# Standards & Conformance — AGS 4.1 | G&

> AGS 4.1 / 4.1.1 is the governing standard for every G& deliverable, and the platform runs a conformance check against the AGS reference implementation — not a certification, approval, or guarantee of acceptance.

## A / Governing standard

- **AGS 4.1 / 4.1.1 governs** — AGS 4.1 / 4.1.1 is the governing standard for all formal deliverables produced in G&. Groups, headings, units and code lists resolve against that dictionary version, and the version is recorded with the package.
- **AGS 4.2 is referenced only** — AGS 4.2 is tracked as a reference. Adoption is not approved. Deltas between 4.1 and 4.2 are registered and maintained so they can be assessed, not applied by default.
- **No silent version conversion** — G& does not convert files between AGS versions without an explicit, recorded instruction. A file submitted as 4.1 leaves as 4.1.

## B / What the conformance check does

- **Structural and dictionary checks** — Group and heading validity, required groups, data types, unit and code-list consistency, and parent–child integrity, checked against the AGS 4.1 reference implementation (python-ags4, the library published by the AGS Data Format Working Group).
- **Full findings, not a verdict** — Every finding is reported with severity, group, row and heading. Nothing is summarised away and nothing is suppressed to produce a clean result.
- **Rule provenance is labelled** — AGS reference rules and platform rules — completeness thresholds and client overlays — are separated in the report, and each finding states which rule set raised it.

## C / What the conformance check does not do

- **Not the official AGS Validator** — G& runs its own conformance check against the reference implementation. It is not the official AGS Validator and is not published by the AGS Data Format Working Group.
- **Not a certification** — A clean conformance report is not a certification, an approval, or a guarantee that a submission will be accepted.
- **Not a replacement for your step** — The receiving party's own validation step still applies in full. G& does not stand in for it.
- **The client's validator is terminal** — Where a client or consultant runs their own validator, that result is the terminal check. G& is upstream of it.

## D / Lossless handling

- **Ingest without silent loss** — Files are read as submitted. Text-type fields are preserved as text — leading zeros, alphanumeric identifiers and coded strings are not coerced into numbers.
- **Import manifest** — Every import produces a manifest of what was read, what was retained, and what was rejected, with the reason for each rejection. Nothing is dropped quietly.
- **File-vs-file comparison** — Two versions of the same package can be compared directly, group by group and heading by heading, so any change between issues is visible and attributable.

## E / Authority chain

| Party | Role |
| --- | --- |
| AGS Data Format Working Group | Defines the format |
| Official AGS Validator / python-ags4 | Reference implementation |
| BGS AGS API | Widely used execution back-end |
| G& | Conformance-claiming implementation |

G& asserts conformance with the reference implementation. G& does not assert authority over the AGS format.

## F / Standards referenced

- **BS 5930** — Code of practice for ground investigations — description and logging practice
- **BS 1377** — Methods of test for soils for civil engineering purposes
- **BS EN ISO 17892** — Geotechnical investigation and testing — laboratory testing of soil
- **ISO 14688 / 14689** — Identification and classification of soil and of rock
- **BS EN ISO 22475** — Sampling methods and groundwater measurements
- **ASTM methods** — Test methods applied where the project specification calls for them