# MCP Verification Gate (MCP conduct register) API

**Canonical:** https://apis.io/apis/horizonshield-dev/mcp-verification-gate-api/  
**Provider:** HORIZON SHIELD — https://apis.io/providers/horizonshield-dev/  
**Base URL:** https://gate.horizonshield.dev  
**Documentation:** https://shield.the-horizons-innovation.com/verify-directory/

MCP Verification Gate (MCP conduct register) API is one of 7 APIs that [HORIZON SHIELD](https://apis.io/providers/horizonshield-dev/) publishes on the [APIs.io](https://apis.io/) network, described by a machine-readable OpenAPI specification. Tagged areas include Verification, MCP, A2A, Transparency Ledger, and Agents. The published artifact set on APIs.io includes an OpenAPI specification, an API reference, API documentation, and a changelog.

Read-only, keyless REST API at https://gate.horizonshield.dev described by an OpenAPI 3.1.0 document (25 operations, version 0.4.7): the public register of MCP endpoints measured nightly against five stated conditions (speaks MCP, publishes an A2A agent card, declares who pays it, identical input gives identical output, the verdict is recomputable), per-endpoint history and change feeds (JSON and Atom), badges and embeds, the A2A Conduct Extension v1 specification, hash recomputation and NIP-01/BIP340 event verification, and the gate's own self-measurement. The same register is exposed over MCP (5 tools at /mcp) and A2A (/a2a), and consumed by the first-party npm client mcp-conduct and a GitHub Action.

## Operations (25)

| Method | Path | Summary |
|---|---|---|
| GET | `/register` | Every row in the register |
| GET | `/verified.json` | Only the rows that passed every measured condition |
| GET | `/history` | Past measurements for one endpoint |
| GET | `/changes` | State changes only |
| GET | `/feed.xml` | The same changes as an Atom feed |
| GET | `/sitemap.xml` | One URL per measured endpoint |
| GET | `/e/{host}{path}` | The permanent page for one measured endpoint |
| GET | `/badge` | A badge drawn from the register at request time |
| GET | `/embed` | The verification envelope, ready to paste on your own site |
| GET | `/badge/seal` | A larger badge, sized for print and for other people's sites |
| GET | `/spec` | The five conditions, stated in full |
| GET | `/ext/conduct/v1` | A2A Conduct Extension v1 (the URI is the identifier) |
| GET | `/self` | This gate measured against its own conditions |
| GET | `/health` | Liveness and the deployed commit |
| POST | `/recompute` | Work out which canonicalization reproduces a claimed hash |
| POST | `/verify-event` | Recompute a NIP-01 event id and verify its BIP340 signature |
| GET | `/mould` | Mould records. What class of assumption a fix came from, where the author searched for it, and what they found. A record with an empty search is published as... |
| GET | `/sweep/last` | When the last scheduled re-measurement ran, under which coordinate rule, and why |
| GET | `/nenrin/window` | The instant coordinate's public window: salt commitment at creation, pinned rule, beacon, salt revealed after the window closes (0.3.5), and since 0.4.0 whet... |
| GET | `/register/lookup` | One read before connecting (conduct-v1.1 section 7): status verified / pending / declined / unknown, the last published ring's counts, where the record lives... |
| GET | `/watchlist` | Endpoints scheduled for re-measurement |
| GET | `/.well-known/agent-card.json` | A2A agent card for this gate |
| GET | `/.well-known/mcp-register.json` | Machine readable summary of the register |
| POST | `/check` | Measure one endpoint now |
| POST | `/mcp` | The same register over MCP |

## Machine-readable artifacts (8)

- **OpenAPI** — https://raw.githubusercontent.com/api-evangelist/horizonshield-dev/refs/heads/main/openapi/horizonshield-dev-mcp-conduct-register-openapi.json
- **OpenAPI** — https://gate.horizonshield.dev/openapi.json
- **APIReference** — https://gate.horizonshield.dev/spec
- **Documentation** — https://github.com/ogasurfproject-jpg/mcp-conduct#readme
- **Overlay** — https://raw.githubusercontent.com/api-evangelist/horizonshield-dev/refs/heads/main/overlays/horizonshield-dev-mcp-conduct-register-overlay.yaml
- **MCPServer** — https://gate.horizonshield.dev/mcp
- **AgentCard** — https://gate.horizonshield.dev/.well-known/agent-card.json
- **ChangeLog** — https://gate.horizonshield.dev/feed.xml

## Other HORIZON SHIELD APIs (6)

- [HORIZON SHIELD KIRA MCP Server](https://apis.io/apis/horizonshield-dev/horizon-shield-kira-mcp-server/)
- [HORIZON SHIELD KIRA A2A Agent](https://apis.io/apis/horizonshield-dev/horizon-shield-kira-a2a-agent/)
- [JIDEC Verification Ledger API](https://apis.io/apis/horizonshield-dev/jidec-verification-ledger-api/)
- [Yakumo Verified-Contractor Directory MCP](https://apis.io/apis/horizonshield-dev/yakumo-verified-contractor-mcp/)
- [HORIZON SHIELD WebMCP Intake Server](https://apis.io/apis/horizonshield-dev/webmcp-intake-server/)
- [HORIZON SHIELD Femtech Source Registry MCP](https://apis.io/apis/horizonshield-dev/femtech-source-registry-mcp/)

## Tags

Verification, MCP, A2A, Transparency Ledger, Agents

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Profiled by [API Evangelist](https://apievangelist.com) and published on [APIs.io](https://apis.io/apis/horizonshield-dev/mcp-verification-gate-api/). The API's provider profile, Kin Score and agent-readiness rating are at https://apis.io/providers/horizonshield-dev/.