Archives

MCP is now stateless. Here's why that's the right call, what actually replaces the old session handshake, and why state didn't disappear

Three frontier labs disclosed that their AI agents breached real companies. None were caught in real time. The problem is not model behavior—it is that the agent is using your identity.

Browser-based agents inherit your session, your cookies, and your identity, with no distinction visible to the service provider. Here's why that's a problem we've already solved once, and what needs to happen next.

A walkthrough of connecting Claude Desktop to PayPal’s remote MCP server over HTTP, highlighting the full OAuth 2.0 flow with Postman from discovery to authorization

MCP explained from the inside out, starting with a real developer workflow then unwrapping the protocol layer by layer: roles, messages, connection lifecycle, and STDIO transport.

OAuth 2.0 could automate client registration and AS discovery, but clients still had to hardcode which authorization server protects a given resource. Protected Resource Metadata fixes that. Here's how PRM completes the dynamic integration story, and why AI agents made it urgent.

Bearer tokens are usable by anyone who possesses them. Certificate-bound tokens, defined in RFC 8705, bind the access token to the client certificate used in the mTLS handshake, so even if a token is intercepted, it's cryptographically worthless without the matching certificate.

Shared secrets can be stolen, leaked, or brute-forced. mTLS-based client authentication uses certificates to prove private key possession. Learn how to apply TLS handshake–based authentication to meet OAuth 2.0 client authentication requirements.

How PKCE (RFC 7636) stops authorization code interception in OAuth 2.0: code_verifier, code_challenge, S256, and a hands-on walkthrough for public clients.

JARM signs OAuth 2.0 authorization responses as JWTs to stop tampering and mix-up attacks. Covers response modes, claims, validation, and a working demo.

Pushed Authorization Requests (RFC 9126) move OAuth request parameters off the browser. How PAR works with JAR, request_uri, and dynamic redirect URIs.

JAR (RFC 9101) signs OAuth 2.0 authorization requests as JWTs. Request objects by value and by reference, validation rules, and how JAR differs from OIDC.

Seven real weaknesses in the OAuth 2.0 authorization code grant, from code interception to mix-up attacks, and the specs (PKCE, PAR, JAR, JARM) that fix them.

Practical OAuth 2.0 Token Exchange (RFC 8693): impersonation vs delegation, the act claim, scope down-scoping, cross-domain and workload identity use cases.

How OAuth 2.0 clients register with an authorization server: out-of-band vs Dynamic Client Registration (RFC 7591) and DCR Management (RFC 7592), with examples.

How OAuth 2.0 clients discover endpoints using Authorization Server Metadata (RFC 8414) and OpenID Connect Discovery, with real .well-known examples.

A complete map of OAuth 2.0: roles, grant types, why implicit and password grants are deprecated, token types, introspection, revocation, DCR, OIDC and UMA.

How to prevent Broken Object Level Authorization (BOLA) and Broken Function Level Authorization (BFLA), top OWASP API risks, using OAuth scopes and policies.

SAML 2.0 Web Browser SSO Profile explained: SP-initiated vs IdP-initiated SSO, Redirect and POST bindings, AuthnRequest and Response anatomy, and RelayState.

How a SAML service provider finds a user's identity provider: common domain cookie, identifier-first login, discovery services, and the OASIS discovery profiles.

Why SAML 2.0 needs metadata: entityID, EntityDescriptor, IdP and SP role descriptors, signing keys, and static vs dynamic metadata exchange between partners.

The building blocks of SAML 2.0: assertions, protocols, the five bindings (Redirect, POST, Artifact, SOAP, PAOS) and profiles, explained for developers.

What problem SAML single sign-on actually solves, how it works at a high level, and when SAML still makes sense next to OpenID Connect for enterprise SSO.