Provenance (tamper-evident ledger)

AbstractRuntime’s ledger is an append-only journal of StepRecord entries. For audit/debug workflows, you can add tamper-evidence via a hash chain: - each record carries prev_hash + record_hash - modifications/reordering become detectable when you verify the chain

Implementation pointers: - model fields: src/abstractruntime/core/models.py (StepRecord.prev_hash, StepRecord.record_hash, StepRecord.signature) - hash-chain decorator + verifier: src/abstractruntime/storage/ledger_chain.py

What is implemented (v0.4.3)

• HashChainedLedgerStore(inner_store) — wraps any LedgerStore to compute hashes on append
• verify_ledger_chain(records) — validates the chain and returns a verification report

Example:

from abstractruntime import Runtime, WorkflowSpec
from abstractruntime.storage import InMemoryLedgerStore, InMemoryRunStore
from abstractruntime.storage.ledger_chain import HashChainedLedgerStore, verify_ledger_chain

ledger = HashChainedLedgerStore(InMemoryLedgerStore())
rt = Runtime(run_store=InMemoryRunStore(), ledger_store=ledger)

# ... run workflows ...

records = rt.get_ledger(run_id="...")  # list[dict]
report = verify_ledger_chain(records)
print(report.get("ok"), report.get("errors"))

What is intentionally not implemented (yet)

• cryptographic signatures (non-forgeability)
• key management / delegation / revocation

Those belong in an optional extra (e.g., abstractruntime[crypto]) once the design is finalized.

See also

• architecture.md — ledger as the source of truth
• evidence capture: src/abstractruntime/evidence/recorder.py (stores external-boundary evidence as artifacts + index)