MCP Server Authorization: Options and Limits

Use the MCP authorization specification for HTTP transport access, then add Grantex when tools must verify agent-specific delegated authority.

MCP authorization is optional and transport-specific. The current MCP authorization specification defines an OAuth-based flow for HTTP transports, including protected-resource metadata and authorization-server discovery. Stdio deployments use their host environment rather than that HTTP flow.

Two distinct Grantex packages

@grantex/mcp: manage Grantex through MCP tools

This MCP server exposes Grantex management operations to a configured MCP client. It uses a Grantex API key supplied by the host environment. It does not by itself turn every third-party MCP server into an authorized resource server.

{
  "mcpServers": {
    "grantex": {
      "command": "npx",
      "args": ["@grantex/mcp"],
      "env": { "GRANTEX_API_KEY": "set-in-the-host-environment" }
    }
  }
}

@grantex/mcp-auth@4.1.0: human-confirmed authorization server

Version 4 renders consent, binds authorization to a host-authenticated human principal, and supports durable shared state. A deployment must configure trusted host login, shared storage, resource binding, local revocation and current issuer-grant checks before protecting tools.

BoundaryVersion 4 behaviorHost responsibility
Human identityRechecks the required principal resolver at approval and callbackVerify human login and tenant-scoped sessions; an OAuth client ID is not the human
ConsentRenders purpose, tools, limits, destination and Allow or DenyConfigure truthful labels and live Grantex passkey enrollment
Shared stateSupports durable adapters and atomic code consumptionProvision Postgres or Redis and run migrations
Current authorityCan check the issuer's current grant before protected executionConfigure both local revocation and trusted current-grant verification

Production enforcement pattern

  1. Implement the current MCP HTTP discovery and authorization requirements with a compatible client and resource server.
  2. Authenticate the human in the host and use a tenant-scoped principal resolver for consent.
  3. At the tool boundary, validate issuer, audience, signature, expiry, principal, and exact scope.
  4. Configure local revocation and current-grant checks; issuer outages must fail closed.
  5. Require a consumed, action-bound human decision for sensitive tools and record actual execution separately.
npm install @grantex/mcp-auth@4.1.0 @grantex/sdk@0.8.2 pg

// At the MCP tool boundary:
// 1. verify the signed grant token and exact scope
// 2. check local revocation and current issuer authority
// 3. consume an action-bound decision when required
// 4. execute and audit the tool only after authorization succeeds
Package installation does not provision human login, passkeys, shared state, or your MCP client's interoperability.

Review the deployment boundary before choosing an MCP path

The release page records exact versions and limitations. The deployment guide covers required host configuration.

MCP Auth deployment guide Release status

Technical review updated 4 October 2026.

Related implementation resources