TM-Spec

Third Matter Specification — declarative YAML/JSONL metalanguage and reference toolchain for DFT/MLIP/MD calculations on atomistic systems, with sanity gates, provenance, NOMAD import/export, and code-agnostic level-of-theory.

Status: v0.3 (draft) · Package: 0.3.0 · License: MIT (code) + CC-BY-4.0 (spec) · Spec home: https://exopoiesis.github.io/tm-spec/

What is it

One YAML file describes a structure, defects, magnetic state, environment, reaction network, DFT/MLIP calculation, workflow (NEB / US / MetaD / MD / MLIP benchmark / single point / relaxation), results, sanity gates (post-hoc) and an optional pre-flight block (predictive), and provenance in a form that:

• Reviewers can read in any text editor without runtime.
• Validators can check against JSON Schema 2020-12 (schemas/0.3.json; legacy 0.2 and 0.1 documents remain supported).
• Tools can ingest: extract from existing ASE/QE/CP2K/ABACUS Python scripts; import public NOMAD archive entries; export TM-Spec documents as a NOMAD upload bundle; lint pilots vs paired scripts; auto-fill sanity gates from run artefacts.
• Cross-codes: the same file describes Quantum ESPRESSO, CP2K, ABACUS, GPAW, MACE, CHGNet, or an imported NOMAD calculation at the same level of detail.

Why

Paper SI today is often either a code-specific input dump (pwscf.in) or a workflow archive that requires specialized runtime to inspect. TM-Spec is the missing middle: one human-readable YAML file per calculation, validatable, exportable to FAIR archives, and reproducible via paired script lint. Zero runtime dependencies for inspection.

What is not the goal

• Replace AiiDA/atomate2 workflow management. They own provenance graphs during work; TM-Spec owns the paper-grade snapshot.
• Be Turing-complete. YAML records declarative state and a pointer to a paired script or external archive entry.

Quickstart

pip install tm-spec       # first PyPI release: v0.2.0

# validate one file
tm-spec validate examples/pyr_smoke.tm.yaml

# validate all bundled examples
tm-spec validate --all examples --strict

# extract a stub from an ASE/QE/CP2K script
tm-spec extract path/to/neb_canonical.py --out tmp/stub.tm.yaml

# import a public NOMAD archive entry (emits spec: tm-spec/0.3 with a
# G09_geometry_origin gate: dft_relaxed for relaxations, dft_static for
# single points, mlip_relaxed for ML methods; prodromos-ready out of the box)
tm-spec import-nomad <entry_id> --out imported.tm.yaml

# import structures from any OPTIMADE provider (Materials Project, NOMAD,
# OQMD, Alexandria). Structure-level only, so geometry_origin is honestly
# "unknown" and calculation is a minimal DFT stub.
tm-spec import-optimade --elements Fe S --provider mp --out fes.tm.yaml
tm-spec import-optimade --reduced-formula FeS2 --json

# import the COMPUTED magnetic ground state from Materials Project (the magnetic
# DEPTH that OPTIMADE/NOMAD lack): ordering + per-site magmoms -> magnetic block.
# Needs a (free) MP_API_KEY env var. AFM subtype unspecified by MP -> AFM-G + warning.
tm-spec import-mp --formula FeS2 --space-group 205 --out pyrite.tm.yaml
tm-spec import-mp --material-id mp-226 --json

# import an EXPERIMENTAL magnetic structure from MAGNDATA (Bilbao) by entry code.
# Experimental ordering anchor for MP's computed magnetism (which can be wrong, e.g.
# troilite/chalcopyrite). FM/AFM derived from the magCIF's own magnetic symmetry ops.
tm-spec import-magndata --code 0.1 --out lamno3.tm.yaml
tm-spec import-magndata --code 0.1 --mcif local_entry.mcif --json   # parse a local .mcif

# merge two TM-Spec docs locally (fill-only, same-material guarded): base
# depth (e.g. NOMAD method/results) is kept, overlay fills the holes (e.g.
# OPTIMADE formula variants + lattice_vectors).
tm-spec merge nomad.tm.yaml optimade.tm.yaml --out merged.tm.yaml

# one-shot: import OPTIMADE and merge each hit into a local NOMAD base
tm-spec import-optimade --reduced-formula FeS2 --merge nomad.tm.yaml --out merged.tm.yaml

# diff a hand-crafted pilot against its paired script
tm-spec lint examples/pyr_smoke.tm.yaml

# auto-fill sanity gates from run artefacts
tm-spec sanity-fill examples/pyr_smoke.tm.yaml \
    --json results/neb_canonical_pyr.json \
    --xyz  results/relaxed_pristine.xyz \
    --out  filled.tm.yaml

# build a NOMAD upload bundle
tm-spec export-nomad examples/*.tm.yaml --out nomad_upload.zip

Without install: python -m tm_spec.cli ... after pip install -e ..

A 30-second TM-Spec example

spec: tm-spec/0.2
kind: NEBCalculation
id: tm.pyr.vs.hint.smoke.2026-04-29
schema_url: https://exopoiesis.github.io/tm-spec/0.2.json

structure:
  formula: Fe32S63H1
  prototype: AB2_cP12_205_a_c
  space_group: { number: 205, symbol: Pa-3 }
  cell: { a: 5.418, c: 5.418 }
  supercell: [2, 2, 2]
  pbc: [true, true, true]

calculation:
  method: DFT
  level:
    xc: PBE+D3(BJ)
    basis: { kind: plane_waves, cutoff_Ry: 60, rho_cutoff_Ry: 240 }
    smearing: { kind: gaussian, width_Ry: 0.005 }
    spin: none
  k_points: { mesh: [2, 2, 2] }
  code: { name: QuantumESPRESSO, version: 7.3.1 }

workflow:
  kind: NEB
  stage: smoke
  endpoints:
    A: { ref: artifacts/endA.extxyz, E_eV: -128055.5404, fmax: 0.027 }
    B: { ref: artifacts/endB.extxyz, E_eV: -128055.5402, fmax: 0.026 }
  n_images: 7
  optimizer: BFGS
  prewrap: idpp

results:
  status: PASS
  paper_quotable: false

sanity:
  - { id: G01_FeS_bond, rule: "min(Fe-S) > 2.00 A", observed: 2.27, pass: true }
  - { id: G04_fmax_endpoints, rule: "fmax(A,B) <= 0.05", observed: [0.027, 0.026], pass: true }

provenance:
  date: 2026-04-29
  author: igor@exopoiesis.space
  parents: ["tm.pyr.vs.hint.pristine@2026-04-29"]
  compute: { host: cloud-gpu, gpu: A100, cost_usd: 4.0, walltime_h: 6.0 }
  hash:
    inputs: sha256:placeholder_to_be_computed
    outputs: sha256:placeholder_to_be_computed

Supported kinds

Optional sections (any kind):

Repository layout

tm-spec/
├── README.md, SPECIFICATION.md, CHANGELOG.md, CITATION.cff
├── LICENSE              # MIT (code)
├── LICENSES/            # MIT + CC-BY-4.0 texts
├── pyproject.toml
├── schemas/
│   ├── 0.1.json
│   ├── 0.2.json
│   └── 0.3.json
├── docs/
│   ├── specification/v0.1.md
│   ├── specification/v0.2.md
│   ├── specification/v0.3.md
│   ├── gate-registry.md
│   ├── design-decisions.md
│   ├── standards-alignment.md
│   ├── landscape.md
│   └── lit-review.md
├── examples/
├── src/tm_spec/
└── tests/

Tests

pip install -e ".[dev]"
pytest -q
ruff check src tests
tm-spec validate --all examples --strict

CI runs on Python 3.10, 3.11, 3.12, and 3.13.

Versioning

tm-spec/<major>.<minor> is part of each YAML document (spec: field). Schema files are versioned in schemas/<major>.<minor>.json. Breaking schema changes bump <major>; additive fields bump <minor>. Code follows SemVer independently (pyproject.toml).

Citation

If TM-Spec helped your paper SI, cite:

Morozov, I. (2026). TM-Spec: a declarative YAML metalanguage for reproducible atomistic calculations. Version 0.3. https://github.com/exopoiesis/tm-spec

License

This project is dual-licensed using the REUSE/SPDX convention:

• Code (src/, tests/, build files) — MIT.
• Specification text & schema (docs/, schemas/, SPECIFICATION.md) — CC-BY-4.0.

Root LICENSE is a copy of MIT so GitHub detects the primary code license.

Contact

Author: Igor Morozov, igor@exopoiesis.space
Issues: https://github.com/exopoiesis/tm-spec/issues