# Lethe Delete

> Provable data-subject deletion for AI memory. On a GDPR/CCPA "delete me" request, Lethe Delete removes a person from your vector store, RAG index, and caches; re-queries to confirm the embeddings are absent; and emits an Ed25519-signed, tamper-evident deletion certificate. Open-source (Apache-2.0), self-hosted, MCP-ready for AI agents.

## What it does
- Removes a data subject across your configured retrieval layers: vector stores (Postgres/pgvector, Pinecone), RAG indexes, and caches.
- Re-queries after deletion to confirm the records and embeddings are absent.
- Emits a signed, tamper-evident certificate stating what was deleted, when, and that it was verified absent at issue time.
- Tag-on-write: wrap your store once and every write tags itself, so a later `forget(subject)` finds and deletes everything — nothing to remember later.

## What the certificate records (schema lethe.cert/2)
- `valid_until`: the absence is asserted from `issued_at` only up to this time — a deletion cert is not eternal, so re-verify past it (the underlying index can change).
- `declared_scope`: the stores Lethe was configured to sweep, so a reader can see what was in scope and infer what was NOT checked.
- per-layer `residual_count` + `verify_method`: how many records the post-delete re-query still found (`0` backs `verified_absent`) and the exact query behind it — evidence, not just a boolean. `index_version` is a nullable slot for a store-native index fingerprint.
- The verifier is version-aware: older `lethe.cert/1` certificates still validate. Available in `pip install lethe-delete` >= 0.2.0.

## Honest scope (do not overstate)
- The certificate proves absence from your CONFIGURED retrieval layers AT ISSUE TIME — not backups, not model weights, not read replicas.
- For eventually-consistent stores (e.g. Pinecone), `verified_absent` reflects a re-query at issue time against the configured endpoint, not a guarantee across replicas.
- A self-signed certificate proves self-consistency; independent third-party attestation is a separate layer.
- Early and pre-revenue. Lethe Delete is a tool that helps you prove deletion — it is not a compliance guarantee and does not guarantee an outcome.

## For AI agents (machine-to-machine)
- Ships an MCP server over stdio (no remote/HTTP MCP today). Six tools (`lethe_status`, `lethe_tag`, `lethe_forget_preview`, `lethe_forget`, `lethe_verify_subject`, `lethe_verify_certificate`); the destructive `lethe_forget` is two-step: `lethe_forget_preview` returns the blast radius plus a single-use confirm token, and `lethe_forget` runs only if the data still matches the preview.
- Verify-only mode: any agent can verify a deletion certificate with no database access, against the operator's pinned public key.
- Full agent integration guide: https://lethe-delete.com/for-agents  ·  Complete machine-readable reference: https://lethe-delete.com/llms-full.txt

## Install
- `pip install lethe-delete` (the import stays `lethe`; CLI: `lethe` and `lethe-mcp`).

## Connectors
- Postgres/pgvector and Pinecone connectors, plus a LangChain integration. No LlamaIndex connector yet.

## Answers to common questions
- What is a deletion certificate? https://lethe-delete.com/what-is-a-deletion-certificate
- How to prove data deletion from a vector database (pgvector, Pinecone): https://lethe-delete.com/prove-deletion-from-a-vector-database

## Links
- Site: https://lethe-delete.com
- Live verify challenge (3 signed certs, 1 pinned key, zero infra — verify them yourself): https://lethe-delete.com/demo
- Verify a certificate: https://lethe-delete.com/verify
- Source (Apache-2.0): https://github.com/bluetieroperations-create/lethe
- Open benchmark "Can Your AI Forget?": https://github.com/bluetieroperations-create/can-your-ai-forget
- Package: https://pypi.org/project/lethe-delete
- Maintainer: BlueTier Operations — bluetier.operations@gmail.com