@agenticprimitives/mcp-oauth

Part of Agentic Primitives — the open-source trust substrate for agentic applications: identity that can sign, authority checked at act time, evidence the owner carries. Developer kit · All packages

MCP OAuth compatibility adapter + Agentic Grant Bundle bridge (spec 277). OAuth is an ingress adapter for public HTTP MCP clients — not the vault authority. A validated token references a grant bundle by id+hash; the normal delegated vault path runs off the bundle.

import { validateMcpBearerToken, resolveGrantBundleFromToken, buildInsufficientScopeResponse } from '@agenticprimitives/mcp-oauth';

const v = await validateMcpBearerToken(parseBearer(req.headers.get('authorization')), {
  verify: (tok) => jwks.verify(tok),          // injected: signature + decode → claims
  audience: 'https://mcp.example.com/mcp',
  requiredScopes: ['mcp:invoke', 'vault:pii:read'],
  requireGrantBinding: true,
});
if (!v.ok) return v.reason === 'insufficient_scope'
  ? buildInsufficientScopeResponse({ missingScopes: v.missingScopes!, resourceMetadataUrl })
  : buildUnauthorizedResponse({ resourceMetadataUrl });

const r = await resolveGrantBundleFromToken(v.claims, grantBundleStore);  // store injected
// r.bundle → delegation/entitlement hashes → normal delegated vault path

Dependency-free + runtime-agnostic. The authorization server, JWT/JWKS verification, and the encrypted grant-bundle store live in the app/runtime. An inbound MCP token is never reused downstream. See spec 277 §6–§8, §15.