Native OO-LD validator driven by the specification rule catalogue

[LukasOro]

What

A native Python validation subsystem under src/oold/validation/, replacing use of the reference harness oold-schema/scripts/validate.mjs as a subprocess.

• 39 checks across 11 families: schema.*, lint.*, context.*, roundtrip.*, generate.*, instance.*, variants, compliance.*, coverage.*, meta.*, and 22 rule.* checks
• CLI: oold validate, oold validate-instance, oold compliance, oold meta, oold rules, oold checks
• MCP server exposing the same validation entry points
• 4 tracked meta-schema versions vendored byte-exact: 0.7.0, 0.8.0, 1.0.0-rc.1, 1.0.0-rc.2

Rationale

• No Node.js dependency, and no subprocess boundary to marshal results across
• Resolves @context chains that leave the schema's own directory, which the reference harness cannot do: its loader only maps its own directory
• One code base validates against several meta-schema versions in a single run

Severity comes from the specification, never from this code

Each rule.* check reports a problem; whether that is a failure or a warning is read from the rule's level in oold-rules.json, the catalogue of numbered normative statements.

• A rule absent from the selected version's catalogue, or deprecated there, is skipped with a message saying so, rather than checked anyway
• Versions predating the catalogue skip the whole rule.* family
• Checks judge the resolved context, not the literal @context, so a schema whose terms arrive through a remote context is not reported as violating them

Meta-schema vendoring

src/oold/validation/meta/<version>/ holds verbatim copies from oold-schema release tags, with a sha256 per file recorded in index.json. Nothing is fetched at runtime for a tracked version, so a released version cannot change meaning between runs. Unreleased upstream state is reachable with --meta remote.

• Files are stored LF and marked -text in .gitattributes; a CRLF copy hashes differently, passing on Windows and failing on Linux
• v1.0.0-rc.2 is the first release to ship the catalogue and the first to split the dialect meta-schema into a wrapper plus the base it $refs, so it declares its own file set
• The fixture slice in tests/data/oold/ is refreshed from the same tag it records in fixtures.tag, so fixtures and meta-schemas never come from different releases

Coupling to oold-schema

The two repositories release on separate schedules, so neither pipeline waits on the other.

• coverage.rules warns when a catalogued rule has no check, rather than failing, so a specification that has moved ahead cannot break this build
• Currently 15 of 40 machine-checkable rules have no check: 4 predate OO-LD/oold-schema#124 and 11 arrived with the rules that release added
• OO-LD/oold-schema#133 reclassifies OOLD-CMP-a05a as not machine-checkable; it reaches this repository at the next release, since tracked catalogues come from tags

Verification

• 530 tests pass; make check, make validate and make docs-test exit 0
• Parity tests assert this port reaches the same verdicts as the reference harness on the same fixtures, including check labels and triple counts: 6/6 with OOLD_SCHEMA_DIR set
• Each deliberately broken fixture in tests/data/oold/broken/ is mapped to the check it must trip, so the checks are proven to fire rather than only to pass on valid input

[github-actions]

Release preview

Merging this PR would release v0.17.0 (current: v0.16.3).

Changelog preview (truncated)

## v0.17.0 (2026-08-15)

### Bug Fixes

- **docs**: Restate and guard Zensical's default Markdown extensions
  ([`ebc3907`](https://github.com/OO-LD/oold-python/commit/ebc3907cae24a685b78edcd856ca514331148a95))

### Chores

- License fix
  ([`daa8d8c`](https://github.com/OO-LD/oold-python/commit/daa8d8cfa325a3745c851c845b9fae7b5e51a0cc))

- **validation**: Vendor the 43-rule catalogue
  ([`cbcf95a`](https://github.com/OO-LD/oold-python/commit/cbcf95a3042c41078c7b670de4ce77b21db36a31))

### Code Style

- Apply ruff-format to the check-registry drift test
  ([`ca11109`](https://github.com/OO-LD/oold-python/commit/ca1110907aa194b32458cfb90599c4b8a51609b5))

- **tests**: Store the hand-written fixtures with LF line endings
  ([`8c965d6`](https://github.com/OO-LD/oold-python/commit/8c965d6cd3aea4963e709fc05e304e789aa73995))

### Continuous Integration

- **release**: Add whats-changed notes with changelog link for zenodo
  ([`147d70f`](https://github.com/OO-LD/oold-python/commit/147d70fbf1c5da070f3cb9055fbe96e831fe8eaa))

- **release**: Update on title and authors
  ([`996c4de`](https://github.com/OO-LD/oold-python/commit/996c4dee6b4f07b6ec994e87cb341155a12e955c))

### Documentation

- Add CLAUDE.md with the conventions agents keep getting wrong
  ([`4fdda5e`](https://github.com/OO-LD/oold-python/commit/4fdda5e796089c4950437918d212c802b4e2e8b4))

- Explain how to turn a specification rule into a check
  ([`988bc38`](https://github.com/OO-LD/oold-python/commit/988bc38de68724a027268721fad8818786bd5184))

- Fix the vendoring procedure and say what a new check owes
  ([`92524af`](https://github.com/OO-LD/oold-python/commit/92524af7fd721819d8d0874757d23dcfbdc6ba92))

- **spec**: Collapse the check mappings into one registry structure
  ([`264d71e`](https://github.com/OO-LD/oold-python/commit/264d71e300095719cdfe52c86726fb5bb64888e1))

- **spec**: Correct the version gate, and cost out a changed rule
  ([`08b9945`](https://github.com/OO-LD/oold-python/commit/08b9945ea338c3a261eb08d28e82b2d2b7a062ea))

- **spec**: Design a check registry and an `oold checks` command
  ([`26ceba9`](https://github.com/OO-LD/oold-python/commit/26ceba9c63a9170baaa376c63b039ebfa666a100))

- **spec**: Pin where compatibility for a new rule's check lives
  ([`3ba00a6`](https://github.com/OO-LD/oold-python/commit/3ba00a6ddff0aa3c739f6739ae7b76b1b11ffda2))

- **spec**: State which ids the registry covers, and fix the grep guard
  ([`3b497b5`](https://github.com/OO-LD/oold-python/commit/3b497b586ed1e8b13699263b492a27e1acdb1141))

- **validation**: Record catalogue's source so a rebase cannot orphan it
  ([`5bcd043`](https://github.com/OO-LD/oold-python/commit/5bcd043721226b48280e7980890264df9cdc623b))

### Features

- **validation**: Add native OO-LD schema and instance validator
  ([`80ee29a`](https://github.com/OO-LD/oold-python/commit/80ee29a1c61cb429f8f39d8db70375508f7a8375))

- **validation**: Check catalogue and fixture slice against facts
  ([`a7a7f3c`](https://github.com/OO-LD/oold-python/commit/a7a7f3cd167e24e38731a117ad9a87494acbd666))

- **validation**: Cite the specification's rule ids in findings
  ([`f39b280`](https://github.com/OO-LD/oold-python/commit/f39b28057f24609789b5718099579fcffb49d560))

- **validation**: Drive rule checks from the specification catalogue
  ([`71c734c`](https://github.com/OO-LD/oold-python/commit/71c734c6fb1864a6d9274efaf017be6032b2b4c6))

- **validation**: Enforce four more catalogued rules
  ([`fb99f5c`](https://github.com/OO-LD/oold-python/commit/fb99f5c3aebdec7227bd2cd68840b4cc2bd8c061))

- **validation**: Enforce narrow-only composition
  ([`13ade19`](https://github.com/OO-LD/oold-python/commit/13ade196c9ba8d6a9a9e8501e20ac213a688aaa6))

_{Preview via python-semantic-release and conventional commits.}

[github-actions]

📊 Benchmark Results

Click to see benchmark comparison

📊 Benchmark Comparison (threshold: 1.3x)
============================================================

➖ Unchanged (within threshold):
  ➖ test_simple_dict_document_store: 0.0019s → 0.0017s (-5.8%)
  ➖ test_sqlite_document_store: 0.0020s → 0.0019s (-5.1%)
  ➖ test_local_sparql_store: 0.0432s → 0.0456s (+5.6%)
  ➖ test_oneof_subschema: 0.0636s → 0.0678s (+6.6%)
  ➖ test_enum_docstrings: 0.0545s → 0.0579s (+6.2%)
  ➖ test_subclass_inheritance: 0.0580s → 0.0607s (+4.7%)
  ➖ test_class_hierarchy: 0.0567s → 0.0575s (+1.5%)
  ➖ test_core[v1]: 0.0412s → 0.0424s (+2.8%)
  ➖ test_core[v2]: 0.0469s → 0.0506s (+8.0%)
  ➖ test_schema_generation[v1]: 0.0018s → 0.0018s (+0.9%)
  ➖ test_schema_generation[v2]: 0.0030s → 0.0032s (+7.6%)
  ➖ test_simple_json: 0.0008s → 0.0007s (-4.2%)
  ➖ test_complex_graph: 0.0017s → 0.0017s (+0.6%)

============================================================
Summary: 0 regressions, 0 improvements, 13 unchanged
============================================================

✅ No significant performance regressions

Threshold: 1.3x (30% slower triggers a regression warning)

Note: Benchmarks are informational only and won't fail the build.

_{💡 Tip: Download the benchmark-results artifact for detailed JSON data}

[codecov]

Codecov Report

❌ Patch coverage is 80.17817% with 623 lines in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
src/oold/validation/pipeline.py	77.6%	62 Missing and 26 partials ⚠️
src/oold/validation/cli.py	69.4%	79 Missing and 6 partials ⚠️
src/oold/validation/resolve.py	77.5%	47 Missing and 15 partials ⚠️
src/oold/validation/generate.py	76.2%	35 Missing and 22 partials ⚠️
src/oold/validation/compliance.py	69.2%	47 Missing and 8 partials ⚠️
src/oold/validation/check_registry.py	89.0%	28 Missing and 26 partials ⚠️
src/oold/validation/mcp_server.py	61.8%	46 Missing and 4 partials ⚠️
src/oold/validation/meta_store.py	84.2%	29 Missing and 10 partials ⚠️
src/oold/validation/context_resolution.py	66.9%	25 Missing and 12 partials ⚠️
src/oold/validation/instance_checks.py	72.8%	18 Missing and 1 partial ⚠️
... and 9 more

📢 Thoughts on this report? Let us know!

[github-actions]

📊 Benchmark Results

Click to see benchmark comparison

📊 Benchmark Comparison (threshold: 1.3x)
============================================================

➖ Unchanged (within threshold):
  ➖ test_simple_dict_document_store: 0.0016s → 0.0016s (+1.3%)
  ➖ test_sqlite_document_store: 0.0017s → 0.0017s (-1.1%)
  ➖ test_local_sparql_store: 0.0370s → 0.0380s (+2.6%)
  ➖ test_oneof_subschema: 0.0543s → 0.0552s (+1.5%)
  ➖ test_enum_docstrings: 0.0458s → 0.0468s (+2.2%)
  ➖ test_subclass_inheritance: 0.0488s → 0.0498s (+2.1%)
  ➖ test_class_hierarchy: 0.0468s → 0.0478s (+2.0%)
  ➖ test_core[v1]: 0.0348s → 0.0355s (+2.0%)
  ➖ test_core[v2]: 0.0398s → 0.0411s (+3.4%)
  ➖ test_schema_generation[v1]: 0.0015s → 0.0015s (+1.1%)
  ➖ test_schema_generation[v2]: 0.0026s → 0.0026s (+0.8%)
  ➖ test_simple_json: 0.0006s → 0.0006s (+0.6%)
  ➖ test_complex_graph: 0.0014s → 0.0015s (+1.9%)

============================================================
Summary: 0 regressions, 0 improvements, 13 unchanged
============================================================

✅ No significant performance regressions

Threshold: 1.3x (30% slower triggers a regression warning)

Note: Benchmarks are informational only and won't fail the build.

_{💡 Tip: Download the benchmark-results artifact for detailed JSON data}