# io.github.lemmaoracle/mcp (remote · mcp.lemma.workers.dev)

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

- Trust score: 67/100 (medium)
- Change this week: +5
- Registry status: active
- Liveness: live
- Owner verified: no
- Last scored: 2026-08-03

## Components

- remote · `mcp.lemma.workers.dev`: 67/100 (this document), [markdown](https://verifymcp.io/servers/lemmaoracle-mcp/mcp.md), [page](https://verifymcp.io/servers/lemmaoracle-mcp/mcp)
- npm · `@lemmaoracle/mcp`: 34/100, [markdown](https://verifymcp.io/servers/lemmaoracle-mcp/lemmaoracle-mcp.md), [page](https://verifymcp.io/servers/lemmaoracle-mcp/lemmaoracle-mcp)

## Channel facts

- Endpoint: `https://mcp.lemma.workers.dev/mcp`
- Transports: `streamable-http`
- Auth: `required`
- Version: `0.0.17`

## Trust breakdown

How this component scores in each security and reliability category. Every signal is checked automatically against the live server, and we only credit what we can confirm. Scores are 0–100 per category. Scoring method: https://verifymcp.io/docs/scoring (what has changed: https://verifymcp.io/docs/scoring/changelog)

Scored 2026-08-03.

- **Endpoint Security**: 63/100
  - The endpoint's TLS certificate is valid, in date, and uses a strong key.
  - No authorisation is required to call this server. Every tool declares its destructiveHint and none is destructive, so open access doesn't expose one.
  - HTTPS not yet verified: we couldn't determine whether a plaintext access path exists.
  - HSTS check failed: the Strict-Transport-Security header is absent.
  - DNSSEC check failed: this domain isn't protected by DNSSEC.
- **Transport & Reachability**: 100/100
  - Verified streamable-http transport via a live MCP handshake.
- **Schema Quality & AI Usability**: 64/100
  - AI-judged instruction clarity (good).
  - Context-footprint check failed: tool/resource definitions use about 949 tokens (~189/item across 5 items; 5 tools + 0 resources), over budget; trim descriptions and params.
  - Usage-examples check failed: none of the tools include examples.
- **Stability & Change Management**: 27/100
  - Stability observed for 8 of 30 days with no destabilising changes; credit accrues until the full window elapses.
- **Tool Coverage**: 100/100
  - 100% of tools have a non-trivial description (not blank, and not just the tool's name).
  - 100% of tool parameters carry a description.
  - Structured output schemas are declared (100% of tools); any adoption earns full credit.
- **Capabilities**: 100/100
  - Implements a supported MCP spec version (2025-11-25); the latest is 2026-07-28.

## Install

### Claude

```bash
claude mcp add --transport http lemmaoracle-mcp https://mcp.lemma.workers.dev/mcp
```

### Codex

```toml
[mcp_servers.lemmaoracle-mcp]
url = "https://mcp.lemma.workers.dev/mcp"
```

### opencode

```json
{
  "$schema": "https://opencode.ai/config.json",
  "mcp": {
    "lemmaoracle-mcp": {
      "type": "remote",
      "url": "https://mcp.lemma.workers.dev/mcp",
      "enabled": true
    }
  }
}
```

### OpenClaw

```bash
openclaw mcp add lemmaoracle-mcp --url https://mcp.lemma.workers.dev/mcp --transport streamable-http
```

### Hermes

```yaml
mcp_servers:
  lemmaoracle-mcp:
    url: "https://mcp.lemma.workers.dev/mcp"
```

### Other

```json
{
  "mcpServers": {
    "lemmaoracle-mcp": {
      "type": "http",
      "url": "https://mcp.lemma.workers.dev/mcp"
    }
  }
}
```

The mcpServers block is a cross-client convention. Remote transports vary, so check your client's docs.

## Changelog

Every change recorded for this component, newest first. Days that predate change tracking, or that we cannot explain, say so: "we were watching and nothing happened" and "we were not watching" are different claims.

### 2026-08-03 (score 67, +1)

No change was recorded against any check on this day. Stability & Change Management went from 23 to 27. That category is still filling its 30-day observation window: 7 days of observed history at the previous scan, 8 at this one. The score rises as the window fills, whether or not the server changes.

### 2026-07-31 (score 66, +2)

- [functional] We updated how we score, so this day's move reflects our rubric, not a change to the server

### 2026-07-30 (score 64, 0)

- [functional] We updated how we score, so this day's move reflects our rubric, not a change to the server

### 2026-07-29 (score 64, +1)

No change was recorded against any check on this day. Stability & Change Management went from 7 to 10. That category is still filling its 30-day observation window: 2 days of observed history at the previous scan, 3 at this one. The score rises as the window fills, whether or not the server changes.

### 2026-07-28 (score 63, +1)

No change was recorded against any check on this day. Stability & Change Management went from 3 to 7. That category is still filling its 30-day observation window: 1 days of observed history at the previous scan, 2 at this one. The score rises as the window fills, whether or not the server changes.

### 2026-07-27 (score 62, 0)

- [functional] We updated how we score, so this day's move reflects our rubric, not a change to the server

### 2026-07-26 (score 62)

First indexed and scored.

## MCP tools (5)

### `lemma_query_verified_attributes` (~244 tokens)

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`.

Input parameters:

- `attributes` (array): Attribute predicates to AND-combine.
- `chainIds` (array): Restrict results to attributes verified on these chain IDs (EVM).
- `limit` (number): Max results per page (1–200). Defaults to API server default (50).
- `offset` (number): Pagination offset. Pair with `hasMore` in the response to walk pages.
- `schemas` (array): Restrict results to documents conforming to these schema IDs.

Output parameters:

- `hasMore` (boolean): True when more results exist beyond this page; pair with `offset` to walk pages.
- `results` (array): Result set; each item has been MCP-enriched with `isVerified`.

### `lemma_get_schema` (~133 tokens)

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.

Input parameters:

- `id` (string, required): Schema ID. Returned in the `schema` field of VerifiedAttributesQueryResponseItem from lemma_query_verified_attributes, or registered via POST /v1/schemas.

Output parameters:

- `description` (string): Human-readable description of the schema.
- `id` (string): Schema ID, echoing the request.
- `normalize` (object): Normalize artifact — WASM that maps raw documents to canonical form.

### `lemma_get_circuit` (~200 tokens)

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.

Input parameters:

- `circuitId` (string, required): Circuit ID. Returned in the `proof.circuitId` field of VerifiedAttributesQueryResponseItem from lemma_query_verified_attributes, or registered via POST /v1/circuits. NOTE: this matches the OpenAPI fi…

Output parameters:

- `artifact` (object): Circuit artifact location (WASM + zkey).
- `circuitId` (string): Circuit ID, echoing the request.
- `description` (string)
- `inputs` (array): Ordered names of the circuit's public/private inputs.
- `schema` (string): Schema ID this circuit is bound to.
- `verifiers` (array): Available verifier configurations for this circuit.

### `lemma_get_generator` (~168 tokens)

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.

Input parameters:

- `generatorId` (string, required): Generator ID. Each generator is bound to a single schema and describes how source documents are produced. Registered via POST /v1/doc-generators. NOTE: this matches the OpenAPI field name `generatorI…

Output parameters:

- `description` (string)
- `generatorId` (string): Generator ID, echoing the request.
- `inputsSpec` (object): Specification of fields the issuer must populate.
- `language` (string): Implementation language (e.g. 'rust', 'typescript').
- `outputsSpec` (object): Specification of fields the generator produces.
- `schema` (string): Schema ID this generator is bound to (1:1 binding).
- `source` (object): Reference to the generator's source code.

### `lemma_get_proof_status` (~204 tokens)

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.

Input parameters:

- `verificationId` (string, required): verificationId returned by lemma_submit_proof. Internally treated as a docHash filter on POST /v1/verified-attributes/query (no dedicated GET /v1/proofs/{id} endpoint in v2 API).

Output parameters:

- `chainId` (number): EVM chain ID where the proof was verified, if applicable.
- `circuitId` (string): Circuit ID this proof was generated against.
- `docHash` (string): Document hash this proof attests to.
- `status` (string): Verification status enum: 'received' | 'verified' | 'onchain-verified' | 'rejected'. Use the SDK's isVerified() helper (or check status === 'verified' || status === 'onchain-verified') for cryptograp…

## Diagnostics

Captured diagnostic sections: TLS, DNSSEC, Authorisation, Transports. The full working is on the page: https://verifymcp.io/servers/lemmaoracle-mcp/mcp#diagnostics

## Score history

- 2026-08-03: 67
- 2026-08-02: 66
- 2026-08-01: 66
- 2026-07-31: 66
- 2026-07-30: 64
- 2026-07-29: 64
- 2026-07-28: 63
- 2026-07-27: 62
- 2026-07-26: 62

## Links

- Remote endpoint: https://mcp.lemma.workers.dev/mcp
- Authorisation metadata: https://mcp.lemma.workers.dev/.well-known/oauth-protected-resource/mcp
- Repository: https://github.com/lemmaoracle/lemma
- Website: https://lemma.frame00.com/
- Changelog RSS feed: https://verifymcp.io/servers/lemmaoracle-mcp/mcp/changelog.xml
- Changelog JSON feed: https://verifymcp.io/servers/lemmaoracle-mcp/mcp/changelog.json
- HTML version of this page: https://verifymcp.io/servers/lemmaoracle-mcp/mcp