attestplane 1.4.7

Apache-2.0 attestation and audit substrate for AI agent evidence chains.

attestplane — Python SDK

Apache-2.0 attestation and audit substrate for AI agent evidence chains.

Status: alpha (v0.0.4a0). APIs may change before v0.1.0. The canonical hash format and conformance vectors, however, are frozen — see ADR-0002. The current CLI attestplane verify path is chain/report-oriented with ProofBundle metadata and policy_trace_refs closure checks. It does not perform full ProofBundle, signature, anchor, or compliance certification verification.

See the project README for background, governance, and trademark policy. The full design rationale for this SDK lives in ADR-0002.

Install

pip install attestplane==0.0.4a0

Requires Python ≥ 3.11.

Optional sidecar extras are deliberately separate from the core substrate:

pip install 'attestplane[anchor]'   # RFC-3161/OCSP/HTTP anchoring helpers
pip install 'attestplane[signing]'  # Ed25519 signing helpers + YAML trust roots

import attestplane works without those extras. Symbols that require optional dependencies are exported only when the corresponding extra is installed.

Quickstart

from attestplane import AttestSubstrate, EventDraft, SubjectRef

sub = AttestSubstrate()

sub.append(
    EventDraft(
        event_type="ai_decision",
        actor="agent://recsys/v1",
        payload={"outcome": "approved", "confidence_bp": 9120},
        session_id="session-2026-05-17-abc",
        subject_ref=SubjectRef(scheme="sha256_salted", value="2c1b...e9"),
    )
)

print(sub.tip())            # ChainHead(seq=0, event_hash=...)
assert sub.verify().ok      # True

What this SDK gives you

• An append-only audit log with cryptographic integrity (SHA-256 hash chain).
• Built-in fields designed toward EU AI Act Art. 12(2)(a) auditability from day one.
• A deterministic canonical format that the TypeScript SDK also verifies; future SDKs must match the same conformance vector file shipped in this package.
• Strong GDPR pseudonymization typing via SubjectRef.

What this SDK does NOT give you (yet)

Feature	Where
Production storage guarantees	JSONL exists as an alpha backend; validate durability and concurrency for your deployment
Multi-process concurrency	Bring your own locking/backend policy for alpha deployments
Full ProofBundle verification	Current CLI is chain/report-oriented only
Signed or anchored CLI verification	Signing/anchoring are sidecar primitives unless an explicit verifier path performs those checks
Retention / truncation policy	Out of scope — deployer responsibility

EU AI Act Article 12(2)(a) mapping

The four enumerated subitems of Art. 12(2)(a) are surfaced as EventDraft fields. All remain optional in v0.0.4a0 — populate the ones your use case requires.

Art. 12(2)(a) language	EventDraft field	Type
"period of each use of the system"	session_id	str | None
"the reference database against which input data has been checked by the system"	reference_db_ref	str | None
"the input data for which the search has resulted in a match"	matched_input_ref	str | None
"the identification of the natural persons involved in the verification of the results"	human_verifier	SubjectRef | None

These are references, not the data itself. A real reference database or matched input must not be inlined into the audit log — that would violate GDPR Art. 5(1)(c) data minimization. Store the data elsewhere (object storage, hashed lookup table) and put a stable, content-addressed identifier here.

Restricted JSON profile

To make Python, TypeScript, and Rust SDKs produce byte-identical hashes, canonicalization is stricter than vanilla JCS (RFC 8785):

Allowed in payload	Forbidden in payload
UTF-8 NFC strings	Other Unicode normalization forms
Signed-int64 integers	Floats, NaN, ±Inf
True / False / None	—
dict (string keys, sorted on emit)	Non-string keys; duplicate keys
list / tuple (order preserved)	—
bytes (emitted as base64url, no padding)	Raw bytes
datetime (RFC 3339 UTC microsecond, Z suffix)	Naive datetimes; non-UTC offsets

Violations raise CanonicalizationError at append time.

If you need to record a real-valued measurement, multiply into a fixed-point integer (e.g., basis points, microseconds, microcents) and document the unit.

Conformance vectors

Ten golden (EventDraft → event_hash hex) pairs live in tests/conformance/vectors.json. These values are a permanent external contract:

• An auditor can re-implement canonicalization from ADR-0002 alone and verify against this file without trusting any SDK code.
• TypeScript and Rust SDKs (M6, M7) MUST produce identical hex for the same inputs, or the release is blocked.
• The file is frozen for schema_version = 1. Adding fields requires a new schema_version and a new vector set under a separate filename; the existing vectors stay valid forever.

The CI conformance test re-derives each hex on every run, so accidental canonicalization drift fails the build immediately.

Threading and processes

AttestSubstrate is safe for concurrent use from multiple threads of the same process. It is not safe across process boundaries — it holds no durable storage and uses a process-local lock. Multi-process / multi-machine backends are deferred to ADR-0004 (anticipated M6).

JSONL storage alpha semantics

JsonlStorageBackend is an opt-in alpha backend for one JSONL record per ChainedEvent. Appends write newline-terminated rows, flush, and fsync by default. Callers may disable fsync with durable=False for tests or explicit best-effort storage.

Reads are fail-closed by default. read_all() raises on malformed JSON, missing fields, invalid UTF-8, or a partial trailing line. scan() is a read-only diagnostic path: it returns the valid prefix plus exact line/byte offset issues, but it never repairs, truncates, or treats corrupted data as a valid full chain.

Concurrency remains single-process. The backend uses a process-local lock only; multi-writer safety, file locking, database semantics, ACID guarantees, and production crash-safety are not claimed.

Development

git clone https://github.com/attestplane/attestplane
cd attestplane/sdk/python
uv venv --python 3.12
. .venv/bin/activate
uv pip install -e '.[dev]'

pytest                  # unit tests + conformance vectors
mypy                    # strict type check
ruff check src tests    # lint

Coverage gate: ≥ 90 % (currently ~ 98 %).

Type check is mypy --strict. The public API is fully type-annotated; consumers should expect type checks against this package to be precise.

License

Apache License 2.0. See LICENSE and NOTICE at the project root.

Reporting issues

• Bugs / feature requests: https://github.com/attestplane/attestplane/issues
• Security vulnerabilities: see SECURITY.md — do not open public issues.
• Trademark questions: see TRADEMARK.md.