# mcp MCP server

Verifiable provenance for AI agents — ZK proofs over confidential documents, no plaintext exposure.

## Links
- Registry page: https://www.getdrio.com/mcp/io-github-lemmaoracle-mcp
- Repository: https://github.com/lemmaoracle/lemma
- Website: https://lemma.frame00.com

## Install
- Command: `npx -y @lemmaoracle/mcp`
- Endpoint: https://mcp.lemma.workers.dev/mcp
- Auth: Auth required by registry metadata

## Setup notes
- Remote header: Authorization (required; secret)
- Package: Npm @lemmaoracle/mcp v0.0.17
- Environment variable: LEMMA_API_KEY (required; secret)
- Environment variable: LEMMA_API_BASE
- The upstream registry signals required auth or secrets.
- Remote endpoint: https://mcp.lemma.workers.dev/mcp
- Header: Authorization

## Tools
- lemma_query_verified_attributes - Query cryptographically verified attributes from Lemma. Use this as the primary tool for finding documents whose attributes match given conditions (e.g., "subject's birthYear lt 2008"). Returns { results: Array<{ docHash, schema, issuerId, subjectId, attributes, isVerified, proof?: { status, circuitId, chainId }, disclosure? }>, hasMore }. The MCP layer enriches each item with an `isVerified` flag derived from `proof.status` (true when status is 'verified' or 'onchain-verified'). Use lemma_get_proof_status to monitor a specific proof; use lemma_get_schema to interpret the keys returned in `attributes`. Endpoint: https://mcp.lemma.workers.dev/mcp
- lemma_get_schema - Retrieve a Lemma schema by its ID via GET /v1/schemas/{id}. A schema declares how documents of a given type are interpreted and normalized. Returns SchemaMeta { id, description? } with additionalProperties open — implementations commonly include a `normalize` artifact (WASM that maps raw documents to canonical form) and its content hash. Use this when you need to interpret attribute keys returned by lemma_query_verified_attributes. Endpoint: https://mcp.lemma.workers.dev/mcp
- lemma_get_circuit - Retrieve a zero-knowledge proof circuit by its circuitId via GET /v1/circuits/{circuitId}. A circuit defines the constraints that proofs must satisfy and binds to a single schema. Returns CircuitMeta { circuitId, schema, description?, inputs?, verifier?: { type: 'onchain'|'offchain', address?, chainId? }, artifact?: { location: { type: 'ipfs'|'https', wasm, zkey } } }. Use this before lemma_submit_proof to confirm the circuit's schema, public inputs, and verifier configuration. Circuits are immutable; new variants get new circuitIds. Endpoint: https://mcp.lemma.workers.dev/mcp
- lemma_get_generator - Retrieve a Lemma document generator by generatorId via GET /v1/doc-generators/{generatorId}. A generator describes how a class of source documents is produced (e.g., what fields a 'KYC-v2' issuer must populate). Returns GeneratorMeta { generatorId, schema, description?, language?, source?: { type: 'url', uri }, inputsSpec?, outputsSpec? }. Each generator is bound to one schema. Use this when onboarding a new issuer or auditing how an existing schema is being populated. Endpoint: https://mcp.lemma.workers.dev/mcp
- lemma_get_proof_status - Get the verification status of a proof. NOTE: the v2 API does not yet expose a dedicated GET /v1/proofs/{id} endpoint, so this tool internally calls POST /v1/verified-attributes/query filtered by docHash (treating the verificationId returned from lemma_submit_proof as a docHash filter). Returns { status, circuitId, chainId, docHash } extracted from the matched item, or undefined if the verificationId is unknown. Status enum: received | verified | onchain-verified | rejected. Use the SDK's isVerified() helper (or check status === 'verified' || status === 'onchain-verified') to determine cryptographic validity. Endpoint: https://mcp.lemma.workers.dev/mcp

## Resources
Not captured

## Prompts
Not captured

## Metadata
- Owner: io.github.lemmaoracle
- Version: 0.0.17
- Runtime: Npm
- Transports: STDIO, HTTP
- License: Not captured
- Language: Not captured
- Stars: Not captured
- Updated: May 18, 2026
- Source: https://registry.modelcontextprotocol.io