# Etch

> Etch is a signed audit chain for AI agent decisions, offline-verifiable against pinned public keys. Every event is signed with a hybrid Ed25519 + FIPS 205 SLH-DSA-SHA2-128f envelope, Merkle-chained into an epoch, and epoch-anchored on Sigstore Rekor + Bitcoin OpenTimestamps.

> world-model-mcp is persistent memory plus a post-quantum-signed, offline-verifiable audit trail for AI coding agents (FIPS 205 hybrid Ed25519 + SLH-DSA), MIT-licensed and fully local.

Etch is a hosted platform + reference OSS verifier. Try it in 30 seconds without signing up: `curl -X POST https://etch.systems/v1/your-project`. The response returns a bearer token and an MCP endpoint. Point any MCP-compliant client at `https://etch.systems/mcp` with the token.

## Key claims (each caveat travels in the same sentence as the number)

- On the pre-registered SWE-bench Verified repeat-mistake benchmark, memory improved the pass rate by +10.2 points as a single-trial upper bound (67.3% to 77.6% on 49 paired instances); the multi-seed mean effect is +0.24 per instance, 95% CI [0, 0.47].
- 14 of 14 chain-tamper attacks in the current adversarial-benchmark corpus are caught by the offline verifier (scope claim, not completeness; new attack classes may be added later).
- Two projects use Etch today: our own world-model-mcp (dogfood) + saha (design partner). Pre-revenue; no paying-customer claim is made anywhere.
- Etch conforms to CSA / Herman Errico's AARM spec; Etch did not coin AARM.
- Try the OSS live-signed demo (no signup, no network): `pip install -U world-model-mcp && world-model demo`. Signs three decisions into a hybrid-signed epoch, verifies VALID, mutates one byte to prove tamper detection fires (INVALID), restores, drops a receipt.

## Product

- [Landing](https://etch.systems/): value proposition + live traction + comparison to hash-only logs + admissibility-grade primitives.
- [Pricing](https://etch.systems/pricing): free tier, Pro, Pilot, Enterprise.
- [Signup](https://etch.systems/signup): 30-second signup for a persistent project.
- [Docs](https://etch.systems/docs): entry point + endpoint catalog.

## Try it now (no signup)

- [Quickstart](https://etch.systems/docs/quickstart): 10-minute walkthrough + try-it-now curl.
- [MCP client integration](https://etch.systems/docs/mcp-clients): per-client config (Claude Code, Cursor, Continue, Cline, Codex).
- [FAQ](https://etch.systems/docs/faq): plain-language answers to the questions asked most often about signed audit chains for AI agents.

## Compare Etch to

- [Etch vs Sigstore Rekor](https://etch.systems/vs/sigstore-rekor): positioning against Sigstore's transparency log.
- [Etch vs C2PA](https://etch.systems/vs/c2pa): positioning against the Coalition for Content Provenance and Authenticity envelope standard.
- [Etch vs hash-only + plain-log](https://etch.systems/): landing comparison table.

## Framework alignment

- [AARM conformance](https://etch.systems/aarm): mapping to SR 11-7, EU AI Act Article 12, ISO 42001, NIST AI RMF, and SOC 2 CC7.
- [Evaluations](https://etch.systems/evals): the axes an auditor should judge a signed-audit-chain product on.
- [RFP response kit](https://etch.systems/rfp-kit): pre-answered RFP for enterprise procurement.

## Open source layer

- [world-model-mcp on PyPI](https://pypi.org/project/world-model-mcp/): the OSS memory server Etch is built on.
- [world-model-mcp on GitHub](https://github.com/SaravananJaichandar/world-model-mcp): source repository, MIT licensed.
- [Etch source](https://github.com/SaravananJaichandar/etch): hosted service source, Business Source License 1.1.

## Provenance and academic references

- [Zenodo DOI 10.5281/zenodo.20834508](https://doi.org/10.5281/zenodo.20834508): the provenance-graded-knowledge technical note.
- FIPS 205 SLH-DSA-SHA2-128f: post-quantum signature scheme used in the hybrid envelope.
- FIPS 186-5 Ed25519: classical signature scheme in the hybrid envelope.
- FIPS 180-4 SHA-256: Merkle-tree hash primitive.

## What Etch is NOT

- Not a media-provenance envelope (that lane is C2PA and SPIF). Etch signs decisions, not content.
- Not a transparency log (that lane is Sigstore Rekor). Etch is a per-project chain that anchors epochs on Rekor.
- Not a watermarking system. Etch records who reviewed an output and what they applied, not whether a specific model touched the text.