Every AI agent decision, in one signed chain you can search, replay, and verify.
Etch records every AI agent decision as a signed event: the prompt, the context, the tools called, the outcome. When production breaks, replay the exact chain. When a reviewer asks six months later, the same record verifies on their laptop against pinned keys. Nothing depends on Etch staying online.
curl -X POST https://etch.systems/v1/your-project
Returns a bearer token and an MCP endpoint URL. Point
any MCP client at etch.systems/mcp and start
writing to a real signed chain. 500 events, 14 days,
convert to a persistent project any time.
See the walkthrough.
ijson parse, no vendor dependency.
Aggregate signal from the hosted platform and the open- source layer that Etch is built on. Refreshed on request. Never per-project or per-caller data.
Signatures prove authorship. Hashes only prove order.
A hash chain detects tampering but does not tell you WHO signed what. An authenticated audit chain does both. Every epoch is Merkle-hashed AND signed under a key the auditor can pin.
| Etch (signed) | Hash-only log | Plain log | |
|---|---|---|---|
| Signature scheme | Hybrid Ed25519 + SLH-DSA-SHA2-128f (FIPS 205) | None (hash only) | None |
| Post-quantum ready | Yes (SLH-DSA is NIST PQC) | No | No |
| Offline reference verifier | Yes (etch-verify, streaming) | Vendor-specific | No |
| Framework mapping (EU AI Act / SOC 2 / ISO) | Article + control IDs cited | Ad hoc | None |
| Signed decision receipts | Yes (per epoch) | No | No |
| Human annotation in-chain | pin_annotation MCP tool | No | No |
| Shareable auditor URL (no login) | Yes (expiring share tokens) | No | No |
One authenticated audit chain. Three surfaces so developers, auditors, and reviewers each get the tool that fits their job.
Four admissibility-grade primitives, available today.
Beyond the signed chain, Etch provides the four primitives that appear in regulated buyers' RFPs and in court. Each is a first-class endpoint on the platform.
Chain-of-custody export bundle
Session-scoped, self-authenticating JSON bundle aligned with Federal Rule of Evidence 902 (11 / 13 / 14) and EU eIDAS. Chain- signed via an on-chain marker so any auditor can recompute the bundle hash offline and match it against the ledger.
HSM / TPM / enclave attestation
Enterprise brings its own HSM (tpm2 / yubikey / aws-nitro / gcp-shielded / azure-attestation / sev-snp / intel-tdx). Etch attaches the vendor attestation blob to the signed event without routing trust through Etch.
Cross-chain federation
A supplier's chain event can reference a customer's chain event by (chain_id, epoch, event_hash). Cryptographically walkable across organizational boundaries with no central coordinator. Offline + optional online verifier modes.
Signed postmortem + retroactive downgrade
First-class signed retrospective: about_event_id, finding, corrective action + signer, optional retroactive confidence downgrade. Closes the "how do you improve governance over time" loop that SR 11-7 / EU AI Act / SS3/18 require.
Full endpoint catalog on the docs page. All 16 endpoints
exercisable from the etch-record CLI on
PyPI.
Ready to audit what your agents actually decide?
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