# com.pcrzero/mcp (remote · mcp.pcrzero.com)

Issue signed receipts for AI agent actions; verify any receipt offline - free, no account.

- Trust score: 66/100 (medium)
- Registry status: active
- Liveness: live
- Owner verified: no
- Last scored: 2026-08-18

## Components

- remote · `mcp.pcrzero.com`: 66/100 (this document), [markdown](https://verifymcp.io/servers/com-pcrzero-mcp/mcp.md), [page](https://verifymcp.io/servers/com-pcrzero-mcp/mcp)
- npm · `@scytalex-llc/pcrzero-mcp`: 68/100, [markdown](https://verifymcp.io/servers/com-pcrzero-mcp/scytalex-llc-pcrzero-mcp.md), [page](https://verifymcp.io/servers/com-pcrzero-mcp/scytalex-llc-pcrzero-mcp)

## Channel facts

- Endpoint: `https://mcp.pcrzero.com/mcp`
- Transports: `streamable-http`
- Auth: `none`
- Version: `0.2.0`

## 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 2026-08-18.

- **Endpoint Security**: 63/100
  - The endpoint's TLS certificate is valid, in date, and uses a strong key.
  - Authorisation not fully verified: no authorisation is required to call this server, and 3 tool(s) never declared a destructiveHint. The MCP spec treats an absent hint as destructive by default, so we cannot call this surface safe.
  - HTTPS is enforced; there's no plaintext access path.
  - The HSTS (Strict-Transport-Security) header is present.
  - 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**: 71/100
  - AI-judged instruction clarity (good).
  - Context-footprint check failed: tool/resource definitions use about 491 tokens (~163/item across 3 items; 3 tools + 0 resources), over budget; trim descriptions and params.
  - Usage-examples check failed: none of the tools include examples.
- **Stability & Change Management**: 17/100
  - Stability observed for 5 of 30 days with no destabilising changes; credit accrues until the full window elapses.
- **Tool Coverage**: 93/100
  - 100% of tools have a non-trivial description (not blank, and not just the tool's name).
  - 78% of tool parameters carry a description.
- **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 com-pcrzero-mcp https://mcp.pcrzero.com/mcp
```

### Codex

```toml
[mcp_servers.com-pcrzero-mcp]
url = "https://mcp.pcrzero.com/mcp"
```

### opencode

```json
{
  "$schema": "https://opencode.ai/config.json",
  "mcp": {
    "com-pcrzero-mcp": {
      "type": "remote",
      "url": "https://mcp.pcrzero.com/mcp",
      "enabled": true
    }
  }
}
```

### OpenClaw

```bash
openclaw mcp add com-pcrzero-mcp --url https://mcp.pcrzero.com/mcp --transport streamable-http
```

### Hermes

```yaml
mcp_servers:
  com-pcrzero-mcp:
    url: "https://mcp.pcrzero.com/mcp"
```

### Other

```json
{
  "mcpServers": {
    "com-pcrzero-mcp": {
      "type": "http",
      "url": "https://mcp.pcrzero.com/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.

### 2026-08-17 (score 66, +1)

No change was recorded against any check on this day. Stability & Change Management went from 10 to 13. That category is still filling its 30-day observation window: 3 days of observed history at the previous scan, 4 at this one. The score rises as the window fills, whether or not the server changes.

### 2026-08-15 (score 65, +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.

### 2026-08-14 (score 64, 0)

- [functional improvement] Stability: unverified → 0.03

### 2026-08-13 (score 64)

First indexed and scored.

## MCP tools (3)

### `issue_receipt` (~223 tokens)

Adjudicates an attestation document against a policy and returns the verdict together with a signed receipt pair — the durable, independently checkable proof that this decision was made, by these keys, over this document. **Metered: every call bills one `receipt_verifications` unit against the API key configured for this server, and a `fail` verdict bills exactly like a `pass`. You are paying for the adjudication, not for the answer you wanted.** This is the only tool here that spends. If you already hold a receipt and want to know whether it is genuine, that is `verify_receipt`, which is free and needs no key.

Input parameters:

- `document` (string): Base64 attestation document (single-document form).
- `documents` (array): Base64 attestation documents (batch form).
- `nonce` (string)
- `policy` (object): Inline policy object (API wire shape).
- `policy_id` (string): Stored policy id (pol_…).
- `receipt` (boolean): Request a signed receipt (default true).

### `verify_receipt` (~189 tokens)

Checks a PCRZERO receipt pair against the signing keyset: whether the signature holds, and whether the receipt says what it appears to say. **Free, with no API key and no account, and it stays free.** Offline by default — supply `keyset` and this call touches the network not at all; omit it and the server fetches the public keyset from api.pcrzero.com once. The result field `keyset_source` tells you which of the two happened, every time. This tool issues nothing, bills nothing, and cannot spend. It is the half of PCRZERO you never pay for.

Input parameters:

- `conformance` (string)
- `keyset` (object): Optional keyset in GET /v1/keys shape. When supplied, no network is used.
- `receipt` (string, required): Base64url receipt envelope from issue_receipt / the API.

### `get_keyset` (~79 tokens)

Returns the current PCRZERO signing keyset — key ids, public halves, and each key's status. Public and unauthenticated: no API key, no cost, no account. This is the same document an outside party fetches to check a PCRZERO receipt without trusting us, and fetching it is how you stop taking our word for anything.

## Diagnostics

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

## Score history

- 2026-08-18: 66
- 2026-08-17: 66
- 2026-08-16: 65
- 2026-08-15: 65
- 2026-08-14: 64
- 2026-08-13: 64

## Links

- Remote endpoint: https://mcp.pcrzero.com/mcp
- Repository: https://github.com/Scytalex-LLC/pcrzero-mcp
- Website: https://pcrzero.com/mcp
- Changelog RSS feed: https://verifymcp.io/servers/com-pcrzero-mcp/mcp.xml
- Changelog JSON feed: https://verifymcp.io/servers/com-pcrzero-mcp/mcp.json
- HTML version of this page: https://verifymcp.io/servers/com-pcrzero-mcp/mcp