| MCP metadata | Safe draft use | Still requires provider review |
|---|---|---|
| Name, title, description, version | Copy as unverified identity and version hints. | Canonical service URI, Nexus draft identifiers, ownership, and one-service-version scope. |
| Package or remote transport | Record an MCP transport hint. | Exact binding, authentication mode, input/output contracts, and selected tool capability. |
| Repository or website URL | Retain as a source hint in the local workbench. | Provenance records and evidence needed to support publication. |
| Registry namespace | Record publisher metadata provenance only. | Trust, quality, safety, compatibility, reachability, permission, and search eligibility. |
MCP metadata is a start, not a service contract.
The official MCP Registry standardizes publisher-supplied server.json metadata. Agent NEXUS needs additional declarations before it can compare a service with a buyer’s protocol, privacy, authority, payment, evidence, and operational requirements.
The Lab imports pasted or uploaded metadata only. It does not discover, fetch, connect to, or invoke an MCP server.
What maps—and what does not
Ten declarations MCP cannot answer for you
- Choose one capability and supply its real input and output schemas.
- Confirm the protocol transport and authentication mode without including credentials.
- Declare price and payment behavior.
- Declare hard input, output, timeout, concurrency, and retry limits.
- State every read, write, network, secret, spend, and side-effect requirement.
- State data classes, retention, and training use.
- Promise only evidence the service actually produces.
- Describe structured failure behavior.
- Supply attributable health and freshness states.
- Provide provenance and ownership evidence through a future Nexus onboarding process.
Change a field only when the service truthfully behaves differently.
A compatibility blocker is not permission to weaken a privacy or authority declaration.
Contract basis
The mapper recognizes the direct MCP server.json shape and the official Registry ServerResponse wrapper. It deliberately ignores registry metadata as proof of quality or trust.
Reviewed against the official MCP Registry documentation and frozen Nexus v1 manifest schema on . The MCP Registry is currently described by its publisher as preview infrastructure.