back from its outputs, its invariants, cost and checks.

## Facts

- **kind:** groupant_fragment
- **status:** partial
- **source:** [`tools/modelcheck/src/syntax.rs`](https://github.com/ElamurAI/mova-free/blob/main/tools/modelcheck/src/syntax.rs)
- **source SHA-256:** `35c315cc9b581bea…`
- **covers:** Projection schema and source header admission (bytes 16015–16547)
- **part of:** [modelcheck-syntax-artifact-integrity](https://md.groupants.elamur.ai/free/en/mova/tools/modelcheck/src/syntax.rs.groupant/artifact-integrity.groupant/)
- **repository folder:** [`tools/modelcheck/src/syntax.rs.groupant/artifact-integrity.groupant/artifact-header.groupant`](https://github.com/ElamurAI/mova-free/tree/main/tools/modelcheck/src/syntax.rs.groupant/artifact-integrity.groupant/artifact-header.groupant)
- **repository commit:** `855da7bd4a7b`

> **Implementation material.** A Mova code model describes this code at one source revision: partial models, finite checks and their stated scope. It is not a reviewed general exposition, and its labels are shown as written, never raised.

## Components

| component | label | where |
|---|---|---|
| **approximant** | partial | [Forward](#forward) |
| **ast** | partial | `../../syntax.json` |
| **cost** | partial | [Cost](#cost) |
| **descriptant** | partial | [Descriptant](#descriptant) |
| **invariant** | partial | [Invariant](#invariant) |
| **tests** | partial | [Tests](#tests) |

## Obernants

The typed relations around the forward model: the behaviour complement (what the code never does), the reverse reconstruction (every input compatible with an output) and specialised views.

| id | type | label | where |
|---|---|---|---|
| `behavior_complement` | behavior_complement | partial relational specification | [behavior_complement](#behavior-complement) |
| `reverse_reconstruction` | reverse_reconstruction | partial relational specification | [reverse_reconstruction](#reverse-reconstruction) |
| `schema_priority` | schema_priority | partial relational specification | [schema_priority](#schema-priority) |
| `root_relative_identity` | root_relative_identity | partial relational specification | [root_relative_identity](#root-relative-identity) |
| `expected_option_boundary` | expected_option_boundary | partial relational specification | [expected_option_boundary](#expected-option-boundary) |
| `header_semantics_gap` | header_semantics_gap | partial relational specification | [header_semantics_gap](#header-semantics-gap) |

## Model text


Subject: current manifest source SHA and exact UTF-8 range [16015,16547). The observation is one completed scoped call with adequate resources; source-derived relations are partial specifications. Filesystem checks describe sequential reads, not an atomic snapshot.

### Forward

Require schema 1 and rust_syntax_projection kind; strip repository prefix from source and require UTF-8 relative path; compare exact artifact path; require Some expected SHA and equal artifact digest before any source read.

### Invariant

Header failure prevents source reread and node inspection. Path comparison uses repository-relative identity supplied by the caller, not artifact-provided path traversal.

### Cost

Constant field checks plus O(path and digest length) comparisons; no node traversal or source IO occurs in this prefix.

### Descriptant

Wave34, 2026-10-31: deeper scope retained under its existing parent without replacing historical views. Decode reuse was proposed before edits and checked against actual reference decoding; behavioral controls and repeated native receipts remain finite evidence. No numerical surrogate is justified for categorical validation outcomes; no percentage accuracy or complete semantic proof is claimed.

### Tests

Exact native test: syntax::artifact_tests::declared_projection_rejects_stale_wrong_source_and_bad_ranges. Parent tests additionally exercise integration and failure order. Current evidence is in ../../wave34-evidence.md; old evidence remains explicitly historical in wave33-evidence.md at the source root.

### behavior_complement

Exclude successful passage with wrong schema/kind, outside-root source, non-UTF-8 relative path, mismatched declared path or absent/stale expected SHA. This prefix does not assert later node acceptance.

Assurance: source-derived partial relation; fixed source revision and stated scope. Oracle: syntax::artifact_tests::declared_projection_rejects_stale_wrong_source_and_bad_ranges. Finite observations do not establish universal completeness.

### reverse_reconstruction

A passed header constrains artifact (schema,kind,path,sha) to (1,rust_syntax_projection,relative(source),expected). All nodes and source current bytes remain compatible until later gates.

Assurance: source-derived partial relation; fixed source revision and stated scope. Oracle: syntax::artifact_tests::declared_projection_rejects_stale_wrong_source_and_bad_ranges. Finite observations do not establish universal completeness.

### schema_priority

When schema and source digest are both invalid, schema error is first. A nonexistent source does not override an earlier malformed header.

Assurance: source-derived partial relation; fixed source revision and stated scope. Oracle: syntax::artifact_tests::declared_projection_rejects_stale_wrong_source_and_bad_ranges. Finite observations do not establish universal completeness.

### root_relative_identity

Fix root and source. The accepted path is exactly strip_prefix(root), converted to UTF-8. Different but canonically equivalent path spellings are not normalized by this prefix.

Assurance: source-derived partial relation; fixed source revision and stated scope. Oracle: syntax::artifact_tests::declared_projection_rejects_stale_wrong_source_and_bad_ranges. Finite observations do not establish universal completeness.

### expected_option_boundary

None expected SHA always rejects even if the artifact field is null. Equality of absent values cannot establish binding.

Assurance: source-derived partial relation; fixed source revision and stated scope. Oracle: syntax::artifact_tests::declared_projection_rejects_stale_wrong_source_and_bad_ranges. Finite observations do not establish universal completeness.

### header_semantics_gap

An artifact can pass this prefix with arbitrary node data. Structural validity and agreement with actual parsed Rust require separate stages and are not inferred.

Assurance: source-derived partial relation; fixed source revision and stated scope. Oracle: syntax::artifact_tests::declared_projection_rejects_stale_wrong_source_and_bad_ranges. Finite observations do not establish universal completeness.